P-40 turn rate/Flight model check

[ZachariasX]

It was a nice read but it demonstrates what I mentioned earlier. This was a restored P-40E without weapons or ammo and with a later model Allison engine that gave about 80 extra HP at combat power and allowed higher boost overall.

Yes it is lighter and a tad more powerful. Still this does not change the basic flying characteristics.

 

Generally, I think performance whise the in game P-40 is very much spot on, maybe with the exception of accelleration in horizontal flight. This is *very* low as we have it now, but be it.

 

What I get from Tallmans writing is how much the "longitudinal instability" is of a gradual nature, yaw basically a function of speed and power setting. Not the oscillations along the vertical axis as we have it now as soon as you touch the rudder or the ailerons, yaw being induced by adverse yaw. Planes generally don't do that (not even sailplanes with their sometimes significant adverse yaw). Here, I guess we as customers are our own worst enemy, because we want this wobble as it is deemed "realistic". It was introduced back then and it is kept as a feature like the A20 gate throughout todays CPUs.

 

 

The easiest way we can get the P-40E improved is to prove the engine was much more durable than represented in game.

I somewhat sympathisize with the devs setting a very cruel limit there. It is my understanding that overboosting the engine just reduces time between service intervalls. To blow it up, you have to make it produce power such that it breaks something inside (20% more power will not do that) by application of too much torque on the shaft and gearings. But since in the game we get a siny brand new plane very time we take off, we could easily afford the engine to be flown at a power setting that is corresponding to a 1 hour service life. Myself, on WoL, I could run it at 5 min service life. With 3500 hp, I'd probably last that long...

 

 

Outside of my control. Crump has the documents. He had some kind of work engagement where he was busy, then apparently he caught the flu. I don't want to pester the man.

You're on it. This is all that matters.

[Dakpilot]

In certain situations overboosting will cause detonation which can cause catastrophic failure in seconds

 

Chers Dakpilot

[6./ZG26_Klaus_Mann]

With every uneven Bump that loads one Wing more than the other, like Passing a Thermal or any other area of rising/falling/turbulent air there will be an adverse Yaw Effect and sudden changes in Wind Direction will further Contribute to Yaw Wobble.

 

Another Problem I see with the P-40 and in Fact most other American fighters as well as the Spitfire is weight Distribution.

[306_Eugenio]

Few days ago I bought P40 just to complete my IL2 plane collection. It's quite a surprise for me that this plane instead of being average fighter is a total disappointment. I predicted that it'll be something similar to LaGG3 but a way or time that P40 is bleeding it's energy totally surprised me. It feels far worse than other planes even those with high wingload. Maybe it's just mine personal feeling, but for me It's also very slow in acceleration.

[19//Moach]

it actually accelerates in a more or less satisfactory (not completely, though) way if you go on and abuse the engine limits profusely

 

in "emergency mode", you can actually draw some surprising oomph from that crate, though only for short well timed bursts - hold it for longer than 30-ish seconds, and you get to learn how well it glides (about as well as a bag of bricks)

 

the lateral sway of the nose makes for a very unpredictable, uncharacteristically precarious flight experience, however - and this helps bleed out even larger gobs of your already scarce supply of energy (side slipping is a maneuver used precisely to slow down)

 

there are no pilot accounts which anyone on this forum has brought up that back up this tendency being anything besides completely wrong - the videos we've seen also support that it simply was not the case, and the p40 was in fact, a stable(er) aircraft than the one we got by a fairly substantial degree 

 

 

I would venture an educated guess that in good likelihood, the turn radius itself isn't wrongly modeled - but the effective turn performance that results from an overly conservative set of engine limits, (which are enforced in a rather extreme way) combined with the under-damped pitch and yaw moments (especially yaw) which are almost certainly incorrect, is nothing short of a major letdown for a combat pilot

 

 

currently, the P40 is the single hardest, most demanding type in the game - it takes about twice the concentration to do just about anything with it than with any other plane - I honestly doubt that if the real aircraft truly behaved THAT bad, it would ever have been accepted as airworthy enough for military service

 

expecting similar performance to the LaGG is indeed a very sound standard,  both were known as underpowered and heavy, though not necessarily poor turners - however, the LaGG holds its own with a much better ingame reputation than it historically had (players rarely call it a death trap) - the p40, does not (and players do call it that, quite often)

 

 

"death trap" is not a characteristic associated the P40 in any accounts we've found -- so definitely, something IS wrong with it - though only our upcoming data (hopefully soon) can really point out what exactly that is

Edited February 28, 2017 by 19//Moach

[Dakpilot]

Or the yaw/roll couple fix which likely will have more effect with P-40...

 

Cheers Dakpilot

[Scojo]

Few days ago I bought P40 just to complete my IL2 plane collection. It's quite a surprise for me that this plane instead of being average fighter is a total disappointment. I predicted that it'll be something similar to LaGG3 but a way or time that P40 is bleeding it's energy totally surprised me. It feels far worse than other planes even those with high wingload. Maybe it's just mine personal feeling, but for me It's also very slow in acceleration.

