Acceleration comparisons

[horseback]

As some of you may be aware, I recently more or less hijacked a thread in the Daidalos Team discussions; it had to do with the apparent sluggishness of the Corsair versus contemporary Japanese fighters, and kind of spread from there to the subject of acceleration and how it is affected by the trim model and the cockpit displays/indicators. I more or less volunteered to perform the tests and report my results, using a consistent test procedure and set of standards, since the latter part of my career in field engineering has been heavily involved with test procedures and validating the results.

I started testing various mid-war fighters’ accelerations at 10,000 ft or 3050m, from a starting speed of 270 kph IAS. Since most of us fly in the cockpit in-game (and frankly, because the Wonder Woman artificial horizon is more of a modern art project than a readable indicator, at least on my monitor), I decided to make my test runs in-cockpit, using the speedbar as my primary speed and altitude reference since it is the same for every aircraft.

I use the Crimea map in the QMB with the time set for noon; no other (AI) aircraft are included and the conditions are set for clear weather. I set the altitude for as close to my test alt as possible, and then get over the sea and head due West (270°) with the radiators open to keep the engines as uniformly cool as possible before starting my test run. Ideally, I will settle into trimmed level flight at my desired altitude (I’ve mostly done the 3050m, but I’m starting a series of 100m tests), and maintaining a speed of 270-280kph indicated on the speedbar. I do NOT start recording at any point; the Save Track function after I exit the mission will save it in the more accurate ‘.TRK’ format. I simply close the rads, and shove the prop pitch and throttle to the firewall and engage WEP if that is an option. I then try to maintain level flight while the aircraft accelerates up to its top speed or it has been in ‘Overheat’ for 60 seconds or so (depending on the aircraft’s overheat model—some will take a while and some will spray oil over your windshield in 30 seconds or less). I then turn off WEP, back off on the throttle and prop pitch, and open the radiator or cowl gills to 100%, turn east and take about seven or eight minutes to return to my starting area before doing it all over again. I try to get at least three runs in before exiting the mission and usually four are possible; I’ve had a few occasions where I damaged the engine and had to end after two or three runs and had to make a new or extra track to get a full set of data.
As I mentioned, I then select the Save Track option after exiting (I forgot a couple of times, which was enormously frustrating—usually a test track of four runs will take over 45 minutes).

That’s the actual testing process. The hard part is extracting the data. It is not just a matter of running the track with a stopwatch in hand; you need to select the points that you will measure and compare, and from those average out your results into something understandable. I ended up creating two sets of tables, one for the basic data and one for analysis. I turned them into a pdf file, which is attached below.

I quickly learned that accelerating into level flight is hard; the smaller and lighter aircraft will almost literally twist with the sudden torque, a lot like a good electric hand drill does when you apply power. This can put you three or four degrees off course, and usually heading sharply up; you have to anticipate it and apply stick and rudder as you shove the throttle forward. You then spend the next 15 or 20 seconds or so frantically applying elevator and rudder trim while you fight your stick’s springs or motor, and pray that you haven’t overdone the trim, because it usually isn’t felt until it’s too late and the nose starts dropping like an anvil.

On the heavier aircraft, there is usually a bit of a nose-high angle at lower speeds and when full throttle is applied they will try to go almost straight up and in the direction of the torque / p-factor. Again, you will need to anticipate this a bit with stick and rudder or you will be a couple of hundred meters higher (and slower) than when you started.

I mention this because it quickly became apparent that there were two big limiting factors to acceleration: weight and drag. Drag exerts itself at the higher end of the speed range, since it increases exponentially as speed increases; if your rudder and/or elevator are not properly centered, you can lose a lot of your potential speed increase. Weight is a constant and is obviously in play as you stray from level flight; climb too much, and you slow down or drop your nose just a little and you get an artificial boost (and it can be quite obvious, if you track altitude and bearing changes between intervals). I needed to at least factor in things like climb and dive between 10 kph intervals if I wanted to get something like valid results.

So my tables include cells for not only time, but course and altitude for each interval. I start by measuring the time from 270 kph to 350 kph, then from 350 to 370, and then every 10 kph thereafter. I also note True Air Speed (TAS), overheat times and top level TAS achieved in each run. How quickly an engine overheats and the top maintainable level speed are useful information, IMHO. Also, I had a couple of aircraft fall just short of the next 10kph before I had to throttle back, and it didn’t seem fair to deprive them of the credit for that last 8-9 kph of IAS.

I obtain my data from watching the track in Wonder Woman view with one finger poised over the P (Pause) key. I normally pause at start and at every key point or interval because there simply isn’t enough time to jot down the data between intervals. Some of the really fast aircraft take less than 2 seconds to go from on 10kph point to the next for several intervals and even the supposedly sluggish types take less than 4 seconds in the early phases. So you practically have to stop the track at every data marker. I normally speed up the track to 8X during the return to start phases to save time, but even so, a complete table normally takes a good 45 minutes to an hour. You get the raw time from the track’s lower right hand corner, the IAS from the speedbar and the precise altitude and course from the WW instrument displays.

I then take the data from the Base Chart to fill out the Analysis Chart; this consists of breaking down the raw track time into the number of seconds between intervals and the meters up or down from the previous interval; these can vary quite a bit between runs, in part because you improve your trimming from one run to the next or because your attention wandered for a second just as the aircraft decided to suddenly drop or raise its nose (this is where the cockpit displays come in; some of the climb & dive, as well as the turn and bank indicators are decidedly off compared to others, and you can find yourself gaining or losing thirty or more meters in altitude in less than three seconds if you are not alert and steady on the stick). After filling in the data for each run, I then try to establish a mean or weighted average based on not only the times but also how much the alt varied over that interval. Most aircraft seem to blast through altitude variations early on, but at the far end of the speed range, a 10m variation can cost you a second or more (and remember that drag is increased in a climb or dive that you’re fighting against).

From the Analysis Charts I then went to the Excel spreadsheet and created the charts attached below and in the following posts. I will be happy to answer questions or provide the charts showing direct comparisons of given types if I have tested them.

cheers,

horseback

[horseback]

Some more Charts. Discuss.

cheers

horseback

[Luno13]

Is there any way to compare this to real-world testing?

Overall, it seems to fit one's expectations.

But I am rather surprised that the Yaks are 'quicker' than the La-5s (in terms of acceleration).

[majorfailure]

Interesting. Slap some water-injection engine in that F6F, and its acceleration performance gets close to Fw190s/P-38s.
Maybe the F6F is not that total dog it seemed before, but the 'sair just shines too bright in that department. Seems though that with the F6F-5 you can easily leave Zeros+Ki-61 wheezing and puffing behind you.

[IceFire]

Interesting. Slap some water-injection engine in that F6F, and its acceleration performance gets close to Fw190s/P-38s.
Maybe the F6F is not that total dog it seemed before, but the 'sair just shines too bright in that department. Seems though that with the F6F-5 you can easily leave Zeros+Ki-61 wheezing and puffing behind you.

The interesting bit about all of this was the initial discussion was centered on the notion that the Corsair was a very slow accelerating aircraft... but the charts show that it's actually quite impressive.

[horseback]

The interesting bit about all of this was the initial discussion was centered on the notion that the Corsair was a very slow accelerating aircraft... but the charts show that it's actually quite impressive.
What the charts don't show is how much trim adjustment the F4U needs; you spend a lot of time pounding away at the elevator trim for nose down AND at the same time the aircraft's attitude/AOA moves down quite a bit, so that flying level at 270kph your crosshairs are pointed quite a bit higher than they are at 450.

This became very obvious when I started doing my tests at 100m, where I had hoped to use the horizon line for a reference instead of staring at the climb or altitude indicators and slowly going cross-eyed. The P-47 and Hellcat are much worse than the Corsair, while the IJN and IJA fighters don't seem to have this problem at all. In comparison to the US inventory, the Japanese fighters, while a bit slow, can be whipped around with a great deal of precision and confidence without burning up a lot of energy. If you get your American birds out of trim, you can't be sure where you'll end up, but you can be sure that you will have bled off a lot of your E in the process.

cheers

horseback

[IceFire]

What the charts don't show is how much trim adjustment the F4U needs; you spend a lot of time pounding away at the elevator trim for nose down AND at the same time the aircraft's attitude/AOA moves down quite a bit, so that flying level at 270kph your crosshairs are pointed quite a bit higher than they are at 450.

This became very obvious when I started doing my tests at 100m, where I had hoped to use the horizon line for a reference instead of staring at the climb or altitude indicators and slowly going cross-eyed. The P-47 and Hellcat are much worse than the Corsair, while the IJN and IJA fighters don't seem to have this problem at all. In comparison to the US inventory, the Japanese fighters, while a bit slow, can be whipped around with a great deal of precision and confidence without burning up a lot of energy. If you get your American birds out of trim, you can't be sure where you'll end up, but you can be sure that you will have bled off a lot of your E in the process.

cheers

horseback

Makes sense that if you're out of trim then the aircraft will not be as efficient. The relative differences between I have no expertise in. If this is accurate or not I can't say but it does make it worthwhile to point out to players that if they want the most out of a specific type... trim is absolutely essential.

[RPS69]

But I am rather surprised that the Yaks are 'quicker' than the La-5s (in terms of acceleration).

I'am much more impressed by the LaGG66 acceleration, and having higher final speed. I think that some of this must be rechecked, and it would be a healthy thing to do.

Horseback, since you were on the WW view, you weren't checking the slip ball by chance? The higher the engine power, the more important it is.

[JtD]

Regarding trim, both the F4U and the F6F as tested by NACA required loads of elevator trim. Stick force changes were in the range of 30lb between 200 and 400 mph in level flight. Trimmed for neutral stick forces at low speed, pilots would sometimes not be able to keep the aircraft in a dive.
Trim as suchs seems to have been a bit more effective than it is in game.

[MaxGunz]

Is giving it full throttle and RPM going to give the best acceleration especially to heavy planes with huge power?

Most prop speed controls will try and maintain prop RPM which at lower speeds may be course enough to stall the prop just keeping it from over-rev. Manual 100% RPM will waste full power but at least be a bit better than prop AOA too high. Either way is "spinning wheels" without smoke and noise to show it.

Getting the most out of a plane isn't 'simply' anything.

If you want accurate data, get a devicelink data logger like UDPSpeed and ditch the stopwatch.

[Luno13]

So, I guess what Horseback is getting at is that the USN aircraft require more trim to accelerate properly than their IJN counterparts, which is unfair/unrealistic

If anything, that has to be a problem with the IJN aircraft. Changing speed in an airplane requires a fair deal of attention to trim. ;)

I can also imagine that part of the problem is the uber-experience of online pilots - thousands of hours of flight time with zero real deaths...Even if you run away properly they can nail you from 500+ meters (and a lot of pilots use zoom to do it from even further).

[horseback]

I'am much more impressed by the LaGG66 acceleration, and having higher final speed. I think that some of this must be rechecked, and it would be a healthy thing to do.

Horseback, since you were on the WW view, you weren't checking the slip ball by chance? The higher the engine power, the more important it is.Actually, I fly the test in cockpit mode and depend upon the depictions of the instruments to keep straight and level. I then watch the track in Wonder Woman because it allows me to obtain the precise altitude and TAS data which I record.

Part of what I'm trying to do is find the best way to fly accurately or get the best out of the aircraft as the average player with TIR and the usual array of controllers would, which is (partly) why I fly the tests in cockpit. In a lot of cases, there appears to be a sort of forced parallax, where the indicators don't align, particularly in the US type artificial horizons (and all of my photos and source material show no such parallax visible, either from the pilot's seat or even from shots taken just outside the cockpit). This tends to make it harder to keep your wings level when you're trying to hold the nose down until the elevator trim can be dialed in. Generally, the in-cockpit slip ball (or T&B needle in the case of British fighters) is at least slightly in conflict with the vector much of the time and the in-cockpit 'ball' is almost always in error versus the WW vector ball during any kind of change in direction or sudden power surges.

About the LaGG, I think that we have to take the altitude (approx 3000m) into account, as well as the fact that in-line engines are both more aerodynamically friendly and seem to 'rev up' more quickly. We also have to think about reputations; the later LaGGs were quite improved over the early models, but the pilots of the VVS appear to have lost faith in it the same way USAAF pilots in the Southwest Pacific lost faith in the Airacobra. At 3000m, the LaGG (66) may be closer to its best performance height than the La-5F and FN, as well as being a bit more aerodynamically refined.

I think that the results at 100m and 1500m will be quite different.

cheers

horseback

[horseback]

So, I guess what Horseback is getting at is that the USN aircraft require more trim to accelerate properly than their IJN counterparts, which is unfair/unrealistic

If anything, that has to be a problem with the IJN aircraft. Changing speed in an airplane requires a fair deal of attention to trim. ;)

I can also imagine that part of the problem is the uber-experience of online pilots - thousands of hours of flight time with zero real deaths...Even if you run away properly they can nail you from 500+ meters (and a lot of pilots use zoom to do it from even further). On the contrary, I am pointing out that it is much harder to make any kind of maneuver in the USN aircraft without lots of trim adjustments. You can easily straighten out and run away (and you will be rewarded by even more speed sooner if you drop your nose a bit), but if you attempt all but the most careful turns or climbs without your eyes glued to the slip ball, you will lose all of your hard won energy rather quickly.

The IJN/IJA fighters do require trim adjustments, but the adjustments are not excessive in terms of button presses and they are consistent and predictable in a way that the Corsair and Hellcat are not. This allows the fairly average IJN flyer a degree of immediate precision that the USN flyer must learn over many times more hours of practice (and if he's using button trim, he's still going to be 'behind the curve' the moment he wiggles his stick).

You can add in the way that the F4U and F6F's noses drop and later rise in level (changing AOA) flight as speed increases (this is also evident in the P-47); most of us use the gunsight or some part of the cockpit framing as a reference to maintain our angle of flight, and this will add to the problems of flying with any degree of precision, especially if competing against aircraft whose trim requirements and flight qualities are best guesses derived from 70 year old documents and pilot reports.

cheers

horseback

[horseback]

Is giving it full throttle and RPM going to give the best acceleration especially to heavy planes with huge power?

Most prop speed controls will try and maintain prop RPM which at lower speeds may be course enough to stall the prop just keeping it from over-rev. Manual 100% RPM will waste full power but at least be a bit better than prop AOA too high. Either way is "spinning wheels" without smoke and noise to show it.

Getting the most out of a plane isn't 'simply' anything.

If you want accurate data, get a devicelink data logger like UDPSpeed and ditch the stopwatch.I'm trying to do this from the general player population's point of view; I expect that anyone using the same methods would be able to get very close to the same results that I do, which is the whole point. I don't use a stopwatch, just the track's time displayed in the lower right hand corner. The tool I use most by far is the 'Pause' key.

As for prop speed, for most cases I use the 100% prop pitch setting because it is loosely analogous to low gear in a car; unfortunately, when I try to get a fast start from first gear in a car, I can gauge how much power to apply by feel, something that is not available to the virtual pilot, so I felt that I had to keep things fairly basic. I tried a few experiments with the Spit IX and the P-51C with the engines at both 2700 and 3000 rpm, which are included in the Spitfirepalooza and USAAF fighters charts. The Spit at 3000rpm is superior to the Spit at 2700 at all speeds, while the Mustang at 3000 will rip past the Mustang at 2800 until they reach about 510 kph indicated, at which point the Pony flying at 2700 rpm passed and reached 530 IAS almost a minute sooner (looking at the data table, the 2700rpm bird actually seems to start gaining speed faster around the 490 kph point, which is where I would suggest 'changing gears' if you have to run away from trouble). The Spit IX and the P-51 have very similar if not exactly the same engines, so I figured it would be a good comparison to work with. I created a special chart demonstrating the differences which I will attach below.

I left the Germans' prop pitch, with their 'automatic transmissions', alone, but most of the other aircraft seemed to respond better to just pushing the prop pitch all the way forward at the same time you shove the throttle to the stops. In all cases, I make sure that the supercharger is in the right stage, the mixture setting is appropriate (for instance, the Soviet fighters all ran better at 80% mixture at 3050m than at 100%, while the CW-21B needed 120% mixture to keep even with the Zeke 21) and that the aircraft is trimmed for level flight at 270 kph IAS at around the suggested rpm for cruise (and that the engine is relatively cool).

If someone expert in one type or another feels that he can obtain better results with different settings in a given type, I invite them to put their oar in and help out the community at large.

cheers

horseback

[Jumoschwanz]

If someone expert in one type or another feels that he can obtain better results with different settings in a given type, I invite them to put their oar in and help out the community at large.
[Horseback

I did acceleration testing of all the aircraft in this sim for many years, not to help the community at large, but to get an edge on them flying online. Sometimes I did post results here and there on various forums, but as Horseback found out, it is time consuming and my hard work was so I could shoot others down, if they were not smart enough or too lazy to do the work I did, then screw them.

The acceleration tests I did were done in a different way. I figured there were two different things to know about my aircraft and how it accelerated.

The first was acceleration at very low speed. Often if you get mixed up in a dogfight you might find yourself at stall speed, or almost stopped in some evasive maneuver. So I tested all aircraft to see what speed they could get to in a set distance, starting at zero.

Once I had the speeds all aircraft could reach in a set distance from zero, then I saw what speed they reached in exactly twice that distance, so then I knew which aircraft could get away from which from almost no speed at all, and I also knew which could gain the most speed when already starting at a high speed. Both very useful in evasive maneuvers and in energy fighting.

I also tested the top speeds of all aircraft both on the deck and at 5000 meters altitude, which was also very useful to know for every common aircraft flown online in popular servers.

Yes, some aircraft need different trimming and other settings to get the most out of them, but that is to be expected as they were different machines manufactured thousands of miles from each other by extremely different cultures and engineers.

That is why making all the aircraft behave exactly the same would be ridiculous whether it trim or any other parameter or control feature, if you do that we may as well get rid of all the aircraft in the sim except for one, we could all just fly 25lb spits.

I say plug the engineering data for each aircraft into the IL2 simulator and fly what you get. Every pilot in WWII had to learn his specific aircraft, if he switched to a different one then he was set back and had to learn many things all over again.

[horseback]

Regarding trim, both the F4U and the F6F as tested by NACA required loads of elevator trim. Stick force changes were in the range of 30lb between 200 and 400 mph in level flight. Trimmed for neutral stick forces at low speed, pilots would sometimes not be able to keep the aircraft in a dive.

Trim as suchs seems to have been a bit more effective than it is in game.I use Francis Dean's America's Hundred Thousand as my primary reference in these things, as well as Barrett Tillman's The Wildcat in WWII, Hellcat: The F6F in WWII, and Corsair: The F4U in WWII and Korea to supplement for 'hard knowledge' on these particular aircraft. I've also had many occasions to talk to men who actually flew these aircraft (my landlord in Coronado many years ago was a former Wildcat, Hellcat and Corsair driver, getting combat time with the Grummans in WWII and with the F4U in Korea; he introduced me to several of his wartime buddies after he noticed my extensive model collection --and bought all my blue airplanes).

On trimming the Corsair, America’s Hundred Thousand says: “The Corsair was easy to trim out for climb. Trim changes from landing gear and flap retraction were minimal, and those for speed and power changes were quite handleable. In cruise condition the airplane could be trimmed for hands and feet off flying with little trouble. Pilots almost universally rated F4U-1C and -1D trimmability as good. In a dive, as with some other US fighters, a considerable amount of rudder trim was required to zero out pedal force which was high if this was not done.”

One the Hellcat’s trim characteristics, it says: “There were nose up trim changes with gear and flap retraction, though they were minimal, and the same was true of initial acceleration into climb. In general, there were substantial both directionally and laterally with speed and power changes, but tab action allowed trimming out control forces to zero except for the rudder. At low speed and high power rudder pedal force could not be trimmed out fully. Most pilots thought trimmability was generally good, though some made the following comments ‘Lack of trimmability”, Excess rudder trim change”, and “Aircraft requires excessive trim” (three pilots). It was noted that in a dive control forces could not be trimmed out quickly enough.

The old Naval aviators I talked to felt without exception that the Hellcat was the easiest aircraft they ever flew off a carrier deck, prop or jet. Of course, most of these old guys were raised on farms or worked at a job demanding a fair amount of physical strength (by modern standards) so a 30lb force difference probably wasn't all that excessive by the standards of the time, especially if you could easily adjust it out with the trim tabs. To be honest, 30lbs (or a bit less than 14kg) doesn't sound like that much to me, but I spent many hours in the pool and the weight room as a younger man.

In-game, trimming out these aircraft is not close to 'easy'.

The point is that many of the aircraft modeled in this sim are based on reports and tests done 70 years ago, and what were called 'mild' or 'light' stick or rudder forces might seem a bit heavy to the average man today. It may not be appropriate to add (over)detailed characteristics to well understood and documented aircraft that have to compete with aircraft that are modeled on older standards that cannot be verified to match the current ones.

Now if you all will excuse me, some miserable sod has released a new patch, and I have to start re-running all of the 100m tests I've done so far...:cry:

cheers

horseback

PS: During the early phase of my tests, I ran the trim all the way out in both directions on a number of aircraft, doing both rudder and elevator, as well as a few ailerons; it takes 80 button pushes in each direction from CENTER, or 160 button pushes from one extreme of trim offset to the other. By comparison, using the CH Quad, a tiny increment seemed to have much greater, but much less predictable results. Pick your poison.

[MaxGunz]

UDPSpeed and UDPGraph will let you put data on-screen while flying offline which I think could include acceleration indicator which should allow dynamic testing to see what effect you could achieve. The hardest part is setup and there were walk-thru's on that last I remember. It's like the difference between hand tools and power tools, once you got power tools they can be a pain at times but mostly tend to put a smile on your face once you get used to them.

The parallax effect is probably due to being in right-eye gunsight mode. Switch back and see, it is easier to fly most fighters in centered view. Up close it's even easier to shoot that way, with practice.

Really, in-game since the start I've found the smartest thing to do before maneuver combat is to neutralize trim and avoid hard G's that lead to wingtip stalls or worse. Slip... easiest to avoid in a P-51 with mini-ball gunsight and hardest in the Spits. We NEED a slip indicator in the speedbar to replace what can be felt IRL.

