Spit/109 sea level speed comparisons in 1.08 beta patch
 

Since there is a bit of current interest in FMs, I did some quick sea level tests for the current beta patch (1.08 ), and compared to generally accepted real life performance. As patches could change any time I didn't want to spend much time doing full speed vs alt tests.
These are the tests (with real life data):

http://i406.photobucket.com/albums/p...waii/Comp2.jpg

My Spit CoD data is using 2700rpm (full boost) instead of 3000rpm to postpone engine failure and allow speed testing. This is not so much of a problem as there does not seem any speed increase from 2700-3000 rpm anyway. Rads full open, canopy closed (although speed effects from these are negligible to nonexistant). The 109E4 uses auto prop pitch, oil and water rads open.

For real life data, the RAE Spit I data is pretty well accepted (although speeds are a little high due to lack of pilot armour and IFF equipment). The real life 109 is a bit difficult, I started a thread on 109 performance a while back and argued that actual 109 performance at sea level was likely to be approximately on the pass/fail mark on the Messerschmitt official specification (475kmh) based on what flight tests were available. Kurfust disagreed and maintained that the appropriate value is 500kmh at sea level (average of Me official spec), which is a defensible position.

http://forum.1cpublishing.eu/showthread.php?t=32259

I think for the sake of CoD using the 500kmh@SL for the 109 would be reasonable, might save a few arguments and work well in multiplayer if it was implemented.

For graphing purposes I plot both 475kmh@SL ("close pass") and 500kmh@SL ("average Me guaranteed") 109s.

http://i406.photobucket.com/albums/p...waii/Comp1.jpg

From the real life data, the 87 octane Spit I (or 100 octane but not using "WEP") was slower than both the 475kmh and 500kmh 109Es. Using the 100 octane +12psi boost, the Spit was faster than the 475kmh 109 but about the same speed as the 500kmh 109E. So taking the 500kmh 109E as a good fit for CoD, we are looking at approximate speed parity for 100 octane Spits and 109s going all out on the deck.

Besides the fact that all speeds are around 50kmh low, the current CoD data is a bit dire in this respect when looking at relative 109/Spit speeds.
It's not too bad just looking at the Spit Ia at +12psi versus the 109 at 1.35ata (5 min limit), with both aircraft at about the same speed (similar to real life Spit + 12psi and "official spec" 500kmh 109). However, there are two big catches.

* First, the CoD 109 has access to it's historical 1 min takeoff only boost (1.45ata), and can use it (unhistorically) practically continuously with no engine problems. This allows it to go 20kmh faster than the CoD Spit all out at +12psi.

* Second, the CoD Spit has extremely time limited access to +12psi without blowing the engine. So very quickly, the Spit will have to turn off the boost cutout and drop back to around 400kmh. The CoD 109 is now 70kmh faster at SL if it continues to keep activating 1.45ata. However it doesn't need to bother as without it is still 50kmh faster than the CoD Spit stuck back at +6psi.

Some quick tests on turning off temp effects are interesting, this increases the SpitIa 100octane speeds by about 10mph/15kmh but doesn't affect the 109. Clearly the temperatures that the Spits run at decrease engine output even when the engine does not fail, which does not occur in the 109.

With temp effects off the Spit can maintain +12psi continuously at around 460kmh, against the 470kmh of the 109 using 1.45ata. It would be rather hard on the 109 driver having to continuously press his 1.45ata while the Spit driver can select +12psi and leave it on though! It would be closest match to historical performance we could get without FM revision though (at least at sea level!)

camber

Good work Camber - as you know we did have a thread dealing with the CLOD Spitfire I and II performance http://forum.1cpublishing.eu/showthread.php?t=33942 and another one has been started http://forum.1cpublishing.eu/showthread.php?t=34075.

1)As shown below, the Merlin was more than capable of running for extended periods at +12 lbs boost (paragraph 4 8 hrs at +12 lbs, terminated by a glycol leak, a problem which was solved by a redesign of the head): Merlin engines should not be overheating or failing almost as soon as the 5 minute limit is up, there needs to be far more leeway than has been given.

2)I have not yet tested the Defiant or Hurricane but, as shown by ACE-OF-Aces, and below, the CLOD Spitfire performance figures do not match real world performance.

http://i91.photobucket.com/albums/k3...spit1-013a.jpg

Actually it can't just be used willy nilly. Activating it at the top of a "zoom" climb when pitch is at 12:00 and your hanging on the prop will blow the engine. I'd also like to add pressing wep at SL when already going all out throttle, pitch and speed at 460 (rarley 480) doesnt add any more speed. The wep seems to add more power at lower sppeds to me.


The graphs having different scales makes it very hard to compare, any chance of putting it all on one graph? - Or at least the same scaled graph?

FT = Full Throttle? I think nearly all the speed tests on the 109 were done at 1.3 or 1.35 Ata were they not? Not full throttle...

Nice work OP... interesting

Your correct on WEP having no effect at higher ALT IMO..

Climbing yes but all out power no.

And I agree also about boost being used as often as you like in the 109...not true and I think this cones from pilots that don't fly it, do it high Altitude continuously and see what happens, so it continuously on max pitch and full throttle with low speed and your kill it too..

That would be an opinion. We need to see a cooling trial to see wheter it's a valid opinion or not. Preferably in a different thread.

the 5 minute limit 'has' to be a guaranteed absolute minimum in order to be an allowed limit, the likelyhood of failure 'at' 5 minutes is low and increases proportionally with time beyond the 5 minutes, I don't care if the failure rate is 100% at 6 minutes it's just highly unrealistic to have guaranteed failure at 5:01.

5 mins was the instruction in the pilots notes. It did not mean instant failure.

Given that combats usually last only a few minutes it should not be a problem too often. Its true though that information on the maximum time before failure needs to be found or, perhaps more correctly, information that will allow the devs to simulate properly the temperature effects of BCO and then, presumably, the temperature effects on the engine will already have been modelled....... ermmmm I say the latter with my tongue in my cheek.

Yep and long periods over 1.3 and deffinatley over 1.4 (usually cos of wep) will destroy the engine even though temps and RPM are normal.

I agree, I am pretty sure the Merlin could operate well beyond 5 minutes at maximum power, if the prescribed temperature limits are also observed at the same time. After all these engines usually went through 100 hour tests before service approval, tested for many many hours at full power, but with controlled oil and coolant temperatures.

As I understand the reason for Merlin engine failures in CLOD are probably related to:

a, Exceeding oil and/or coolant operating temperatures of the Merlin. Obviously engine failure is a very obvious conseqence of too high temperatures, so the real question is IMHO
aa, how long the Spit / Hurri could be run at + 6 1/4
ab) how long the Spit / Hurri could be run at + 12, which is about 30% more power/heat load.

b, Fall of oil pressure during negative-g manouvers, resulting that the engine is insufficiently lubricated, which can and will destroy an engine in very short order, any engine, and should be correct for the 1940 neg-g sensitve Spit/Hurri (which's manual specifically warns against negative-g and low oil pressure conditions), so I sense that Red pilots not knowing/ignoring this limitation may be at the culprit.

Hi Farber,

Sounds like I may be overstating the ease and safety of 1.45ata use in the 109. In my speed tests I tried restarting it a few times at SL and didn't see engine problems but didn't try many variations. I got 450kmh without and 470 kmh with it on, is that consistent with you?. The 1.45ata in combat makes it harder to work out how best to configure the 109 in CoD, if you gave the 109 500kmh at around 1.3ata and combat access to 1.45ata, you have a VERY fast bird indeed in CoD considering historical information.

For the 109 tests I left auto prop pitch on and had the throttle fully open, with the boost regulation giving 1.35ata or 1.45ata. FT is full throttle as you surmise.