If you don't have a buddy or altitude, it's not going to be a very good fighter.

 

I like to take it with a bomb and a friend, that way I can blow some stuff up and then help with CAP. The 6 .50s, in my opinion, are a nice change of pace and also pretty good.

 

The plane's preferred location is definitely 14k+ ft. Up there you're much more likely to be above something and you don't have to worry about micro managing the engine too much. Then its dive speed and aileron authority give you good evasive and diving pursuit capability.

 

At the end of the day though you can't really take on fights in which you won't have a starting advantage.

 

But on topic with everyone else, I'm all for heavily looking into the FM. This is definitely one plane that can easily warrant the attention, especially given the fact that it's engine management is different from the rest of the planes currently in our hangers

Edited February 28, 2017 by 71st_AH_Scojo

[19//Moach]

Or the yaw/roll couple fix which likely will have more effect with P-40...

 

 

 

 

I have looked around for confirmation that this is being worked on, and couldn't find anything that wasn't at least several months (or even a year+) old in the official announcements

 

what source do we have to absolutely confirm that there is a yaw/roll stability fix waiting in the wings for a (hopefully soon to come) future update? - I can't seem to find it

 

 

could we be holding on to an unfounded fabrication of our own wishful thinking?  -- is there truly a yaw/roll coupling fix being worked on? or is this mere speculation?

 

'cause if this isn't being worked on - it pretty well should be

 

 

 

edit - so far I could only determine that the the only yaw/roll stability update was actually deployed with 2.004 - nothing since that has been mentioned about the subject in the developer diaries or Q&A thread - is there another source?

 

without an official source, we must then accede that there is possibly no such upcoming fix that we can rely on - and this makes our quest here all the more pressing, if we ever want a p40 that holds up to its historical counterpart

Edited February 28, 2017 by 19//Moach

[ZachariasX]

In certain situations overboosting will cause detonation which can cause catastrophic failure in seconds

 

Chers Dakpilot

Oh yes. But you hear the engine running rough when that starts to happen. On the other hand, has manifold temperature been an issue here, ever? Talk about asking for the engine to start "knocking". In the P-40 we have, there are hardly any cues beyond the maifold pressure gauge that your engine is overcompressing. (yes, technochat). The thing is, as the P-40 has automixture, overboosting is somewhat controlled by increasing mixture. The engine will start smoking a bit and performance does not increase that much anymore, even at increasing manifold pressures.

[Dakpilot]

I have looked around for confirmation that this is being worked on, and couldn't find anything that wasn't at least several months (or even a year+) old in the official announcements

 

what source do we have to absolutely confirm that there is a yaw/roll stability fix waiting in the wings for a (hopefully soon to come) future update? - I can't seem to find it

 

 

could we be holding on to an unfounded fabrication of our own wishful thinking?  -- is there truly a yaw/roll coupling fix being worked on? or is this mere speculation?

 

'cause if this isn't being worked on - it pretty well should be

 

 

 

edit - so far I could only determine that the the only yaw/roll stability update was actually deployed with 2.004 - nothing since that has been mentioned about the subject in the developer diaries or Q&A thread - is there another source?

 

without an official source, we must then accede that there is possibly no such upcoming fix that we can rely on - and this makes our quest here all the more pressing, if we ever want a p40 that holds up to its historical counterpart

 

Not deployed yet

 

Jason mention he has experienced the latest in house build of this roll/yaw couple update a couple of days ago and was  impressed with the results

 

25th Feb 2017

 

Really a great experience though and thanks to Petrovich for setting it all up. We also had some good discussions about our FMs and I've seen some of the improvements he's made to the rudder inputs and feels much better than before. I think you guys will like it.

 

 

 

Cheers Dakpilot

[19//Moach]

oh awesome - so it is a thing! sweet! - that's probably gonna help the Old Crate (they actually called it that back then) perform a bit closer to the real thing

 

 

this could potentially cure the wobble issue - and then if it does, I'm somewhat confident most of the performance problems should come down to the engine

 

 

and not to sound like we only want things that improve performance - the other obvious (and already proven) difference from the real plane is the seemingly "magic" coolant radiator we got -- there's no way to boil the thing on the ground, like the video I posted made so abundantly clear to be a big concern with that plane....

 

 

it actually would make sense to increase the boost "timers" and reduce cooling to match historical behavior -- it'd be far more in line with the behavior seen on all the other planes in the sim which normally overheat before exploding, whereas the p40 has it the other way around

Edited February 28, 2017 by 19//Moach

[ACG_KaiLae]

currently, the P40 is the single hardest, most demanding type in the game - it takes about twice the concentration to do just about anything with it than with any other plane - I honestly doubt that if the real aircraft truly behaved THAT bad, it would ever have been accepted as airworthy enough for military service

 

expecting similar performance to the LaGG is indeed a very sound standard,  both were known as underpowered and heavy, though not necessarily poor turners - however, the LaGG holds its own with a much better ingame reputation than it historically had (players rarely call it a death trap) - the p40, does not (and players do call it that, quite often)

 

 

"death trap" is not a characteristic associated the P40 in any accounts we've found -- so definitely, something IS wrong with it - though only our upcoming data (hopefully soon) can really point out what exactly that is

 

LaGG-3 in game doesn't have the manufacturing defects that were common on this plane, which made it frequently much less capable than the spec sheet lists. This isn't something that you would, or even should, see in the sim, but it makes a difference. Also...kinda suspect that the LaGG overperforms in some ways. Would really like to see where it lists the roll rate of this plane, but I think I might need to read russian to do that.