----------------------------------------------------------------------------------

Back in December I thought to interface Arduino to IL-2 but first there was an MP3 module to deal with. It took over 4 months to find out that the fix is shorting 2 whisker-tiny pins on a surface-mount chip which no way I can do so now there's a new module that's got its own hangups... 115200 serial may not work well breadboarding or I dunno what else is the hangup -- I'm a programmer who can do some hardware so aware that I have my own hardware limits. This will be either GO or NO GO, I won't try another, and then on to other pursuits that have been on hold like an autopilot robot. :-P
As it is, I think my forehead is flat and I have no hair above my ears/eyebrows.

Today, after reading about trim I got a real narsty idea... the same controller that runs the stick could be made to do "smart trim", couldn't it? Or maybe not, having the nose seek to bring the stick to center after some-odd seconds might be a bad thing at times, like when you're just about to shoot! Perhaps a button, like I asked Oleg for back in 2002.

[horseback]

Yes, some aircraft need different trimming and other settings to get the most out of them, but that is to be expected as they were different machines manufactured thousands of miles from each other by extremely different cultures and engineers.

That is why making all the aircraft behave exactly the same would be ridiculous whether it trim or any other parameter or control feature, if you do that we may as well get rid of all the aircraft in the sim except for one, we could all just fly 25lb spits.

I say plug the engineering data for each aircraft into the IL2 simulator and fly what you get. Every pilot in WWII had to learn his specific aircraft, if he switched to a different one then he was set back and had to learn many things all over again.
Fine by me, but let's limit the engineering data to what was known and documented in 1945, instead of a steady diet of revised, new & improved data taken with newer and better measuring sticks for just the one group of (aging) aircraft. I spent a good sized chunk of my life testing refurbished and rebuilt weapons and fire control systems that date back to the 1960s; one of our ongoing problems was that modern testing and measurement methods are far more accurate than the ones used to establish the original performance parameters of these systems back in the day. We often had to demonstrate to the Government representative who had to sign off on the performance that these new testing systems left us a whole lot less 'wiggle room' than the ones devised during the Nixon Administration, and that we were still meeting and exceeding the original specifications that could be measured when the specs were written.

Excessive trim modeling is a very good way to keep a good aircraft's performance down in practice while still allowing it to achieve its accepted performance figures; the historical record says quite clearly that the Corsair, the Mustang, the P-47 and the Hellcat were 'easily trimmed', specifically in reference to the earlier US fighters like the Wildcat, P-39 and particularly the P-40, all of which enjoy relatively similar (and easy) trim models in the game compared to the other depicted fighters of WWII (as of version 4.11.1; time will tell if 4.12 is any better).

Of the later fighters, only the Hellcat needed 'much' trim adjustment, but it was considered easily done. That is obviously not my experience in this simulation. The Merlin Mustang from every contemporary account and description needed very little or no trim adjustment for minor changes in speed or throttle (the Allison Mustangs needed practically none at any speed), but the in-game version needs trim adjustment in elevator and rudder for every variation of 10kph (that's only 6 mph, fellow Yanks) in speed or 5% of throttle, which is considerably more than either of the two best known study simulations of the P-51 depict (and strangely enough, I found a quote from a pilot in America's Hundred Thousand that complains of exactly that sort of behavior in the P-40,only for speed variations of as little as 10 mph (or 16 kph), which tells me that the trim model would be overdone by at least 60% even if it were assigned to the universally acknowledged worst trimming American fighter of the war).

The real P-38 needed NO elevator (or rudder) trim for speed and throttle variations (per America’s Hundred Thousand), but the Il-2 Sturmovik Lightning will go literally straight up when you push the throttle forward without shoving the stick three quarters of the way forward at the same instant and punching the elevator trim button constantly for as long as the speed continues to increase. (and it's a lot slower than the real thing was)

The real life P-47 needed no elevator trim for initial acceleration, but the in-game version does the same thing as the Lightning, with the added entertainment value of needing a ton of right rudder as well, and like the Corsair, the nose tends to dip as speed increases in the level plane; by this I mean that the angle of attack varies significantly with speed, something I've never read or heard about in these aircraft in over 45 years of reading, modeling or personally talking to men who flew these aircraft (you'd think that somebody would have mentioned it...).

As for the Spitfire, I have no documentation or discussions of its trimming requirements at all, which would indicate to me that it was fairly well-behaved by the standards of the day (it was well-enough known as an easy aircraft to fly that even German pilots would say "Anyone can fly a Spitfire," which implies to me that they considered themselves more manly because they had tamed the 109...). Yet the Il-2 Sturmovik Spitfires demand a lot of trim adjustment, about the same degree as the Mustang, although with the added difficulty of that hard to read Turn and Bank needle arrangement.

In short, in this simulation these specific aircraft are much harder to trim and control than the real ones were, particularly when measured against the other WWII fighters depicted in this sim, and all of them demand un-historic trim adjustment in the form of multiple button presses for relatively minor variations in speed and throttle settings, as well as climb or diving conditions, and it is next to impossible to roll your trim settings to a set position in anticipation of a sudden change in speed or throttle, as the real-life pilots did regularly.

Exaggerated behaviors like the ones we experience in this sim would have made these fighters practically unacceptable as combat aircraft, and make "historical tactics" next to impossible. No amount of brains in the world is going to change that.

cheers

horseback

[horseback]

The parallax effect is probably due to being in right-eye gunsight mode. Switch back and see, it is easier to fly most fighters in centered view. Up close it's even easier to shoot that way, with practice.

Really, in-game since the start I've found the smartest thing to do before maneuver combat is to neutralize trim and avoid hard G's that lead to wingtip stalls or worse. Slip... easiest to avoid in a P-51 with mini-ball gunsight and hardest in the Spits. We NEED a slip indicator in the speedbar to replace what can be felt IRL.

Today, after reading about trim I got a real narsty idea... the same controller that runs the stick could be made to do "smart trim", couldn't it? Or maybe not, having the nose seek to bring the stick to center after some-odd seconds might be a bad thing at times, like when you're just about to shoot! Perhaps a button, like I asked Oleg for back in 2002.

Since getting TIR about seven years ago, I hardly ever use the Toggle Gunsight button, particularly since 6DOF was introduced in the stock game. The parallax is there from either view in every case, and I assume that it is there as a result of 'artistic license', because it isn't visible in any pictures that I have on hand of existing aircraft (Kinzey's Detail & Scale series has excellent cockpit photos for each of the WWII US fighters, in most cases including extensive shots of each variant) or my own observations in museums and air show displays.

I like the suggestion about neutralizing trim once maneuvering begins, but I believe that the trim models for these aircraft need to be put in line with the other 'stock' aircraft in the game, or that we get a short-term HUD display indicating your trim displacement every time you make an adjustment (like when you change radiator, PP or throttle), so that you know just where the hell you are in terms of trim state--as I pointed out in earlier posts, a RL pilot would roll in more trim to a pre-set point in anticipation of a dive or increased throttle.

I've also been toying with making a trim box with a 20:1 gearbox on each pot so that I can make the teeny-tiny adjustments to my pots that the game demands (and how is it that one button press of 1/80th of total deflection is so necessary?) and at the same time make the larger changes for something I'm about to do.

cheers

horseback

[JG27CaptStubing]

Interesting to see what TD did to some of the FWs... No wonder you can easily get caught with your pants done

[Mustang]

Great Post Horseback !!

Thats take long time to do.

But now...
what aircraft are OP ? vs RL

[horseback]

Interesting to see what TD did to some of the FWs... No wonder you can easily get caught with your pants done

To be fair, this set of tests were done at just about the worst possible height for the FW; 3000m is quite close to the alt at which its supercharger moves from low to high blower, so the engine is not at its best here. I've just started doing the sea level (100m) tests, which should be more flattering to the Wurger.

cheers

horseback

[IceFire]

Probably a good idea to point out that context is extremely important. As these acceleration tests were all done at the same altitude. Some aircraft will be better and others worse at this altitude... nothing stays the same across the range. It's not one acceleration level that extends from 0 to 10,000 meters.

You have to know your plane. I know that the Tempest V between 3000 and 4000 meters is less capable against the FW190D-9 (which I consider to be its chief rival) as the stage 1 supercharger starts to run out of steam and you're just about to switch to the stage 2. Depending on the D-9 model year... this is the worst altitude to fight at. Take it lower or higher and the Tempest is faster and more able. Context!

[MaxGunz]

I would have problems with a plane that didn't get noticeably more lift for a 6 mph speed increase.

Check around, there are 10-turn and IIRC 20-turn pots in various ranges.

Less fine-adjusting but oh so desirable, check the unit price:
http://www.futurlec.com/PotSliding.shtml
There is a shipping charge but that can be as low as $4 to $5.
http://www.futurlec.com/Delivery.shtml
The package comes from Hong Kong so expect about 2-3 weeks wait.

Something else you could do is put a 10k or smaller pot in series with a 100k pot (or a 1k and 10k) and have both coarse and fine adjustment knobs on the same circuit.

[majorfailure]

The real P-38 needed NO elevator (or rudder) trim for speed and throttle variations (per America’s Hundred Thousand), but the Il-2 Sturmovik Lightning will go literally straight up when you push the throttle forward without shoving the stick three quarters of the way forward at the same instant and punching the elevator trim button constantly for as long as the speed continues to increase. (and it's a lot slower than the real thing was)
That makes no sense, as this would mean the P-38s wing would generate the same lift all over its speed range. But compared to http://www.wwiiaircraftperformance.org/ data its speed seems fine.


The real life P-47 needed no elevator trim for initial acceleration, but the in-game version does the same thing as the Lightning, with the added entertainment value of needing a ton of right rudder as well, and like the Corsair, the nose tends to dip as speed increases in the level plane; by this I mean that the angle of attack varies significantly with speed, something I've never read or heard about in these aircraft in over 45 years of reading, modeling or personally talking to men who flew these aircraft (you'd think that somebody would have mentioned it...).

And how else if not with changing AoA should a plane regulate its lift when changing speed? Faster plane - wings generate more lift with same AoA, to keep the plane level AoA needs to decrease.


As for the Spitfire, I have no documentation or discussions of its trimming requirements at all, which would indicate to me that it was fairly well-behaved by the standards of the day (it was well-enough known as an easy aircraft to fly that even German pilots would say "Anyone can fly a Spitfire," which implies to me that they considered themselves more manly because they had tamed the 109...). Yet the Il-2 Sturmovik Spitfires demand a lot of trim adjustment, about the same degree as the Mustang, although with the added difficulty of that hard to read Turn and Bank needle arrangement.

I'd think the reference that anyone could fly a Spit does not mean the plane is trimmed easily, but it is easy to fly in combat maneuvres, and it does not stall viciously and recovers good (I'd think the IL-2 Spitfire meets all those criteria).


In short, in this simulation these specific aircraft are much harder to trim and control than the real ones were, particularly when measured against the other WWII fighters depicted in this sim, and all of them demand un-historic trim adjustment in the form of multiple button presses for relatively minor variations in speed and throttle settings, as well as climb or diving conditions, and it is next to impossible to roll your trim settings to a set position in anticipation of a sudden change in speed or throttle, as the real-life pilots did regularly.

Yes, we need some indicator or gradation or whatever to see where trim currently is, and how much we apply. Then one could remember:
SpitIX, 90%, 3.5k alt, left 7 (or 1.5° or whatever) trim, down 34 (or XX° or whatever) trim - flies straight. Currently we can only do this if we reset trim to 0 and then apply trim settings, but this is counterproductive, 'cause except at landing speed a Spit with neutral trim severly noses up.

[horseback]

The following paragraphs are taken whole out of America’s Hundred Thousand by Francis Dean. These are the complete sections labeled Trimming with nothing left out. Bear in mind that these are all American fighters, and any comparisons the pilots quoted herein are to other American fighters, not the Zero, not the Spitfire, not the Lavotchkin and not the Bf 109. This is just part of the picture the author paints; the sections on Ground Handling, Takeoff & Climb, Dive & Recovery, Maneuvering, Approach & Landing, Stalls & Spins, and the Gun Platform and Weapon performance paint a pretty complete picture of how these aircraft flew from a generally American perspective. Most tend to reinforce the picture painted in the Trimming sections. I have underlined or italicized key words or phrases in some cases.

I simply lack the time and patience to transcribe all these in full, even assuming that it would not violate some copyright rules. I would recommend however, that anyone who wishes to argue the point transcribes at least the full paragraph that he is citing instead of engaging in the usual cherry picking.

One interesting note: The second paragraph in the P-40’s Maneuvering section starts with “…P-40 airplanes were very maneuverable for US Army fighters, some said better than a P-51.”

Trimming Sections from America’s Hundred Thousand:

P-38

The P-38 could be trimmed out to be pleasant to fly, and trimmability was rated good to fair by the majority of pilots in one survey. No adjustment of rudder or elevator trim was required with power or speed changes.

P-39

P-39 trimmability was good. Elevator tab action allowed stick force to be trimmed to zero throughout the speed range. Aileron trim changes with speed or power were negligible to 400 mph IAS. Above that speed, there was an erratic trim force change, possibly caused by aileron fabric bulging. There were directional trim changes in climbing and diving, but they were not extreme.

P-40

A major aspect of flying the P-40 series airplane was handling trim changes from power and speed changes. A veteran AAF pilot stated “The trim changes with speed were more than in other contemporary fighters.” Typical of many single engine propeller fighters, the vertical tail fin was slightly offset to counter propeller slipstream effect at cruising speed. In a dive, as speed increased, more and more left rudder had to be added; slowing down in a climb some right rudder was needed. One pilot said “—a drawback was having to virtually stand on the left rudder pedal to keep the ball centered—it could be a real handful in a loop” (where trim reversed from dive to climb and then back again). Although directional trim tab power was available to zero out pedal force, left rudder trim could not be rolled in fast enough with high dive acceleration. No matter what P-40 version was involved, it was the same: “In the air, the Tomahawk tended to yaw considerably with speed changes”, needing directional trim, and for the P-40E/H87A: “Every power and speed change brings an immediate trim change which the pilot must either counteract or trim out”. The H87 was, if anything, worse than the H81 Tomahawk.

On the P-40E lowering the landing gear made the aircraft slightly nose heavy; there was no appreciable trim change with flap positioning. Dropping a belly tank resulted in minor tail heaviness. The elevator trim system could take care of these effects as well as longitudinal variations due to speed and power changes.

P-47

There were some differences in trimmability between models. “The P-47D-25 trimmed harder than the D-15” but generally longitudinal and lateral trimmability was satisfactory on the P-47, and the tabs were very sensitive. There was very little trim change with gear retraction and initial acceleration; dropping flaps made the airplane slightly nose heavy. Longitudinal trim changes with power and speed changes were small, and elevator tab power was sufficient to trim stick forces to zero at all speeds and all normal center of gravity locations. The aileron trim tab action was sufficiently powerful for all flight conditions, and the rudder tab could trim pedal forces to zero at all speeds above 120 mph IAS in the power on clean condition. But as with other fighters, like the P-40, the rudder trim force change with changing power or speed was objectionably high.

P-51

ALLISON powered Mustangs were particularly notable for lack of required trim changes. Power or flap setting changes gave only small trim variations, and the same was true of gear retraction. The changes in tab settings for climbing and diving were negligible. Tab controls were sensitive and had to be used carefully.

Trimmability was also quite good in MERLIN Mustangs, and tabs were sensitive. In these versions directional trim changed more with speed and power changes. When the rudder trim system was changed and rigged as an anti-balance tab to give opposite boost, a resulting disadvantage was more tab was required to trim the aircraft from a climb into a dive.

Along with trimming the airplane for longer term steady flight conditions, some pilots trimmed their aircraft almost continuously to wash out any high stick or pedal force during maneuvering in combat.

F4U

The Corsair was easy to trim out for climb. Trim changes from landing gear and flap retraction were minimal, and those for speed and power changes were quite handleable. In cruise condition the airplane could be trimmed for hands and feet off flying with little trouble. Pilots almost universally rated F4U-1C and -1D trimmability as good. In a dive, as with some other US fighters, a considerable amount of rudder trim was required to zero out pedal force which was high if this was not done.

F6F

There were nose up trim changes with gear and flap retraction, though they were minimal, and the same was true of initial acceleration into climb. In general, there were substantial trim changes both directionally and laterally with speed and power changes, but tab action allowed trimming out control forces to zero except for the rudder. At low speed and high power rudder pedal force could not be trimmed out fully. Most pilots thought trimmability was generally good, though some made the following comments ‘Lack of trimmability”, Excess rudder trim change”, and “Aircraft requires excessive trim” (three pilots). It was noted that in a dive control forces could not be trimmed out quickly enough.

MY COMMENTS:

P-38: the in-game model forces you to apply a LOT of nose down pressure and trim when you apply power, which contradicts the description from Dean. It is also quite a bit slower to accelerate than the in-game P-51B/C, which just doesn’t make sense, if you look at the test records, even those comparing the early P-51Bs without the fuselage overload tank. From the descriptions from several wartime pilots’ memoirs and historical reports as well as from America’s Hundred Thousand, I expected that the Lightning would ‘dither’ for a tiny split second before surging almost straight ahead when full power is applied, but the in-game version will immediately head almost straight up when 100% prop pitch and full power is applied if you don’t anticipate it and force the stick/yoke well forward immediately and start punching in nose down elevator trim with your eyes fixed closely on the climb & dive indicator. I expected to dial in some trim as speed increased, but I didn't expect to have to bang the stick almost all the way forward just to stay level.

P-39:A bit of a shock when I read Dean’s comments on the Airacobra; I thought it would be a bit of a trim hog, but instead the real thing seems to have trimmed out fairly easily at most level speeds. The problems it had were apparently not due to trimming issues so much as the sensitivity of its controls compared to other fighters of its time—I assume that unless the pilot had fully mastered its (several) unique quirks, he could get himself in trouble if he fell back on ‘muscle memory’ acquired in other types. The in-game ‘Cobra is a bit twitchy (you always feel like you are balancing on the head of a pin) and at the same time a bit too good if you don’t remember that the ‘Cobra’s issues with the USAAF in the Pacific in 1942-43 were more because of poor maintenance and field reassembly of hurriedly shipped in aircraft due to a lack of experience and documentation rather than to poor design or quality of production at the factory.

P-40: The Tomahawk and Warhawk were considered to be among the most maneuverable of the Western built fighters in WWII as long as they stayed below 15,000 ft, but it took a very good pilot (and a strong one, at that) to get the most out of it. It was not a good aircraft for persons with attention deficit disorders, because it was notorious for needing constant trim and engine adjustments—nobody relaxed in a Warhawk unless it had been on the ground with the engine off for a good twenty minutes. After mastering the P-40, most WWII pilots would find almost any other fighter of the period relatively easy to control and exploit (the P-38 was easy to fly but hard to master, but veteran combat groups in the Pacific transitioned into it seamlessly from the P-40). I was well aware that the P-40 series was considered very tricky to take off and land, and that taxiing it was considered a bit of a trial, so the Il-2 Sturmovik Forgotten Battles/’46 depiction has always seemed far too user friendly to me. In-game, it requires much less trim adjustment than even the P-39, and is one of the easiest fighters in the game to master. It is by far the most charitable depiction out of all the American built fighters depicted in the game.

P-47: This one is like the P-38 in some ways; in-game, the elevator trim is consistently excessive, and the rudder is fairly easy (too easy, if Dean is to be believed) to adjust. In-game, at 270kph/170 mph, it wallows like a pig and is seriously unstable with a pronounced nose high attitude, which hardly makes sense for a range of speeds that was commonly used for economy cruise and landing approach. In addition, the angle of attack will lower significantly as speed rises, which makes it hard for the pilot to judge whether he is actually keeping anything like level flight, and will complicate your firing solution when diving on an opponent. Like the P-38, the in-game P-47 wants to go sharply up the moment power is applied, and it also wants to turn left because of torque and p factor; if you don’t apply significant nose down pressure on the stick and kick in a LOT of right rudder as you punch the throttle and prop pitch forward, you’re going to waste all that power going in the wrong direction. Again, given the weight of the Thunderbolt, I would expect a slightly longer ‘dither’ than the Lightning, but it should surge more straight ahead than up, at least at first. Also, my reading leads me to believe that the P-47 was pretty fast in a straight line, even if it took a while to get there (especially with the early ‘toothpick prop’ versions) at lower altitudes, while Il-2 Sturmovik ‘46’s depiction makes it not only slow to reach top speed (and very prone to overheat) at 10,000 ft, but that top speed seems a bit short of what it should be.

P-51C: The Mustang should be the easiest US fighter in the game other than the P-38 to trim in almost any conditions by a fairly wide margin, if we are to believe Dean and testimony from pilots of the era. The consensus seems to be that the in-game Mustang demands elevator and rudder adjustments for every 10kph/5mph variation in speed. To put it lightly, that is bogus; Dean’s description says that the Merlin Mustang’s trimmability was “also quite good” in obvious reference to the standard of the Allison powered versions which needed almost no trim adjustments for speed or power changes.

The flight models of both the DCS Mustang and the Wings of Power P-51D for FSX tell me that the rudder trim requires slight adjustments for power increases of 10-15% (5-8 inches of added manifold pressure)or speed increases in the 25-35 mph (40-55 kph) range and that the elevator trim hardly needs touching at all, which is consistent with wartime reports and comparisons that suggest to me that the Mustang was rated more highly in maneuverability than it might have technically deserved because it was much more easily flown with precision than its contemporaries;; i.e., a Mustang pilot could take his aircraft to its limits with more confidence right away than the pilots of other high performance fighters of the period—there was considerably less of an exploratory period needed for it.

The in-game version’s extra acceleration, which is clearly superior to the much lighter Spitfire Mk IX, seems like an attempt to mollify those players who know that the Mustang was one of the all-time great fighter aircraft—the difficulty of bringing your guns to bear because of oversensitive elevator and rudder trim (added to the sheer unreliability of the needle and ball the microsecond you stray from the straight and level) or of achieving coordinated maneuvers are supposed to be excused by the old song and dance about superior training & numbers, plus the—(“See? See? We didn’t really nerf it.”)—speed and range.

F4U:This one is treated a lot like the Mustang in that it has been given almost spectacular speed, but it needs an awful lot of trim adjustment to maintain its E advantages. The moment you start to roll into a turn or pull up into a climb, you will be out of trim and bleeding energy in arterial spurts. Again, this seems to be contrary to the historical record. It is also like the P-47 in that the angle of attack in level flight changes radically (it seems like a drop of several degrees, but if we use the gunsight circle as the standard, it is about half to two-thirds the circle’s diameter down from the 270kph starting speed) during acceleration, but not so much at the same speeds when flying back to the starting point. At certain speeds, it will seem to drop suddenly (or else I’ve been very consistent about over-applying the nose down trim), and the pilot has to pull up on the stick sharply but very precisely in order to stay level.