I scaled the plots seperately because I wanted to talk about relative speeds in real life and game. Both plots have a 120kmh range on the y axis, the CoD one starts 50kmh lower because all speeds in CoD are roughly 50kmh low. These tests are really a bit basic..only sea level max speeds done singly offline.

I was more reflecting to the (baseless) part of the claim, that "Merlin engines should not overheat within 5 minutes"

Actually they can, like any other engine, depending on conditions.

The manual says that if possible, the pilot should not operate the engine for more than five minutes at + 6.25 (+12) boost / 3000 rpm, AND that the maximum oil and coolant (iirc 125 degrees Celsius) temperatures during that period are NOT to be exceeded. The overstepping five minutes is less a problem, it will wear out the engine quicker for sure, but temperatures will kill it much quicker. If you run the engine coolant/oil at 160 degrees Celsius it will fail anyway, and I would say, likely well before 5 minutes.

I agree.

I guess that is because this is a fairly new feature in recent beta patches (1.07 onwards afik). It used to be just as you described it...

I haven't got enough hours in 109 in 1.08 to comment on that to be honest. I managed to damage the engine when I forgot to open the water rad, but I never damaged it by using the WEP as long as my rpm weren't too high.

The effect you get from execissve use at certain instances of Boost is not the same as cooking your engine throuh heat, I'm not sure what damage is modeled in game but you suffer with lack of power and can't seem to get your rpm as high as normal..can't remember the exact figure as I try not to do it often

The Merlin engines in the Spitfire MK 1a 100 octane die at 97 C oil temp for all boost and rpms settings in beta 1.08.

Are you sure about this Camber?

Edit: Test conducted with Spit Ia100oct, prop as near to feathered as possible.

http://www.youtube.com/watch?v=ksCmgBaTrtQ

Merlin II & III Temperatures: Oil = 90-95°, coolant <90° and 120° emergency maximum for five minutes.

Using high boost at low rpm can lead to pre-ignition, although I haven't yet tried it to see what happens in CLOD: the Pilot's Notes General advise raising the rpm before increasing boost and reduce the boost before decreasing rpm to cruising level.

Just looking at ATAG-Dutch's demo the rpm doesn't seem to go above 1,600 in two tests 130-440 mph...hmmm.

Regarding the comment on relative difficulty in operating the 109 WEP vs just leaving the 12lbs 'on' with the Spit, please note that when operating the BCO one has to piddle about with the mixture, which isn't always that easy, or rough running occurs.

Regarding the oil pressure drop causing damage. RR performed tests on this and one Hurricane was subjected to 100 continuous rolls before any signs of damage occurred.

Hi Typhoon, the test was conducted with the csp brought back to as close to feathered as possible, plus throttle zero. This was to minimize the other drag effects other than the radiator. Trims were not altogether uniform in the three runs either. However, in a vertical dive, gravity assisted only, the radiator shutter caused a full 3 second discrepancy from minimum time at 50% rad and maximum time at 100%.

I'll happily upload the mission I did this with in FMB if anyone would like to carry out the test themselves. The times in 100ths of a second were from the counter in windows movie-maker. This meant i could measure the time from the frame first 'unpaused' to the ASI hitting 440mph. Well, the next line on the gauge after 420.

On a positive note, losing the rudder far below its rated 450 mph IAS helps reduce the Spitfire's roll rate in a dive. Usually the ailerons and elevator are quick to go as well. Losing the elevator ensures the pilot will not overstrain the airframe even if he hauls back on the control column excessively. The airframe should thus remain relatively intact until impact with the ground. It's all good.

Thank you for you intelligent and polite reply. Hopefully it can be an example for this thread so it doesnt get locked.

My squad mates and I have been discussing the difference between the E4 auto pitch and the E1 and E3 manual pitch which is quite different. I would also go as far to say when your using autopitch your almost using the AI FM in some respects. The exact difference is hard to describe and establish exactly... The auto pitch also runs at a lower RPM than I would manually, although it gets more acceleration, better fuel economy and is overall superior except when you rapidly climb and dive continiously and it cannot keep up with you. 5./JG27Gruber could explain more on this than I think, I will see if he wants to contribute.

I can achieve 460kmh sea level with out any wep during the acceleration... Occasionally if I have my aircraft trimmed perfectly and the planets align I can get a steady 480 kmh... At 5km altitude its more like 420kmh.

Klem started a thread about speed and the 109 was discussed also. I made some quick tracks [Strike]which I will attempt to attach here.[/Strike] (they are messed up, I will fraps it and upload to youtube...) Close to sea level tests and 5km level flight speed tests 1.3 Ata and 2350 U/pm if I recall. I think these runs were made in 1.07. As far as I am aware the only difference to the 109 FM is the rad drag... - Which is neglible to a degree.

-Ultimatley, I am only Human. I'm proberbly not the best at flying straight and level and maybe I am even doing it wrong? I will let others be the judge of it.


EDIT1: WOW was I wrong?! 100% Fuel gave some interesting results but I need to test 50% also for comparison. There have been changes to Bf109 FM in 1.08.

Interesting .... http://www.spitfireperformance.com/n3171-cooling.jpg

From: http://www.spitfireperformance.com/n3171.html

I agree there is some drag effect with the rads.

However, do you realize guys that there was no 100oct fuel during BoB ?

Wonder what you are looking after here?!!

Regarding the speed achieved by the tester, isn't it the same one that wasn't able to achieve 270 in a hurri ? I mean teh kind of guy taking off with a cold engine, flying hood open, at 400kph cruise speed and complaining about overheating in combat ?

I think it says it all...

I am sory but when I read "real life MkI 100oct" it really push me out of my brain.

Nice test Dutch, I remembered how much like I liked CoD watching Spitfires plummeting toward the green leafy fields of England.

For the last couple of patches, I found that rad position had slight effects on level speeds but only a few mph at best. I was rounding to nearest 5mph, so often the rad effect rounded out. I didn't try canopy this patch but the previous one couldn't detect anything.

From your test it looks like that rad has much more of an effect on accelleration between speeds, which is an interesting finding.

Troll

Excellent. It should be tested in the sim under the same conditions (though this test was done in the winter) to wheter the sim has similar cooling modelling.

A vague look though tells me that the temps are rising slowly but steadily even at 6 1/4 / 2600 rpm. Overall it just looks just suitable for climbing conditions at lower powers.

That's just it though, some seem to want a 30,000 high power climb with no cooling problems.

Hi Tomcat

Er, not sure if it is an English issue, but that reads like a hilarious insult so I will reply as such.

Maybe I (it) WAS the kind of tester that wasn't able to achieve 270 (mph?) in a Hurri while complaining. But what would you say if it got back to the airfield, abducted Spitgirl from the officer's mess, and took her to the nightspots of Picadilly in an open top Lagonda?

Looking back the only flight test of a Hurri I remember was 240-245mph on the deck in the first beta patch with FM revision (slowing Hurris down). I think it was a fair bit faster in the previous retail patch 1.05.

Will not comment on the fuel with high round number
in case the padlock gods are roused from fitful slumber.

Cheers M8

Priceless

:grin::grin::grin: I see ATAG_Dutch has been doing some tests, with interesting results, http://forum.1cpublishing.eu/showthr...624#post457624

I have done the tests using the values in the table for the DB 601 A and B manual. I believe the new compressor is modeled, so in the box "Flying Altitude" I used the left hand column, as there is significant drop off in Ata at 4.5 to 5km rather than 4 to 4.5km... I also performed the test on a multiplayer server in case FM's are different in single player.


Using ATAG_Keller's IAS TAS converter the results are:

Test 1 Sea level 1.3Ata 2400U/pm IAS 440 TAS 440 or 273 mph
Test 2 Sea level 1.23Ata 2300U/pm IAS 430 TAS 430 or 267 mph
Test 3 Sea level 1.15Ata 2200U/pm IAS 420 TAS 420 or 261 mph

Test 4 4500metres 1.3Ata 2400U/pm IAS 400 TAS 518 or 322 mph
Test 5 5000metres 1.23Ata 2400U/pm IAS 390 TAS 518 or 322 mph
Test 6 4900metres 1.15Ata 2200U/pm IAS 370 TAS 489 or 304 mph

http://youtu.be/O4jHSMyYdkg <---- Video of tests.