[Dakpilot]

LaGG-3 in game doesn't have the manufacturing defects that were common on this plane, which made it frequently much less capable than the spec sheet lists. This isn't something that you would, or even should, see in the sim, but it makes a difference. Also...kinda suspect that the LaGG overperforms in some ways. Would really like to see where it lists the roll rate of this plane, but I think I might need to read russian to do that.

 

Lagg 3 we have in game is series 29, quite different from earlier versions, and again quite different from last series 66 version of 1944

 

earlier production versions with 105PA engines were not much regarded, and there were production quality issues, but that reputation should not be pushed on all versions 

 

Cheers Dakpilot

[BlitzPig_EL]

Indeed, the last series was faster than the La5 as well, not sure how it compared to La5FN but I do think it might have been faster at higher altitude.

 

Back to the P40, I do hope that when the documents are obtained that a well laid out case can be presented to the developers to sort out the Hawk's aero issues, and have it more realistically reflect it's place in history.

 

I know that may be a tall order, as they way we use planes in the sim is a far cry from how they were used historically, but even in that context, the P40 is so different from the way that any other aircraft in the sim behaves, that it really begs the question of why it got this way.

[Scojo]

I know that may be a tall order, as they way we use planes in the sim is a far cry from how they were used historically, but even in that context, the P40 is so different from the way that any other aircraft in the sim behaves, that it really begs the question of why it got this way.

IMO, you can't blanket the sim with that statement. SP missions, organized MP events, and continuous MP servers are all very different flying environments. Of course continuous MP servers are going to be a-historical, but I don't think well made SP missions or MP missions with structured teams/squadrons would be extremely far from reality. Of course they will be to some degree, but I don't think it's too far off

 

In fact many accounts from the Eastern front I've heard sound pretty close to some of the engagements I've experienced in FNBF. Especially flying the IL-2.

 

WoL? Now that's so a-historical that it's pretty comedic

The only way to survive WoL in a P-40 is to always climb safely to 15k ft before going close to enemy territory lol

[BlitzPig_EL]

I flew some campaigns in the old IL2 where things were more historical, so I understand where you are coming from, but there will always be one thing that really does have an effect on how all of us approach sim flying, that cannot be simulated in the least...

 

Fear of death.

 

It is the ultimate cost, and consequence, of making a mistake in the real world of combat aviation, and I don't care how well crafted and immersive the mission, and how dedicated we are to flying as historically accurate as possible, that fear of death factor is never there informing our decisions.

 

Just how it is, and frankly I'd never want that much realism in anything I do for fun, except perhaps for riding my motorcycle, and driving at track days in the car, then that fear serves a real purpose.

 

[Scojo]

Well obviously...

 

But even that is better simulated in SP or structured MP missions as there's more incentive to be cautious when flying as groups. When I Lone wolf, I'm way more risky than flying with others since while flying with a group, I need to make sure I don't get in trouble so I can be there to help my squad if they get in a bad situation

[Farky]

A lot of good points and I hope the developers will address most of them. However, there are a few issues listed that I have a somewhat different opinion on:

 

First of all is the wobbling: I mind the wobblieness very much and the way some aircraft in this sim wobbles puts me off and I simply don't fly them very often for that very reason and those are the F4, G2 and in some sense the P-40 only as we know the P-40 has other issues as well. Also, no cockpit videos I have seen support this kind of rubber band connection between roll and yaw. So here I would definitely like to see a fix.

 

 

I think we are on the same page here. I don't mind very decent wobbling, but I hate this in F4, G2 and P-40 too.

 

 

Second is the horizontal manouverability: I too find it difficult to reconcile pilot accounts with the in-game peformance we see but this I think is coupled to my last point which again is about the power:

 

AFAIK the Allison could be run at higher boost for extended periods of time and probably was. I you assume that pilots broke the rules on this point then I think you can reconcile the pilot accounts with the calculated performance because if you assume the higher boost then the P-40 is right there with the others so no reason it would not perform as well as the others.

 

...

 

So to sum up I still think this (the abuse of the official power limits) is the reason behind the pilot accounts that the P-40 IRL could hold it's own against fighters which on paper had a higher P/W ratio. It's either that or the P-40 was endowed with some special aerodynamic properties that the other designers missed out on incorporating.

 

However, Using Occam's razor my money is still on the pilots bending the boost rules in the heat of combat rather than the P-40 being an aerodynamic unicorn.

