I realize that the P-51 CoG was moved but,

[Pursuivant]

Originally Posted by IceFire

I will definitely corroborate the second part of this and that is that at 50% or less that the Mustang is much easier to handle. All of the people who take it for a 5 minute dogfight jaunt at 100% fuel are handicapping themselves big time.

That's why I always take 50% fuel or less for any QMB mission. It doesn't take that long and arguably it's "realistic" since QMB missions start in the air, presumably after the planes have been patrolling for a while.

[Woke Up Dead]

Horseback, all the things you mention are on par with the "fit and finish" of most other planes in this game.

Inaccurate or slow gauges? The P-11's fuel gauge still does not work, even though it was the very first extra plane introduced in a patch to the original IL-2 title. And didn't that plane fly with its rudder working in the opposite way than control input for a long time? Talk about hobbling. Is that too some sort of Russian conspiracy from the makers of this game, anti-Polish this time?

Also, have you seen the Pe-2's airspeed gauge between 300 and 350km/h? It looks like a four-year old drew the 10km/h interval lines with a Crayola. Speaking of bombers, in most of them the airspeed gauge in the pilot's cockpit does not match the reading of the gauge next to the bombardier's seat. And I can't recall the climb and dive indicator NOT being a second or two slow to respond in any plane in this game, though I don't pay attention to the Japanese ones much.

Inaccurate toughness? The P-51 has a glass engine and average wings, but I rarely if ever get disabled controls or get PK'd in it. Soviet planes were supposed to be tough, but the supposedly toughest of them all, the IL-2, loses its controls and its tail as easily as a lizard. Yaks become useless with a scratch on their wing, and the Pe-2 appears to have its wings glued to the fuselage with bubble-gum.

Ease of flight and stalls? You can see the supposedly easier to fly Spitfires do spins and stalls all over the place in a server with lots of rookie pilots, and they're harder to recover from than in a P-51. Their elevator trim needs is more intensive than that of the P-51, and their "arrow" (British equivalent of the ball) bounces from side to side with speed changes even more. Besides, "ease of flight" is so subjective and open to interpretation, and likely means different things to real pilots who spend 95% of their flight time bored, and players of this game.

[MaxGunz]

The delay on The Ball is modeled down to what type of fluid was used in the tube. That's not a mistake, real gauges have delays, these are not 21st century Cessna's as has been noted somewhere lately.

As Joe Worsley who learned to fly in the USAAF during WWII had noted years ago, if you tried to "fly the needle" then "you'd be all over the sky".

It's not all errors. Some, maybe maybe most is attempted realism.

[horseback]

Originally Posted by MaxGunz

I can get behind what you say but not how you say it. I wonder just what you expect when I've read the same material and don't come away with descriptions like yours.

In Bud Anderson's account the need to change trim was no surprise to him but as stated something you just do from regular practice, like tuning a car radio in those same times. But then from training on he was taking planes across the speed range quickly regularly.

Anderson, like all the pilots of that era did have a lot of practice at trim adjustment, but he also had the 'feel' that the virtual pilot is denied, and as I pointed out, the account that everyone loves to quote covers one fight at between 25 and 30 thousand feet; at that altitude, the IAS is relatively low, especially as both combatants were trying to extend their zoom climbs (and oddly enough, that is where the comment about constantly trimming comes up). As I understand it, flight performance is consistent with indicated airspeed regardless of altitude, and at low IAS, the rudder needs a lot of adjustment, but not the elevators or the ailerons to any great degree.

At low speed you don't get enough air over the elevator and ailerons to make high stick forces but propwash on the tail will be high in proportion to prop speed and power and worse on the ground when the tail is down. At cruise the plane should be closest to trim neutral by design. Do you find any accounts for any plane of the stick being "set in cement" at low speed? At high speed, yes.