F6F: With this one, you are almost constantly adding and subtracting trim; three clicks nose down to get it to react, then one or two up to correct, wait two seconds and then repeat the process. Again, once the initial rudder trims are made, it seems to stabilize directionally (which seems to me to contradict Dean's description). Bear in mind that we are talking about speed changes of 10 kph, or a bit over six miles an hour; there's quote in the P-40 Comments section where one pilot complains that he had to make adjustments for every ten miles an hour, or about 16 kph. If adjusting for 16 kph variations in speed are excessive, what does that make adjustments (and I mean absolutely necessary adjustments; if your attention wanders for two or three seconds, your altitude can change by two or three hundred feet at those speeds) for speeds of less than two thirds of that?

In every case except for the P-40 (which appears to be sort of a charity case), the trim requirements are grossly excessive. Compared to say, the Ki-43 or Ki-61 (or any late-model Soviet fighter), the elevator trim requirements in particular for late model American fighters (and the Spitfire, for that matter) are cartoonish, especially for the Mustang and the P-47. In fact, I would class the trim modelling for the Mustang, P-47 and Hellcat about one and a half to two times what should be required for the P-40 in the context of this sim.

The 'straight up' when accelerating tendency in the P-47 and P-38 is counter-intuitive; these were big heavy fighters, and as Dean confirms, should surge almost straight ahead at first, especially the P-47, which like the P-40, was well-known to almost resist entering a climb from level flight. The AOA thing is particularly troubling in aircraft that need to land on a carrier. I could accept some drop in the nose as speed increased, but not to that degree. Of all the fighters of WWII that I have read any amount of information about, only the Focke-Wulf was acknowledged as having a lowered AOA with cruising/combat speed (and I recall some howling over the Il-2 Sturmovik/Forgotten Battles Butcherbirds lacking that feature).

In my test runs so far, the FW doesn't seem to dip as much as the Corsair, Hellcat or P-47; I'm going to have to take a few screenshots for comparison while I do my sea level tests, since the horizon will make it easier to judge.

As I have said, anyone should be able to duplicate my results and see for themselves what I am describing. If you normally place your stick on a keyboard tray, I would recommend that you make sure that you have enough clearance from the desk edge so that you won't lose the skin off your knuckles when you have to shove your stick forward after you punch the throttle.

cheers

horseback

[Woke Up Dead]

Hey Horseback, in your Soviet planes chart you have two for the La-5FN; I assume the slower one is actually the La-5?

[horseback]

I would have problems with a plane that didn't get noticeably more lift for a 6 mph speed increase.
That might be appropriate for a general aviation private plane with a maximum speed of 170 knots, but for a fighter capable of advanced acrobatics with an engine spinning twice as many blades three times as long (& at least five times as heavy) and hosting five to ten times as many horses? :?

cheers

horseback

[horseback]

Hey Horseback, in your Soviet planes chart you have two for the La-5FN; I assume the slower one is actually the La-5?The two La-5FN data lines are the same; apparently, I managed to double select its data for the chart somehow. There is a separate line for the La-5F (a rather attractive sky blue, I believe), and yes, it is slower than the La-5FN.

cheers

horseback

[MaxGunz]

That might be appropriate for a general aviation private plane with a maximum speed of 170 knots, but for a fighter capable of advanced acrobatics with an engine spinning twice as many blades three times as long (& at least five times as heavy) and hosting five to ten times as many horses? :?

cheers

horseback

Still the same only more so. Lift is by speed squared, AOA and constant factors aspect ratio and wing area. As speed increases, AOA must decrease to keep level flight.

However the tailplane part of the airplane balancing act also has a lift and it's own AOI relative to the main wings which must affect need for trim.

If the P-38 tailplane actually forces the nose down more with increasing speed then the COL moving back as critical mach is approached would turn that into a bad thing... which may or may not be part of the P-38 death dive phenomenon.

I would be very careful pulling text out of books and treating everything with a key word as if on an equal basis with every other. Those comments come from people with different backgrounds and if filtered through yet another party with another background and then evaluated by a reader with a completely different background it's all too easy to end up in a subjective mess especially if the last person tries to use unqualified statements as hard references.

Ie, stick with controlled test data or have your experts on hand to qualify and explain just what they mean.
Don't play at guessing to arrive at your own conclusions even when you have some facts to go with the guessing. I have facts about lift and balance but only questions and not conclusions about the FM to make from those.

If the P-38 didn't need trim then why is it there? Did that quote about not needing trim with power of speed changes apply to small changes or to the full safe operating range? We all know that at some speeds that use of trim and slowing down did become needed, don't we?

BTW, what do you think of using 2 pots for coarse and fine adjustment? I've never seen such but series resistances do add.

[RPS69]

There are commercial potentiometers, that allow you to turn around 10 times, and have a numerical track of your position.
They are very precise, and can move fast if well kept. Still, don't play unneadlessly with them, because they get noisy after so many changes. Still, they may work fine for around 10 years on an everyday use.

http://www.schukat.com/schukat/schukat_cms_en.nsf/index/CMSFFEDE67DB7032C11C1256DF1003EF651?OpenDocument&wg=C3515&refDoc=CMSCD2F7906C0610E56C1256D710038A548&kb=DIAL15111

That was the first example I stumbled upon. Don't know how good they are though...

[zipper]

Horseback

Nice observations and I would agree with your assessment. You note the rudder boost tab reversal mod (from boost tab to anti-boost tab) on the P-51 and its effect on rudder use but you didn't note the same change was made to the long-tail P-40's rudder with the same result. Something else that I have difficulty with is all Mustangs seem to be able to snap the wings off in a dive with the same ease when there should be a very noticeable difference between elevator bob weight modded and un-modded aircraft. (Elevator bob weight mods were also installed on Spits starting with mid Vb.)


:grin:

[MaxGunz]

There are commercial potentiometers, that allow you to turn around 10 times, and have a numerical track of your position.
They are very precise, and can move fast if well kept. Still, don't play unneadlessly with them, because they get noisy after so many changes. Still, they may work fine for around 10 years on an everyday use.

http://www.schukat.com/schukat/schukat_cms_en.nsf/index/CMSFFEDE67DB7032C11C1256DF1003EF651?OpenDocument&wg=C3515&refDoc=CMSCD2F7906C0610E56C1256D710038A548&kb=DIAL15111

That was the first example I stumbled upon. Don't know how good they are though...

There's 20 turn pots too, made with high precision for test instruments. They're not cheap. Check Mouser, Digikey or some other electronics house for listings. Sometimes you can find the parts cheaper, just make sure of manufacturer and check the datasheet.

Here's the thing about multi-turn pots: how do you keep track of how many turns you have made? A single turn pot or linear slider is so much simpler.

[RPS69]

Here's the thing about multi-turn pots: how do you keep track of how many turns you have made?

They got numbers... and they allow you to reach the exact position, while sliders may lack precision.

[jameson]

Following this thread with some interest. I've always thought that regarding trim vs speed, the drag created by being slightly out of trim ingame was and is way overdone. Just a feeling on my part, but still...
Anyway I refer you to R&M 2361, The Royal Aircraft Establishment report regarding a Me109 E3 captured in France in 1940.
http://kurfurst.org/Tactical_trials/109E_UKtrials/Morgan.html
You may read the whole thing, and it's quite long, but of most relevence here is Fig. 13 near the bottom of the page. This figure shows tailplane incidence vs speed (elevator trim achieved on 109 by moving the tailplane and not a tab on the elevator) in the lower graph of the figure. Suprisingly it shows that between 100 mph and 350 mph (160 kph and 560kph) with full throttle the tailplane only needs to be moved 1 degree to maintain level flight. (+ adjustment is nose down and - up). The tailplane is controlled in cockpit by a wheel 300mm in dia, and is geared at 2:1, i.e. one turn = 2 degrees of tailplane movement. Thus it appears that about a half turn is all that would be required between those speeds, so just slight tweaks on the wheel as speed increased/decreased.
I'd also like some trim indication being given onscreen, airstart being a case in point it, seems that trim is neutral? at the start of the mission and the plane out of control as a result. All this though does raise the question of how accurate drag is modelled ingame and it's level of sophistication, it seem fairly crude and overdone to me, and possibly a one size fits all kind of thing.

[MaxGunz]

From 2002 discussions on trim with Oleg I got some answers.

Question was why holding the stick steady off center doesn't get the same speed/acceleration as stick centered by trim. After all, trim will move a hands-off stick or column.

Answer worked out to that we think the stick is held steady but it is not. This is mainly due to hardware, short gaming sticks and small involuntary muscle tremors.

This is partly borne out by the reported results from those who made and use full size sticks to play IL-2.

And since 2002 the impact of needing to be trimmed has been less.

For my part, and you can easily check this yourself, there are two things that help.

1) use a light touch on your joystick. Try flying holding the stick with just 2 fingers and thumb just for while.
When you catch yourself resting your arm weight on the stick or elbow on the table, get your arm up so it's not weighing the stick down. If you find yourself clenching the stick, loosen up. Besides the weight and ham-handing those are great ways to transmit tiny muscle tremors to the stick.

2) go into stick sensitivity and add FILTER to the pitch/elevator axis. Try about 50% at first. Maybe you need more or less but you should see results in minutes of testing. FILTER will flatten out the small and fast shakes even at less than 50% while yes, slowing your jerk-speed by a fraction of a second that you can see by watching the red and green blocks in the stick test area of the same stick sensitivity screen.

It's not perfect but you should gain something if you're not already light-handed and using FILTER.

[horseback]

This is all very interesting, but it is still obvious that the elevators on all of these aircraft are far too sensitive and that trim displacement is disproportionately ineffective compared to other aircraft modeled on the basis of old data and reputation. “Easily trimmed” means easily trimmed no matter how you want to parse it. If an aircraft has “sensitive tabs” I would expect it to mean that the elevator and rudder require fairly minor displacement to wash out higher stick or pedal forces over a wide range of speeds. When one aircraft type is clearly identified by everyone who flew it as excessively demanding of trim and other aircraft types are specifically identified as needing very little or no trim adjustment by the same group of people I tend to think that I should need to adjust the one type fairly regularly and the others considerably less.

Let’s try to put ourselves in the 1930s-era high performance aircraft designer’s shoes. Aircraft are starting to exceed level speeds of 300mph (480kph), and if you didn’t place and design the control surfaces just right, control forces became greater than the average pilot could exert. The vast majority of trim tabs were on the rudders of monoplanes, usually big ones like the Martin B-10 until the mid-30s, at which point the technical issues appear to have been largely overcome and they start showing up on the rudders and elevators of an expanding variety of aircraft (and the ailerons of aircraft that had wing tanks).

The best pilots of the era tended to be drawn from the physical elites not least because you still had to exert fine control at a high force and because the buyers of high-performance military aircraft tended to be skeptical of depending upon new-fangled trim adjustment to keep the aircraft controllable. With good reason; changing trim was often clumsy and slow, unable to keep up with the higher speeds and acceleration of the modern monoplane fighters, so the designer/manufacturer was still expected to minimize the need (as opposed to the option) for trim for small speed variations. Trim was all mechanical, based on cables, pulleys, rods and screws motivated by human muscle and it was much slower than the digitally sensed and controlled systems we take for granted today, which were originally developed for high speed jets and found their way into civilian aviation, once they became cheap enough.

Simply put, trim adjustment in the late 1930s and early 1940s was considered a necessary evil to be avoided where possible and emphatically NOT a desirable convenience that obviates the need to exert even more (expensive) fineness in design and execution of the aircraft’s wings and control surfaces. It added weight and complexity to the aircraft, as well as cost.

So a wide range of speed change without requiring an adjustment in elevator or rudder was naturally going to be a primary design consideration. I would maintain that the Mustang was the most sophisticated high performance aircraft design around at the time of its introduction, and that the sophistication of its design would therefore be relatively sensitive to very minor changes.

How sensitive to change is the Mustang’s wing to minor changes? The wing was filler finished and hand polished. The upper and lower wings were covered with a surface to assure smoothness of the airfoil sections. The metal covered ailerons are statically, dynamically and aerodynamically balanced, and the wing’s efficiency is well known to be adversely affected by nicks, dents and scratches on the surface. Look at any shot of a Mustang in flight taken from above, and check out the wings—you will see nothing like the panel lines and obvious distinct panels of the fuselage on those wings (I think of all the Mustang models I built over the years and the care with which I ‘detailed’ those wing panels for the sake of ‘authenticity’…), even on aircraft that were in constant combat operations. I can picture the engineering officer responsible for maintaining those aircraft ordering 55 gallon drums of putty and reams of sandpaper to the bemusement of his buddies whose squadrons flew P-47s.

How adversely? It was found during factory tests that with a strip of wire 1/16 of an inch (roughly 1.6mm) taped along the leading edge of the wing, the aircraft would not leave the ground. America’s Hundred Thousand and every pilot I've ever read or talked to on the subject reports that the Mustang needed very little trim adjustment throughout its performance range and that tabs had to be applied with care; if the wings were that sensitive to minor changes, I would expect the elevators and rudder to be in very nearly the same class, that is, that very small adjustments would have great effect, and that they would not be necessary until a great deal of change in speed or power had taken place.

Is that consistent with what we see in the Il-2 Sturmovik ’46 Mustangs? Are the other aircraft I've mentioned treated in proportion?

cheers

horseback

[horseback]

From 2002 discussions on trim with Oleg I got some answers.

Question was why holding the stick steady off center doesn't get the same speed/acceleration as stick centered by trim. After all, trim will move a hands-off stick or column.

Answer worked out to that we think the stick is held steady but it is not. This is mainly due to hardware, short gaming sticks and small involuntary muscle tremors.

This is partly borne out by the reported results from those who made and use full size sticks to play IL-2.

And since 2002 the impact of needing to be trimmed has been less.

For my part, and you can easily check this yourself, there are two things that help.

1) use a light touch on your joystick. Try flying holding the stick with just 2 fingers and thumb just for while.
When you catch yourself resting your arm weight on the stick or elbow on the table, get your arm up so it's not weighing the stick down. If you find yourself clenching the stick, loosen up. Besides the weight and ham-handing those are great ways to transmit tiny muscle tremors to the stick.

2) go into stick sensitivity and add FILTER to the pitch/elevator axis. Try about 50% at first. Maybe you need more or less but you should see results in minutes of testing. FILTER will flatten out the small and fast shakes even at less than 50% while yes, slowing your jerk-speed by a fraction of a second that you can see by watching the red and green blocks in the stick test area of the same stick sensitivity screen.

It's not perfect but you should gain something if you're not already light-handed and using FILTER.I long ago came to the conclusion that I needed to ensure that my stick position was consistent and properly anchored, in order to limit things like resting forearms on the desk and the like; to that end, I bought a 5/8” (approx. 16mm) thick seasoned hardwood plank about 28” long and 13” wide. My flight sim computer’s desk has a keyboard tray about 24” wide, so I cut out 2”x 2”sections out of the corners (which keeps the tray from sliding in & out on me) and then cut out holes that closely match the outlines of my CH Combatstick and Pro Throttle, with the Combatstick almost in the center of the tray (3” offset to the right). The stick fits in the hole rather snugly, and the stick will stay where it is while I thrash it about. I recommend the idea to anyone who has trouble keeping his stick from running away from him.

So for the last six or seven years, my stick, pedals and throttle have been in exactly the same spot, which cut down on a lot of problems that plague other simmers, especially the ones who use sticks that feature heavy springs and no way to anchor the darn things.

I haven't played with filtering very much, though; that's a worthwhile suggestion. Thanks.

The addition of a smaller pot in series with the larger one is also a good idea; one of my nephews managed to break the case of my CH Yoke several years back so I took it apart and used the electronics as a base for a trim and button box; trouble is, the pots will only use about (the most linear) 60 degrees of rotation, so just breathing on them can be excessive when I try to use them for trim in Il-2 (not so much with FSX or the DCS Mustang, but you still have to be careful).

cheers

horseback

[MaxGunz]

60 degrees turn? You can get better ones.

What matters is how many ohms range you get from stop to stop and how many ohms your hardware uses. Ohms is resistance. I would start with the pot you currently use and put a meter across one of the outside legs of the pot to the center leg to find out what you got.

The standard plug into the gameport stick runs from 0 to 100k ohms. 1/100th of a turn covers 1k ohms. If I put that in series with a 10k pot then that pot will be 1/10th as sensitive as the 100k. The digitizer measures how much voltage gets through with 0 ohms meaning full and increasing ohms going towards none, 110k total as opposed to 100k is not a big deal and should only affect calibration.

That's why I tell that you can have one pot/slider for coarse adjustment and the other for fine adjustment. If you want 20x fine then for a 100k coarse you would add a 5k fine that would change the total resistance 1/20th as much for the same turn as the coarse knob.
Maybe the better setup would be a coarse long slider and turn pot for fine adjustment.

What your stick uses for values, you will have to find out for yourself. If you're up for it there are hobby controller electronics in the $60 and under range like the BUO-series at leobodnar.com (has 12-bit A/D) and less-accurate (10-bit) but far cheaper DIY MCU's like the Teensy's and Leonardo's (that can use external ADC chips to get more bits resolution but that's 'cheating', hehe) and make your own stick which is not for the faint of heart or mind.

The hard part could be making acceptable knobs, grips, and bases, ie the mechanical bits. Plaster molds and bondo then hours of sanding, filling, etc?

I can code the latter and breadboard them but have no shop space and am lousy at soldering and fine work due to shaky hands. The newer controllers and software (since 2008) make it easier than ever but I say that already knowing C since the 80's. Your mileage may vary, learning to code from zip may not be worth what you get. There's a lot of help available from Leo for his products (already coded) and on the Arduino forum for those.

In the last two years I have recovered/relearned a lot of my old "skillz" playing with Arduino. I have even made leds that self-adjust with changes to ambient light (LOL Fehler, how much resistor? MINE changes itself!).

[JtD]

...but it is still obvious that the elevators on all of these aircraft are far too sensitive...Actually, if anything is obvious, it's that the control surfaces are far too insensitive. There's a whole bunch of fighter aircraft that could reach the stall angle of attack or designed load factor with as little as 10% control input from trimmed level flight. And as trim is linked to control sensitivity, obviously, trim is too insensitive as well.

[MaxGunz]

If you can't overcontrol at high speeds or in turbulent conditions then you'll get sweet F-A control at low speeds.

Terms to look up are Maneuver Speed and V-Speeds.
Going from flight sims in the past, maneuver speed being the fastest you can pull full stick deflection on ONE AXIS is about 240-250 mph for the P-51. By 360 mph it's -probably- not safe to pull half way, I leave it to someone else to guess why.

Note that in WWII fighters the pilot can't take what the plane can. They had feel and were less prone to trying things that gamers who have no feel take for granted. Also that IL-2 is a simulation. When some G-limit (like 12 G's) is reached even momentarily it is bye-bye wings. Pilot blackout though seems to have a time element.

BTW, I just came across FreeChecklists.net. Here is the P-51 page:
http://freechecklists.net/Resources/North+American/P-51+Mustang/

And from the 1944 manual on page 19 under Maneuvers Prohibited:
"It is impossible to do a good snap roll with the airplane and most attempts usually end up in a power spin."

[horseback]

Actually, if anything is obvious, it's that the control surfaces are far too insensitive. There's a whole bunch of fighter aircraft that could reach the stall angle of attack or designed load factor with as little as 10% control input from trimmed level flight. And as trim is linked to control sensitivity, obviously, trim is too insensitive as well.
Maybe what I should have said is that the aircraft themselves are too sensitive to speed variation and that they are insensitive to elevator or rudder trim while being oversensitive to small rudder and elevator inputs as speed changes. The point remains that constant trim adjustment is demanded over a very small range of speed and that when compared to other aircraft of the era (and especially aircraft well-known to be less aerodynamically sophisticated, as in the case of the P-40 series) the trim model is grossly out of proportion for this relatively tiny group of fighters. It seems to me that the original game was optimized for FFB sticks, and for those of us in the majority with spring tension sticks, trimming out by 'feel' is a bit impractical, because the spring tension is just as high with the stick 5 degrees out of center as it does with it 45 degrees' deflection.

It is just silly to require the Player to click the elevator trim three or four times for every speed variation of less than 20kph indicated (plus a couple of clicks of rudder trim to compensate for nose angle immediately afterwards) for aircraft that history (and multiple current examples) shows (1) didn't require it and (2) will be constantly varying in speed and angle of attack with no accurate on screen display to indicate vector/trim state.

That this group is composed almost entirely of aircraft that exist in large numbers that fly to this day leads me to wonder if their FMs are a bit too detailed for the game engine or that there might be some kind of common mathematical error somewhere, possibly as a result of the conversion from Imperial measurements to metric.

Most of the aircraft instrument panel displays are hard to read at best (always in Wide View, and often in 'Normal' view) and far too many of them are grossly inaccurate; artificial horizons that are indistinct or offset to an exaggerated degree, climb indicators that are slow and frankly, lie much of the time (when you have an indicator that measures feet of climb in feet per minute, and one deflection division mark is supposed to represent 100 feet, you shouldn't be able to change heights by 60 or more feet in less than 3 seconds with the needle just above the '0' mark, and I experienced this routinely in a great many of the aircraft I've tested so far, the notable exceptions being the Soviet and the IJA fighters).

Two changes seem obvious to me; first, the addition of a temporary trim state display similar to the ones we get when we adjust throttle, prop pitch, supercharger or radiator settings. I'd like to see something along the lines of x% up Elevator Trim, x% Right Rudder Trim, and x% Right Aileron Trim with full trim deflection being 100%.

Second, make the cockpit instrument displays consistently accurate to exactly the same standard for every aircraft; currently, there seems to be a great deal of variation in instrument accuracy and readability from inside the cockpit.

I understand that unless there is one common conversion error that is easily detected, major changes in FMs is way more work than can be fairly asked of TD, in the near or far term, but the community shouldn't pretend that the inaccuracies aren't there.

cheers

horseback

[horseback]

60 degrees turn? You can get better ones.