 

While I agree with your logic and with the fact that Allison could be run at higher boost for extended periods of time, I am still very nervous from the idea of "unrestricted" overboost. Because if we fix horizontal manouverability this way, we will create another problem - top speed and climb rate of P-40 at low altitude will be too good. As I have never read that P-40 was less manouverable than Bf 109, I also never read anything about P-40 faster than Bf 109. I wrote this few times - we need to be very careful with overboost, it can be gamechanger (and not in good way).

 

We can probably explain a 360° turn in 19 seconds of P-40E with overboost, but in that case, why they don't used overboost for maximum speed? And why report for P-40C shows 360° turn in 18 seconds? Because I am pretty sure they don't use overboost in P-40C, C-model Allisons weren't very tolerant to abuse.I am really confused by this.

 

Another thing - I can tell you right now that acounts about use of overboost in maneuvering fight do not exist, is it always about use to disengage and running away. Even later, on P-40s with official War Emergency Ratings (WER), pilots very rarely used overboost. Pilots of late P-40s do not use WER on regular basis in fight and still all acounts from both sides are saying that P-40 was better in turning fight. I am not saing that overboost was never used in dogfight, but we don't have any proof for this.

 

I am not against use of overboost in P-40E, 56inHg for 5 minutes limit seems ok to me. But in my opinion is absolutely necessary to correct the behavior of oil and coolant temperature first. This should prevent unhistorical prolonged slow speed dogfights with overboost. Because the player will not be able to keep the temperature within maximum limits for long time, as was the case in real airplane.

 

 

IMO, you can't blanket the sim with that statement. SP missions, organized MP events, and continuous MP servers are all very different flying environments. Of course continuous MP servers are going to be a-historical, but I don't think well made SP missions or MP missions with structured teams/squadrons would be extremely far from reality. Of course they will be to some degree, but I don't think it's too far off

 

In fact many accounts from the Eastern front I've heard sound pretty close to some of the engagements I've experienced in FNBF. Especially flying the IL-2.

 

You are basically talking about use of historical tactics. But another thing is for example unhistorical use of flaps in turning fight or flying on mission with less than 100% of fuel. I understand why we all do this, including me, but we can not pretend that we are always flying same way as pilots in WWII. Because we don't.

[19//Moach]

Another thing - I can tell you right now that acounts about use of overboost in maneuvering fight do not exist, is it always about use to disengage and running away. Even later, on P-40s with official War Emergency Ratings (WER), pilots very rarely used overboost. Pilots of late P-40s do not use WER on regular basis in fight and still all acounts from both sides are saying that P-40 was better in turning fight. I am not saing that overboost was never used in dogfight, but we don't have any proof for this.

 

 

 

they totally did overboost it, here: https://docs.google.com/viewer?url=http%3A%2F%2Fwww.wwiiaircraftperformance.org%2FP-40%2FV-1710_Service_Use_of_High_Power_Outputs.pdf

 

 

seems those guys were not at all shy with that throttle handle

 

sure, it's not good for the engine - but as stated, it did not immediately and reliably discombobulate after 30ish seconds at 45-50 inches as ours does - it reportedly did so at around 60~70" (damn!) within that time frame

 

 

 

the game considers anything above 43" to be "emergency power" - and allows a bit less than a minute of such, depending on conditions

 

 

the document above clearly points out that the limits set in game are at least 10" of boost too strict, against the real thing

[ACG_KaiLae]

I don't think anyone is advocating unlimited overboost. However, having 3000 rpm automatically as "combat mode" regardless of manifold pressures may not be accurate. Also one source I read said that as rpm came up the manifold pressure would go down, not up like in game.

 

It's just very fragile as done now.

 

Also, people complain about the wobbling, but what I notice is the "slow speed" handling. At 150-180 mph the plane is very mushy handling overall. Anyone know why, because this doesn't seem to be something remarked in the documentation.

 

Also, what is the in game plane calculated clmax now? JtD listed it at 1.1 in another thread.

Edited March 2, 2017 by Kai_Lae

[unreasonable]

Also, what is the in game plane calculated clmax now? JtD listed it at 1.1 in another thread.

 

I doubt that very much. Using the Tech Specs data the CLmax is 1.32-1.35, depending on the speed/weight configuration: which is a little higher than that for any of the other Soviet fighters. 

[Scojo]

You are basically talking about use of historical tactics. But another thing is for example unhistorical use of flaps in turning fight or flying on mission with less than 100% of fuel. I understand why we all do this, including me, but we can not pretend that we are always flying same way as pilots in WWII. Because we don't.

No I'm not just talking about tactics. You absolutely missed the point I was making and I never said we fly 100% like they did IRL. There's much more to recreating the experiences in the theatre than just not using flaps and taking 100% fuel...

Edited March 2, 2017 by 71st_AH_Scojo

[Scojo]

Nice find, Moach. That was an interesting read.