Now we need to dig out the real life tests and compare.


The effect of WEP also seems to have changed. I tried making it break the engine in the usual ways but could not manage it... It also seems to have effect at all altitudes now.

As I remember it I use to fly with a much higher pitch setting to get speed. You need to increase the blade angle. At alt, it's much around 2k or 2.1k.

Otherwise you can't convert the power of the engine into speed. Maybe there is a need to tweak the game engine.

Hi. The purpose of these test to see the ingame performances, when you keep the original engine operation limits (DB 601 A-B Btriebs und Wartungsvorschrift Ausgabe C (Okt 1940) 60AE 601-XXII C10 1940). You can see this table on the first seconds of the video.

http://www.rolfwolf.de/daten/E4/Emil.html


Auszüge aus Flugzeugdatenblatt Bf 109 E-1, E-3 nach L.Dv.556/3


Motor DB601A mit Alter Lader "Old Supercharger"


Höchstgeschwindigkeiten in Steig/Kampfleistung (Diagram)

2300 U/min 1.23 ata

http://www.rolfwolf.de/daten/E4/Emil_html_4785a2b8.gif

Höchstgeschwindigkeiten in Steig/Kampfleistung (Tabelle)

2300 U/min 1.23 ata

Code:

---

0km                  460km/h

1km                  480km/h

2km                  500km/h

3km                  520km/h

4km                  540km/h

5km                  555km/h

6km                  555km/h

7km                  550km/h

---

bugmenot,

So it would appear at sea level the 109 is too slow by at least 30kmh. However I felt that IL2:clod used the new supercharger as the Ata does not drop off untill higher altitudes which seems to match the new one. So essentially its even SLOWER than it actually should be! The new compressor gave the 109 a higher effective cieling before the Ata dropped off and therefore made it faster at a slightly higher altitude.

Are your speeds in TAS?


I also found this which was of worth:

http://www.ww2aircraft.net/forum/fli...mki-26994.html

So we know all the aircraft are too slow and roughly by how much although I have not seen a through test (video) which shows values for RL and clod but I believe they have been done by some trust worthy people... Having this info here in this thread would be nice.


However:

What about climb, dive, turn and roll? Speeds are one thing and need addressing but are not these more fundamental? Especially from the perspective of a Hurricane pilot who are being overshadowed by the spits?

Sadly the dive, turn and roll parameters where not typically parameters they tested for in WWII..

This is not to say that you can not find any WWII testing of drive, turn and roll, only that they were not typically part of 'performance' testing in WWII.

Thus most if not all flight sims have to 'calculate' these values.. That is to say you will be hard pressed to find real world data on these values, so they have to calcualte them.

The two important performance values of WWII and thus the two you can typically find are climb (ROC) and speed (TSPA).

There is a third, which is really just part of the ROC and that is the time to climb (TTC).

Which from the minute amount of this information I followed before - I thought as much...

Shame.

However hopefully we can come to some kind of accord and present the data to 1c:MG...


This is the part where we must choose what I would call "Folklore" (eye witness accounts) and "facts" actual graphs... I dont see how you can truely have purley one or the other and I think this is where the real nitty gritty arguments break out... So with an open mind I am finding myself more in the "feeling" group than the facts but with a balance of both.

We can have all the facts nailed on the head like ROC and TAS but as you say we are still guessing the rest which is where "folklore" fills the gap... However then we are down to the spit always out turns the 109 and vice versa... - from pilot accounts...

So, its a mine field...

Should we try to get 1c:MG nail the "fact" figures as close as possible and then the "pilot account" things like turn and roll?


This is my first forray into a FM debate... So forgive the open mindedness and lack of direction.

S!

Agreed

When it comes to calculating data.. I am sure 1C can do it as well if not better than any member of this forum.. The math is the math! The only time the math comes into question is when it does not match reality.. And in this case, where we have no reality to compare to, no one can say one way or the other how good the math is doing in simulating the aircraft.

Considering the fact that people can find a way to argue about the hard data (graphs) it is no wonder they can argue about the folklore.

The difference is the hard data (graphs) can be reviewed such as to minimize the errors..

Which is not the case with folklore!

There are just too many unknowns associated with the folklore to make it useful. Some people think they can do some statistically analysis of all the folklore and come up with some sort of consensus.. But it is just not the case.. Or should I say that in the past 20 years of flight simming, I have seen many make that claim, but no one has yet do pull it off.

Which is not surprising, in that we are NOT talking about gathering up folklore statements that somewhat agree..

For example, assume 3 WWII pilots said they could climb to 20kft in 9.2min, 10.2min, 9.8min.. And we say, hey that is great, we will just take the average of those three staments and call it good. NOPE! What we have is folklore that is many cases is 180 out! Fore example, there are WWII Spitfire pilots that said they could easily out turn or turn with a Bf109.. At the same time we have WWII Bf109 pilots who say they could easily out turn or turn with the Spitfire.

What do we do in that case?

Flip a coin?

I think not!

That is why most if not all folklore (pilot accounts, pilot action reports, etc) are so useless! In that they typically never provide enough information to even recreate the scenario in the game.

For example, a P51 pilot reports says he got behind a Bf109, closed in on it, and shot it down.

Ok..

Did he dive down from above to get on the 109s six? Or did he climb up to the Bf109? Or was he at co-alt and got in behind the 109? Did the 109 even know the P51 was behind him? Was the 109 pilot wounded and just trying to make it home, was the 109 engine damaged from a previous dog fight that just ended..

The list of un-knows is ENDLESS!

Which is why most if not all folklore is useless when it comes to tweaking the FM! IMHO your better off relying on the math and leaving it at that!

Long story short, typicall folkloare (pilot accounts and reports) tell us alot about the 'men' and thier 'tatics' but they tell us very little about the 'performance' of the planes.

Most but not all.. In that as I noted above, even with hard data like graphs, there are some unknowns associated with it that can cast doubt on the data..

The funny ones are the folks with double standards that will cast doubt on a test of a plane they don't like but at the same time accept lesser data for the planes they love as proof positive! It would be funny if it was not so sad!

Disagree

There may be a handful of folklore accounts that are 'useful'

But as noted above, most if not all folklore is useless!

Just to many unknowns!

Not to mention the fact that most if not all pilot reports are ONE SIDED STORIES!

That and they typicall dont include enough info to re-produce the scenario in the game to see if the plane the pilot was flying can do what he said, let alone the fact that we have absolutely no idea of what the state of the other plane and pilot was!

Bingo!

No not in my honest opinion, best to rely on the math when there is no real world data to compare to

No worries!

The results of a calculation (what you call maths) is only as good as its data. Also there are equations and equations. Some are highly approxamtive and only thump rules for quick estimates, others may be closer to reality but also very complicated and requiring a lot of divers input data.

I would agree to use mathematical relationships to deduce aircraft behaviour if we had enough reliable data or data at all for input into the equation and some reliable data to verify the results.

My guess is the data we would need to calculate it is not available. I mean what would be great if we had all the aerodynamic coefficients as a function of Mach number and angle of attack and the corresponding reference area for each plane.

"Equations" deducing turn performance from the wing loading, sorry, this is far from anything near accurate. I would not like to have the fm built on this kind of thump rules. Then I'd rather prefer anecdotical evidence.

AoA, you seem to agree with what I thought before... Folklore is fairly useless except from that particular pilots expericence... and the maths and graphs is what counts...

I am interested in what swift has to say... He makes good points.