What matters is how many ohms range you get from stop to stop and how many ohms your hardware uses. Ohms is resistance. I would start with the pot you currently use and put a meter across one of the outside legs of the pot to the center leg to find out what you got.

The standard plug into the gameport stick runs from 0 to 100k ohms. 1/100th of a turn covers 1k ohms. If I put that in series with a 10k pot then that pot will be 1/10th as sensitive as the 100k. The digitizer measures how much voltage gets through with 0 ohms meaning full and increasing ohms going towards none, 110k total as opposed to 100k is not a big deal and should only affect calibration.

That's why I tell that you can have one pot/slider for coarse adjustment and the other for fine adjustment. If you want 20x fine then for a 100k coarse you would add a 5k fine that would change the total resistance 1/20th as much for the same turn as the coarse knob.
Maybe the better setup would be a coarse long slider and turn pot for fine adjustment.

What your stick uses for values, you will have to find out for yourself. If you're up for it there are hobby controller electronics in the $60 and under range like the BUO-series at leobodnar.com (has 12-bit A/D) and less-accurate (10-bit) but far cheaper DIY MCU's like the Teensy's and Leonardo's (that can use external ADC chips to get more bits resolution but that's 'cheating', hehe) and make your own stick which is not for the faint of heart or mind.

The hard part could be making acceptable knobs, grips, and bases, ie the mechanical bits. Plaster molds and bondo then hours of sanding, filling, etc?

I can code the latter and breadboard them but have no shop space and am lousy at soldering and fine work due to shaky hands. The newer controllers and software (since 2008) make it easier than ever but I say that already knowing C since the 80's. Your mileage may vary, learning to code from zip may not be worth what you get. There's a lot of help available from Leo for his products (already coded) and on the Arduino forum for those.

In the last two years I have recovered/relearned a lot of my old "skillz" playing with Arduino. I have even made leds that self-adjust with changes to ambient light (LOL Fehler, how much resistor? MINE changes itself!).I'm fairly aware of ohms and resistance; they covered it pretty thoroughly while I was attending the USN's Electronics Technician 'A' School at Great Lakes over the winter of '75-'76 (August to April, which was the full Magilla back then), and I have applied that knowledge & training fairly regularly as a field & test engineer over the last 30+ years.

The pots that CH used for my old yoke are all 270 ohms, but they use only the 'middle range' of the pots because that is where the change in resistance is most consistent; the resistance between the 10th and 11th degrees is almost exactly the same as the resistance between degrees 45 and 46. This allows them to use less expensive pots and still give you pretty good precision across the range of movement that their mechanical setup allows.

Since little Joey only cracked the plastic case and one of the Yoke handles (it was only a drop of about six feet!), I was able to recover the CH control circuit card as well as the five axes and the 12 buttons plus POV hat; this means that when I plug the USB into my computer it sees a CH Yoke and automatically puts me into the CH Control Manager software, which allows me to combine it with my other CH controllers into one or two (rather than four or five) controllers for Il-2, which I'd rather not lose.

I was able to cut out the throttle/prop pitch/mixture levers' mounts so those three axes are intact, while the X-Y axes are now mounted in the box as twist knobs, with that short range of movement I was complaining about; I'm wondering if rather than putting another potentiometer in series, it might be better to put one in parallel to get that fine control. I'm also still looking at those gear kits that Tamiya makes for robots and RF controlled vehicles with an eye to adapting one of those to my needs with something along the lines of 20:1 ratios.

I'm not very familiar with programming (one course in Basic back in college 25 years ago), so tossing the little CH CCA is something I hesitate to do.

cheers

horseback

[horseback]

Two more charts and data tables; USN/USMC fighters at 100m/330ft, and Mid-War Soviet Fighters @100m/330ft.

A few notes:

1. The Soviet fighters really shine at this altitude (this means that I said "Holy *&^%*&%$%!!!!" a lot when I reviewed the data and had to slow the track down to half or quarter speed to catch the speed changes in time); compared to the 3000m data, they are far more impressive. The La-5FN is indisputably 'king of the hill' at this level, although I have yet to do the Seafire LF III.

2. The Soviet fighters also tended to drop their noses as speed increased, generally around the 360 to 400 kph range, but it was only about half the radius of the gunsight circle in WW view. I started taking screenshots at certain intervals to confirm this, so I am certain that it is happening.

3. The USN/USMC fighters are mostly 4.11.1 versions that I had already completed before the patch was released; after three comparisons to 4.12 runs, it became obvious that there were no changes.

4. I haven't had a chance to do the same sort of screen shot comparisons with the Corsair and Hellcat that I did with the Soviet fighters because the idea didn't come to me until I was doing the Russian runs; I have started a folder labeled 'nose drops' and will use it for fodder on another thread, I think.

5. Using Max' suggestion of applying 50% filter to my ailerons, elevator and rudder axes made some difference; still, very tiny movements in elevator or rudder when I attention wandered from the climb or alt indicator or artificial horizon (and when these instruments are obscured or widely separated, I had some real issues) resulted in big swoops and climbs in a matter of two or three seconds, often well out of proportion to the indicated displays (as mentioned in an earlier post)

Enjoy, discuss, debate.

cheers

horseback

[majorfailure]

2. The Soviet fighters also tended to drop their noses as speed increased, generally around the 360 to 400 kph range, but it was only about half the radius of the gunsight circle in WW view. I started taking screenshots at certain intervals to confirm this, so I am certain that it is happening.
I'll ask again, how else do you think the wing can generate the same lift at a higher speed (e. g. plane stays level), else than decreasing AoA?

[horseback]

I'll ask again, how else do you think the wing can generate the same lift at a higher speed (e. g. plane stays level), else than decreasing AoA?First of all, I meant it as a matter of degree; there has to be a reasonable limit of movement down as a result of the direction of thrust and limiting action of the elevator. I don't buy into the notion of an aircraft like the Thunderbolt wallowing with its nose up in the air at the speeds it travels when it enters the landing circuit or in economy cruise. It is simply exaggerated, and again, appears to be limited to that same group of fighters that there is the greatest amount of data and modern pilot reports about. We are talking about relatively straight, high lift wings across a fairly limited (by modern standards) range of speeds. We aren't talking about swept-wing jets here.

The Soviet aircraft all have a 'drop' of around a quarter of the WW gunsight circle's diameter, and it generally takes place between 370 to 400 kph ias, varying somewhat from Yak to LaGG to La. It also appears that the drop is not as great when the aircraft is in a constant speed compared to when it accelerates and that some aircraft have little or no 'drop' with acceleration or greater speed in general.

My impression so far is that aircraft like the Lightning, Corsair, Hellcat and P-47 have much greater 'drops' and that at certain speeds the nose will suddenly rise again somewhat at higher speeds. I haven't fully quantified it yet (as I have said, it takes about 45 minutes to actually make a 4 run track and at least the same amount of time to replay it and transcribe the raw data) but I think that these aircraft's noses raise and lower (and sometimes raise again) by nearly the full diameter of the WW gunsight circle, possibly more. At 100m, that puts the 'pipper' well below the horizon, while the Soviet fighters' gunsight center is just a bit above it (and at considerably higher speeds in many cases).

I contend that it is way too much variation, and plan to create a separate thread about it, but only once I have my ducks in a row. Right now I'm struggling to maintain level flight and have noticed that my key visual references are either unreliable in the case of my cockpit instrument displays or are changing on me in the case of the view of the horizon, which I could normally 'set' at a certain point in my cockpit framing to keep level. I need to (a) fly a reasonably level course while accelerating through the speed range and (b) take a series of screen shots from the track after doing so to confirm what are so far just impressions.

If I'm wrong I will say so; it won't be the first time.

cheers

horseback

[MaxGunz]

Series resistance will give you linear changes.
Rtotal = R1 + R2

Parallel resistance will give you curves and the total will be less than the smallest resistance (pot adjustment) and relative to it.
(1/Rtotal) = (1/R1) + (1/R2)

A microcontroller can use a lookup table to correct non-linearity of the sensor. There's room in a Teensy 2.0 to adjust _every_ step of all 12 10-bit analog inputs and still have room for useful code.

The most accurate stick I ever had used optical encoding. That wasn't analog at all. When the new hardware came out something changed and it wouldn't work so I sent it off to Rookie from the old Delphi FSF.

[RPS69]

Did you tried Hall efect sensors?
it is a must for home made ones. Nothing is more precise than that.

[RPS69]

Horseback, you are complaining exactly about what on trim, that it requires too much touchs to reach the desired position, that it is not working as it should, or both?

On the P38, you must be carefull with what you read. The P38 may not need rudder trim, as most other single engined, and bi motors whithout counter rotating engines did. But elevator trim may be assumed as allways needed.

In game trim management will be far better if there was a x10 adjustment, at least for those people that don't have a free axis for trim on thier joys.

[horseback]

Horseback, you are complaining exactly about what on trim, that it requires too much touchs to reach the desired position, that it is not working as it should, or both?

On the P38, you must be carefull with what you read. The P38 may not need rudder trim, as most other single engined, and bi motors whithout counter rotating engines did. But elevator trim may be assumed as allways needed.

In game trim management will be far better if there was a x10 adjustment, at least for those people that don't have a free axis for trim on thier joys.Both, in most cases. In this game, trim is a value essentially concealed from the player, but in certain aircraft, mainly the late-war US fighters and the various Spitfire models, it is often crucial in the FM (and by most accounts, it was not nearly so important in RL) and almost impossible to apply effectively. When I try to apply it in axis form (with for instance, my CH Throttle Quad), it is almost always excessive; moving the lever the slightest bit results in the nose suddenly going up or down or in the case of rudder trim, sideways. Using button trim, I will be forcing the nose down with the my (non-FFB) stick about halfway forward while clicking repeatedly on the nose down elevator trim button without noticeable effect until the nose suddenly drops like a rock. Even in what should be level cruise, you cannot seem to get these aircraft leveled out; one click has your nose moving down, or the ball offset by half a diameter to one side and clicking trim in the other direction has the nose going up or the ball offset a bit to the other side.

On this specific group of aircraft, it almost seems as though the trim is not applied until I have clicked the button a certain minimum number of times and then it is all applied at once. It is quite similar to the visual effect of applying trim; you apply four or five clicks, and only then do you see the rudder or elevator move slightly.

As for the P-38 comment, let me say that I am almost 60 years old, and that my father retired from the US Air Force just before my 18th birthday. I have been interested in WWII’s air war since I was about seven, when we were transferred to Great Britain just after the 20th anniversary of the Battle of Britain (it was kind of a big deal over there). I’ve met a great many pilots who flew Warhawks, Lightnings, Thunderbolts, Mustangs and the naval fighters during the war over the years (strangely, only one admitted that he flew a P-39—and by the way, being curious about the aircraft your girlfriend’s Dad flew can make a big difference in what time you have to get her home), and most of them were happy to talk about flying them if not always about combat. I also read everything that I could find about those airplanes, their pilots and the air war in general once I mastered the printed page. I made hundreds if not thousands of scale models of every major fighter type that could be found in 1/72nd and 1/48th scales (including paying ridiculously high prices for the crude east of the Iron Curtain stuff that gave the only semi-accurate depictions of Sturmoviks, Yaks and LaGGs).

Back to the pilots’ testimonies:

P-40 drivers always mentioned that it was like an unruly horse that had to be tamed every time you got behind the stick (with the implication that you had to be a ‘real’ man to fly it well) and a couple mentioned the constant manipulation of the rudder trim. Thunderbolt pilots talked about how safe they felt in it and how smooth it was (the turbosupercharger gave them all of the engine’s power at any altitude, so they never felt that they had to compensate for more or less power as they climbed or dove (and their dive stories were full of superlatives), and Mustang pilots tend to go on about how you just felt in control of every little thing and how you almost automatically knew what you could get away with (one guy said that it wasn’t just that it was responsive so much as it told you how responsive it would be and let you know exactly where the limits were).

The P-38 guys talked climb, acceleration (according to the comparisons on pages 603 and 604 of America’s Hundred Thousand, at sea level the P-38F accelerated from 250 mph at 2.30 ft/sec/sec (roughly 70.7cm/sec/sec) and the P-38L would do 4.13 ft/sec/sec (or about 1.27m/sec/sec), this was about 0.15 ft/sec/sec faster than the early P-47D models or the Allison Mustangs for the F and the L was about 0.11ft/sec/sec faster than the M model Jug and 0.28 ft/sec/sec faster than the P-51D; the -1 and -4 Corsairs were well back from that among US fighters) and firepower. Like the P-47, the Lightning had the GE turbosuperchargers, which gave them all the engines’ power at any altitude. If the Lightning guy served in the Pacific, it was THE airplane; if he flew the later models in the European or Med theaters, it was a cold and unreliable SOB at high altitudes. They all said the P-38 didn’t use a lot of trim unless you were going up or going down; one guy said that it was a good thing it didn’t, because the elevator trim wheel was so hard to get at (America’s Hundred Thousand says that the 1944 Fighter Pilots’ Conference voted the P-38’s cockpit arrangement the worst of the US fighters and that the flap and landing gear controls were particularly hard to reach). From what I’ve seen, if you were wearing gloves thick enough to allow you to avoid frostbite, everything except the yoke and the rudder pedals was hard to manipulate at high altitudes in the P-38, so constantly grabbing and adjusting that tiny little knob on the wheel right next to your left knee in gloves with any precision would be hard. See the attached photo; the elevator trim wheel is that little thingie with the little wooden knob on the side of the black box; from other photos I have it seems as though the thing would be digging into your knee all the time.

All of these details have been confirmed in dozens of books, magazine articles and in some cases, the training films I’ve been able to view over the years. Only the P-40 was ever described as being hard to keep up with in terms of trim in level flight, and that is consistent with the recognition that it was an early design and that it was an adaptation of the radial engined P-36 (which is universally praised as a well-balanced fighter, if a bit slow post 1939). Every other aircraft was designed for a specific range of speeds and the idea that trim should be convenience rather than a necessity. When trim tabs are referred to as sensitive, there is usually a line about how you only need to add or subtract it in small increments in the pilot manuals. Given that Il-2 ‘46’s trim model gives you 160 clicks of trim from stop to stop, it seems to me that two or three clicks from ought to cover any need for trim for changes in speed up to 35-40kph or of 10-15% throttle/rpm in all but the most extreme cases in either rudder or elevator.

What I’m seeing is five or six clicks nose down, then two up, then a couple of clicks of rudder one way, then one or two the other direction; then wait a couple of seconds to settle and begin the whole process over again for normal level flight for this specific group. When you look at the external views of these aircraft in normal level cruise trim, the elevators are all visibly deflected down. Compared to the dozens of in-flight photos I have found of these same aircraft in apparent level flight it looks as though these do not have any appreciable deflection up or down.

If you look back from the cockpit at the Il-2 ’46 Spitfire’s elevators while in flight, most of the time the balance horn is sticking up well past the upper surface of the stabilizer. Find a video on YouTube where a guy from The Guardian is learning to fly a Spit in a two seat conversion of the Mk IX (there appear to be several): the in-flight shots of his face while he flies clearly show the elevator balance horn flicking up occasionally (without the immediate bouncing up and down that Il-2 ’46 depicts), but generally it is not constantly above or below the stabilizer while in level flight.

So trim demands for these aircraft seem to me to be excessive and at the same time, trim is impossible to track, excessive in axis form and much too small and unintuitive in button form.

cheers

horseback

[MaxGunz]

Did you tried Hall efect sensors?
it is a must for home made ones. Nothing is more precise than that.

Only as precise as you align the sensor and magnet.

Make sure you get linear analog Hall sensor, *not* one of many others especially the bipolar switch security type.

Being non-mechanical in operation they are preferable.

[MaxGunz]

The 1 or 2 click trim that we fumble around trying to get perfect IRL means less than an ounce of force on something like a P-38 control column.

Most of use use a short toy (regardless of cost) joystick with no feedback at all let alone realistic movement and forces. The short stick multiplies every little twitch and tremor compared to a full size stick.
If that's not part of your analysis, if you get demand-y regardless then you're going to be SOL as to satisfaction.

[RPS69]

Only as precise as you align the sensor and magnet.

Make sure you get linear analog Hall sensor, *not* one of many others especially the bipolar switch security type.

Being non-mechanical in operation they are preferable.

Agreed, aligning it could be tricky. The linear is also truth.

It also have a great advantage. You could place it at the bottom of a long stick, and still have precision, while pots moving in a very short arc are far less reliable.

To achieve that kind of precision with optics, you will need some demultiplying system.

Now... so much precision got a draw back, filtering is MANDATORY!

[RPS69]

Horseback, I agree.

A better triming interface should enter the wishlist.

Still, from your findings, I may build a guess, and it is that the coding got a min¡mum value that don't allow you to achieve a middle step, meaning that the optimal trim position can't be achieved the way it is coded, at least not allways.

Also, some of your headaches, must be related to the trim delay insert. That could make trimming any plane far more tricky than it was supposed to be. Originally implemented to avoid the "online trim exploit". A bad solution to a questionable problem.

[MaxGunz]

Agreed, aligning it could be tricky. The linear is also truth.

It also have a great advantage. You could place it at the bottom of a long stick, and still have precision, while pots moving in a very short arc are far less reliable.

Distance from the magnet is not how to get linear angle from a Hall sensor! The Hall reads only on 1 axis. You align the axis dead center over the magnet center between N and S poles. When the magnet turns, the strength of the field along the Hall axis changes. That is what you measure.
Try the other way, you will need more than 1 magnet and the fields will affect each other, merge, and you won't get good results.

To achieve that kind of precision with optics, you will need some demultiplying system.

Now... so much precision got a draw back, filtering is MANDATORY!

Optical... a lot can be done using laser-printed transparency graphics you can get printed at most any office store.

Have you ever looked at how ball mice track motion? Or used a vernier?

I have read that working with the dimensions of a Young's double-slit can yield a high number of interference bands. Perhaps diffraction from a single slit can also be used.

Really, the number of ways is a study in itself.

[RPS69]

Distance from the magnet is not how to get linear angle from a Hall sensor! The Hall reads only on 1 axis. You align the axis dead center over the magnet center between N and S poles. When the magnet turns, the strength of the field along the Hall axis changes. That is what you measure.
Try the other way, you will need more than 1 magnet and the fields will affect each other, merge, and you won't get good results.

You wrong! believe me! just one sensor is enough.



Optical... a lot can be done using laser-printed transparency graphics you can get printed at most any office store.

Have you ever looked at how ball mice track motion? Or used a vernier?

I have read that working with the dimensions of a Young's double-slit can yield a high number of interference bands. Perhaps diffraction from a single slit can also be used.

Really, the number of ways is a study in itself.

There are many optical encoder devices available, and I have tried them. Magnetic is better.

This is a good topic on itself, meybe we start it into another thread, or we may end hijacking this one.

[MaxGunz]

You wrong! believe me! just one sensor is enough.

If you say so. I have sensors and AVR's, I'd like to see better ways. ;^)


There are many optical encoder devices available, and I have tried them.

I made my own to test ideas out, digital and analog but I won't say they're better than industrial resolvers because they aren't.

Magnetic is better.

It's only as good as your alignment and your ADC... unless you do something like use gears/spokes and magnetic tooth counters or better.

This is a good topic on itself, meybe we start it into another thread, or we may end hijacking this one.

I agree. I will look for it.

[horseback]

I apologize for the delay; I started adding screenshots to the track review process in order to track the nose drop phenomenon and I think that I have found some interesting things, but I need to do some more research before I start that thread.

Here are the Mid War USAAF Fighters, the Japanese Fighters and the FW 190 series. A couple of notes: the P-40E and P-40M disparity appears to have been fixed in 4.12; the M version is both quicker and faster than the earlier E version, and they seem to me to need a bit more trim adjustment (but still not nearly as much as the P-47, the Hellcat, Corsair or Mustang).

The acceleration of the A6M3 and A6M5 from 270 to about 400 kph is almost jaw-dropping at 100m; I don't chart the intervals between 270 to 350, but I feel that from 270 to about 330, these two fighters may be quicker off the mark than all but the La-5FN and possibly the Seafire LIII. Below 1600m/5000ft, Allied fighters are well advised to keep their speed up and not attempt any change of direction (including climbs) until they have 3 or 4 km of separation. Zekes don't appear to loose any energy in a turn or climb, so in any low and slow scenario they hold all the cards.

The P-38 is pretty impressive at this altitude as well, but that should not surprise anyone; with the turbosuperchargers it packed, its Allison engines drew full power from down in the weeds right up to 30,000ft.

FW 190A is fairly tractable at all speeds; I realized early on that I was doing myself more harm than good when I tried to make small rudder adjustments--it hardly needs any except at slower speeds, and the Turn & Bank ball is a bit behind the Wonder Woman vector ball, and the Wurger is not affected by small offsets in the ball the way a Corsair or Hellcat is. The nose drops noticeably at around 360-380 kph indicated (but not nearly as much as most of the US heavyweights) and the gradations on the gunsight's crosshairs make it easier to measure your attitude and fly a more level course most of the time. The hardest thing with this bird is losing speed; it will burble along at 300 kph at less than 30% throttle almost forever before it slows down to 270.

Enjoy.

cheers

horseback

[MaxGunz]

Design Analysis of the Zeke 32 (Hamp)
(That's a Mitsubishi A6M3 Zero for those not up on WWII Allied code names. - Ed.)

http://rwebs.net/avhistory/history/zeke32.htm

I see a very light plane 5155 lbs normal gross wt with a 1020 HP engine.
It's small and light, which cuts drag at all speeds.

[majorfailure]

Here are the Mid War USAAF Fighters, the Japanese Fighters and the FW 190 series. A couple of notes: the P-40E and P-40M disparity appears to have been fixed in 4.12; the M version is both quicker and faster than the earlier E version, and they seem to me to need a bit more trim adjustment (but still not nearly as much as the P-47, the Hellcat, Corsair or Mustang).

I would bet there has not been a large change in the P-40s FM.
It has all to do with Full throttle height - and the way the power curves get due to it. P-40M very low will have an advantage, then its steeper power curve (higher FTH) crosses the P-40Es, and in medium height it is slower than the P-40E. But the P-40E maxes out at ~3000m, and then the power cirve goes backwards again, and crosses the P-40Ms curve again, so at alts of around 4k the P-40M should be faster again.

