The P40 thread

[ZachariasX]

Please understand, I'm not advocating for 70" of manifold.

 

I posted that to show that the Allison V1710, as modeled in this sim, is so far from the reality of what it was capable of that using the word "simulation" and this P40 in the same sentence is laughable at best.

 

As the report said, pilots were running 70 inches for extended periods, whereas in our little bit of fantasy land you cannot get close to that for a few seconds before your engine has a catastrophic failure.

 

How long will "our" P40 run at 50 inches?  Or even 45?

 

 

I fear for the P39, and heaven help the F4F drivers in Battle of Midway.

As long as increase of carb temperature and the conditions for predetonation are modelled, using the in game athmosphere, I guess we have to live with some cruel decisions from the devs side to force a somewhat propper usage of the throttle.

 

First, lets see how bad the imposed flight/engine regime will be once we have the FM patch. Second, there are ways to deal with the situation. On is to make it clearly audible if you are abusing your engine. RoF did that well with the Höhengas, where you could walk that one until you heard the nasty sound. You get a clear idea "when the timer starts", as well as you hear that when your oponent abuses his engine. The other is calculating carb air temperature to adjust the power output (as one should), the other is calculating for detonation, as well as adjusting power output once predetonation starts.

 

Remember, currently we just dont have predetonation in our game. We just have the punishing consequences of it (unnoticeably) occurring.

 

In the real world, the allison would only produce 1800 hp or so under very special conditions. In our gane, currently power grows about linearly to MAP, which it shouldn't once you leave rated conditions, meaning our Allison is way too good in this sense.

 

There are planes for simulators out there that have all these effects modelled wonderfully and it is a joy to to "work" the engine, getting best performance from it. In this sense, planes without a governor are in fact a lot of fun to fly.

 

The compromise made by the devs, cutting short of some effects may be justified, given the very affordable price asked for the planes. But cutting short of some engine effects raise problems in some conditions, notably when the player himself has to adjust everything.

 

For me, the simplest solution would be just adding an engine sound that makes it clear you abuse the engine. You can play that as soon As "the timers start". It shouldn't require much effort. Better yet, asking more money for the Pacific series and adding that engine computations to early planes. Until then we get the "Höhengas sounds".

[thermoregulator]

Adding to what has been previously stated here, that if you go off of the spec sheet for the game, a 110 will outturn a P-40 on the deck. This despite the fact that multiple combat reports from both allied and axis stated it was a better turner than the 109.

 

Waiting though to see what comes out of the patch before taking this up again.

 

Bf 110 wasnt bad turner, Bf 110 C shoul turn better tahn bf 109 F at low speed...

[Farky]

As the report said, pilots were running 70 inches for extended periods, whereas in our little bit of fantasy land you cannot get close to that for a few seconds before your engine has a catastrophic failure.

 

But we don't know how many pilots did that or for how long it was, do we? And on other hand, we don't know how many pilot destroyed engine when they try that.

Name ten pilots who used 70inHg in P-40E and survived to tell the tale, good luck.

 

We can talk about 56inHg in V-1710-39, because we know that this engine was capable withstand such overload. Since everything above 56inHg was out of the structural limits of this engine, I personally don't like idea of P-40E running with more than 56inHg without punishment. It sometimes happens in real life, for sure, but it was out of any limits and extremely dangerous. If this will be the case in game, I am ok with that.

 

Remember, currently we just dont have predetonation in our game. We just have the punishing consequences of it (unnoticeably) occurring.

 

 

There is one tiny problem - we know for sure that all Allisons V-1710 with 6.65:1 compression ratio, 8.8:1 blower ratio and 9.5 inches dia impeller (i.e. V-1710-35, -37, -39, - 63 or -73) stayed away from detonation point even at 60inHg@3000rpm with carburetor air temperature at 120°F (48.9°C). Those models of V-1710 were limited by structural limitations, not by detonations. Therefore for example V-1710-39 was cleared for maximum 56inHg MAP and V-1710-73 was cleared for 60inHg MAP, altought those engines were with regard to detonations identical.