In these days, is there surely not computer models that could aid us? - as for 1c:MG doing the maths... they are surley not doing quite a good job? ;)


I state somethings in argument... Like do we use the folklore, maths or combination? I agree with your statement on folklore... Adrenaline, fear and rapid actions can distort the memory... Unless it can be proved just by maths what else can you do?!

Correction..

The 6DOF math (what you call thumb rules) is more than adequate to simulate flight!

And the 'data' that the 6DOF math uses has nothing to do with any of the real world performance data (ROC, TSPA, etc). The 'data' the 6DOF math uses is coefficients only. That is to say the 6DOF math for a P51 is the same as that for a Bf109, what makes a P51 a P51 is the coefficients loaded into the 6DOF equation. That is to say, no where do you 'load' say the ROC or TSPA values from a WWII performance test.

The only time you make use of the WWII performance data is in the validation of the 'outputs' of the 6DOF math and the corsponding coefficients selected.

That is to say the math never changes, only the coefficients.

Basically they can get a good set of coefficients to use based off the geometry of the plane (CL, CD, mass, wing loading, etc). Than they 'tweak' the coefficients until the outputs of the equations match the real world data. As part of all this the power plant (engine) is also simulated and is one of the inputs to the 6DOF (thrust) equation.

The more complicated versions were an issue back in the early 90s.. Where games like AOTP made use of fixed point math, in that the floating point processors were just not fast enough to do the complex calculations in real time. Mater of fact back then they were even limited to a 3DOF flight model, but than around 1995 a flight sim called Pacific Air War 1942 came out, that was one of if not the first PC flight sim to implement a 6DOF flight model, it still used fixed point math. These days there is no need for fixed point math and thus no need to use the simplified versions of the 6DOF flight model equations.

Who wouldn't?

Depends on which data your referring too.. As noted above, a good estimate of the 6DOF coefficients can be derived from the planes geometry. Actually the hard part to simulate is the engine! In that many of those records do not exist and no good way to derive them from looking at the dementions of the engine.

As noted above, if they have enough info to draw the plane in 3D, then they have enough info to derive many if not all the coefficients for the 6DOF FM.. What is lacking in the power plant info (thrust)

Disagree 100%

To each his own than

In many cases all we have is math to fill in the blanks.. Sad but true! ;)

Well this is a proactive thread so get cracking and then show us some results! :-P

My point is that you will have difficulties to derive reliable coefficients and you seem to agree on this. I do know a little about flight mechanics and trajectory computation (where the 6dof equations intervene) and about coefficient determinations (it is my daily business).

At work we frequently use a simplified tool to calculate the aerodynamic coefficients for subsonic and transsonic flight conditions and I can tell you I would not trust them for applications such as CoD. We use them for different applications where the impact is minor so we can live with it. But CoD would rely heavily on these coefficients and I'd say to obtain something that is halfway close to reality such a tool is not sufficient. And from experts working for years in the aerospace business using modern and highly sophisticated cfd tools I know that using these methods for subsonic regions is far from trivial. And it would take hours to days to calculate just one flight point for one configuration and probably would take longer if one would take into account the viscious terms instead of relying on simplified Euler calculations.

But what we need in CoD does not stop at the determination of lift, drag and lateral force coefficients and the moment coefficients about the three axis. We also need the derivate coefficients to obtain a believable flight model. Up to now the means with which these are "determined" is more than crude and very little reliable.

This gets even more complicated when one considers that each flap, rudder and aileron movement will have an impact on the aerodynamic coefficients (the 6 static coefficients and the derivates). You'd need a database set for several flap, rudder and aileron deflection combination. Then we have the trimmed and untrimmed flight conditions and other aerodynamic control surfaces such as flaps and airbrakes. Now let's talk about canopy open or closed and radiator and oil cooler openings ...

And these are just the coefficients for the airframe. We'd also need reliable data for the propulsion set.

I really do not believe in being able to obtain a full AEDB that will result in a flight performance that will be close to the real thing anyway, provided we even know where the real thing was. I think it is smarter to take the bottom up approach by tweaking the used coefficients in such a way that they fit to the experienced behaviour including test results and, where values are missing, to anecdotical evidence as long as there is a bunch of anecdotes saying the same.

BTW: CoD is definitely using 6dof. What we are disputing is how they come up with the forces and moments they inject into the 6dof equations.

I had a sad 109 experience yesterday. Flying in overcast it is easy to get confused between the top and bottom of the aircraft, leading to the following:

http://i406.photobucket.com/albums/p.../IMG_06451.jpg

Seeing as you are doing some altitude 109 tests I did the same on patch 1.08. It seems not to have changed the last two patches though.

At 5000m 1.23ata 2400rpm I get IAS 400kmh which seems consistent with your Test 5 above.

The 109 does not change max speed between 2100 and 2400rpm which simplifies things.

Messerschmitt "guaranteed" top speed: (backed up by the flight test record)

570kmh TAS @ 5000m, 2400rpm, 1.3 ata (5 min limit).

CloD 109E4 (manual prop pitch) top speeds:

425kmh IAS = 561kmh TAS @5000m, 2400rpm, 1.32 ata

Full throttle boost has dropped below 1.35ata at 5000m. However the 109 1 minute takeoff boost is still working and oddly enough will still increment boost at 5000m (to 1.42ata).

440kmh IAS = 581kmh TAS @5000m, 2400rpm, 1.42ata.

So the CloD 109E4 at 5000m is 10kmh slow at the 1.3ata combat setting (will assume boosts in the 1.3-1.35ata range can be considered effectively the same). However it has access to the takeoff boost at altitude, which enables it to be 10kmh faster than the real life version.

Cheers, camber

Offline tests, cockpit off, speeds rounded to 5kmh, 4950-5050m, oil/water rads fully open, OAT 25/1000ft rule for IAS/TAS conversion.

AoA will need some direction and study material...first link Spitfire study 1941

http://ntrs.nasa.gov/search.jsp?R=19...re%2520lateral

http://ntrs.nasa.gov/search.jsp?R=19...e%2520spitfire

http://www.bing.com/search?q=+NATION...ox&FORM=IE8SRC

really good thread so far, and very good and interesting post!

Key word being reliable..

Now ask yourself..

How do you prove to yourself they are reliable?

Answer is you compare the results (outputs, such as tas, roc, roll-rates, turn rates, etc) of the 6DOF using these coefficients to the real world data..

Which is pretty easy to do when you have the real world data!

But what do you do when you don't have any real world data?

You guess it.. You rely on, aka trust, the math!

That is my point

That being we do NOT have real world data on each aspect of the WWII plane.. So unless we come up with a time machine, we are going to have to rely on calculated results (the math) for not only simulation but validation.

You too? Here as WSMR we use a lot of trajectory math to calculate the launch to impact site of the missiles we test here. We also have our own flight simulation software that we call RAGE

http://www.csc.com/public_sector/suc...tual_landscape

I work with the guy who wrote that software on a daily bases.. I also write plug-ins for RAGE but he is the true gu-roo of the software. All in all a great job, on my way to work I may see anything from a F22 to a UAV fly by at tree top level (landing or taking off from holloman).. It can be dangerous sometimes.. In that I am always looking up in the blue instead of looking forward at the road! ;)

Well than I guess we will have to agree to disagree on that point

Note I never said it was easy or trivial.. My only point is it is doable! Many have for many years now.

I know of only one PC flight sim that implemented a real-time computational fluid dynamics flight model (what you call 'viscious') and that was FLIGHT Unlimited

http://en.wikipedia.org/wiki/Flight_Unlimited

It was done back in 1995.. And was not only overkill IMHO but too much for the PCs of that time. Maybe even today, I don't know in that not many make use of it in that the 6DOF (what you call simple euler) has proven itself to be more than adequate for military applications, thus more than adequate for PC games IMHO.

Key word being believable..

Now ask yourself..