[horseback]

I would bet there has not been a large change in the P-40s FM.
It has all to do with Full throttle height - and the way the power curves get due to it. P-40M very low will have an advantage, then its steeper power curve (higher FTH) crosses the P-40Es, and in medium height it is slower than the P-40E. But the P-40E maxes out at ~3000m, and then the power cirve goes backwards again, and crosses the P-40Ms curve again, so at alts of around 4k the P-40M should be faster again.No, there definitely were some changes--the Hawk 81A is quite a bit faster in the 4.12 patch at 100m, and so is the P-40M, although I must have tossed the chart I did on it before the new patch came out. Fortunately, I kept my 'original' 4.11.1 version and reloaded the 4.12 version on a different drive from the original DVD and patched up from scratch, so I re-flew the 4.11.1 P-40M and re-recorded the intervals.

Attached is the chart I created just for you; there is very little, if any, change in the P-40E from 4.11.1, but the P-40M is a good deal faster, as one would expect from an upgraded engine and better (full wartime) production quality.

cheers

horseback

[SadoMarxist]

As far as the acceleration comparisons go, there was a nutter on WoP forums a few years ago who claimed that the ability of an aircraft to accelerate can be expressed and evaluated by something called Specific Excess Power (Ps). Furthermore, said person was audacious enough to claim that the information necessary to compare the acceleration performance of one airplane relative to another is contained within the IL- 2 Compare diagrams. I can't find the thread now, but never mind, it was long and boring anyway. However, I was able to find a document which explains Ps:

http://www.aviation.org.uk/docs/flighttest.navair.navy.milunrestricted-FTM108/c5.pdf

Regarding the trim characteristics of a certain airplane, this will have to do with stability and control. While contributing factors of the control surfaces can be modeled, the peculiarities of inception mechanisms (sticks, yokes, pedals, hydraulic augmentators, balance weights,... ) scarcely can be. Luckily, one can assign trim to axis and then use IL- 2 Joy proggie to adjust the response curve of the trimmer to one's liking :).

[horseback]

Regarding the trim characteristics of a certain airplane, this will have to do with stability and control. While contributing factors of the control surfaces can be modeled, the peculiarities of inception mechanisms (sticks, yokes, pedals, hydraulic augmentators, balance weights,... ) scarcely can be. Luckily, one can assign trim to axis and than use IL- 2 Joy proggie to adjust the response curve of the trimmer to one's liking .While I'm all for maths and technobabble in their proper places, I feel that in a forum like this, they usually do far more to obscure than they do to explain.

As I've pointed out, the trim issue seems to be confined to a relatively small group of aircraft, and I've done extensive experimenting over the eleven years I've been playing this game and its predecessor with trimming methods and controllers. Button trim usually is the more accurate of the two, since it is input in quite tiny increments (about 160 clicks from one extreme to the other), and on most aircraft it is more than adequate, in the sense that you can get to a 'zone' where one more click up or down makes no discernible difference. However, on some aircraft the transition from one click down or one click up always seems to be excessive at any throttle/pp setting; you will either be climbing or losing altitude, in a slight skid or slide or rolling to one side or the other unless you hold your stick absolutely rock steady precisely at angle X/Y. On these same aircraft, I also notice that you need to trim precisely for very small changes in speed and power, or the penalties in performance and speed loss can be severe.

When it consistently happens with aircraft I know were easily trimmed for hands off or at least reasonably stable flight, I have to wonder why, when so many other aircraft described by contemporary pilots act as described in the game (or considerably better). If the programmers can simulate the trimming characteristics of plane A (the P-40 series) from records 70 years old, then how is it that planes B, C and D need to be adjusted at least 150% more often than the acknowledged worst trimming aircraft in the US inventory?

cheers

horseback

[gaunt1]

As far as the acceleration comparisons go, there was a nutter on WoP forums a few years ago who claimed that the ability of an aircraft to accelerate can be expressed and evaluated by something called Specific Excess Power (Ps). Furthermore, said person was audacious enough to claim that the information necessary to compare the acceleration performance of one airplane relative to another is contained within the IL- 2 Compare diagrams. I can't find the thread now, but never mind, it was long and boring anyway. However, I was able to find a document which explains Ps:

http://www.aviation.org.uk/docs/flighttest.navair.navy.milunrestricted-FTM108/c5.pdf


Im not good at maths at all, so how is that working? Acceleration is proportional to excess power, or exponential?
Im asking this because something is fishy with the acceleration of some aircraft, primarily the La-5FN. Compared to La-5F, it has ~12% more powerful engine, slightly lower weight, and about the same drag. But acceleration is far-far better. So either the La-5F is porked, or the La-5FN is an UFO in this regard. I suspect the latter. Because if we take the factors above into account, I think it should have only about 15-20% better acceleration, for example 270 to 500 should take about 44-48 seconds, not 36.

As far as I know VK-105 Yaks all have very good FM, so LaGG-3 S66 is also fishy, because its slightly better than even the Yak-1b. I doubt that its OK.

Correct me if Im wrong.

[horseback]

Im not good at maths at all, so how is that working? Acceleration is proportional to excess power, or exponential?
Im asking this because something is fishy with the acceleration of some aircraft, primarily the La-5FN. Compared to La-5F, it has ~12% more powerful engine, slightly lower weight, and about the same drag. But acceleration is far-far better. So either the La-5F is porked, or the La-5FN is an UFO in this regard. I suspect the latter. Because if we take the factors above into account, I think it should have only about 15-20% better acceleration, for example 270 to 500 should take about 44-48 seconds, not 36.

As far as I know VK-105 Yaks all have very good FM, so LaGG-3 S66 is also fishy, because its slightly better than even the Yak-1b. I doubt that its OK.

Correct me if Im wrong.First thing you have to recognize is that my test results have to be expressed as whole seconds; I use the track time shown in the lower right hand corner of the screen, and stop the track at every listed interval (270-350, 350 to 370 and every 10kph after that). While I try to average the interval times of three or most often, four runs, I also note the altitude changes and 'weight' the average accordingly.

Since no one can fly absolutely level acceleration courses in cockpit and in real time (I'm trying to duplicate what the average player could do), no two 'runs' are the same, especially if there is a wide separation between the variometer and the altimeter (the artificial horizon can also be a factor); you can only focus on one thing at a time, and an exceptionally level run will have variations of 'only' 15-20 meters (that's thirty to sixty five feet) over the course of the full run. Many times, I've had changes in altitude of 30 meters or more (up or down in almost even proportion) in an interval lasting less than 4 seconds.

What I have noticed is that some aircraft will literally 'blast' through the early intervals at almost exactly the same times even when there are rather large climbs or losses of altitude (and even if they are considered to be on the 'draggy' side), and some others are affected to varying degrees by varying altitude; I believe that the aircraft that generally have powerful engines tend to do the 'blasting', while the ones with lower power to weight ratios tend to require a very level flight in order to achieve their best times.

Over the total course, aircraft with the weaker engines tend to slow more quickly as drag (which increases exponentially with speed) exerts its influence, even when they are very clean aerodynamically. The Zero series is a good example of this; initially, the engine is able to overcome the inertia of flying at 270kph and pick up speed quickly because the aircraft is so light compared to its fairly large size/wing area, but as drag increases, its acceleration bogs down rather quickly.

Heavier (or compact, in the case of the FW 190A series) but still aerodynamically clean aircraft like the Mustang with a good power to weight ratio will not only 'blast' through the early stages, but the kinetic energy of their greater weight carries them through those sudden little climbs or periods where the trim is out of whack (skids and sideslips) with less of a penalty. At the far ends of a run, I find that staying level and in good trim becomes more critical with the 'heavies'.

If the aircraft is both heavy and underpowered...

As for the 'proportional' aspect of the La-5F vs the La-5FN, my understanding is that the FN had an extra 200 hp at full boost over the F, and that makes it significantly 'quicker' when full boost is applied, a maximum of two minutes in RL, if I remember correctly. On a 3360kg (7400 lb) aircraft, that will be felt. I would expect that as production progressed, there would have been incremental improvements in finish and quality as well, and there was still room for the La-7 with essentially the same powerplant as the La-5FN to 'clean up' and demonstrate even better performance.

As for the LaGG, remember that this was the final version of the aircraft that had been improved quite a bit over the early war versions, and the game assumes it to be in ideal condition, not at the normal RL condition that it apparently came to the Front in. With the same engine & a bit more weight than the Yak-1b, it should be fairly close.

cheers

horseback

[MaxGunz]

Just what planes always button trim with no left over up or down? I've never gotten that except through luck or throttle adjustment.

I have always found the 109's susceptible to nose bob after slowing down even a little.

the peculiarities of inception mechanisms (sticks, yokes, pedals, hydraulic augmentators, balance weights,... ) scarcely can be.

(LOL, that's above average 8th grade level. You lost half the readers.)

Those who don't figure out the implications of the quote above, implications which have been presented over and over for more than 10 years now are still trying to find answers elsewhere. For them it's endless 'persecution' and WTF.

P-51 could be more stable. Move the CoG forward. Then listen to the whines that say stick force is too heavy, I have a book that says so.

[MaxGunz]

As far as the acceleration comparisons go, there was a nutter on WoP forums a few years ago who claimed that the ability of an aircraft to accelerate can be expressed and evaluated by something called Specific Excess Power (Ps). Furthermore, said person was audacious enough to claim that the information necessary to compare the acceleration performance of one airplane relative to another is contained within the IL- 2 Compare diagrams. I can't find the thread now, but never mind, it was long and boring anyway. However, I was able to find a document which explains Ps:

http://www.aviation.org.uk/docs/flighttest.navair.navy.milunrestricted-FTM108/c5.pdf



Anybody can know that science is just opinion at best and lies straight from the Pits of Hell the rest of the time! Right?

LOL, thanks for the comedy! I couldn't resist adding a line!

IL2Compare is an approximation you can beat at very low speeds, but good for comparison purposes if not all in-game results. One other shortcoming is the single 1000m alt turn curves given. It's possible to look at the climb charts to get an idea of how one plane may gain or lose at some other alt but that's guesswork.

A set of Ps curves for many altitudes for every plane would be a real boon but the hard part is cleanly flying enough stretches to chart even one plane. With NTRKs of flight that conforms (full power always: steady alt straight and level or straight climb at steady speed, check for what else I probably forgot) it should be possible to make charts of some value if not perfect.

IMO steady TAS climb would serve best since it covers multiple altitudes per run.

Last time I was up for it I was asking about using segments of data where for X seconds the necessary variables were steady, and how long X seconds would need to be? That way data might be extracted from tests that are not perfect the whole way. X should not be small is as far as I got.

Anyhow I think that a good set of Ps curves would tell more about the game than we have so far.

[FC99]

Im not good at maths at all, so how is that working? Acceleration is proportional to excess power, or exponential?
Im asking this because something is fishy with the acceleration of some aircraft, primarily the La-5FN. Compared to La-5F, it has ~12% more powerful engine, slightly lower weight, and about the same drag. But acceleration is far-far better. So either the La-5F is porked, or the La-5FN is an UFO in this regard. I suspect the latter. Because if we take the factors above into account, I think it should have only about 15-20% better acceleration, for example 270 to 500 should take about 44-48 seconds, not 36.

Ps=(VT-VD)/W [m/s]
VT(La5FN) > VT(La5F) - more powerful engine -> more thrust
DT(La5FN) < DT(La5F) - cleaner airframe -> less drag
W(La5FN) < W(La5F) - La5FN is lighter


Ps=dEh/dt
Eh=h+V^2/2g [m] - Energy height

From that you can calculate acceleration.



All of the above combine = big difference in performance
When you know specific excess power, you can calculate climb and acceleration performance. Or you can go backward and measure acceleration(Like horseback is doing) and calculate Ps and rate of climb from it.

[horseback]

Just what planes always button trim with no left over up or down? I've never gotten that except through luck or throttle adjustment.

I have always found the 109's susceptible to nose bob after slowing down even a little.

(LOL, that's above average 8th grade level. You lost half the readers.)

Those who don't figure out the implications of the quote above, implications which have been presented over and over for more than 10 years now are still trying to find answers elsewhere. For them it's endless 'persecution' and WTF.

P-51 could be more stable. Move the CoG forward. Then listen to the whines that say stick force is too heavy, I have a book that says so.The key word in my description is excessive. Most aircraft have an easily determined 'sweet spot' where just holding your hand on the stick will keep the aircraft level and steady (not banking to one side or the other). If you take your hand off the stick, the change will be gradual over two or three seconds, maybe five to ten degrees of roll (and it will usually be random--left one time, right the next). "Nose bob" is one thing and most aircraft have it to a greater or lesser degree. Usually the greater the nose bob, the more the aircraft is out of trim; if you are way out of trim, the bob becomes a yo-yo. If you need to constantly re-trim for the slightest change in state (nose up, nose down, bank, 5-10 KPH gain or loss of speed, 5% more or less throttle or prop pitch), you're screwed.

With the Spitfire (any Spit/Seafire) in this game, there is a tendency to roll right at all speeds; it has no aileron trim and the tendency and amount of pressure to the left is the same throughout its speed range. Take your hand off the stick and it will roll 15 - 20 degrees in about two seconds. The P-47 has the same tendency, except if you add one click of left aileron trim, it has the tendency to roll left at the same strength: about 15-20 degrees in a couple of seconds. I call that 'excessive'.

I also wonder where it comes from, because in over fifty years of reading and asking former and current pilots of these types (say "Spitfire" to Bob Hoover, and you would get twenty minutes contrasting and comparing it to the Mustang, P-39 and P-40; unfortunately, when I asked him the cassette recorder hadn't been invented yet) about every little thing, and no one ever said that there was always this little bit of pressure to roll right. Very short 'throw' on the elevators vs a full arc on the ailerons, yes. Tendency to quickly overheat on the ground, yes. No incipient roll to the right was ever mentioned in print or verbally.

With the Mustang (and to a greater degree, the Hellcat, Corsair and P-47 in that order), you cannot achieve the state of consistent trim I described above; there is always that bit of pressure against the stick and one click up means that you are fighting a climb and one click down means that you're in a shallow dive (and either case means that the rudder is going to need a tiny bit of pressure one way or the other and it will inevitably be too much and the 'ball' will shoot across the T&B indicator). You can do it with the Airacobras and the P-40s, but not the later, more sophisticated designs, which were all described as equal or (much) better in this regard.

The in-game P-38 (like the Mustang and the others) needs constant elevator trim adjustment every 10-15 kph of of speed up or down, contrary to every description I've read or heard of the real thing. As I've pointed out, WWII era pilots all carped constantly about the fact that the P-40 series all needed to be trimmed for speed changes of as little as 10 miles an hour (16 kph). That is about four miles an hour more than you need to trim the in-game P-51 for.

Excessive.

You like to go on about game controller joysticks vs the extended 'real things', but how is it that the 109 and the so many other aircraft modeled in the game are capable of precise flight with easy trimmability but this one group of aircraft all described as equal or superior (by both sides) in this respect cannot be modeled to be equally capable of that precision without an inhuman awareness of trim state (that is not accurately depicted by the instruments' display) and an ability to input micro units of trim at precisely the right time?

It is not just a matter of one aircraft's center of gravity or people not having their joysticks adjusted properly. There is a basic error at work here. It could be mathematical or it could be a personal prejudice. Something is stacking the deck against these aircraft.

cheers

horseback

[MaxGunz]

I "trim" the roll in the Spits with rudder and zero slip at the same time. The cause is propwash, the fix is rudder.

As to why the toy/short sticks matter is because every little bit of motion is magnified on that short-short lever without the balance of forces a real stick has. We have centering springs always pull their way. This is a major disconnect from reality.

IRL it's not a big problem to hold the stick against slight force. You know the moment that changes on your fingers. But try trimming for hands off and change your speed 10 mph. It won't be the same as IL2, the real stick will move a tiny bit. That's feedback we don't get, part of the disconnect.

Another problem is there is no weight distribution in IL2 models. It's all calculated from center. The heavier planes may suffer because of that. I don't know what to say about power in IL2 FM but that it has to line up with weight somewhere in there and IIRC there was some problem with differential power in turning with the P-38 that got down to a modeling shortcut -- perhaps thrust gets averaged and applied on center, FatCat can probably tell.

I'd rather not focus on the small cracks in the model except to find ways around them. I get the feeling that you would get so much out of a full length stick setup that you'd rename your firstborn or something. Think of the difference between a twisty stick and a good set of pedals then take that into 2 more axes.

[gaunt1]

Ps=(VT-VD)/W [m/s]
VT(La5FN) > VT(La5F) - more powerful engine -> more thrust
DT(La5FN) < DT(La5F) - cleaner airframe -> less drag
W(La5FN) < W(La5F) - La5FN is lighter


Ps=dEh/dt
Eh=h+V^2/2g [m] - Energy height

From that you can calculate acceleration.



All of the above combine = big difference in performance
When you know specific excess power, you can calculate climb and acceleration performance. Or you can go backward and measure acceleration(Like horseback is doing) and calculate Ps and rate of climb from it.

Dont know... Still fishy for me. La-5FN is only 150hp more powerful, but according to NII VVS tests, it is actually heavier (60-100kg) than La-5F. I strongly suspect that ingame FM is based on the performance of the prototype SN 39210102. If you look at horseback's chart, the performance of the FN is suspiciously better than the F. It should be of course better than the F, but not that much, maybe only 15-20%.

[horseback]

Dont know... Still fishy for me. La-5FN is only 150hp more powerful, but according to NII VVS tests, it is actually heavier (60-100kg) than La-5F. I strongly suspect that ingame FM is based on the performance of the prototype SN 39210102. If you look at horseback's chart, the performance of the FN is suspiciously better than the F. It should be of course better than the F, but not that much, maybe only 15-20%.The tables in Soviet Combat Aircraft Volume 1 by Yefim Gordon and Dmitri Khazanov show a top speed of 573 kph at sea level for the -5FN and 551 kph for the -5F, and I got a (rounded off) 560 kph indicated at 100m for the -5FN and a (rounded off) 530 kph for the -5F. True airspeed would be somewhere north of 578 kph and 548 kph respectively, so both aircraft models appear to be close to the RL records. Further reading seems to indicate that the -5F was flown most often with the canopy open in practice, due to accumulated exhaust fumes and (possibly) poor visibility, so there may be some compensation for that in the FM.

However, this is an acceleration comparison, and the extra horsepower of the M-82FN translated into better acceleration even more than better top speed, which with the similar airframes meant about the same major limiter to top speed; the -5FN reaches its intervals sooner (and really, it is only a second and a fraction difference at the initial stages, but the differences are cumulative--they add up over time).

Let's look at another indicator of the added power of the M-82FN taken from the same book I referred to earlier; the takeoff runs of the production La-5F were measured at 350m--compare that to the production La-5FN's 290m. That's a good deal more than a 10-12% difference right there, and I think it means that the FMs for these two aircraft are fairly accurate in this respect within the limits of the game engine.

cheers

horseback

[MaxGunz]

578/560 = 1.032, 3.2% more.

At 100m the difference should be less than 1% in standard conditions.

[gaunt1]

The tables in Soviet Combat Aircraft Volume 1 by Yefim Gordon and Dmitri Khazanov show a top speed of 573 kph at sea level for the -5FN and 551 kph for the -5F, and I got a (rounded off) 560 kph indicated at 100m for the -5FN and a (rounded off) 530 kph for the -5F. True airspeed would be somewhere north of 578 kph and 548 kph respectively, so both aircraft models appear to be close to the RL records. Further reading seems to indicate that the -5F was flown most often with the canopy open in practice, due to accumulated exhaust fumes and (possibly) poor visibility, so there may be some compensation for that in the FM.

However, this is an acceleration comparison, and the extra horsepower of the M-82FN translated into better acceleration even more than better top speed, which with the similar airframes meant about the same major limiter to top speed; the -5FN reaches its intervals sooner (and really, it is only a second and a fraction difference at the initial stages, but the differences are cumulative--they add up over time).

Let's look at another indicator of the added power of the M-82FN taken from the same book I referred to earlier; the takeoff runs of the production La-5F were measured at 350m--compare that to the production La-5FN's 290m. That's a good deal more than a 10-12% difference right there, and I think it means that the FMs for these two aircraft are fairly accurate in this respect within the limits of the game engine.

cheers

horseback

That book is a good source, the data matches the NII VVS test results.
Regarding the exhaust fumes, I think the FN still had the same problem.
Im not a too good pilot, so I used IL2 compare for La-5F and FN speed data, and it shows close to prototype performance for the FN. Turn performance is also corresponds to prototype La-5FN. This is why I think that acceleration is also based on that.
I dont know how accurate IL2 compare is, but one thing is sure, all Lavochkins benefit from using Forsazh at all altitudes, while in reality it could be used only up to ~2700-3000m.

[horseback]

578/560 = 1.032, 3.2% more.

At 100m the difference should be less than 1% in standard conditions.
I'm using the on-screen display in Wonder woman view from the tracks as my reference, which is what I expect the average player would do; doing the calculations is more work than I want, and I expect it will confuse a majority of the people who are following this thread.

cheers

horseback

[MaxGunz]

Something there isn't right, IAS or TAS.

[IceFire]

That book is a good source, the data matches the NII VVS test results.
Regarding the exhaust fumes, I think the FN still had the same problem.
Im not a too good pilot, so I used IL2 compare for La-5F and FN speed data, and it shows close to prototype performance for the FN. Turn performance is also corresponds to prototype La-5FN. This is why I think that acceleration is also based on that.
I dont know how accurate IL2 compare is, but one thing is sure, all Lavochkins benefit from using Forsazh at all altitudes, while in reality it could be used only up to ~2700-3000m.

That is the biggest problem with some of the engine boosts. It works well for the types that affected power at all altitudes but not at the ones that had limited altitude applications (except the very specialized GM-1).

The one thing I don't understand about Forsazh is why it has a limit in altitude. Was it something to do with fuel/air mixtures? The way that the supercharger on the engine interacted with higher pressures at altitude? I have no idea.

Also curious... La-5FN prototype... I know it was hand built but how different was it from a stock performance version from middle to late 1944? I was figuring that unless weight was substantially different (i.e. due to inclusion of standard equipment like guns, ammo, radio, etc.) it should be fairly similar to the later models that the game represents. The 1943 tag next to the La-5FN should probably be changed to 1944.