"At cruise the aircraft should be closest to trim neutral by design." What happens when you have an air start with the Mustang in-game? Your starting speed is what, around 300kph/185 mph? The Mustang (and almost every other late-war US fighter except the Hellcat) drops like a rock; you can lose 1,500 ft before you recover, even with pushing the throttle and prop pitch well forward and mashing in nose up trim while pulling back on the stick and trying to avoid a stall. Then, once you get leveled, you're fighting a climb because there is no discernible balance or transition point. You simply start fighting your stick in the other direction and mashing in nose down trim. Elevator trim on the Mustang should be minimal, not a constant battle with the joystick's springs, and the difference between 185 mph indicated and the normal cruise speed of around 240 mph IAS (2700 rpm and about 35-40" manifold pressure in the DCS Mustang), and the rudder shouldn't need a couple of clicks (1/80th of the trim range) for every 10kph/6mph in speed variation--as noted before in previous posts, the P-40 was thought extremely trim hungry because it needed a rudder trim adjust for every 16kph/10mph of speed variation.

Check any reliable source, and the P-40 would be rated well below any model of the P-51 in the matter of trimmability or trim demands. Even with the recent changes to the FM, the Il-2 '46 Warhawk is still not the trim hog the Il-2 '46 Mustang is; the Warhawk is still fairly predictable and quite intuitive, and a far better gun platform as a result.

Trim is normal for most planes for not just speed change but engine setting change. When you change the propwash spiral you need to adjust the rudder to match though it's easily enough done first and sometimes (like the 109) only with the feet.

Here, I agree with you in principle, but the degree of change required to minimize stick force seems excessive to me; it's 160 clicks of rudder or elevator trim from one extreme to the other, and you can feel the difference of one click (and usually, you find yourself giving it three clicks in one direction and then one click back on the elevators and then you adjust the rudder trim in approximately the same way, and then if your nose isn't perfectly level, you're either speeding up or slowing down a little bit and the trim has to be adjusted again). Elevator-elevator- elevator; UN-elevator -rudder-rudder-Unrudder--oops--UN-elevator-UN-elevator, rudder. Lather, rinse, repeat. In most cases of Il-2 FMS I believe that the elevator trim is much too excessive--on average, I think that we are applying trim at least two to four times as often as we should have to in proportion to rudder trim.

This is where I read/listen close to accounts, what are the conditions and are there any clues about all those things that don't get written or mentioned which is why Bud's statement starting off with how trim is one of those things and why really sticks out. It doesn't mean trim every second but in maneuvering combat it happened often and for an accomplished pilot was no big deal, something done without thought.

Still the IL-2 P-51 is trim needy as are most all of the models and in IL-2 it's not simple at all to get right (in fact it's a PITA) nor do we players have the feel of G's and slip side-pull and changing stick force that let these things become automatic. It's a pain no matter what plane, some degree of that plays a part in P-51's so how do you say how much is the game itself and how much the model? Oh, by comparing to enemy planes!

On the contrary, I have always compared the Mustang FM to other US fighters, and there appears to be a clear historical hierarchy that can be established from worst to best. The P-38 was the least trim needy, closely followed by the Mustang, and the P-40 was far and away the worst with most of the rest grouped somewhere close to the middle--and this may be why Oleg was so sure that US fighters 'got worser' as they were developed--it is generally agreed that the P-40's trim issues became more pronounced with every new model and the Soviets received almost every Warhawk variant via Lend Lease. Since 1C appears to have used TsAGI wartime testing as their primary source of data for their FMs well into the life of the sim, and TsAGI had little in the way of first hand data on the late war US fighters (particularly the Naval fighters), I think that some extrapolation went on, and that there was a certain prejudice at work. We had several instances of US sources of official documentation being rejected by 1C because they were 'propaganda'.
If we could assume that the original game and Forgotten Battles/Pacific Fighters had the P-39 and the P-40 series properly 'slotted' in terms of capabilities and firepower versus the Soviet and German aircraft that the Soviets exhaustively tested during and after the war (and players' results in the game seemed to reflect that slotting), we should expect that the superior late war aircraft should be superior to the P-39 and P-40 in most, if not all respects.

Instead, there's this insistence that more advanced means more complicated and harder means more realistic.

How many degrees is elevator trim? And how many clicks is the total range? A couple of clicks is barely anything!