How do you prove to yourself they are believable?

Answer is you compare the results (outputs, such as tas, roc, roll-rates, turn rates, etc) of the 6DOF using these coefficients to the real world data..

Which is pretty easy to do when you have the real world data!

But what do you do when you don't have any real world data?

You guess it.. You rely on, aka trust, the math!

That is my point

That being we do NOT have real world data on each aspect of the WWII plane.. So unless we come up with a time machine, we are going to have to rely on calculated results (the math) for not only simulation but validation.

Well than I guess we will have to agree to disagree on that point

Which has all been done before and done for years!

Better yet..

To drive my point home..

Let talk about you going out and finding the real world test data for each plane in the game of the 'effects' of the canopy open vs. the canopy closed on each aspect of the plane (tas, roc, roll-rate, turn-rate, etc)

Allow me to spare you that effort!

In that you wont find such data! ;)

Thus, back to square one of my point

You will have to trust the math and how it says the canopy open vs. closed will 'affect' the flight

Oh sure you may find some anecdotical evidence for some of the planes.. For example we have all read the stories.. Like the Me262 that was stuck in a high speed dive, until the pilot popped the canopy and started to bail out, at which point he noticed that popping the canopy 'changed something' such that he was able to regain control, and thus didn't bail out. What is not 'clear' about such stories is the parameters to re-create that scenario in the game to see (validate) the flight model. For example..

What was his altitude when he popped the canopy?
What was his speed when he popped the canopy?
What was his dive angel when he popped the canopy?
What was his flap setting when he popped the canopy?
What was his trim setting when he popped the canopy?

The list goes on and that is only for the point in time of when he popped the canopy..

So all we know from that story is that 'something' changed.. For all we know his plane was slowing down and the popping of the canopy had NOTHING to do with it.. It could have just been a coincidence that he popped the canopy at the same time the plane had slowed down enough that he was able to regain control

Ah, glad to see you agree with what I said in my last post!

So not all is lost, in that we can agree on some things! ;)

Bingo!

So do we give up?

Or do we trust the math and move on?

Which is exactly what I was saying minus the anecdotical evidence (aka pilot combat reports)

Just too many variables involved to make most if not all anecdotical evidence useful

As I noted early on

Many 'feel' the can derive some sort of statistical average of the anecdotical evidence.. Many have tried, all have failed! Which is not surprising when you consider the fact that the anecdotical evidence is not something that varies a 'little' As in one reports says the top speed is 305, another say 307, and another says 302, and another say 310. If that was the case it would be a simple mater of taking the average and calling it good! But that is not the case for anecdotical evidence, what we have there is Spitfire pilots saying they could out turn 109s and 109 pilots saying they could out turn Spitfires. So based on that it is not surprising that those who have tried have failed.

Ah, glad to see you agree with what I said in my last post!

So not all is lost, in that we can agree on some things! ;)

No, we know how they come up with them.. What we are disputing IMHO is how they validate the flight model.. For the aspects of which we have no real world test data to use in the validation. In such situations I am saying we have to trust the math to fill in the blanks, where as your saying we should use anecdotical evidence to fill in the blanks..

In summary

I put more faith in the 6DOF math than you do
You put more faith in anecdotical evidence than I do

Other than that I think we agree

You do not need to do this surgical argument deplugging (what I always feel to be a bit rude although I understand that you do not mean it this way). I understood perfectly where you want to go.

My point is that with the maths what you have in mind you will be likely as far off the reality as with what we have right now in the game if you cannot check it against reality.

So you apply maths but the chances are great that you will be far off the mark as with the current methods (which might by the way be based on some simplified maths I guess). You will never know if you will be below or above the mark. So I could as well trust in what we have now. I could as well trust in anecdotical evidence provided the sample is large enough to allow a statistically sound picture about the real thing. If 1000 pilots say the spit could outturn the 109 I'd tend to believe that 1000 pilots cannot be wrong even if I do not know the 1000 initial conditions. The number of pilot accounts however may suggest that the variety of initial conditions in which these guys made their observation was large enough to provide for a good hint about a qualitative not measurable behaviour.

It will be simply an impossible task to have fully viscious cfd simulations for each aircraft for a game that is basically just a niche product. It had perhaps been tried once. It has never been done again. This talks books. And cfd is again basically useless anyway if it cannot be checked against wind tunnel tests. Now this won't ever happen anyway.

And don't mix up the effort you and your company can put into a product for which your company will be payed a fortune with the possibilities of a small game developer company.

I suppose there could be a way to settle this. If AoA used his method on a spitIa and Swift used his method on a SpitIa and we had some results?

Aside from having different approches to the same problem, what about some results?

There was another monster silly thread over this issue.

It appears all of the aircraft are slow by a similar margin of error.

So while actual performance is not correct, relative performance is not effected.

Oh yes it is, unfortunately. ;)

Right. :rolleyes:

Not a need as much as a style that I find useful and actually respectful in that I take the time to address each of your comments.

PS wrt my style, I have spoken with several mods and it does not break any forum rules!!

Really? Because I did not get that impression

Yes we have already established that you do not trust the math..

Got it!

So if not math.. Than what should we trust?

And how far off is it?

Only way to tell is to apply some math and derive a percent error

Agreed 100%

The part we don't agree on is the definition of reality..

I for one am all for checking against reality when reality exists.. Like real world test data

But when real world test data does not exist, than my point is you have to trust the math to fill in the blanks

Where as you want to fill in the blanks with anecdotical evidence..

And I have already given several examples of why that is a bad idea

If large enough?

Again, as I noted, EASY to say, but until you try you don't know just how hard it is to try and do that..

Many have made that claim over the my past 20 years of simming

All have failed!

All in all I would still take my chances with 6DOF math over some sort of statistical conclusion drawn from anecdotical evidence..

Why?

Because there is something you are forgetting about anecdotical evidence

We only hear from (read the reports of) the pilots that made it home to write about it..

Thus a filtered set of data!

In short, we don't know how many Spitfire pilots were SHOT DOWN trying to turn with a 109 and thus never got a chance to write about it!

Chances are it will not..

Again, not trying to bum you out

All I am saying is that many like yourself have made such claims over my past 20 years of simming

All have failed

But who knows, maybe your different?

Maybe you are the one to do it?

On that note, don't take this wrong, but talk is cheap!

Do it and than lets talk about it!

My guess is the main reason it has not been done is that it is over kill from the get go..

That is to say the benefits of it are so small that most would not even notice the difference..

At the human level that is!

Yes as I pointed out, FLIGHT Unlimited tried it back in 1995, and as I noted in my last post, I don't know of anyone else that has tried it since.

LOL

Trust me, we are as small if not smaller than 1C when it comes to budgets

Sh, I tell you a secret: CloD is already based on 6dof ... but don't tell anybody ;)

Huh?

It is no secret..

You will be hard pressed to find a PC flight sim made in the past 10 years that is NOT using a 6DOF FM..

Except maybe for some of the x-box quake types of flight sims..

So...

No comment on the FACT that we only hear from (read the reports of) the pilots that made it home to write about it..

So maybe now you can see my point of view as to why anecdotical evidence is 'flittered data' and thus not useful in any sort of statistical summary!

It would be like going to San Francisco or New York city and asking people on the street how good of a job they think the president is doing and using those results to place a bet on the next election! ;)

And that is just one problem with anecdotical evidence!

Let's not forget that anecdotical evidence is typically, if not allways, a 'one sided' story!

That is to say you will be hard pressed to find a WWII after action reports that consist of both comments from the Spitfire pilot and the Bf109 pilot in that report talking about the same encounter..

Thus math ftw! ;)

So aside from this intellectual joust - what about some results?

We do know exactly how the 109 turned, the math was done in the 1940s, so whats the fuss about? And the last time I check the turn times, its about right in CLOD.