[horseback]

Also curious... La-5FN prototype... I know it was hand built but how different was it from a stock performance version from middle to late 1944? I was figuring that unless weight was substantially different (i.e. due to inclusion of standard equipment like guns, ammo, radio, etc.) it should be fairly similar to the later models that the game represents. The 1943 tag next to the La-5FN should probably be changed to 1944.Generally, prototypes are handbuilt byskilled & experienced workers in close collaboration with the design engineers. Chances are that the early production La-5s, in many cases built from LaGG-3 airframes and parts lacked the fit and finish that makes an aircraft that last 10-30 mph faster.

When we talk about production models, you have to consider what conditions the work force operated under, how long they had been on the job, and how well the plant is run. In the US and Britain, early war production was performed in many cases by workers relatively inexperienced in the higher quality demands of aviation construction, but they were largely well supervised and worked in (generally) safe and secure facilities, so they improved rapidly and by mid-war, the vastly increased production quality was as good as or better than the pre-war 'artisan' standard.

Mid-war, probably most of the Soviet aircraft production was coming out of factories that had literally been picked up and moved a thousand kilometers or more just a few months earlier; the workers were often plucked off of the local farms and towns and had nothing like industrial experience and education to draw from, so they had to learn from 'scratch' and the surviving workers from the original facilities had to supervise them closely. The facilities where they worked were not as 'complete' as the ones that originally built that bureau's aircraft, and were considerably less comfortable and safe than their Western counterparts. It took them a bit longer to get their standards up to pre-war levels, and given where most of them started and the conditions they worked under, it was an exceptional achievement that they did so by the end of 1943/early 1944.

Japanese and German production quality appears to have gone the other way; the attrition of skilled workers to military demands, material shortages and enemy attacks coupled with the growing dependence upon captive labor made their production quality increasingly worse, particularly for the Japanese (that fighting to the last man ethos cost them a great many skilled technicians who should have been evacuated when things looked bad).

cheers

horseback

[JtD]

Forsazh on the Ash-82 could only be used in first charger gear. The second gear could not handle the high boost. In game, there's no performance benefit due to the increased boost in second gear to mirror this, even though you can switch it on at all altitudes.

[MaxGunz]

Is that like switching on WEP before you cross 100% throttle?

[gaunt1]

Forsazh on the Ash-82 could only be used in first charger gear. The second gear could not handle the high boost. In game, there's no performance benefit due to the increased boost in second gear to mirror this, even though you can switch it on at all altitudes.

I dont agree. For example, @ 5000m, according to IL-2 compare, La-5FN can reach 612 km/h with WEP. Just tried it myself, I also reached 612 km/h at that altitude. (10km/h faster than the best serial La-5FN tested by NII VVS)

Also curious... La-5FN prototype... I know it was hand built but how different was it from a stock performance version from middle to late 1944? I was figuring that unless weight was substantially different (i.e. due to inclusion of standard equipment like guns, ammo, radio, etc.) it should be fairly similar to the later models that the game represents. The 1943 tag next to the La-5FN should probably be changed to 1944.

Check attached NII VVS test chart. The prototype is named La-5 M-82FN SN39210102 It is almost 200kg lighter than a serial production version. It is even better than an early La-7! Ingame, the performance is between this, and the best performing serial plane, but usually closer to the prototype (SN39210495).

[MaxGunz]

612/602 = 1.0166.....

1.66 percent.

Oh, the horror!

Does it compare to the whining over it?

[gaunt1]

620 vs 640 @ 6km....

[JtD]

I dont agree.That doesn't matter - it's a fact. You should have checked the boost gauge. There's no Forsazh (1180mm)in second supercharger gear. All power and speed increases are related to increasing rpm from 2400 to 2500, something that was not impossible or forbidden to do with the original engine. The increased rpm have the main effect of increasing full throttle altitude and performance at high altitude.

[MaxGunz]

620 vs 640 @ 6km....

You need help with that?

[SadoMarxist]

As I've pointed out, the trim issue seems to be confined to a relatively small group of aircraft, and I've done extensive experimenting over the eleven years I've been playing this game and its predecessor with trimming methods and controllers. Button trim usually is the more accurate of the two, since it is input in quite tiny increments (about 160 clicks from one extreme to the other), and on most aircraft it is more than adequate, in the sense that you can get to a 'zone' where one more click up or down makes no discernible difference. However, on some aircraft the transition from one click down or one click up always seems to be excessive at any throttle/pp setting; you will either be climbing or losing altitude, in a slight skid or slide or rolling to one side or the other unless you hold your stick absolutely rock steady precisely at angle X/Y. On these same aircraft, I also notice that you need to trim precisely for very small changes in speed and power, or the penalties in performance and speed loss can be severe.



Since I've only ever used trim on a hatswitch this may not be helpful, while being aware that trim characteristics of some planes have become less benign, experimenting with the response curves of trimmers assigned to axes (polynomial curves of the second or third power, maybe even exponential) could yield good results. There are also four control profiles available to save one's configurations for different planes. Well, awfully sorry if this wasn't helpful.



Im not good at maths at all, so how is that working? Acceleration is proportional to excess power, or exponential?



While it would prove hazardous to claim the acceleration in level flight to be exponentially dependent on Ps, one could say that it is directly proportional to gravitational acceleration and inversely proportional to the airspeed at the same time, at the alt and airspeed for which the Ps value is known. MaxGunz and FatCat have explained things wonderfully.



Because if we take the factors above into account, I think it should have only about 15-20% better acceleration, for example 270 to 500 should take about 44-48 seconds, not 36.



Just going from IL-2 Compare graphs, at sea level, that's exactly what the difference is: about 20% without WEP on and 15,something% with it... admittedly, I haven't done any tests myself.



LOL, thanks for the comedy! I couldn't resist adding a line!



:)

[IceFire]

I dont agree. For example, @ 5000m, according to IL-2 compare, La-5FN can reach 612 km/h with WEP. Just tried it myself, I also reached 612 km/h at that altitude. (10km/h faster than the best serial La-5FN tested by NII VVS)



Check attached NII VVS test chart. The prototype is named La-5 M-82FN SN39210102 It is almost 200kg lighter than a serial production version. It is even better than an early La-7! Ingame, the performance is between this, and the best performing serial plane, but usually closer to the prototype (SN39210495).

200kg lighter would definitely be giving a different performance level. Certainly.

[horseback]

Here's the latest: Mustangs (all of them) at 100M. There's a clear difference between the razorback and the bubbletops at this alt; also, if you take another look at the FW 190A series chart, you'll see that between around 400-540kph, the Butcherbird is a bit quicker than the Mustang, although the D model Ponies (eventually) have a higher top speed.

In the works: Jugs & Lightnings, mid & early war Spitfires and 109s at 100m.

Now if you will all excuse me, I'm going to ice the thumb I use for trimming.

cheers

horseback

[Wea0versd]

I will be happy to answer questions or provide the charts showing direct comparisons of given types if I have tested them.http://fulton.acswomen.com/01.jpghttp://fulton.acswomen.com/02.jpghttp://fulton.acswomen.com/03.jpghttp://fulton.acswomen.com/04.jpghttp://fulton.acswomen.com/05.jpg

[gaunt1]

Thank you again Horseback! :)

Just going from IL-2 Compare graphs, at sea level, that's exactly what the difference is: about 20% without WEP on and 15,something% with it... admittedly, I haven't done any tests myself.


How can I check that? Is there an update/patch that adds acceleration graph? My version (4.11) has only summary, speed, rate of climb, ROC vs climb speed, turn time and fan plot.

[majorfailure]

Thank you again Horseback! :)



How can I check that? Is there an update/patch that adds acceleration graph? My version (4.11) has only summary, speed, rate of climb, ROC vs climb speed, turn time and fan plot.

I think initial acceleration is roughly proportional to max RoC.

[MaxGunz]

I think initial acceleration is roughly proportional to max RoC.

As Far As I Can Tell Right Now:

As long as you can hold TAS steady, Ps = change in height / change in time.

And there's correction for when you can't that with 10/sec data rate from devicelink should be possible to get closely.

See equation 7.2 on page 14 of this PDF:
http://www.aviation.org.uk/docs/flighttest.navair.navy.milunrestricted-FTM108/c7.pdf

When change in TAS = 0, the correction factor goes away. A tiny change in TAS at low airspeed will make a small correction necessary.

Ps =dh/dt + VT / g * dVT / dt

where
d is "change in"
h is height
t is time
VT is TAS
g is gravity

dVT being change in TAS, if it is 0 then everything past dh/dt is 0

I have found close to steady IAS climbs to be easier to fly in IL2 than trying to keep level at full power from 200 kph to full speed.

Remember that Ps changes with both speed and alt. Whatever tests are run need to cover as much of the range as you want to chart. You don't have to get speed at every last kph or alt at every meter but the closer you get the smoother/more accurate your connect-the-data-dots curves will be.

That's as good as my NOT-AN-AE-SELF can do right now, the simple things.

[SadoMarxist]

Quote:
Originally Posted by gaunt1 View Post
Thank you again Horseback!



How can I check that? Is there an update/patch that adds acceleration graph? My version (4.11) has only summary, speed, rate of climb, ROC vs climb speed, turn time and fan plot.

I think initial acceleration is roughly proportional to max RoC.


Exactly. The climb vs TAS diagram for a certain altitude also represents the Ps diagram for that altitude. To get the exact value of acceleration an aero plane can have in level flight at a certain altitude and airspeed multiply Ps value for said altitude and airspeed by gravitational acceleration and divide it by airspeed. Comparison of the ability of two aircraft to accelerate in level flight takes only a look at the ROC vs airspeed diagram in IL- 2 compare with the two aircraft selected: that which can out climb can also out accelerate. To express that in percents for a certain airspeed just calculate the percentage of advantage in ROC one aero plane holds over the other. Off course, we only have these diagrams available for sea level, but MaxGunz already explained this.

[MaxGunz]

I thought we only have them for 1000m.

But for many speeds at whatever alt we can compare FW accel to other planes *at the same speed*.

For the math challenged who can use the Windoze calculator, if you take the speed of the faster plane and divide by the speed of the slower plane then subtract 1 and multiply the result by 100 you will get the percent that the faster plane is faster.

640 / 620 = 1.032258064516129032258064516129

subtract 1 to get .032258064516129032258064516129

times 100 is 3.2258064516129032258064516129

640 is 3.2% faster than 620.

Comparing acceleration is the same way only it's acceleration, not speed.

Now repeat after me: The Sky Is Falling! The Sky Is Falling! It's A Conspiracy! The Sky Is Falling!

[gaunt1]

According to that formula, La-5FN acceleration is 55.555...% better than La-5F. I think 15-20, maybe even 30% would be acceptable for a meager 150hp more powerful engine + a tiny little less drag (but 60-100kg higher weight). If you check NII VVS tests, you can see maximum 20-25% improvement in other performance charts, (speed, climb, turn time) nowhere near the 55%. Obviously prototype performance. If you still think this isnt suspicious...

[majorfailure]

According to that formula, La-5FN acceleration is 55.555...% better than La-5F. I think 15-20, maybe even 30% would be acceptable for a meager 150hp more powerful engine + a tiny little less drag (but 60-100kg higher weight). If you check NII VVS tests, you can see maximum 20-25% improvement in other performance charts, (speed, climb, turn time) nowhere near the 55%. Obviously prototype performance. If you still think this isnt suspicious...

I really don't see where your 55% come from, from il2compare I get climb at sea level La-5F: 17.5 (21.5 with boost) and La-5FN 21.2 (25.3), which both is around 20% better acceleration for La-5FN

[SadoMarxist]

According to that formula, La-5FN acceleration is 55.555...% better than La-5F. I think 15-20, maybe even 30% would be acceptable for a meager 150hp more powerful engine + a tiny little less drag (but 60-100kg higher weight). If you check NII VVS tests, you can see maximum 20-25% improvement in other performance charts, (speed, climb, turn time) nowhere near the 55%. Obviously prototype performance. If you still think this isnt suspicious...

I'm starting to wonder whether I'm reading the charts correctly as the ROC advantage the La- 5FN holds over the La- 5F appears to be 4 m/s at it's greatest. At 280 km/h the rate of climb of La- 5FN is 22 m/s, while the La- 5F has the rate of climb of 18 m/s. That hardly constitutes a 50% advantage. 27 m/s of ROC for the La- 5FN would constitute that. This conclusion was reached by looking at the Airspeed vs ROC diagram in IL- 2 Compare, which doesn't include ROC with WEP used. Altitude vs ROC does (darker lines), and the best climbing speeds at sea level appear to be 25,3 m/s for the La- 5FN and 21,5 m/s for the La- 5F, which is, once again, between 15% and 20%.

[SadoMarxist]

I really don't see where your 55% come from, from il2compare I get climb at sea level La-5F: 17.5 (21.5 with boost) and La-5FN 21.2 (25.3), which both is around 20% better acceleration for La-5FN

Beat me to it :)

[MaxGunz]

Ps is for both altitude and speed.

There is no one ratio at any height that expresses La5 vs La5FN.
Even worse is trying to nail one number as the complete plane vs plane comparison.

I have IL2Compare 4.07m. I never bothered to upgrade since because why?

La5 at 0m alt ROC at TAS 280 kph is about 18 m/s and La5FN about 22.
La5 at 0m alt ROC at TAS 400 kph is about 12 m/s and La5FN about 16.
La5 at 0m alt ROC at TAS 500 kph is about 2 m/s and La5FN about 7.

La5FN to La5 Ps ratios?

At 280 kph, 122%. At 400 kph, 133%. At 500 kph, 350%.

FWIW, playing on performance margins is and has been part of aerial combat since fighter pilots noticed such margins in WWI.

And once you get over the charts (some never do) you might realize that what Pilot A can do in Plane X vs what Pilot B can do in Plane Y is -part- of the real difference with start conditions able to overturn that which is why aerial combat tactics always begins with initial positioning and speed.

IL2 has high realism. History tells of whining fighter pilots, at least in the USAAF where they wouldn't get shot for it.

[JtD]

At 280 kph, 122%. At 400 kph, 133%. At 500 kph, 350%.Highlighted for importance.

[SadoMarxist]

Ps is for both altitude and speed.

There is no one ratio at any height that expresses La5 vs La5FN.
Even worse is trying to nail one number as the complete plane vs plane comparison.

I have IL2Compare 4.07m. I never bothered to upgrade since because why?

La5 at 0m alt ROC at TAS 280 kph is about 18 m/s and La5FN about 22.
La5 at 0m alt ROC at TAS 400 kph is about 12 m/s and La5FN about 16.
La5 at 0m alt ROC at TAS 500 kph is about 2 m/s and La5FN about 7.

La5FN to La5 Ps ratios?

At 280 kph, 122%. At 400 kph, 133%. At 500 kph, 350%.

FWIW, playing on performance margins is and has been part of aerial combat since fighter pilots noticed such margins in WWI.

And once you get over the charts (some never do) you might realize that what Pilot A can do in Plane X vs what Pilot B can do in Plane Y is -part- of the real difference with start conditions able to overturn that which is why aerial combat tactics always begins with initial positioning and speed.

IL2 has high realism. History tells of whining fighter pilots, at least in the USAAF where they wouldn't get shot for it.

I guess I still prefer to have some idea where one fighter can outperform the other, but I guess that's why I'll never get over the charts. Off course, nothing beats experience :) .

[IceFire]

I guess I still prefer to have some idea where one fighter can outperform the other, but I guess that's why I'll never get over the charts. Off course, nothing beats experience :) .

Having that knowledge gets you started I feel. It's good to know your opponents potential... but if that potential is exploited is another story altogether, isn't it?

[MaxGunz]

Back when I first started getting online plus about a year this new game came out, Red Baron 2. I got it in Feb 1998 and while searching for info I found the Flight Sim Forum at Delphi and so began my entry into the Flight Sim Community that had been going on for years already.

One of the old terms in the community was "Spit Dweeb". I think it originated in either the Air Warrior or Aces High, or both, community.

A Spit Dweeb is a player that grabs the "best plane" and expects to always have the upper hand. Then when they get out-flown or out-anything especially if they get shot down, they go up on a forum and say the game is wrong.

Charts are great. I love them. But I don't have steady enough hands or the 'flying skills' to make them so that leaves me knowing that plane X under my control is not going to do as well as a better flier in plane X.

[Cloyd]

Hey Horseback,

Thanks for your work on this. As a crap plane enthusiast, your exercise for me is academic at best - I'm always going to end up in the slower, lower airplane. ;-) But I do appreciate your work on actual in game data.

Cloyd

[horseback]

Okay, here's the final installment in the 100m series: late war USAAF, Mid war Spitfires and the Mid war Bf 109 series.

I added the Mustang III and the P-47D (Late)to the USAAF fighters out of curiosity; I normally avoid the 'pumped up' stuff unless I feel that the original offering was less than accurate. I must say that the rankings of the US fighters seems a bit off; the P-38 should be the champion at all altitudes, at least from start (170mph) to about 350 mph indicated, so the L (Late) sort of restores the natural order. Every resource I have says that this was the case, and that the P-47 and the Mustang were neck-and-neck once the Jug finally got a propeller worthy of the R-2800. The P-47M was supposed to be faster to accelerate than the D/K Mustangs (when it worked). Bear in mind that both the Lightning and the Jug used turbosuperchargers, which allowed them to use every bit of the engines' horsepower from the ground right up to around 30,000 ft, so their performance in terms of IAS was fairly consistent.

Note also that the D model Mustangs are significantly superior to the razorback versions (less the Mustang III) at low levels; this is consistent with the fact that the earlier models were optimized for high altitude, so if you're going to take it down in the weeds, a bubbletop is the better choice.

As for the Bf 109s, I should point out that for the G-2 I experimented with closing the rads once I reached about 400 kph indicated but left them in Auto for the G-6. The G-6 rarely overheated, but the G-2 would overheat pretty quickly once the rads were closed--the payoff is that you will get faster sooner. Note that in every case, the automatic transmission of the LW fighters makes them initially slower to accelerate than their Allied counterparts, but once the transition is made, the speed can pick up quickly.

One of the things this project has helped me with is to identify not only which aircraft have the better response in terms of power (and where), but which ones handle better, i.e., which ones require less trim or have the more reliable instrument displays (critical for flying level or in proper trim). Being aware that the 'ball' has to be offset a bit to one side or the other in some aircraft in order to be properly trimmed is a handy thing to know. I'm probably a much more effective pilot as a result.

Next stop: 5000 feet or around 1500m.

cheers

horseback

[gaunt1]

I really don't see where your 55% come from, from il2compare I get climb at sea level La-5F: 17.5 (21.5 with boost) and La-5FN 21.2 (25.3), which both is around 20% better acceleration for La-5FN

Please... Check the ACCELERATION chart made by HORSEBACK. (page 6, post # 44) It clearly shows the insane advantage of the FN over the F. For example, 270 to 500 km/h takes 56 seconds for F, and 36 seconds for FN. Thats 55.5% better performance.

[FC99]

Please... Check the ACCELERATION chart made by HORSEBACK. (page 6, post # 44) It clearly shows the insane advantage of the FN over the F. For example, 270 to 500 km/h takes 56 seconds for F, and 36 seconds for FN. Thats 55.5% better performance.
JtD already pointed at something important in post #100 of this thread,I'll repeat it again.


La5FN to La5 Ps ratios?
At 280 kph, 122%. At 400 kph, 133%. At 500 kph, 350%.

[MaxGunz]

Highlighted for importance.

La5FN to La5 Ps ratios?
At 280 kph, 122%. At 400 kph, 133%. At 500 kph, 350%.

Keep in mind that the last ratio is between La5 being near to zero climb at 2 m/s and La5FN at 7 m/s. The absolute differences all down the curves run La5FN as from 4/ms to 5 m/s more even though the ratios change so greatly.

Besides, the real shock is when the La5FN can still climb while the La5 has to fly a shallow dive to keep the same speed.

Compare a FW190A-3 to a contemporary Spit VB. Tactic for the 190 is to force the Spit to higher speeds. Tactic for the Spit is to force the FW to turn.

[MaxGunz]

Please... Check the ACCELERATION chart made by HORSEBACK. (page 6, post # 44) It clearly shows the insane advantage of the FN over the F. For example, 270 to 500 km/h takes 56 seconds for F, and 36 seconds for FN. Thats 55.5% better performance.

Does someone have to walk through how acceleration, distance and time relate?

I can't promise you'll get it. If you're lost at ratios then squares and roots will look like tricks.

Sorry but I stuck with math for years to understand how I do, what I do. It's not an insane advantage that you're seeing. It's to be expected and understood and have tactics made on.

Last time I felt like this the 'issue' was over dive accelerations and the inability to dive beyond guns range from 100 m or less in a few seconds.

[majorfailure]

Please... Check the ACCELERATION chart made by HORSEBACK. (page 6, post # 44) It clearly shows the insane advantage of the FN over the F. For example, 270 to 500 km/h takes 56 seconds for F, and 36 seconds for FN. Thats 55.5% better performance.

You are making the mistake of assuming acceleration to be constant, but it changes with speed, and changes differently with each plane.
Use the ROC vs speed diagram in Il2compare and I bet it will fit the data okay.
Very rough comparison: La5FN flies 420kph at half time(18s), so lets compare acceleration at 420 to La-5F, ~15m/s to ~10m/s, so 50% better is okay.

[horseback]

Please... Check the ACCELERATION chart made by HORSEBACK. (page 6, post # 44) It clearly shows the insane advantage of the FN over the F. For example, 270 to 500 km/h takes 56 seconds for F, and 36 seconds for FN. Thats 55.5% better performance.I'd say that it's more like 55.5% better time. The lead one develops through each 10kph interval is added to the next one, and the next, sort of like compounded interest. If you have a power advantage of 20%, it is applied in each interval, and that advantage increases with every subsequent interval.

Acceleration is usually expressed in terms of both time and distance: some many meters per second per second (or per second squared). It is an ongoing process, and the primary limitation is air resistance, or drag, which increases as a cube of the velocity, if I remember correctly. In any case, you need exponentially more power to overcome drag as speed increases, which is why my charts depict curves instead of straight lines.

cheers

horseback

[MaxGunz]

There's 2 main kinds of drag operating here. A total drag graph is U shaped.

At lower speed **for the plane with wing loading a big factor** is induced drag. This is a real killer for the FW's until maybe 340-360 kph.

From middle speed on up, parasite drag goes up by squares, twice the speed is 4x the parasite drag even as induced drag falls due to lift squaring with increased speed allowing the nose to drop while keeping level flight. (trim)

Ps is excess thrust, total thrust minus drag. The faster a prop plane goes, the less thrust it has which is where the steepness of Ps curve at high speed sets in. It's not a constant minus the drag U but a downward slanted line minus the drag U.