 

And I feel the same way at slow speeds in the 40, Kai. It almost feels like there's no real air flow around parts of the plane at slower speeds

[Farky]

they totally did overboost it, here: https://docs.google.com/viewer?url=http%3A%2F%2Fwww.wwiiaircraftperformance.org%2FP-40%2FV-1710_Service_Use_of_High_Power_Outputs.pdf

 

 

Generally? Yes, they did use overboost. In dogfight? We don't know. This Allison memo from December 1942 is well known, if you like it, you will love this -

 

 

 

Engine was discussed in detail here -https://forum.il2sturmovik.com/topic/21234-p-40-engine-settings-i-found-them-bit-weird/ , I highly recommend read this thread. It is long and messy thread, but there are very good informations about Allison. Here is my opinion from there - https://forum.il2sturmovik.com/topic/21234-p-40-engine-settings-i-found-them-bit-weird/?p=378272

 

 

I don't think anyone is advocating unlimited overboost.

 

You are absolutely right, that's why I wrote "unlimited" and not just unlimited. Next time I will write it more clearly, my bad.

 

 

However, having 3000 rpm automatically as "combat mode" regardless of manifold pressures may not be accurate.

 

So what limit do you recommend and why? Maximum limit for Normal Rated Power was 2600 rpm in all manuals.

 

 

Also one source I read said that as rpm came up the manifold pressure would go down, not up like in game.

 

Strange, can you post an exact quote?

 

 

No I'm not just talking about tactics. You absolutely missed the point I was making and I never said we fly 100% like they did IRL. There's much more to recreating the experiences in the theatre than just not using flaps and taking 100% fuel...

 

I think i get your point Scojo. You are talking about philosophy "flying like pilots in WWII as close as possible", I get it. This philosophy is however implemented through use of historical tactics and procedures, that was my point. I know you don't said we fly 100% like they did IRL. When I wrote "we can not pretend that we are always flying same way as pilots in WWII", it was about players in general, not specifically about you and your post.

 

 

Nice find, Moach. That was an interesting read.

 

If document posted by Moach is new to you, you can find very interesting informations also here, in thread about V-1710 - https://forum.il2sturmovik.com/topic/21234-p-40-engine-settings-i-found-them-bit-weird/

[ACG_KaiLae]

Nice find, Moach. That was an interesting read.

 

And I feel the same way at slow speeds in the 40, Kai. It almost feels like there's no real air flow around parts of the plane at slower speeds

See the thing is that this isn't very slow. IIRC 150 is recommended climb speed, and these speeds are about double stall speed where it would make sense to be mushy. I'd really like to know what drives this FM wise because I doubt the upcoming rudder update will correct this.

[Scojo]

See the thing is that this isn't very slow. IIRC 150 is recommended climb speed, and these speeds are about double stall speed where it would make sense to be mushy. I'd really like to know what drives this FM wise because I doubt the upcoming rudder update will correct this.

Oh I know what you mean. I was implying it was slow, just talking about the lower end of its operable speed range

[ZachariasX]

 

 

So what limit do you recommend and why?

 

rpm x torque[Nm] / 9.55 = Power[kW]

 

You need to factor rpm with torque to get the (combat) power. You can windmill the engine at 3000 rpm with hardly any power output from the engine. rpm alone doesn't say much about the power output. But it for sure limits the max power that is theroretically possible.

[Farky]

rpm x torque[Nm] / 9.55 = Power[kW]

 

You need to factor rpm with torque to get the (combat) power. You can windmill the engine at 3000 rpm with hardly any power output from the engine. rpm alone doesn't say much about the power output. But it for sure limits the max power that is theroretically possible.

 

Ok. So, what do you recommend?

 

Very complex simulation of engine with all details? Ain't gonna happen in PC game.

 

Or set limit for Nominal (unlimited time) rating to 1000 bhp (in case of P-40E)? I'm afraid, that this i not only about power. You can reach 1000 bhp with different combinations of MAP and rpm of course, but sometimes engines do not like some of them or they are very inefficient. Limits in manuals are not only just limits, but also recommended (most efficient) combinations of MAP and rpm. For example, if we run V-1710-39 on 37.5inHg/2600rpm, we get 1000 bhp. If we run on 37.5inHg/3000rpm, we get just very slightly more than 1000 bhp - because higher rpm = higher friction horsepower. In game, you are little bit faster with 37.5inHg/3000 rpm. However, the difference is less than 5 mph. In other words, following limits (combinations of MAP and rpm) in the manual is a good idea. For lot of reasons, some of them do not play a role in the game, just because game is in comparison to reality simplified.

 

Anyway, when you run engine in game with higher rpm than 2600, it triggers Combat power. But triggered Combat power doesn't mean that from this moment you have only five minutes. For example, we can run on 37.5inHg/3000rpm for more than 10 minutes (13-14 min) without any problem. Engine "timeouts" in the game are generally far more sophisticated than it might appear at first glance. There is also incorporated a certain element of randomness, if I remember well, engine is not damaged always in the same time. But I could be wrong, it's been a while since I tested it.

 

Are engine limits in game perfect? No, of course not. For example - engines usually withstand much longer run on the combat power than five minutes IRL, all of them. On other hand, we really need some rules/limits for our twisted simulator reality, because the game will never be able to truly simulate reality.

 

Since I have no idea how exactly are engines simulated in the game (i.e. I know nothing about "guts" of the game), I cannot say that it could be done better. In an ideal world, where simulators have an unlimited budget, I would call for much more sophisticated simulation of a engine. Unfortunately, we are in real world.