But what about roll rate, climb and level speed? Swift and AoA are jousting but not getting anywhere. The devs only acknowledge the bug tracker so the information will have to collected and agreed upon and submitted there...

Before you can move forward..

And obtain results..

You first have to agree upon some basics and some pass fail criteria..

I have tried to open up the conversation of how to validate a flight model..

And the first thing that comes up is what I have seen come up time and time again over the past 20 years of flight simming..

That anecdotical evidence should be used to validate the flight model..

I have pointed out some of the short comings and pit falls of anecdotical evidence..

And why I feel it should not and can not be used in the validation of a flight model..

But all I get in return is more of the same and/or restating things I already knew to be true (CoD is 6DOF)

I have an open mind on this, if swift or anyone else can 'do' what they say can be 'done' than great! But as I noted, many in the past have made the same claims that swift is making, and nothing ever comes from it!

So, I don't see any 'results' coming from this conversation..

In that it is not a conversation..

It is just me expressing my concerns about anecdotical evidence, looking for a reply back that will provide some information that will elevate my concerns

But as noted above all I get in return is more of the same and/or restating things I already knew to be true (CoD is 6DOF)

I can not say I am surprised, in that this is not the first time this has come up in the past 20 years of PC flight sims

And I suspect it will not be the last

I keep hoping someone will prove me wrong about anecdotical evidence, in that the more data the better!

But it has not happened yet

Your problem, AoA, is that you only accept results that are in accordance with your philosophy. I'd say IL2 1947 came up with results that used anecdotical evidence where hard data was not available and the job was not bad. You refuse this on a categoric basis and that is why we won't get anywhere in this discussion.

I do not convince you obviously.

You don't convince me either because I do think that anecdotical evidence can be used as a support (also because I do not believe your claim that those spit pilots if outturned by a 109 would inevitably have been killed. I am convinced that there would have been sufficient cases of lucky blokes who would have escaped nonetheless to report about them being outturned by a 109. Now even if their number would have been small we have to see that there is just zero accounts on this).

We might continue jousting but this won't lead to anything. So let's agree that we disagree.

Not true

I am willing to accept anything, as I noted, I have an open mind on this..

As a mater of fact, 20 years ago I was making the same argument your making now!

But over the past 20 years I have come to the conclusion that it can not be done (read I and others tried it)!

As noted, I wish someone could prove me wrong on this!

So, who knows, maybe you are the one who can do it?

But up to now you have not provided anything to elevate the concerns I have brought up!

To re-cap, I have brought up two concerns (two of many, but the two I find to be the most important)

1) anecdotical evidence is typically, if not always a one sided story
2) anecdotical evidence is written by those who lived to write about it

For Examples..

WRT item 1) You will be hard pressed to find an after actions report that has input from both the axis and allied pilot with regards to the encounter (say dog fight).
WRT item 2) Using your example of 1,000 Spitfires saying they could out turn a 109, you don't know how many Spitfire pilots were shot down trying to turn with a 109.

Explain to me how you account for these two items in your statistical analysis and than maybe I can start to see it from your point of view..

Because you just saying 'this method worked' wrt IL-2 explains nothing..

And has that used car salesman "trust me" feel to it..

Better yet, give us an example of how you applied this method in IL-2!!

Just one!

Than maybe I can see it from your point of view?

Interesting debate, I thought I'd throw my 2 pence worth in..

You're both right, you need the maths, but you also need the combat reports.

You do the maths, then check to see if what's happening relates to what actually happened.

As far as I know combat reports and pilot's recollections are the only record of the use of these aircraft in the role they were designed for, combat.

I've read literally hundreds of combat reports from the Battle of Britain, both sides. Most of these guys were professionals, and eventually if you read enough, you can build a picture of what happened. OK, there's no numbers, but it's foolish to disregard them.

As Geoffry Wellum P/O 19 squadron BoB said "People ask me how can I remember it all, I just say, how could I forget?"

Read Brian Lanes account of a turning battle with a 109 where he sees the aileron snatch on the 109 , read Gallands stories of diving down onto Spits and being able to engage and disengage at will. Both from men who knew what they were doing.

The truth is a blend, where the math's ends the history helps.

Don't be partisan about it, there's enough people on here from both sides with enough knowledge to make CLoD/BoM the definitive sim.... If everyone would just stop arguing....

There you go, I think they call this "sitting on the fence".. oh well.

+1


(Nothing wrong with fence sitting...or is there? ;) )

Well if we are using anecdotal and pilot accounts lets throw these into the fire:

http://www.virtualpilots.fi/feature/articles/109myths/

I stongley urge the red fliers especially to read this. Its a shed load of pilot accounts with sources, all about the 109 and what an Uber plane she really is! :-P



I found this:

http://www.rolfwolf.de/daten/E4/Emil.html


http://www.rolfwolf.de/daten/E4/Emil_html_4785a2b8.gif
I assume these are full throttle speeds.

Höchstgeschwindigkeiten in Steig/Kampfleistung (Tabelle)
I assume this is TAS

0km 460km/h

1km 480km/h

2km 500km/h

3km 520km/h

4km 540km/h

5km 555km/h

6km 555km/h

7km 550km/h

Yes farber the 109 is slower than it should be, i remember seeing this on aonther thread somewhere. I think if they can get the speed, climb rate, turn rate and acceleration of the planes sorted that would go along way to the realistic settings, then add plane specifics after, such as stalling in the spits in hard turns or aerliron snatching in the 109 with the slats etc. We'd be getting there.

Is the basic info available as fact? If so then the basics shouldnt be a problem for the devs to sort out, and in my opinion should have done already.

Yes macro, I think which ever way you look at it people would be happy either way if the figures added up for all aircraft - mathmatically or by accounts.

Thing is the devs dont come here. Only B6. If you want somethign doing you have to do the hard work then submit a bug report. We all know the phantom (ghost) formations were here from the start, people spoke of them on this forum but the devs did nothing because they didnt know, only after I got off my backside and submitted a bug report and evidence (ntrk) did they even know about it. The next patch is supposedly the steam official and after which no more changes specific to clod will be added - as I have read. So its vitally important we get it done now!

POST 19:

http://forum.1cpublishing.eu/showthr...t=32600&page=2

I think the devs and the community would be best served by focusing on modeling the comparative differences between the fighters. Using historical documents, pilot testimonials, and any other sources available to create a flight model that feels historical. Let's ask ourselves some basic questions about the 3 major single seat fighters of BoB. In order how do the aircraft rank in _____ performance:

High Alt Speed:
Low Alt Speed:
Acceleration:
Climb:
Dive:
Roll:
Turn:

Maybe this should be a different thread as we, as a community, might come to some kind of agreement of what we would expect to see without focusing on absolute numbers.

From what iv read in reports and such

High alt speed spit slightly faster
Low alt 109 slightly faster
Roll: spit rolls slower at high speeds but about same at slow speeds. The 109 more stable at slow speed roll due to slats.
Spit could catch 109 accell in dive with+12 boost. 109 Elevator very heavy and hard to pull out of dive at high speeds.
Iv read the common tactic of steep but rarher slow climb of 109 was actually used by 109 pilots to get away from spits. Sounds like this is realistic in game.

Turn rate in spit was better that 109 when pushed to the limit, would need some sort of stall characteristic in spit for game balance.

Am i right or well off the mark? Not read enough about hurri to comment my opinion

I read exactly the opposite.

Spit faster at low level, 109 faster at very high altitude.
Spit rolling slower at very low speed, both Spit and 109 ailerons becoming very hard to move at speeds above ~ 600 km/h / 400 mph.

Spits controls overall slightly less heavy at high speed.

I also don't see what the 109 slats have to do with rolling or why the plane would be more stable because of them.