I just had a look at La5F vs La5FN (IL2C 4.07m) and the La5F Ps curve looks the same as the La5 Ps curve when switching back and forth.

What's the difference between a Spit VB and a Spit LFVB besides supercharger?

At 240 kph, Spit VB = 13.5 -- Spit LFVB = 17.3 --- 128%
At 320 kph, Spit VB = 10.5 -- Spit LFVB = 15.5 --- 148%
At 400 kph, Spit VB = 3.8 -- Spit LFVB = 9.9 ------ 260%
At 430 kph, Spit VB = 0 -- Spit LFVB = 7 ----------- PWNED! :wink:
What % longer will the Spit VB take to reach 440 kph in level flight? If 50% longer is insane then what is forever?

[horseback]

What's the difference between a Spit VB and a Spit LFVB besides supercharger?

At 240 kph, Spit VB = 13.5 -- Spit LFVB = 17.3 --- 128%
At 320 kph, Spit VB = 10.5 -- Spit LFVB = 15.5 --- 148%
At 400 kph, Spit VB = 3.8 -- Spit LFVB = 9.9 ------ 260%
At 430 kph, Spit VB = 0 -- Spit LFVB = 7 ----------- PWNED!
What % longer will the Spit VB take to reach 440 kph in level flight? If 50% longer is insane then what is forever?Depends on the flavor of Mk Vb we're talking about; the early ('41) version has a bit less 'oomph' over all, the late ('42) version is essentially the same as the '43 clipped wing version with slightly less wing loading, and the Merlin 46 type has a different engine which is (I assume) optimized for high-medium alts.

Minor variations may be ascribed to my faults as a test pilot, or arbitrary decisions about averaging out the results of the four runs for a given type.

cheers

horseback

[MaxGunz]

Those are the ones in IL2Compare 4.07m, the last IL2C I have.

[IceFire]

Those are the ones in IL2Compare 4.07m, the last IL2C I have.

There's a 4.11 IL2 Compare kicking around. Haven't seen a 4.12 yet...

[Monty_Thrud]

There's a 4.11 IL2 Compare kicking around. Haven't seen a 4.12 yet...

http://forum.1cpublishing.eu/showthread.php?t=29744

Scroll down for 4.11

[MaxGunz]

I've had IL2C 4.11 and 4.07m for a while it turns out, just only a shortcut to 4.07m on the desktop. 4.07m version is off now, 4.11 link in place and holy cow now I see the confusion! I forgot about the rabbit Spitfire versions and now I have to wonder why is there no P-51D with empty fuselage tank and CoG to match? Then we could hear a new verse or chorus to 'stang-whining based upon stick forces too high.

[pandacat]

It's quite interesting to see post-510kph, 2700rpm actually accelerates faster than 3000rpm for p51c. Btw, do you have similar data on P51Ds? 5nt and 20na. I would expect slightly worse performance. Also, it's surprising to see 109G series has slower acceleration than mustangs given 109 has higher power to mass ratio.

[MaxGunz]

Consider how CSP's work in the case of the P-51.

[pandacat]

Consider how CSP's work in the case of the P-51.

But doesn't everybody else have CSP, too? Spit, 109, 190? Or P51's CSP is somewhat special? For spit and 109, it seems from the charts that 3000rpm always accelerates faster than 2700rpm

[MaxGunz]

At what speed and altitude? Compare the whole Ps graphs.

Consider the drag as size and coefficient, P-51 is bigger.

Where is the supercharger working best compared to the alt?

The speed of the plane has much to do with the optimal blade angle but mostly...

When you command more prop rpm than the plane has power to support, the prop will flatten a bit and you'll lose some thrust.

Most IL2 planes have some form of pilot-controlled CSP and some are even more automated though there are pre and early war models that don't have CSP all the way down to fixed props.

[horseback]

But doesn't everybody else have CSP, too? Spit, 109, 190? Or P51's CSP is somewhat special? For spit and 109, it seems from the charts that 3000rpm always accelerates faster than 2700rpmMustang's throttle is supposed to control manifold pressure directly, rather than just the amount of fuel going to the engine,as in other types. During the 10k tests, I ran the Spit IX LF at 2700 and 3000 rpm to see if there was a difference, and 3000 rpm was always superior at all speeds.

The Mustang is a bit different. If you look at the 10k charts, there is a point at which the Mustang at 2700 rpm will accelerate more quickly than at 3000rpm, and it reaches top speed much sooner after the three or so earlier 10 kph intervals. In the thicker air at 100 meters, this doesn't seem to happen, or at least it isn't as obvious.

Currently building my 5k database, which will probably show a transitional difference somewhat less than the 10k tests for the Mustang at 2700 vs 3000rpm; it will probably be more pronounced at 15k and 25k.

cheers

horseback

[MaxGunz]

Would you need to do as much trim change in a constant TAS climb as you do in a constant height drag race? You'd probably use trim just to adjust IAS as needed every few 100 to 1000 ft.
Climb rate = Ps analog at 1 speed and many alts.

P-51 can climb at speeds the SpitIX can only be losing alt to maintain. Throw that in with the percentage statistics, performance has scale as well as percentages.

[FC99]

First of all, it is always appreciated and respected when somebody "do the walk".

Now the bad part.

1. This kind of tests is best done with the utility written for such purpose.
You can find it here.
http://lesnihu.wz.cz/autopilot/autopilot.html
It is easy to set it up and it will execute script which will control the plane instead of you. It is much easier to test planes that way and what is even more important this is way more precise and repeatable test method.

2. Flying the plane is just half of the job, second part is logging the flight parameters. You can do it your way but there is a better and easier way. Use UDPGraph, you can get various parameters on the screen and in the file.
Download it here:
http://avcpage.achilikin.com/il2dl/graph_en.htm

Once you get these two utilities working you will be able to watch TV while your PC is doing the work for you and as a bonus you will get much better results.

[Woke Up Dead]

There's still merit in doing it "by hand" though, Horseback made a lot of useful observations about the difficulty of trimming some planes as they accelerate. I am curious about how much difference trim makes though, maybe someone familiar with that tool could set up a similar test for a couple of the planes that Horseback thought were hard to trim to see how much better the results are.

[horseback]

First of all, it is always appreciated and respected when somebody "do the walk".

Now the bad part.

1. This kind of tests is best done with the utility written for such purpose.
You can find it here.
http://lesnihu.wz.cz/autopilot/autopilot.html
It is easy to set it up and it will execute script which will control the plane instead of you. It is much easier to test planes that way and what is even more important this is way more precise and repeatable test method.

2. Flying the plane is just half of the job, second part is logging the flight parameters. You can do it your way but there is a better and easier way. Use UDPGraph, you can get various parameters on the screen and in the file.
Download it here:
http://avcpage.achilikin.com/il2dl/graph_en.htm

Once you get these two utilities working you will be able to watch TV while your PC is doing the work for you and as a bonus you will get much better results.The whole point of this exercise is to do it by hand; if the average player cannot duplicate the results of the tests without a ton of specialized controllers, or be able to overcome some of the problems inherent in flying a given aircraft without many, many hours of practice, meeting the 'book' numbers is meaningless.

This highlights some of the reasons that the ai so consistently outperform human players in certain aircraft and why some aircraft that should have many more users based on their historical records are less successful with occasional users.

cheers

horseback

[FC99]

There's still merit in doing it "by hand" though, Horseback made a lot of useful observations about the difficulty of trimming some planes as they accelerate. I am curious about how much difference trim makes though, maybe someone familiar with that tool could set up a similar test for a couple of the planes that Horseback thought were hard to trim to see how much better the results are.
It's not about better results ( good pilot will do as good as AP), it's about consistency and ease of testing. And trimming issues are highly exaggerated, you can make good runs without messing with trim much, even in "hard to trim" planes. Just make a plane nose heavy before you start your run and you will not have any problem in making smooth run with minimal altitude deviation.

The whole point of this exercise is to do it by hand; if the average player cannot duplicate the results of the tests without a ton of specialized controllers, or be able to overcome some of the problems inherent in flying a given aircraft without many, many hours of practice, meeting the 'book' numbers is meaningless.

"Book" numbers are not what average pilots could do, they are what highly trained test pilots could do.

[horseback]

Originally Posted by Woke Up Dead
There's still merit in doing it "by hand" though, Horseback made a lot of useful observations about the difficulty of trimming some planes as they accelerate. I am curious about how much difference trim makes though, maybe someone familiar with that tool could set up a similar test for a couple of the planes that Horseback thought were hard to trim to see how much better the results are.

It's not about better results ( good pilot will do as good as AP), it's about consistency and ease of testing. And trimming issues are highly exaggerated, you can make good runs without messing with trim much, even in "hard to trim" planes. Just make a plane nose heavy before you start your run and you will not have any problem in making smooth run with minimal altitude deviation.
The trimming issues are generally pretty specific to a given aircraft and seem to be not just a matter of adding nose down trim; certain aircraft will consistently raise or drop their noses abruptly at certain speeds after an extended period of acceleration in level flight, even when you try it flying in the Wonder Woman view (which is the only view option that actually provides consistently accurate and timely climb/altitude and trim data). If you do your runs 'in the cockpit' as I do, shifts in AOA as speed changes make using outside reference points (like the horizon) impractical, and dishonest, inconsistent, illegible or slow Turn & Bank indicators, variometers, altitude indicators and artificial horizons make certain specific aircraft extremely difficult to keep level, when added to their trimming problems. Certain other aircraft of similar performance seem to need much less adjustment and have either consistent or particularly accurate in-cockpit instrument displays, some of them in direct contradiction to reports of the period.

In my opinion, many of the 'hard to trim' class seem to be hypersensitive to minor stick inputs as speed increases; I use the same low stick sensitivities for all aircraft testing, as well as 50% filtering, and attempting to maintain level flight in the 'hard to trim' group with the stick and pedals is just as difficult as trying to add or subtract elevator and rudder trim with button or axis inputs, and sometimes worse.
Originally Posted by horseback
The whole point of this exercise is to do it by hand; if the average player cannot duplicate the results of the tests without a ton of specialized controllers, or be able to overcome some of the problems inherent in flying a given aircraft without many, many hours of practice, meeting the 'book' numbers is meaningless.

"Book" numbers are not what average pilots could do, they are what highly trained test pilots could do.
Test pilots of the 1930s and WWII era were largely self-taught; actual 'training' and schools for test piloting came much later. Military training required a higher standard of precision than general aviation because the military required a level of teamwork and predictability between aircraft un-needed in civilian aviation. Generally, military testing showed much less optimistic results than the manufacturers' in-house tests in the 1930s and early 1940s.

Regardless, the "Book" numbers are a basis of comparison for the average pilots; if plane a can accelerate from 270 to 450 kph in under 40 seconds and plane b takes almost a minute with the same pilot, their "book" numbers should be at least proportional. When other factors intrude or are artificially injected, the proportional differences can get a little lopsided.

cheers

horseback

[MaxGunz]

And when you don't understand what's going on you can believe any conclusion you might come up with.

Now it's time for me to watch the new UFO's from Niburu video.

[sniperton]

Maybe I'm wrong, but it seems to me that you -- horseback and woke up dead on the one side, and FC99 and MaxGunz on the other -- grind in two mills. One issue is the performance of aircrafts optimally exploited by the AI, and another is the ability/inability of the human pilot to achieve that optimum using standard game controllers (i.e. a short stick), watching a monitor less than 90 cm in diameter, and relying on flight data as displayed on the cockpit gauges. These limitations on the human player's side vary from user to user, but still there they are, and should be addressed properly when we discuss 'realism' (whatever it means for us). 'Correct' flight performance is one issue, it's actual 'feasibility' is another. Simply because we don't use the same peripherals as the AI does or r/l pilots did.

[MaxGunz]

You don't represent me at all there.

As far as test pilots, historically less than 1% of all pilots make the cut mostly because of the discipline needed. Read up, a lot of WWII Aces tried for the job and didn't make it. And yeah yeah not all test pilots made good combat pilots if that's what it takes to stop the crying, but it takes the quality of a test pilot to fly the necessary tests. Chuck Yeager made it and was noted as a natural, the two jobs are not exclusive but talent and discipline are.

If during a run the plane goes up and down even 1 or 2 meters that will change the acceleration and trim state. By the time the plane has come back down it's going to look like a sudden change. Sound familiar? Guess why I quit trying to make test runs? I'm not good enough!

From what I have read of the pro books, it takes several flights to get one segment of a test done right and many segments to make a total run. They don't just firewall it from stall and burn till top end a few times then land for beer and number crunching.

Well, what Horseback is doing is still way better than steep dive yanked into climb and then however long it takes to get down to just over 109 steady climb speed is where you call it done - check the height - claim FM bias as suspected not like the "test" wasn't set up to do just that.

[RPS69]

Maybe I'm wrong, but it seems to me that you -- horseback and woke up dead on the one side, and FC99 and MaxGunz on the other -- grind in two mills.

Nope, TD only tries to use a common reference for everybody, and they need to use a criteria and stick to it, even if some other resources says something is different.

Whenever you attack a particular set of aircrafts from a different resources, if they agree to changeit, you are opening the door for someone else to claim another resource for another particular set of aircrafts.

Let them stick to what they decided as a normal path, just try to give support on bizarre things, and improving some effects implementations.

[sniperton]

If during a run the plane goes up and down even 1 or 2 meters that will change the acceleration and trim state. By the time the plane has come back down it's going to look like a sudden change. Sound familiar? Guess why I quit trying to make test runs? I'm not good enough!

You're not good enough, OK. I'm not good enough, OK. My point is different: under the given circumstances mentioned in my post, is there any living human (could there be any living human) who could be good enough to make the trick? Don't misunderstand me, I don't have problems with aircraft performances, and I don't complain for this or that plane being 'porked'. I simply try to draw attention to an important factor of the game beyond maths: there's a gap between 'objective' values (which I don't dispute) and how far they are practically relevant for the player. They are 'reference values', that's OK. But we can move one step further and ask why the player (you and me) is not good enough to achieve them. My problem relates to the way we communicate with the game engine and not to the parameters it is programmed to work with. :)

[MaxGunz]

So get a Volvo universal joint, about 5 meters of square steel tubing, a seat, various other hardware bits and some electronics and wire then do the cutting, bending and welding and you can join the elites who have.

IRL test pilots did and do fly the tests.You and I are not test pilots and probably never could have been. We're not theoretical physicists either, or gold medal downhill skiers or heavyweight boxing champions. I for one am totally unsuited to be a playboy bunny for at matters.

It's more important for online combat to have good SA than to be able to squeeze the most from your plane. It's more important to have a good wingmate that you act in unison with. It's even more important to be a hotshot marksman than to close the last few percent in pilot skills.

IL-2 is not a test pilot game, it's a fighter pilot game.

[sniperton]

So get a Volvo universal joint, about 5 meters of square steel tubing, a seat, various other hardware bits and some electronics and wire then do the cutting, bending and welding and you can join the elites who have.

It's more important for online combat to have good SA than to be able to squeeze the most from your plane. It's more important to have a good wingmate that you act in unison with. It's even more important to be a hotshot marksman than to close the last few percent in pilot skills.

I basically agree, but I put the emphasis elsewhere. Our personal performance and 'feel of flight' is affected by three factors: 1) the potential flight performance of our plane as best exploited by the AI and represented in test charts; 2) our personal skills as listed by you; and 3) the ways and means we apply our skills to the game via various peripherals. This latter is very much compromised and gives a huge 'deadband' as to personal performances: no wonder that some people build custom cockpits to narrow this deadband (exactly what you suggested ironically), and remember how much advantage 6DoF gives over the hat switch. My point is that this No. 3 affects our experience much more than a few kph's change in No. 1, so that it would make much more sense to discuss the 'realism' of peripherals and displays than the 'realism' of the charts.

[JtD]

If the potential flight performance is best exploited by AI, how come I can beat them 9 out of 10? They don't even know how to properly use radiator and pitch.

[MaxGunz]

Let me start with the end which is:
I'm not complaining but I am pointing out why some of the conclusions I've seen in this thread are wrong.

My point is that this No. 3 affects our experience much more than a few kph's change in No. 1, so that it would make much more sense to discuss the 'realism' of peripherals and displays than the 'realism' of the charts.

As far as the game goes that is true. But when we try and determine the performance of the game's models and start interpreting results of flaws in our procedures as flaws in the model then it's something else.

IMO this stems from fantasies about Ace pilots and becoming one in-game. At the heart of most FM-whining posts I've seen there is the assumption that the player is test-pilot good and has an absolute understanding of everything that happened in whatever event set them off, point of view and what they didn't see having no effect on their omniscience. It must have happened as, how and why they think it did.
Accounts from WWII pilots are taken as absolute truth to the tiniest detail. If the pilot said it was a Tiger tank then it was regardless of the times when USAAF pilots strafed and bombed Shermans, all the data that says NO is ignored while data that says YES or even MAYBE is taken as absolute support.

Especially in more arcade flight sims ( pretty much all sims I had before 1998 ) it was -easy- to be a top pilot and shooter too. Table driven sims got you there almost automatically. Even IL-2 which is *not* perfect now added whole not-before-included factors as of 4.0 that didn't get complimented by a different control interface method until 4.07.

I consider it a benchmark when a sim includes factors that players have to learn and get used to to even begin to get near top performance.

IRL I spent hours trying to hold a plane +/- 50 ft in steady level flight. I did manage that and note that speed changed more than a couple knots the whole time. A real pilot with more time would hold the porpoising down closer to zero and might get there or really damned close for a short time but how many can stay within 1 meter long enough to pull reliable data out while changing speed?

Now imagine anyone trying to get it exact for a whole full power run from stall to top speed and being so confident in their flying that they use data derived from that to point out flaws in the plane? The difference in gear or whether the pilot is sitting in a moving plane or a chair behind a desk goes not cover the similarity of trying to do that IRL or in game, the only difference is in chutzpah.

We've seen much worse. We've had G... and T... and The Joke who went beyond honest I-didn't-know mistakes to full blown BS creation so:

I'm not complaining but I am pointing out why some of the conclusions I've seen in this thread are wrong.

[sniperton]

If the potential flight performance is best exploited by AI, how come I can beat them 9 out of 10? They don't even know how to properly use radiator and pitch.

I, too, can beat the AI thank to my superior intelligence. ;)
What I can't do is to fly and land my fav plane as smoothly as the AI does. :)

[sniperton]

As far as the game goes that is true. But when we try and determine the performance of the game's models and start interpreting results of flaws in our procedures as flaws in the model then it's something else.
I'm not complaining but I am pointing out why some of the conclusions I've seen in this thread are wrong.

As you might have seen, I'm not really interested in minor performance issues, which I regard secondary in importance. What I'm interested in are the reasons behind the 'flaws in our procedures' -- yours and mines. Many of our flaws, I believe, have something to do with the game interface being 'realistic' in a questionable way. E.g. the 'realistic' image of a cockpit, as we have it on our monitor, is rather unrealistic and mutilated if compared to the full visual perception one might have in that cockpit. Imagine you have to drive your car relying on the image of a single board camera. The image you get is 'realistic', but the visual experience is not. Discussing and debating such issues would be probably more useful than adjusting the charts IMHO.

[MaxGunz]

As you might have seen, I'm not really interested in minor performance issues, which I regard secondary in importance. What I'm interested in are the reasons behind the 'flaws in our procedures' -- yours and mines. Many of our flaws, I believe, have something to do with the game interface being 'realistic' in a questionable way. E.g. the 'realistic' image of a cockpit, as we have it on our monitor, is rather unrealistic and mutilated if compared to the full visual perception one might have in that cockpit. Imagine you have to drive your car relying on the image of a single board camera. The image you get is 'realistic', but the visual experience is not. Discussing and debating such issues would be probably more useful than adjusting the charts IMHO.

I think we agree though I do feel that for really good reasons like there have been in the past, adjustments are warranted. I'd love to see a P-51D or two with empty or mostly empty fuselage tank!

The other issues I am used to seeing since I first got into the flight sim community back in 1998. They are definitely good topics and the discussions got lively at times even before the wow kind of stuff available now was ever known.

Yes, we as players are quite hampered, even with head tracking. That's one reason why I always stood for search keys, not everyone has head tracking (I never did).

There is the monocular view issue with canopy spars blocking view that would not be blocked with stereo vision. When IL-2 came out and during development average players didn't have enough video power to ghost the spars which while not perfect would help simulate stereo vision. This is something that IL-2 will probably never get.

We don't get any feel sitting in stationary chairs. IRL you can feel slip or skid as a pull to the side kind of thing. IRL you know when you're pulling G's, rising or descending, tilt, G-forces and turbulence.
In sims you have only visual cues and instruments. One major sim skill is integrating those into 'feel' where changes in speed or VSI or The Ball mean something just through practice.
And yes, this is also something that used to come up for discussion. What you brought up is kind of a minefield of topics that it's probably good to bring up now and again.

I can suggest some help with the regular joystick (I have an X52) which is to add a lot of FILTER to the pitch axis in the stick sensitivity screen. I mean like 40% or more. It doesn't add much delay to stick moves, a fraction of a second, but it will really smooth your flying out.

Another thing, and this takes loads of practice, is to not let yourself rest the weight of your hand or arm on the joystick. It's something you really have to work hard at catching yourself doing, especially when things get exciting. But when you do keep a light touch it pays off well in performance. Try flying no combat with just thumb and 1 or 2 fingers on the stick for a few minutes and see. What's worse than resting arm weight is the stick ham hand death grip that we all do at some time.
With a full length stick that doesn't matter as much but still a light touch is better just as IRL.

AI takeoffs and landings are scripted. The AI can't fly the models down near stall without rolling over and spinning. What I find amazing is how well the AI does fly the models at all. More than once I had urged that the AI's should fly table-driven models as IMO that would make the AI code simpler not just flying but for AI tactical planning and would nail down what the AI could do. It wouldn't take much to have a different table for each level AI.

[horseback]

Notes on USN/USMC Fighters tested @ 5K ft.