 

 

 

In our gane, currently power grows about linearly to MAP, which it shouldn't once you leave rated conditions, meaning our Allison is way too good in this sense.

 

 

Are you sure about that?

 

[Stig]

As the report said, pilots were running 70 inches for extended periods, whereas in our little bit of fantasy land you cannot get close to that for a few seconds before your engine has a catastrophic failure

 

 

In the quote I posted, Shortround questions whether the over boosting was actually making much difference. Were the pilots running at 70 inches on the gauge  getting much more power out of the engine? 

[6./ZG26_Klaus_Mann]

In the quote I posted, Shortround questions whether the over boosting was actually making much difference. Were the pilots running at 70 inches on the gauge  getting much more power out of the engine? 

Look at the Chart. It's a massive Difference. 

[ZachariasX]

Hi Farky, these are news to me, great find! I assumed that they actually would give the engine the strenght and supercharger gearing to reach detonation. This is why I said, once you pass detonation point, there is no more linear power increase like that.

 

Looking at your sources, the devs actually have a very tough decision to take. As we are getting (factory) new aircraft with each sortie, we can waste the engines at 60''+ Hg, making sure that the engine is for the bin afterwards and not ready for a second flight. So the devs made everything right by not adding funny sounds at high MAP. All they added was the kick in the crotch for the pilot not adhering to the flight manual.

 

Let's see what the FM patch does. I stil think there should be a warning sound of some sort when the timer sets in. I know it is unrealistic, but it maybe takes something unrealistic to mend an unrealistic situation.

[Farky]

n the quote I posted, Shortround questions whether the over boosting was actually making much difference. Were the pilots running at 70 inches on the gauge getting much more power out of the engine?

 

 

I don't think Shortround questions whether the overboosting was actually making much difference, but rather numbers. He is right, while we know that in standard conditions (atmospheric pressure 29.92 inHg and 59°F) 70 inHg MAP resulted in 1780 bhp (depends of source), results in hot Africe were different.

 

Let's say that atmospheric pressure is standard 29.92 inHg . As a rule of thumb, for every 10°F of temperature deviation above standard 59°F temperature, you need substract 1% from power. This for example means - if temperature is 40°C (104°F), deviation from standard is 45°F = power is reduced by 4.5%. So with 40°C temperature, your power at 70 inHg MAP isn't 1780 bhp, but "just" 1717 1700 bhp. On the other hand, if temperature is -15°C (5°F), you are at 70 inHg MAP running with 1876 bhp.

 

EDIT : 1717 to 1700 bhp

Edited August 1, 2017 by Farky

[-=PHX=-SuperEtendard]

With 50"-51" (82% throttle IIRC) and 3000 RPM the P-40 does around 515 kmh at the deck with radiators in neutral position, which is more or less similar speed to the Yak-1. Maybe it could be a good compromise to let it use this setting for some time.

Edited August 1, 2017 by -=PHX=-SuperEtendard

[Stig]

I don't think Shortround questions whether the overboosting was actually making much difference, but rather numbers. He is right, while we know that in standard conditions (atmospheric pressure 29.92 inHg and 59°F) 70 inHg MAP resulted in 1780 bhp (depends of source), results in hot Africe were different.

 

 

 

Well, I understood it as he is saying how there is some doubt about much power they were actually getting 'in the field'. I don't know whether he's right, but I still think it's an interesting observation.

 

What might back him up is, that no matter how much the pilots flogged their engines, the 3 major operators of the P-40 all came to the same conclusion: it wasn't quite good enough. In that respect, it certainly doesn't seem to have made much difference.  

[chris455]

What type of fuel is being modeled in our current P-40, and is this an issue regarding safe power settings in-game?

I am hearing references to differences in fuel grades ( presumably Russian vs western grades) and I'm looking at charts that invariably list 100 octane avgas as the standard.