As I said, I have checked on several aircraft, and it's the same for all; 80 button clicks from neutral to full trim in each direction, or 160 clicks from one extreme to the other. You're right; a couple of clicks is barely anything. Or at least it should be. Amazingly, much of the time one click is too little and two clicks is excessive; you still find yourself fighting the stick or making constant micro corrections when you should be able to just hold the stick steady and maintain straight and level flight once you've stopped accelerating and keep the throttle and prop pitch constant on aircraft with an established reputation for stability.

If something needs to be fixed it also has to determined how much fix and not enter magic wand land.

If something needs to be fixed, the responsible parties first have to agree that it should be fixed; a partly nerfed Mustang seems to have a lot of supporters in the Il-2 '46 community, not least because of some fashionable historical revisionism and cherry picking.

BTW, plural orders of magnitude more is 100x, 1000x, 10000x, not 2x or 3x more. Please, significant is 10%, 1/10th more, and 50% more or less is extremely remarkable where 25% alone is remarkable. Orders of magnitude is not a statement to be thrown around. It has numbers attached that beg qualification despite how often number-challenged people misuse the term. Cargo capacity of a ship tends to be orders of magnitude more than that of a truck. A modern jet might fly a single order of magnitude faster than a Piper Cub. Changing trim 100x more than what Bud described you mean never removing a hand from the trim wheel.

Depends on your background; you appear to be using an engineering standard as in ten to the x power. I might be overstating my case, but I tend to think in terms of squares and cubes as orders of magnitude. When you have 160 squared (160 rudder X 160 elevator plus maybe a little aileron here and there) shades of trim adjustment and you have to use every one of those steps in some part of the flight regime (plus several in between) for an aircraft that historically is described as needing very small amounts of trim (and mostly rudder trim), that's reasonably close to an order of magnitude in my book.

I have to be a lot more ham-handed than usual to get The Ball to misbehave anything like what you describe.

Maybe you're not chasing ai Me 110s that will twitch out of your sights just as you get within effective gun range; the moment I correct to get the guns back on the target, the ball under the sight is squirting all the way to one side or the other; I realized a while back that most of the time it isn't remotely accurate unless you've been flying straight and level for a minute or so. Of course, I probably drink a lot more coffee than you do, but it is a lot more 'active' than most other aircraft's T&Bs in response to minor inputs. As I said, the cockpit displays in the Japanese fighters are far more stable, accurate and timely, but they are based on what someone thinks they should be like (and that someone probably owns a Honda or a Toyota), because they have next to no documentation on them, and they cannot imagine a time when good quality in a Japanese product would be a surprise to anyone who encountered it. The German instruments are slower and less accurate than the Japanese, for Pete's sake. That is just upside down and backwards from the historical record.

I understand that the instruments in many aircraft are modeled as illegible or slow & inaccurate, but this is a flight simulation without 360 degree field of view or moving cockpit; we don't get the cues that the real pilots got, and ones we do get are slow or false in selected cases to a greater or lesser degree. I have argued in other threads on this forum that the flight instruments depicted in the game cockpits should at least meet a single standard of accuracy and clarity, the clearer and more accurate the better.

Find the date that Zeno's Flight Characteristics film was made. Clues: it's a P-51B being introduced as new. There is NO mention of the fuselage tank and CoG caveats we see mentioned later as you would expect if there was a fuselage tank and "these reports were part of the training regimen" which BTW that film was.
My conclusion is that at that time there was no concern because there was no fuselage tank to be concerned about. Still, once it is EMPTY the result *might* be the same or close to the film.

Let's start with the film; at 2:20 we briefly see an Olive Drab D model without a fin fillet, so it's safe to say that the film probably is late '43 at the earliest (first production 'B' models came off the line in late May or early June of that year, and the cutdown fuselage and bubbletop were in the works before New Year's Day 1944).

At 3:20, Mr Deitz (the bald guy) says "And we're putting an 85 gallon tank in the fuselage, back of the pilot's seat." This means that it's a done deal, the tests were passed, the concept works and we're either in production or about to enter it. No earlier than August of '43 for that portion of the script; the wording is vague and he could mean that they were already doing it at that time or that they were about to.