Just make them the same then pilot skill will be the wild card:-P

We did that briefly in ATAG's Server #2 a couple of weeks ago. The Engine Temperature Management was temporarily switched off so we could evaluate the effects of radiator drag without overheating the engines. (Radiators are closed by default and cannot be opened). The 109 E4 and the Spitfire MK 1a 100 octane had the exact same speed at sea level at full WEP (109) and 11 lbs boost (Spitfire). Both aircraft would travel literally wingtip to wingtip for miles above the waves going full out - neither aircraft gaining an inch on the other. On cue (using Teamspeak) both aircraft were then pulled hard up into a vertical climb, engines remaining at full throttle WEP/11 lbs boost. Both aircraft climbed to the same height wingtip to wingtip, stalling out at precisely the same instant.

We did this online so we could easily do plane vs plane comparos, but you can test this easily offline with your favourite aircraft simply by unchecking Engine Temperature Management in your Realism Options. The flight models tested to be the same offline and online.

This was a very brief test on Server 2, it was soon put back to Full Switch. But for a brief time it was exhilarating to fly a Spit in equal terms with a 109. Makes for some very long -- and exciting -- dogfights between equal pilots. Once Engine Temperature Management is turned back on, the Spits are saddled with huge, no......make that HUGE.....radiator drag penalties in terms of square area, drag coefficients, and no apparent modelling of the Meredith Effect.

Don't get me wrong..

I think combat reports are great for many things..

Just not great for validating a flight model!

Combat reports say more about the men and their mind set and their tactics..

But very little about the planes performance!

I will say this, you can gleam flying qualities from combat reports.. Stuff like

'I felt a slight buzz in the stick just before the stall while turning with the 109'..

But that description tells you nothing about the stall speed at which this occurred..

As I already pointed out..

Most combat reports don't include enough info to recreate the scenario in the game to see if you get the same results in-game..

Unlike real world data (test reports) that are performed using strict and repeatable methods..

For example..

I can recreate an ROC test in-game using the same real world methods to see if the real world results match the in-game results..

But how do I recreate a scenario to test from a combat report that says..

'In my Spitfire, I dove down on a 109, who spotted me at the last second and tried to evade me before I shot him down'

You cant!

There is not enough information there to recreate the scenario to see if the in-game results match the real world results..

That and the results depend more on the relative pilot experience..

That is to say assume you did try to re-create this scenario in the game..

Put a good pilot in the 109 and a Cherry in the Spitfire and there is a chance the 109 will NOT get shot down..

Does this test prove the 109 flight model is uber and the Spitfire flight model is broken?

NOT AT ALL!

All this proves is the relative experience of the sim pilots involved in the scenario affect the outcome more than the performance of the plane!

Same can be said wrt the orginal combat reports (anecdotical evidence), you don't know how much of 'it' was due to the relative experience of the pilots!

As in was the Spitfire pilot able to turn with the 109 because he was a better pilot?

All in all do we really want our flight models tweaked based on the results of some sim pilot's atempt re-create of a poorly documented WWII event?

I THINK NOT!

But I digress!

Combat reports are also useful to gain in site as to what was actually going in the trenches vs. what the generals thought was going on..

A good case in point is the whole 100 oct usage

As noted

Combat reports are great for determining how the pilots used these aircraft and the tactics they used..

Just not good for validating a flight model

Like in the stick buzz example above..

We know it stalled (the event)
We know the pilot felt something in the stick before the stall (the useful flying quality info)
We DON'T know what the stall speed was (what is needed to validate the flight model)
We DON'T know what the throttle setting was (what is needed to validate the flight model)
We DON'T know what the flap setting was (what is needed to validate the flight model)
We DON'T know what the e state was (what is needed to validate the flight model)
We DON'T know what the altitude was (what is needed to validate the flight model)

This list goes on but you should be starting to see my point

TOO MANY UNKNOWNS!

Problem with that method is you can have two people read the same reports and draw two very different pictures of what happened

That is the problem with human nature

Where as with math

1 + 1 = 2

And nobody but raaaid could disagree with that! ;)

A good example of tactics

But not a good example of how to validate a flight model

All that statement really proves is the plane with a better 'e' state will control the fight, until that pilot does something stupid to give up his 'e' advantage! ;)

And here is a perfect example of what I was refering to, that being how two people can read the same 'accounts' and get different results

Where as 1 + 1 = 2 in real world test data and you would be hard pressed to find anyone to disagree with that! ;)

1+1=10 ;)

I stand corrected.. raaaid and JtD! ;)

ok maybe i got it completly wrong lol! :confused:

i thought the slats were the to give stability at low speeds? but maybe wrong about that also :confused:

And i think AoA is correct, math is math. it it adds up it cant be denied.

best get your calculator out mate and get to work cos that sort of math well beyond me lol :(

1+1=11 :P

I wasn't writing that i read the same accounts (no idea what accounts he read anyway, definately never read that the Spit rolls worse than the 109 E at high speed though) or that what i read is (more) correct.

I think these planes are quite well documented, as opposed to WW1 planes for instance. I also wouldn't say that those two planes "feel" totally unrealistic regarding rollrate, turnrate or whatever in CloD, except for the too low speed of these planes, unlikely engine reliability (impossibility to run the Merlin using historical limits) etc.

I don't think we would have many FM discussions, if the speed would be close to the avaliable data.

Ok, Ill reword it and remove the word 'the same' to read as follow..

And here is a perfect example of what I was refering to, that being how two people can read 'pilot accounts' and get different results

http://i51.photobucket.com/albums/f3...Ball/Spit2.jpg
http://i51.photobucket.com/albums/f3...Ball/Spit3.jpg
http://i51.photobucket.com/albums/f3...Ball/Spit1.jpg

From the 1941 study, it sounds to me that hi-speed rolling was not a strong point

This is a Spitfire V with metal covered ailerons, tested up to 300 mph. The Spitfire I/II with fabric covered ailerons are a lot worse, and at 400 mph IAS pretty much hopeless - ineffective ailerons combined with a rather flexible wing. British tests indicate a roll rate of about 12°/s at 400 mph with 50 lbs stick force for early Spitfires - in other words half a minute for a 360° roll.

Also sorry for the cheap joke above, but I would say that while people may not disagree on the math, they may very well have different opinions regarding the input and different interpretations regarding the output. I'd also say that anecdotal evidence is valuable in getting input and interpretation right. For example, popular numbers regarding sea level top speed show the F4F to be faster than the A6M-2, however, anecdotal evidence from both sides agrees that the A6M-2 could and would outrun an F4F. A good enough indication that the numbers are not plausible and some research is warranted...but data for the A6M-2 just isn't around in quality and quantity as it is for say Spitfires and 109's.

Rolling was never really a Spitfire strength, partly because of the large area of wing tip outside of the aileron; the clipped-wing Spitfires had a better roll-rate at all speeds than those with conventional wing tips while those with pointed, high altitude tips were worse. Another part of the problem was the fabric covered ailerons, still fitted to the NACA Spitfire Va, which tended to "balloon" at high speeds, further reducing their effectiveness.

Which is why the NACA report specifically notes that metal ailerons were fitted to the Spitfire Mark VA tested, right?

As you may know, he's counting, correctly, in binary.

Because leading edge slats were fitted for exactly to this reason. Its no coincidence that slats cover the wing area ahead of ailerons, and maintain steady airflow without stalling at that part of the wing. Slats allow for higher Angle of attack without stalling - meaning the airplane is still controllable is rolling plane. The brief aileron snatching noted on the 109E while the slats deployed, until fully open is also due to this reason. It was fixed on later models of the 109 though, either through the redesign of the wing or through the redesign of the slat actuating mechanism.