At the same time we hear of Russian fuels and lubricants that are allegedly cruder than their western analogues.

So what are we burning in our P-40E-1?

[-=PHX=-SuperEtendard]

AFAIK we have 100 octane fuel, otherwise we wouldn't be able to reach such high manifold pressure settings. I think there is a manual that lists 47" as the max with 91 octane fuel?

[7.GShAP/Silas]

What type of fuel is being modeled in our current P-40, and is this an issue regarding safe power settings in-game?

I am hearing references to differences in fuel grades ( presumably Russian vs western grades) and I'm looking at charts that invariably list 100 octane avgas as the standard.

At the same time we hear of Russian fuels and lubricants that are allegedly cruder than their western analogues.

So what are we burning in our P-40E-1?

 

 

The fuel used in them was all lend-lease American fuel, I believe.  In fact, I think the vast majority of all Soviet aviation fuel used over the course of the war was lend-lease.

 

 

Brano or Lucas would know for sure.

Edited August 1, 2017 by 7-GvShAP/Silas

[ZachariasX]

The fuel qualities differed a bit even amongst the allies. The fuel used in the Pacific was better than what was used in the ETO, both being of similar octane rating. Remember, octane rating was also achieved by additives, not fuel quality itself. The Allison on the Lightnings were much more troublesome in Europe than in the Pacific, where the P-38 was better to operate. So it would depend on the source of the fuel. If it was shipped from the US to Russia, then I'd expect very high grade fuel, if shipped from British oil companies, less so.

 

 

Still, knowing that we have a mostly power dependent "timer" (rather than detonation dependent) that lets the Allison seize, how to implement that best?

 

For the moment, I would have the following solution:

 

Let the player use very high boost 65''+ Hg MAP, but the higher you go, the shorter a timer will run to seize your engine. As soon as you go over allowed max power output, the max. possible MAP decreases before the timer resumes again.

 

This way, using high power makes your plane more of a lemon *during the same sortie*.

 

The timer may well be 10 minutes or so before your engine will quit. But the nearer to the end of the timer you are, the less MAP you can give until the engine gives strang noises again and timer is counting down again.

 

Now, I know that this is not exactly realistic. But it would force care to the engine on one side while still permitting use of full power. The lenght of the timer run should be set in relation to an average sortie duration.

 

In all cases, it would help a lot if the player got more cues about how he handles his engine than just the semi legible gauge down there.

 

Or are there better ideas?

[Farky]

What might back him up is, that no matter how much the pilots flogged their engines, the 3 major operators of the P-40 all came to the same conclusion: it wasn't quite good enough. In that respect, it certainly doesn't seem to have made much difference.

 

 

Sorry, but this is very strange argumentation. Nobody is talking about something like - with overboost, P-40E was awesome airplane, on par with airplane xyz (Mustang, Spitfire etc.). That is not the point and never was.

Of course it wasn't quite good enough, simply because there were better airplanes around. It's nice to have up to 1800 bhp on the deck, but you still have only 1150 bhp at 12 000 ft (without ram), you can not change that no matter what. In that respect, sure, that's not good enough. Was overboost up to 70 inHg able change barely average Curtiss P-40E to super fighter? Of course not.

 

 

The Allison on the Lightnings were much more troublesome in Europe than in the Pacific, where the P-38 was better to operate.

 

 

Right, but this wasn't about different quality of fuel, but rather different tactic for Lightnings. More here in this post - https://forum.il2sturmovik.com/topic/21234-p-40-engine-settings-i-found-them-bit-weird/?p=377326

 

 

Or are there better ideas?

 

I have some ideas how to do it ( I am not saying they are better than yours) . I wrote those ideas few times on forum already and I don't wanna repeat my self again. Here is the thing - right now, developers do not have time (resources) to change engines limits or the way engines behave (as far as i know). Maybe in future. So right now are any ideas we can come with just a waist of time.