[19//Moach]

(...)

 cannot say that it could be done better. In an ideal world, where simulators have an unlimited budget, I would call for much more sophisticated simulation of a engine. Unfortunately, we are in real world.

 

it definitely could be done better - at least as well as the other planes in the fleet - the others handle in ways that one can accept as "close enough" to how it is in the real world - this one unfortunately, falls way short of the bar they set

 

we're not actually asking for anything beyond the ordinary here -- the P40 is at a massive contrast to every other plane in the game, due to how unforgiving it is to even the slightest shift of attention - what we got is just unairworthy as it stands, scoring at least a 6~7 (8~9 more likely) in the scale:

 

this would have most likely never been accepted into service had it performed in such a dismal way as represented in the sim - it is therefore wholly unconvincing as a depiction of the real thing -- it simply cannot be possible that a plane this dangerous would have received a reputation of anything better than "widowmaker" - though it is held in high regard by its veterans - there are no known accounts of traits like "unpredictable" or "extremely demanding" associated with this plane

 

what we have here is a plane that's not measuring up to even the most conservative of performance expectations, let alone the many positive historical accounts of it which have been brought up since it's release... combat is not even considered, as mere survival at the elusively fleeting controls is in itself a battle

 

 

 

all we ask is that it be brought to the same standard of quality set for every other plane in the simulator - this one stands out as a grossly sub-par exception to the otherwise very credible modelling of aircraft handling characteristics in the IL2 series

 

 

 

 

further reading on pilot assessment of aircraft handling: https://docs.google.com/viewer?url=https%3A%2F%2Fntrs.nasa.gov%2Farchive%2Fnasa%2Fcasi.ntrs.nasa.gov%2F19690013177.pdf

Edited March 5, 2017 by 19//Moach

[Farky]

it definitely could be done better - at least as well as the other planes in the fleet - the others handle in ways that one can accept as "close enough" to how it is in the real world - this one unfortunately, falls way short of the bar they set

 

 

Are you sure that you are talking about same thing as I do? Because my post was exclusively about simulation of an aircraft engine in game.

[19//Moach]

Are you sure that you are talking about same thing as I do? Because my post was exclusively about simulation of an aircraft engine in game.

 

I did mean it more in general - but then again, there's no need for new technology to correctly represent a believable P40 here - it's probably just off in its parameters - and thus could indeed be a lot better

 

I also reckon the so called "engine timers" are very likely more than just that - it is not simply a matter of seconds before it blows up, and other factors are accounted for, no doubt

 

though nevertheless - it does blow up in the end, and most certainly does so well ahead of its real life counterpart

Edited March 5, 2017 by 19//Moach

[6./ZG26_Klaus_Mann]

I would rate it 3 to 4. 

[19//Moach]

found a study made on the effectiveness of the P40-E rudder upon the transitioning to the Merlin powered F series - which appears to be the point where yaw instability was introduced, there is no mention of inherent yaw instability prior to the F model, nor any comment towards an oscillatory "hunting" behaviour (aka: wobble)

 

 

read up - this is a very relevant find:  http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA800732

 

you can download the pdf from the link in there - there's a wealth of very specific charts on rudder deflections and yaw angles  - the kind of data that can be used to check against sim behavior for definitive quantifiable results

[Farky]

found a study made on the effectiveness of the P40-E rudder upon the transitioning to the Merlin powered F series - which appears to be the point where yaw instability was introduced, there is no mention of inherent yaw instability prior to the F model, nor any comment towards an oscillatory "hunting" behaviour (aka: wobble)

 

 

read up - this is a very relevant find:  http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA800732

 

you can download the pdf from the link in there - there's a wealth of very specific charts on rudder deflections and yaw angles  - the kind of data that can be used to check against sim behavior for definitive quantifiable results

 

"Cleaner" version of NACA report L-547 is here - https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930092648.pdf

 

Already posted and already tested - game is wrong. However, developers are working on something - DD150: "Our lead engineer has finished preliminary preparations and now works on making behavior of a plane while using rudder or side slipping even more realistic." We'll see if it solves "the sideslip problem" with P-40E, I hope so.

 

Btw, this study was reaction to issues with P-40E. And yaw instability wasn't "introduced" with P-40F. Just saying.

 

 

I did mean it more in general - but then again, there's no need for new technology to correctly represent a believable P40 here - it's probably just off in its parameters - and thus could indeed be a lot better

 

I agree, 100%. There's no need for new technology to correctly represent a believable P40E in game. I think we all agree with that.

[JtD]

I was away for a while, playing a bit of catch up now:

 

The 1.1 cl I was referring to comes from the turn time figures, not the maximum lift coefficient from level flight. It's totally possible that a higher clmax than 1.1 can be utilized in a turn, however, the developers figures don't use it.

 

The game does calculate lift from all sorts of sources, including the tail. However, if we take our reference numbers, we don't. So if the game gives the wing a 1.3 and the tail an additional something, we end up at 1.4 or so for our reference area. Still, we need to keep in mind that the ratio of lift area/reference area is larger on the P-40 than it is on several other aircraft, so we should not just say plane A has 1.35, P-40 has 1.35, so all is well. It would IMHO take away a bit from the P-40.