Again, it's an overload tank, and I agree that the aircraft in the film probably didn't have it (no white cross near the data panel is visible, but the film could have been made before it became common practice). As mentioned in the film, the heavier Merlin 60 series moved the CG a bit forward from the P-51A, and I am aware that the newer radios were more compact and lighter than those in the earlier models, so adding the extra bracing, fittings and the tank probably put the CG much nearer to where it was intended. Since the consensus is that once the tank had less than 45 gallons in it, the aircraft would behave normally, the extra 235 to 260 lbs of weight from that first forty gallons of fuel was the critical part that hosed the CoG up. America's Hundred-Thousand says that as a class, the Merlin Mustangs needed a bit more trim than the Allison powered models, but that they were still very good in that regard. We could argue that a Merlin Mustang with the empty tank was closer to the ideal CG of the P-51A than the first P-51Bs without it.

Now regarding trim, at 13:40 in the movie the Major in the tower asks the pilot "How is she on directional trim changes as speed and horsepower are varied?"

Response:"The aircraft is stable at all normal loadings but the directional trim changes at low speeds as speed and horsepower is varied. However, the rudder tab corrects this with just a slight adjustment and it should be used as necessary. Normally, there is no trouble as the plane is naturally stable."

--At this point Deitz breaks in and says "That means that the P-51B will remain at any altitude without adjusting the trim tabs."

The Colonel responds "Less work for the pilot."

The trimming section on the P-51 in Francis Dean's America's Hundred-Thousand is transcribed in full below:

"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."

What I take from the movie and the testimony from Dean (and a good forty or fifty other pilots' accounts and personal testimony that I have read or heard over the last 40-50 years) is that the original P-51 was very well behaved in flight, and that very little trim was necessary to maintain straight and level flight throughout the speed range, and the Merlin Mustangs were also very good. In fact, so little adjustment was needed that pilots had to be warned that the tabs were sensitive & had to be applied carefully.

We're not talking about a Cessna 172 here, with 160hp and a full flight speed range of 60-160mph--we are talking about an aircraft that stalls around 95mph and achieves a level indicated speed of around 380 mph at 5000 ft (and was controllable at much higher speeds).

It was designed for a much greater degree of stability over a much greater range of speeds; if it weren't fairly stable over that range of speeds, particularly over the subset range of speeds normally attained in combat, it would have been nearly useless as a gun platform, which is what so many would-be users of the Il-2 Sturmovik '46 Mustangs are put off by, because it is completely unintuitive and you have to just keep at it until you learn to fly it by rote and muscle memory and ignore your instruments at critical moments.

We -KNOW- that with the tank more than half full that the change was big not only from the manual but pilot accounts such as Clostermann's.

Please don't quote Clostermann to me; the guy could tell a good story, but his 'official' victory total had increased significantly over his RAF credits by the time he left this world, so I tend to discount his authority in much the same way as I do with Martin Caiden. I'm not aware that he flew the Mustang in operations (I believe he was a Spitfire and Tempest guy), so I have to wonder what the hell he would know about the subject beyond hearsay.

I would take his word on what constituted a good pastry, though.

I know you have a passion for the subject but it keeps going to the fundamentalist religion level. If you get a blackboard, you could approach the Beck level from where you may never come back to sane reasoning and start using first letters in arranged words to make your own truth. Did you ever know Von Helton?

I have no idea who you are referring to. Are those the voices in your head?

cheers

horseback

[MaxGunz]

I don't tail chase. I shoot deflection.

The P-51 in the film did not have a fuselage tank.

Bud Anderson's words, I added the highlights and underlines:

A lot of this is just instinct now. Things are happening too fast to think everything out. You steer with your right hand and feet. The right hand also triggers the guns. With your left, you work the throttle, and keep the airplane in trim, which is easier to do than describe.