1. The early Wildcats seem to compare with what I know of their performance, not spectacular but stable; however, the FM-2, which was 500 lbs lighter & somewhat aerodynamically cleaner than the F4F-4, as well as enjoying a 160 hp power advantage at altitudes up to nearly 20,000 ft, is portrayed in-game as even more sluggish than its predecessors. I was so surprised by this, I ended up re-running the FM-2 to ensure that I hadn't left the landing gear hanging down or something, but it was just as sluggish and 'meh' as the first time. Historically, this was simply not the case. The FM-2 was widely acknowledged as the 'wilder' Wildcat; being lighter, cleaner and more powerful at low and medium altitudes, it had superior climb and acceleration, and a somewhat better top speed at low and medium altitudes. It was a much better match for the Zero, even the later models. Someone's got some 'splaining to do.

2. There is very little if any difference between the F4U-1/Corsair Mk I and the F4U-1A, which makes little sense, given the -1A's water injection and the fact that the runs made in the -1A were all much more level overall. The Dash 1A is ultimately faster once you reach 480 kph, but it should be no contest from the start. This just doesn't seem right. I also added the Dash 1D, and it has a noticeably better jump, but the same general top end.

3. Both models of Hellcat continue to be a huge letdown. With or without water injection, it is portrayed as a slug, and much slower than the official numbers I have found. A standard F6F-3 should be capable of 290 kts/330 mph true airspeed, or about 530 kph at this altitude. If the Wonder Woman 'speedometer' is correct, that would mean an IAS of about 470/480 kph in-game. The best level TAS I got from the F6F-3 was just over 510 kph, and the best level TAS on the F6F-5 was around 515 kph, or about 460 kph indicated for both. Again, there was very little difference in acceleration between the two, in spite of the extra 200 hp or so that the water injection of the Dash 5 is supposed to have. Again, I re-ran the Dash 5 to make sure that I hadn't done something wrong. The main difference is in top speed, but from 270 to 380 IAS indicated, there is no difference.

cheers

horseback

[JtD]

The problem with the F4F is twofold, first, the FM-2 appears to be indeed slightly undermodelled, and second, the F4F-3 and F4F-4 are modelled very generously, climb rates exceeding documented data in the region of 20%. This turn historical relations upside down.

Which charger gears were you using for the F6F and F4U?

[sniperton]

Yes, we as players are quite hampered, even with head tracking.

There is the monocular view issue with canopy spars blocking view that would not be blocked with stereo vision.

We don't get any feel sitting in stationary chairs. IRL you can feel slip or skid as a pull to the side kind of thing. IRL you know when you're pulling G's, rising or descending, tilt, G-forces and turbulence.

In sims you have only visual cues and instruments. One major sim skill is integrating those into 'feel' where changes in speed or VSI or The Ball mean something just through practice.

And yes, this is also something that used to come up for discussion. What you brought up is kind of a minefield of topics that it's probably good to bring up now and again.

I think it's clear that G-forces and the rest you mentioned are simply outside the scope of a sim, at least under armchair conditions. Still, they too can be transformed or translated into visual cues, something like as Wonder Woman View does (surely a bit too generously). WWV is a constructed image which makes a wide range of sensual information available in visual form, and in this sense it's more realistic than a faithful camera image which filters out all non-visual sensual input.

Now turning to the purely visual cues one might have in a RL cockpit, I feel that they too are rather compromised in the 'faithful' camera image we have. Even with a TIR you need several huge monitors to have everything relevant appear in a meaningful distance and a meaningful size (and with the use of huge monitors we have already left the realm of 'airmchair conditions', btw -- ask the wife ;)). The instruments are too close and the skies are too far, and the camera view with its zoom function can hardly replicate the ease the human eye and mind adjusts itself to the task IRL. My solution would be a third type of view with a split screen with fixed FOV for both the static lower instrument part and the dynamic upper combat part (with some zoom allowed when using gunsight view). Just an idea, don't kill me :)

[jameson]

Horseback, you should check the 109g6 if it's an ingame porked fm you're looking for. Real life figures according to Kurfurst's 109 site of 1.3 ata and 2600 rpm at 480m should give 530kph. At emergency power (110%) a g6 should do 590kph at sea level. Kurfurst believes that the 530kph @ 1.3ata on the deck (480m if we're nitpicking!) was the defacto acceptance test for the Luftwaffe of this aircraft, if it couldn't do it, it went back to the factory. The only performformance plot I seen, again on K's site, that comes near the ingame performance is of a g6 carring a full 300litre droptank. I live in hope that someday it's performance ingame will be "historical", but nobody seems all that bothered about fixing it.

[JtD]

There's a gazillion of tests showing 520-530 kph on the deck for G model 109's at combat power. Now if you were to use the emergency power (1 minute time limit) to increase that speed, you'd end up at around 540-550. Not that you'd get there within a minute. 590 is totally out of question, unless you're using MW50. You'd need about 1800-1900 hp to achieve that speed.

[majorfailure]

Notes on USN/USMC Fighters tested @ 5K ft.

1. The early Wildcats seem to compare with what I know of their performance, not spectacular but stable; however, the FM-2, which was 500 lbs lighter & somewhat aerodynamically cleaner than the F4F-4, as well as enjoying a 160 hp power advantage at altitudes up to nearly 20,000 ft, is portrayed in-game as even more sluggish than its predecessors. I was so surprised by this, I ended up re-running the FM-2 to ensure that I hadn't left the landing gear hanging down or something, but it was just as sluggish and 'meh' as the first time. Historically, this was simply not the case. The FM-2 was widely acknowledged as the 'wilder' Wildcat; being lighter, cleaner and more powerful at low and medium altitudes, it had superior climb and acceleration, and a somewhat better top speed at low and medium altitudes. It was a much better match for the Zero, even the later models. Someone's got some 'splaining to do.
Again: Just because an an engine model does more hp at some alt, it does not mean it does more hp at any alt. 5kft is near FTH of first stage of F4F -good alt for it. Try at 5km alt - FM-2 will be better than F4F.


3. Both models of Hellcat continue to be a huge letdown. With or without water injection, it is portrayed as a slug, and much slower than the official numbers I have found. A standard F6F-3 should be capable of 290 kts/330 mph true airspeed, or about 530 kph at this altitude. If the Wonder Woman 'speedometer' is correct, that would mean an IAS of about 470/480 kph in-game. The best level TAS I got from the F6F-3 was just over 510 kph, and the best level TAS on the F6F-5 was around 515 kph, or about 460 kph indicated for both. Again, there was very little difference in acceleration between the two, in spite of the extra 200 hp or so that the water injection of the Dash 5 is supposed to have. Again, I re-ran the Dash 5 to make sure that I hadn't done something wrong. The main difference is in top speed, but from 270 to 380 IAS indicated, there is no difference.

cheers

horseback
At http://www.wwiiaircraftperformance.org/f6f/f6f.html I can find only 315mph at 5kft for an F6F-3 without water injection. Other tests are either with water injection, do not cover that alt or are not fully loaded fighters.

http://www.wwiiaircraftperformance.org/f6f/f6f-3-02982.pdf
is interesting because it states that early F6Fs were problematic to rudder trim in a power climb.

[MaxGunz]

Water injection in game is with WEP?

[jameson]

"There's a gazillion of tests showing 520-530 kph on the deck for G model 109's at combat power."
JtD, lol. Try it ingame and let us know how fast you can get it, 480? if that? At 110% I get sometimes 520ish...
A minute of climb at 110% in a fight can be an awfully long time and would be even better if ingame matched RL "historical" peformance. If it did there'd also be more grunt throughout the power curve ingame. Takeoffs would start to get very interesting with correctly modelled torque. Forget to lock the tail wheel in RL and the rudder couldn't stop it making a left turn, with usually fatal results... Ingame?
Gunz I believe that WEP is water injection, it may be in the manual, been a while though since I read it.

[JtD]

"There's a gazillion of tests showing 520-530 kph on the deck for G model 109's at combat power."
JtD, lol.I was confirming what you said right there, but if you think you need to laugh about it, so be it.

[horseback]

The problem with the F4F is twofold, first, the FM-2 appears to be indeed slightly undermodelled, and second, the F4F-3 and F4F-4 are modelled very generously, climb rates exceeding documented data in the region of 20%. This turn historical relations upside down.

Which charger gears were you using for the F6F and F4U?I used the first stage (which should be analogous to 'Neutral' on the real things) blower for all the USN-USMC fighters; as I recall, the second stage shouldn't be engaged until about 8000 ft. Mixture was the standard 100%. While I have read that the superchargers had two gears for each stage, this doesn't seem to be modeled.

All of these aircraft seem to fall well short of generally accepted performance figures for speed at sea level and 5000 ft for military power (much less War Emergency Power), including the Wildcats, and the relationships seem a bit skewed. I would think that the Hellcat should initially be a good deal closer to the Corsair; the weight difference is not that great (with full internal fuel, some sources show the Corsair as the heavier of the two), they're using the same engines and drag shouldn't exert that great an influence until later in the speed range.

Interestingly, the top speed results I got for the F6F-5 are very close to numbers I have seen quoted for it carrying a drop tank and two 1000 lb bombs. Since the Corsair didn't 'officially' become equipped for bombs until the -1C/D models, I have no figures for a 'bombed up' Corsair until the we get to the -1C/D versions (and TBH, I haven't been looking).

Both models of the Hellcat and the later (-1A and later) Corsairs are recorded to have retained their drop tanks during combat on several occasions; their performance was sufficiently superior to the mid-war Japanese fighters that keeping the tanks was sometimes both possible and practical. I have to wonder if at least some of their numbers may be off because someone didn't notice the sets of numbers they were using included the belly tanks.

cheers

horseback

[JtD]

You'll need to engage low gear (2nd stage in game) in order to get any benefit from water injection. Both with and without water injection you're operating above full throttle altitude, where the benefit of water injection is nearly zero.

I would like to know what your "generally accepted" speed performance figures for the Wildcats are. I can tell you right now that they match or exceed the figures given in Americas 100000 as well as the figures quoted on ww2aircraftperformance.com.

F6F and F4U performance is modelled for clean aircraft.

[horseback]

Again: Just because an an engine model does more hp at some alt, it does not mean it does more hp at any alt. 5kft is near FTH of first stage of F4F -good alt for it. Try at 5km alt - FM-2 will be better than F4F. Every source I have shows the FM-2 superior to the F4F-3/4 up to around 18-20,000 ft. The same site you link has tests for both which indicates that the FM-2 at 5K will do a bit over 310mph, or within an eyelash of 500kph; the F4F-4 at 4500 ft is listed at 283 mph or 455 kph, a difference I consider significant.

At http://www.wwiiaircraftperformance.org/f6f/f6f.html I can find only 315mph at 5kft for an F6F-3 without water injection. Other tests are either with water injection, do not cover that alt or are not fully loaded fighters. I can't find much mention whether the engine was a plain vanilla -8 or -10, or a -8W or -10W, which indicates water injection, but it was not always noted back then. That still leaves the questionable performance of the F6F-5, which should do at least 330 mph at that altitude, or about 15-20 kph more than I could get in seven test runs.

http://www.wwiiaircraftperformance.org/f6f/f6f-3-02982.pdf
is interesting because it states that early F6Fs were problematic to rudder trim in a power climb. I don't know if you're a native English speaker, major, but we refer to this sort of thing as "cherry picking." I'm sure you'll find it a useful term;).

Like many high performance fighters, the rudder corrections for extreme changes in speed (as experienced in a sudden climb or dive) could not be rolled in quickly enough on the Hellcat, sometimes requiring the pilot to exert pressure on the rudder pedals; the same phenomenon was noted for the P-40, P-47, P-51 and the Corsair to some degree, much greater in the case of the P-40 (meaning that the Warhawk was a couple of orders of magnitude worse than the Hellcat), about the same as in the P-47 and less in the other types. If the rudder issues you refer to consist of the notation on page 8, it was a minor issue and quite acceptable (and clearly superior to the rudder input demands placed on a pilot flying a Bf 109 or FW 190). AFAIK, it was common to all models of the Hellcat, and considered a fairly mild vice.

Edit: The reason it was mentioned is that the original contract probably specified that rudder forces would be trimmable throughout the aircraft's performance (I'd have to re-read Tillman's book to be sure); this turned out to be impossible with the engine and propeller changes from the original R-2600 and Curtiss Electric combination envisioned for the Hellcat, so it was just noted and signed off on every acceptance test rather than go to the massively complicated task of revising all the contract documents in the possession of Grumman and the Navy Department (this was the age of hand-typed documents and carbon copies, remember; they hired thousands of young women to type and file and keep track of all the hard copies, and had warehouses full of the original documents) and getting them re-signed. I can tell you from personal experience that some government contracts still get this sort of standard waiver treatment for minor issues and that if the government rep who had to inspect the paperwork was transferred, you'd better be able to produce the original paper trail for his or her replacement.

cheers

horseback

[horseback]

You'll need to engage low gear (2nd stage in game) in order to get any benefit from water injection. Both with and without water injection you're operating above full throttle altitude, where the benefit of water injection is nearly zero.

I would like to know what your "generally accepted" speed performance figures for the Wildcats are. I can tell you right now that they match or exceed the figures given in Americas 100000 as well as the figures quoted on ww2aircraftperformance.com.

F6F and F4U performance is modelled for clean aircraft.The 'HUD' message telling you that water injection is engaged goes up even so. Who knew that the game would lie to me like that?:shock:

As mentioned in an earlier post, ww2aircraftperformance.com shows a test for the FM-2 with a level speed at 5000 ft of 312 mph true (502 kph); an F4F test for 4600 ft shows a true airspeed of 283 mph (455 kph).

Attached is a blowup of the chart from America's Hundred-Thousand for the Wildcats' various models' Speed and Climb performance, scanned from the book and then printed on graph paper in the forlorn hope that it would be made a bit clearer (Murphy made his usual appearance, alas). The FM-2's speed graph line is highlighted in pink, the F4F-4 is in blue and the F4F-3 is in green. As you can see, the FM-2's line at 5000 ft is clearly east of the 300 mph line, while the F4F-3/-4's lines are well to the west of it, around 285 mph.

I used the same references you claim you used.

cheers

horseback

[horseback]

"There's a gazillion of tests showing 520-530 kph on the deck for G model 109's at combat power."
JtD, lol. Try it ingame and let us know how fast you can get it, 480? if that? At 110% I get sometimes 520ish...
A minute of climb at 110% in a fight can be an awfully long time and would be even better if ingame matched RL "historical" peformance. If it did there'd also be more grunt throughout the power curve ingame. Takeoffs would start to get very interesting with correctly modelled torque. Forget to lock the tail wheel in RL and the rudder couldn't stop it making a left turn, with usually fatal results... Ingame?
Gunz I believe that WEP is water injection, it may be in the manual, been a while though since I read it.Try closing your radiators at about the time you hit 450 kph indicated; it will bump up your top speed and final stages of acceleration a bit, as long as you count to about 30 seconds or so after the overheat message pops up and then open them up and slow down.

I can't imagine adding RL levels of torque in the game at this point in its life; the 109 and P-40 would become almost impossible, never mind 'interesting', to land or take off for the vast majority of players.

Personally, I already have a full 'whine' cellar.:cool:

cheers

horseback

[JtD]

The HUD tells you the water injection is active because it is. It works above full throttle altitude. It did in real life. There's just no increased boost any more, and therefore there's no meaningful extra power. As it is in real life.

In game, the F4F manage around 295 mph at 5000ft. So clearly, the Wildcats do not "fall well short of generally accepted performance figures". Two of them are clearly overmodelled, and one of them falls "somewhat" short of generally accepted performance figures, and that not even at all altitudes. Unfortunately though, at the important ones.

[MaxGunz]

I can't imagine adding RL levels of torque in the game at this point in its life; the 109 and P-40 would become almost impossible, never mind 'interesting', to land or take off for the vast majority of players.

That's low speed nose high propwash. Use rudder, not side stick. Keep the prop revs high and power low in case you have to go around.

Funny thing how I read from guys allowed to try out a 109 because they qualify and still going off the strip just trying to take off the first time.

[Woke Up Dead]

The HUD tells you the water injection is active because it is. It works above full throttle altitude. It did in real life. There's just no increased boost any more, and therefore there's no meaningful extra power. As it is in real life.

I think IL2 Compare helps you figure out at what altitude boost no longer makes a difference. There are two lines on each maximum speed graph: the speed at 100% throttle, and the speed at 110%/boost. In some planes, like the Hurricane and Spitfire, the two lines meet at 4-5000m.

[majorfailure]

I can't find much mention whether the engine was a plain vanilla -8 or -10, or a -8W or -10W, which indicates water injection, but it was not always noted back then. That still leaves the questionable performance of the F6F-5, which should do at least 330 mph at that altitude, or about 15-20 kph more than I could get in seven test runs.
Most test documents state the engine the plane was equipped, if not usually it can be deduced from loadout given, there is some amount (16gallons?) of anti-detonant mentioned when water injection was used.

The document above states: "Rudder trim effectiveness was not sufficient to trim in the high power climb." If I get this correctly it means though FULL rudder trim was applied in a high power climb the plane still deviated from flying straight. So at least early F6F-3s were trim hogs in rudder when climbing with full power - and I doubt that later model F6F behaved much different - even if a larger trim tab or different rudder were added, changing from clevel flight to climb would still require lots of trim change in rudder.

Water injection does "move" the power curve towards more power AND towards lower alt. So while the F6F-3 will be faster with first stage of the charger at 5kft (FTH~1000m), the F6F-5 will be faster when water injection is engaged in the second stage at that alt.
Same for the Corsairs: F4U-1 in first stage and F4U-1A in second stage when using WI above~1000m.
Water injection will work and will use water/methanol mix in first stage though, BUT will not have much of an effect.

Just compare the two power curves of the F6F-3(without WI) and and the F6F-5 in IL2compare. (Or F4U-1//F4U-1a)

[jameson]

Horseback, thanks for the effort you've put into this thread and my apologies for hijacking it somewhat. Your suggestion regarding 109 radiators is noted and I'll give it a go. In RL according to Finnish 109 pilots. the effect on speed was pretty minimal to the point of not being noticed, whether rads were open or closed. If 109G6's ever get an fm makeover perhaps this'll get fixed as well.
There was a very early mod from the AAA days which did up the torque effects for the 109, how accurate it was I couldn't say, but slamming the throttle to the wall at take off wasn't wise as it did have a gap where the rudder was non resposive and if the tail was lifted too early it got a bit tense!

[horseback]

The HUD tells you the water injection is active because it is. It works above full throttle altitude. It did in real life. There's just no increased boost any more, and therefore there's no meaningful extra power. As it is in real life.

In game, the F4F manage around 295 mph at 5000ft. So clearly, the Wildcats do not "fall well short of generally accepted performance figures". Two of them are clearly overmodelled, and one of them falls "somewhat" short of generally accepted performance figures, and that not even at all altitudes. Unfortunately though, at the important ones.I used the term 'well short of accepted figures' for the Navy fighters as a group, which was a bit sloppy of me. The Wildcats are, however, shockingly sssllllloooooowwww by any measure; over 10 seconds to gain a bit over 6 miles an hour can seem like hours after testing the Corsair at sea level. When you're struggling to maintain level flight by detecting whether the altimeter needle is moving (the variometer is at least a second behind the curve), the intervals take forever to go by, and when you finally reach the point where there just ain't no more, you glance at the speedbar and think "WTF?"

Even if they are about 20 kph faster than they should be, that impression is hard to shake.

In any case, the FM-2 is poorly represented, and if former pilots' direct testimony to me is to be believed, the tall-tail Wildcat could accelerate with the Zeros and Oscars they encountered in the Marianas and the Philippines (the old guys picked out all of the Japanese fighters from my then-extensive collection of 1/72nd scale models and named each one --and corrected some of the color choices I made). Even accounting for the usual hypercompetitive BS factor present any time Navy veterans of any age meet, that means that like its climb, the FM-2's acceleration should be pretty good as well, even if measured against beat-up, poorly maintained A6M5s of the later war period. My former landlord said (realizing for the first time that my wife was present) that the FM-2 was "a he-heck of a lot uh, peppier than the Dash Fours or even the Threes."

If it was anything like the one we have in Il-2 '46, there wouldn't have been three 70-something year old men in my living room that day in 1985.

cheers

horseback

[horseback]

The document above states: "Rudder trim effectiveness was not sufficient to trim in the high power climb." If I get this correctly it means though FULL rudder trim was applied in a high power climb the plane still deviated from flying straight. So at least early F6F-3s were trim hogs in rudder when climbing with full power - and I doubt that later model F6F behaved much different - even if a larger trim tab or different rudder were added, changing from clevel flight to climb would still require lots of trim change in rudder.If you read my post containing the trim sections from America's Hundred Thousand, you'll recognize the passage below:

"There were nose up trim changes with gear and flap retraction, though they were minimal, and the same was true of initial acceleration into climb. In general, there were substantial both directionally and laterally with speed and power changes, but tab action allowed trimming out control forces to zero except for the rudder. At low speed and high power rudder pedal force could not be trimmed out fully. Most pilots thought trimmability was generally good, though some made the following comments ‘Lack of trimmability”, Excess rudder trim change”, and “Aircraft requires excessive trim” (three pilots). It was noted that in a dive control forces could not be trimmed out quickly enough."

Trim adjustment was a relatively new practice in military aviation in the early 1940s, and most American fighters appear to have had some points in their performance where full trim input did not completely wash out the need for a bit of rudder input, or where it couldn't be input as quickly as the demand increased. The extra amount of right rudder needed didn't result in the unbalanced muscular deformities claimed by long-time P-40 or Bf 109 drivers, so it wasn't a severe problem, but it was something that wasn't supposed to be there, according to either the original request for proposal or the resulting contract language for the F6F-1.

The phraseology used sounds like a standardized bullet point in the test documentation to my long time government contracting ears; I would expect that that phrase, or some minor variation of it is found in almost every Hellcat acceptance test document. Without it in there, a battalion of government bureaucrats would have had a near fatal case of the vapors, and the US war effort might have ground to a complete halt.

As I pointed out, the FW 190A and Bf 109 lacked any in-flight trimming capability for their rudders, even though rudder had to be added or subtracted as attitudes and speeds changed; does that mean that they were 'trim-hogs' in the rudder department too? I know that US pilots doing comparison tests of German aircraft were quick to criticize that particular feature of those aircraft, but that it didn't seem to limit their combat effectiveness.

So it was with the Hellcat.

I'll try using the second stage of supercharger with the Hellcats and Corsairs as you suggested; if the results are significantly better with the initial test runs, I'll revise the charts.

cheers

horseback