Designers always aimed to maintain aileron control near the stall, ie. that the wing root would stall sooner than the part before the ailerons, so that ailerons remain effective. Slatless airplanes typically aimed for this by using washout, a sort of twist in the wing that gave the outer wing less AoA in any flight condition, and a result delayed the stalling point and made the ailerons effective longer. This of course decreased the lift generated by the wing in all conditions, since lift is more or less equal to wing area x AoA. Though slats do the same, their plus side is that they only deploy when needed, and otherwise the aircrafts wings develop their full lift potential. Therefore, they combine the best features for high speed flight, TO/Landing and turn fight.

I did see that in the report...back then, from the graph, would it be safe to watch for/anticipate that a pilot would favor/maybe even trained, to favor doing a roll to the right.

Also, I'm always amazed at your sig, taxiing must have been hell with that line of sight he has, I wish it was modeled in this sim as-well (our pilot seems to sit just a little higher). Do you have any history of the plane and pilot.

My bad -the NACA Spitfire had metal covered ailerons, I should have absorbed the first sentence before reading the report ;) - still, that does not invalidate anything I said about the damping effect of the wingtips on the Spitfire's roll-rate. A report on a clipped wing Spitfire V vs standard bears this out:

http://i91.photobucket.com/albums/k3...-page-005a.jpg
http://i91.photobucket.com/albums/k3...s-page-006.jpg

It is interesting to see how small aerodynamic alterations can alter flight characteristics - the total area of the wingtips removed was 12sq ft but, because this was all outboard of the ailerons, removing the wingtips increased the aileron's effectiveness up to 25,000 feet. It probably increased the torsional stiffness of the wings as well.

Just for interest the P-47N also showed the benefits of "clipped" wings:
http://i91.photobucket.com/albums/k3...e-page-003.jpg

I think in that case, the pilots got different results.

Unless you really try very hard to make one plane appear better or worse than the other, ie abusing historical pilot reports to support your point of view. But who cares. :-P

I generally base my idea of how these planes compared (maneuverability wise), on reports of pilots, who flew both (or more) types. And most of those reports fit each other exceptionally well. Which might not be the "correct" approach, but atleast it rules out some bias.

(sorry for cutting your post)

I'm totally aware of that and how slats work, but i don't think that's what macro meant when he compared slow speed rolling. But i probably misunderstood his post or interpreted it wrongly.

Anyway, yes, in the case you describe, slats definately help rolling and are in case of the 109 (lacking washout) a requirement for controllability at critically low speeds / high AoA.

So yes, the slats help, when they come out. Wether or not they are an advantage compared to washout or similar design features of a plane, regarding roll "performance", is a different thing though.

http://www.rolfwolf.de/daten/E4/Emil.html


Leistungen

Motorleistungen DB601A

Kurzleistung (1 min) 1100PS bei 2400 U/min 1.4 ata

Startleistung 990PS bei 2400 U/min 1.30 ata

Steig/Kampflleistung 910PS bei 2300 U/min 1.23 ata

Volldruckhöhe 4000m


http://www.rolfwolf.de/daten/E4/Emil_html_4785a2b8.gif


Farber, Bf109E-3 data, shown in Kennblatt has been obtained on 30 min Steig/Kampflleistung bei 2300 U/min 1.23 ata of aircraft with DB601A-1 'bei altem Lader'

Yes, this is TAS -Wirklich Geschwindigkeit

http://www.wwiiaircraftperformance.o...dbookcurve.jpg

I cant tell what your trying to say? - Just to add a graph? Mein Deutsch ist Scheiße

Vielleicht kannst du im schule zuruck gehen? Never mind, so's mine. :D

ok I got it. That graph is not full throttle but the limited combat setting and it also uses the old compressor which begins to loose Ata at 4500metres not 5000metres. Therefore the results are lesser than they should be in clod which seems to use the new compressor.

I wonder when the new compressor was rolled out into the field and at what rate?

Maybe.. maybe not

The point being..

Two people can read a combat report and draw two different conclusions..

Due to their background and biases

Where as..

Two people can add 1 + 1 and draw the same conclusion.. i.e. 2

Independent of their background and biases

In summary..

The problem with anecdotical evidence (aka after action pilot reports) is as follows

1) anecdotical evidence is a one sided story.
2) anecdotical evidence is written by those who lived to write about it.
3) anecdotical evidence does not contain enough info to recreate the scenario in-game.
4) anecdotical evidence is subject to interpretation.

For example of each..

WRT 1) As most of us know there are two sides to every story, and you will not find anecdotical evidence that has input from both side (axis and allied pilot) with regards to the encounter being described.

WRT 2) As most of us know a statistical result depends on the input data. The fact that anecdotical evidence was written by the pilots who lived to write about it excludes the pilots who did not live to write about it. Which makes the statistical result based on the anecdotical evidence biased/filtered towards pilots who lived to write about it. For example, assume there are 100 after actions reports describing how the pilot in his 109 out turned a Spitfire.. We don't know how many 109 pilots died while trying to turn with a Spitfire a thus un-able to write about it, was it 10, 100, 1000? We don't know.

WRT 3) As most of us know anecdotical evidence does not contain enough information about the scenario to recreate scenario in game to preform a test to see if the results are the same. That and the results in both case (real and recreated simulation) depend more on the relative pilot experience than the relative plane performance. That is to say change the pilots and you can change the outcome of the scenario. In essence you would be making changes to the flight modeled based on the relative experience of the pilots not the relative performance of the planes. This is why they did testing under formal and controlled conditions. (see sig)

WRT 4) As most of us know people are different, and therefore peoples take on events will be based on their life experiences. That is to say two people can read the same anecdotical evidence and draw to very different conclusions. Ask any cop who has interviewed several people who have witnessed a crime and they will tell you how peoples perceptions of events can vary. Where as 1 + 1 = 2 is not open to interpretation. (math ftw)

PS in each statement above, there are no absolutes! To improve the readability, in this post I removed my previous qualifying text where I said things like 'typically this' or 'typically that' or 'you will be hard pressed to find'. That is to say, you may be able to find a couple of cases where both an axis and allied pilot had input to an after actions report, but this exception to the rule does NOT change the rule. Also note, I am not saying math is without error, only that math is your best hope of being on the same sheet of music, in that it removes most if not all human bias and interpretation errors. In short, given time, you can track down the source of math errors, where as even with all the time in the world you would still be hard pressed to track down the source of human bias and interpretation errors! ;)

Comparative performance between the major single seat fighters from "The Most Dangerous Enemy" by Stephen Bungay.

http://i153.photobucket.com/albums/s...7/IMAG0145.jpg

That is a strange looking turning circles graph..

Altitude vs. Radius?

Where alt units state ('000 ft)

Something is strange here.. as in some info is missing (calc at a fixxed speed?)

I mean based on that graph the Spit is not able to go above 700ft in alt?

At a glance one might conclude that the Spit and Hurry have better turn radius..

But it is allmost as if that was done on purpose..

Does the book say more about that graph and how Mr. Ackroyd calculated it?

At first glance I though the altitudes were reading as 600,000 to 900,000 ft -

shades of the Dr Who Spitfires!

It appears the Turning Circle chart is poorly presented. It's not an X-axis/Y-axis graph at all that I can see. It's simply drawing the turning circle arcs showing the relative diameters; all at "000 ft" which I take to be sea level.

Secondly, have a look at the relative speed charts between the Hurricane I, 109 E3, and the Spitfire I. The speed curve for the Spitfire I looks remarkably like the one for the much-decried "Über Sissyfire IIa" in the current retail version 1.05, as does the curve for the E3 to the CoD v. 1.05 E3, and, by gosh.....there's JTDawg's old Rotol!!!!!

Obviously that chart is wrong and the author sadly misinformed. :rolleyes:

Typical....

Most of these history are written by amateurs who know very little about the science of aircraft.


I think the author is a Management consultant.

No doubt. Barely able to tie his shoelaces, I should think!

I did not say the guy was stupid, Snapper. He is very intelligent and well respected. He has also written some good books.

He is not an aircraft performance engineer or an aerodynamicist.