Any airplane with a single propeller produces torque. The more horsepower you have, the more the prop will pull you off to one side. The Mustangs I flew used a 12-cylinder Packard Merlin engine that displaced 1,649 cubic inches. That is 10 times the size of the engine that powers an Indy car. It developed power enough that you never applied full power sitting still on the ground because it would pull the plane's tail up off the runway and the propeller would chew up the concrete. With so much power, you were continually making minor adjustments on the controls to keep the Mustang and its wing-mounted guns pointed straight.

There were three little palm-sized wheels you had to keep fiddling with. They trimmed you up for hands-off level flight. One was for the little trim tab on the tail's rudder, the vertical slab which moves the plane left or right. Another adjusted the tab on the tail's horizontal elevators that raise or lower the nose and help reduce the force you had to apply for hard turning. The third was for aileron trim, to keep your wings level, although you didn't have to fuss much with that one. Your left hand was down there a lot if you were changing speeds, as in combat . . . while at the same time you were making minor adjustments with your feet on the rudder pedals and your hand on the stick. At first it was awkward. But, with experience, it was something you did without thinking, like driving a car and twirling the radio dial.

It's a little unnerving to think about how many things you have to deal with all at once to fly combat.

If you get that as only applying to extreme maneuver combat at high altitude then you probably never did well on reading comprehension scores. Perhaps you have those voices you write about distracting you, or some other attention problem.

Your left hand was down there a lot if you were changing speeds[/B], as in combat...

says "as in", not "only in" let alone "only in at high altitude".
And just what kind of test were you trying to carry out?
So just maybe constant TAS climbs would be easier to do.

[JtD]

Guys, please keep it civil. Stay nice, show respect, you know the drill.

[Pursuivant]

Given that there are a lot of Mustangs still flying, maybe rather than quoting books at each other, maybe we ought to ask an actual Mustang driver what trim control is like?

While I'm hugely enjoying the debate between two long-time flight simmers who have a lot of knowledge to back them up, it seems like we ought to defer to the actual experts who fly the things. (With some leeway for the fact that most modern 'stangs no longer fly with guns, armor plate, overflow tanks and all the other stuff that 1944-era planes carried.)

Furthermore, having a few actual warbird pilots confirm or deny our suspicions that the Mustang is nerfed would carry a lot more weight with TD than more "chart wars."

[IceFire]

Originally Posted by Pursuivant

Given that there are a lot of Mustangs still flying, maybe rather than quoting books at each other, maybe we ought to ask an actual Mustang driver what trim control is like?

While I'm hugely enjoying the debate between two long-time flight simmers who have a lot of knowledge to back them up, it seems like we ought to defer to the actual experts who fly the things. (With some leeway for the fact that most modern 'stangs no longer fly with guns, armor plate, overflow tanks and all the other stuff that 1944-era planes carried.)

Furthermore, having a few actual warbird pilots confirm or deny our suspicions that the Mustang is nerfed would carry a lot more weight with TD than more "chart wars."

Not the first time this thought has come up but keep in mind that warbirds won't always represent their wartime equivalents perfectly. Generally being lighter and their pilots often flying them with less power and in less adverse conditions.

There's also a fair bit of love for the Mustang so even if it had bad trim they would still love it to death and tell you the trim was godly. You'd need to get a hold of a real warbird pilot expert with more of a test pilot like attitude.

[MaxGunz]

Find one war loaded and balanced first. It's got to have dummy guns and ammo and armor.

[Pursuivant]

Originally Posted by IceFire

There's also a fair bit of love for the Mustang so even if it had bad trim they would still love it to death and tell you the trim was godly. You'd need to get a hold of a real warbird pilot expert with more of a test pilot like attitude.

What does Capt. Eric Brown have to say about the P-51's trim and handling? He seems to be most knowledgeable about the different warbird types and fairly even-handed in his assessment of them.

I recall him praising the Mustang's range effusively, but being a bit more reserved about its maneuverability.

Also, it seems a bit strange that instruments in each plane in IL2 are modeled individually. Most countries standardized around one or two models of a particular instrument, so a particular model should be the same regardless of what plane it's installed in.