[BlitzPig_EL]

It is very easy for those of us that are not engineers to fall into the trap of just comparing numbers.  I have thought this since my early days in the original IL2.   There are many people that will make the argument that if aircraft A and aircraft B have the same wing loading then they will behave identically in turns, and other maneuvers.

 

This does not take into account airfoil type, wing shapes, wing placement, CG, etc...

 

I think this is one of the big problems we are facing with the P40, and generally in all aircraft to be fair.  The subtleties that make each aircraft different from one another are the hardest thing to do.  Hitting the well known performance numbers (time to climb, top speed,etc...) are much easier than how an aircraft actually "feels", and reacts to the real pilot.

[Holtzauge]

It is very easy for those of us that are not engineers to fall into the trap of just comparing numbers.  I have thought this since my early days in the original IL2.   There are many people that will make the argument that if aircraft A and aircraft B have the same wing loading then they will behave identically in turns, and other maneuvers.

 

This does not take into account airfoil type, wing shapes, wing placement, CG, etc...

 

I think this is one of the big problems we are facing with the P40, and generally in all aircraft to be fair.  The subtleties that make each aircraft different from one another are the hardest thing to do.  Hitting the well known performance numbers (time to climb, top speed,etc...) are much easier than how an aircraft actually "feels", and reacts to the real pilot.

 

While it is true that a different wing profile and a different wing plan form will have an effect I think the differences are in general rather small and second order effects: The reason for this was that profile technology at the time was mature and it was not until the laminar profiles arrived that you got profiles which were significantly different. If you look at the profiles of the time they all had pros and cons and the profiles selected was as always a compromise. C.g. is of course also important but if you were to look at this as well I would venture to say that most designs either have the c.g. pretty much where it should be or carry ballast to get there. So the ballast fixes the c.g. but at a cost in weight and then we are right back where we started, comparing power- and wing loading.

 

Another way of looking at all of this it is to assume that there is a certain level of technological know-how at a certain period in history and that designers in different countries and different firms were pretty much on par only they used slightly different approaches in their designs. I think this is the case not only in aeronautics but in most walks of engineering life. For example, take formula 1: For years during the 60 and 70’s there were V8’s and V12’s. They both did the job but in a slightly different way. Had either V8’s or V12’s been significantly better, the designers would have converged and gravitated rather quickly on one design but they didn’t. Different ways to skin the cat that’s all. There are of course paradigm shifts now and then: For example, when the Germans fielded the thick Göttingen profiles on the Fokker Dr1 and D7. But when that sort of thing happens the other design firms are rather quick to pick up on that and hop on the bus. The dawn of the jet age and swept wing technology is another example: If breakthrough technology arrives, all design firms are rather quick to pick up on it.

 

OTOH hand the P-40 is as far as I can tell a very conventional design: Nothing new or distinguishing either in terms of engine, propeller technology or aerodynamics and hence there is every reason to believe it will perform in the same bracket as the other contemporary designs, i.e. ruled by the same laws of nature where a well designed airplane will perform pretty much depending on the P/W and W/S ratios the designers managed to get in there and not depending on if the designer were fuelled by blini, hamburgers or Sauerkraut.....

[ZachariasX]

 

 

Very complex simulation of engine with all details? Ain't gonna happen in PC game.

Depands what you call complex. I think engine management is rather complex, as for calculated power output it uses air desity and temperature (humidity, maybe, maybe not) to calculate maximum permissible compression ratio. as well as expected power output at given rpm.

 

The "problem" that I have with that is that I find it not very realistic. I mean you hear very, very clearly once an engine starts to "knock". I don't get any acustic cues (remember the funny sound of excessive "Höhengas" on the D.VIIF in RoF?).

 

On the other hand, people are flying at full power with rads closed as if a radiator had least drag when it's closed. Not to mention that you WILL blow up a real world engine quickly by doing so.

 

We have a complex situation here. But as it is now, people are using th systems in a way that is not as you would operate a real world engine.

[Farky]

Depands what you call complex. I think engine management is rather complex, as for calculated power output it uses air desity and temperature (humidity, maybe, maybe not) to calculate maximum permissible compression ratio. as well as expected power output at given rpm.

 

The "problem" that I have with that is that I find it not very realistic. I mean you hear very, very clearly once an engine starts to "knock". I don't get any acustic cues (remember the funny sound of excessive "Höhengas" on the D.VIIF in RoF?).

 

On the other hand, people are flying at full power with rads closed as if a radiator had least drag when it's closed. Not to mention that you WILL blow up a real world engine quickly by doing so.

 

We have a complex situation here. But as it is now, people are using th systems in a way that is not as you would operate a real world engine.

 

You are right, we don't have knocking, backfiring, carburetor icing e.t.c. But (there is always "but"), to simulate these things right, you need very complex model of engine and/or practically complete documentation. From top of my head - when knocking occurs in V-1710-39 and why? What are the consequences for the engine? And for how long can engine withstand this consequences without destruction? You need absolutely precise answers for this questions (and "hundreds" more) and you need them for every single engine in game. That is what I mean by "very complex simulation of engine with all details".

 

All the possibilities of the game will be always exploited by players, that is normal. We all want everything historically accurate as possible while constantly doing things real pilots would never do. 

 

I still think that here is a "easy" way how can engine limits (and engines in general) works much better. In my opinion, temperatures are the key. "Il-2 classic" in current version solved it IMHO very well and it works beautifully.

[ZachariasX]

You are right, we don't have knocking, backfiring, carburetor icing e.t.c. But (there is always "but"), to simulate these things right, you need very complex model of engine and/or practically complete documentation. From top of my head - when knocking occurs in V-1710-39 and why? What are the consequences for the engine? And for how long can engine withstand this consequences without destruction? You need absolutely precise answers for this questions (and "hundreds" more) and you need them for every single engine in game. That is what I mean by "very complex simulation of engine with all details".

 

All the possibilities of the game will be always exploited by players, that is normal. We all want everything historically accurate as possible while constantly doing things real pilots would never do. 

 

I still think that here is a "easy" way how can engine limits (and engines in general) works much better. In my opinion, temperatures are the key. "Il-2 classic" in current version solved it IMHO very well and it works beautifully.

(Permissible) power output is dependent on athmosphere as much as on the cooling. The whole cooling issue is a can of worms. It is discussed often, and often enough it gets a sour tone.

 

The only consistent approach for modelling engine wear that I find for sim airplaes is done by A2A simulations through their Accusim software, computing all the stuff needed to model engine wear for many parts of the engine. But this is not something we would need here. It has no place in a combat sim as this one as the purpose of this rather elaborate software is to simulate the lifetime and service life of an aircraft depending on how you fly it. If you fly nioce and according to the books, it will last the hours it is specified for, if you handle it more coarse, things start to break sooner. Here, we don't need that. Aircraft have a service life of one mission. Besides, we're not paying $50+ for a single aircraft here.

 

So, what do we have? Judging from the P-40 and reading the technochat, "Nominal Power"/"Combat Power"/"Emergency Power" are ONLY judged fron the manifold pressure indicated. This means I can shove the throttle all the way forward and as long as I set rpm low enough (like 30% or so) the engine will not produce the Hp (or torque?) required for "Combat Power"/"Emergency Power".

 

This has funny consequences. I can (same as in CloD) use highest torque possible without any punishment whatsoever.

 

To destroy your Merlin engine (MAP governor) you do usually the following:

-high torque

-high manifold pressure

-low mixture

-high temperature

 

The Allison in the P-40 has the advantage that at S/L you can just desroy it by

-overcompression/knocking

by firewalling the throttle. I guess we kill most engines in game like that. We don't (or at least I don't) get the sound of a detonating engine. You do hear when an engine is run such that it comes apart instantly. In game, I don't get that. All we have is that nervous little gauge. (Or technochat).

 

The problem is that this makes engine operation in game being far from realistic. What is good practise on a real engine will get you killed on MP servers. What is good in game will set you back a million bucks very soon with a real life engine.

 

In the game, I see absolutely no punisment for flying at

-too low mixture

-excessive torque

-closed radiators (shorter, full power stints)

 

If the mixture is too lean, there is just a power loss. But increased mixture helps hetting additional manifold pressure (at the cost of impaired combustion efficiency). So if you WANT to have excessive MAP in the P-40, you can, but you have to go "full rich" and you will not get as much additional power past the 42' or so Hg, as you add A LOT MORE fuel to cool the mixture. It will start to smoke more, but you "have your high MAP". Thus, you can control detonation somewhat in your airplane. You can have excessive MAP to some degree, it is just not so efficient anymore. Then again, when you need to do that, you're deep in anyway.

 

There is also the strange impression I get that planes are fastest when ALL coolers are closed. If you go full power, you NEED to dissipate heat from 1200 Hp. Closing all coolers will make your engine overheat and break within a minute. Stalingrad winters or not. As long as you can dissipate heat, power production of an engine is not a problem. TORQUE is. Torque destroys crankshafts, bearings, gears... Heat as well as steel loses strenght at high teperatures. The hotter it gets, the sooner it will break. But people (telling from reading the forum) are getting most from their plane by flying them 1°C below cooking at highest power they can get.

 

Another thing: Not all radiators have least drag when closed. They are made for a certain amout of airflow to pass through. Closing all the way will increase drag, as well as opening them all the way. Aircraft (such as the Spitfire etc.) have the position of minimal drag marked as lever setting. The Spitfire has a red triangle mark at the map box to indicate the lever position. I wonder when we get the Mk.V if that one also is faster with the rad closed instead of about open 1/3. The P-47 has these intercooler and oil rad positions indicated as "neutral".

 

Anyhow, we can see it is extremely difficult to get a single logic that computes drag and cooling efficiency thoughout all aircraft statisfactorily. You don't need bias for that. It's just a really diffiult thing to model.