[ACG_KaiLae]

The best way to go with the engine is IMO to use settings that were used during actual wartime, which can be seen below. Also note, these would be out about when BoS would have been going on.

 

 

All this is premature since we don't know what we will have at the end of the month. Honestly I'm expecting it to stop the hunting of the nose that you see at low speeds which will help the aircraft. What I don't think it will do is address the abnormally low critical AoA the wing has. It won't address engine limits. It won't answer why the aircraft turns so poorly when RL reports state otherwise (repeatedly from every source). At least with this I can understand the devs problem because documentation is very difficult to find. It also probably won't address the seemingly wrong data they've used with regards to rudder stability.

 

But we will wait and see. If you want this process to go faster, we need good data, so if you can find some, now's the time to say so.

[Farky]

The best way to go with the engine is IMO to use settings that were used during actual wartime, which can be seen below. Also note, these would be out about when BoS would have been going on.

 

 

 

Well, game is using settings that were officially used during actual wartime. Engine limits in the game are in perfect match with the limits prescribed by the manuals for P-40E from 1942-43.

 

This chart is from manual issued in 1944, which is conveniently cut out from the left side of the picture (not by you, i know that). Date in left top corner doesn't mean date of issue of this table, but date of issue of general specification AN-H-8 about engines. What I am trying to say is this - V-1710-39 in P-40Es wasn't cleared for limits in this table until 1944. Also, we don't have engine with streamline manifolds, all V-1710-39 were produced with backfire screens. Streamline manifolds were installed to some V-1710-39s during overhauls. And War Emergency Rating wasn't allowed for engines without automatic manifold pressure regulator. Automatic manifold pressure regulators were installed to some P-40Es in autumn 1943, after they were being withdrawn from combat units.

 

Although I generally agree with these limits, we need to be careful here. If we accept limits for engines with non-standard or late war modifications, we will open the Pandora's box. In that case, it will be fair to give Bf 109G-2 maximum MAP 1.42 ata for example.

[Brano]

The fuel used in them was all lend-lease American fuel, I believe.  In fact, I think the vast majority of all Soviet aviation fuel used over the course of the war was lend-lease.

 

 

Brano or Lucas would know for sure.

 

http://www.oilru.com/or/47/1006/

 

Alltogether 558,428 tons with octane numbers above 99 from Lend-Lease. Doing quick´n´dirty calculation there were cca 15000 fighters and bombers of western origin delivered to USSR (of some combat significance like P-39,40,A-20,hurris...) so it was like 37 ton of fuel per aircraft. I guess it was enough.

Original soviet aircraft engines of "new generation" ran on 95 octane aviation fuel.

- for Klimov M-105 it was  3B-78 which had around 95 octane with addition of R-9 additive

- for Shvetsov M-82 and Mikulin AM-35/38 it was 4B-78 with roughly same octane nr (95) with R-9 additive.

Main component of additive was TEL (tetraethyl lead) delivered from USA. Germans also got their share from Standard Oil   

[Stig]

 

 

Sorry, but this is very strange argumentation. Nobody is talking about something like - with overboost, P-40E was awesome airplane, on par with airplane xyz (Mustang, Spitfire etc.). That is not the point and never was. Of course it wasn't quite good enough, simply because there were better airplanes around. It's nice to have up to 1800 bhp on the deck, but you still have only 1150 bhp at 12 000 ft (without ram), you can not change that no matter what. In that respect, sure, that's not good enough. Was overboost up to 70 inHg able change barely average Curtiss P-40E to super fighter? Of course not.  

 

I have read a lot of P-40 threads on various aviation forums over the last 10 years. I can assure you that there are fans of this aircraft with some very optimistic expectations to it's performance and capability.  

[JtD]

I'm a fan of the aircraft and I have different expectations to it's performance and capability when compared to what we're currently offered in game. I wouldn't consider my expectations optimistic, though.

 

I wish we'd have the P-40 on the +5% side of things, like several other aircraft in game. But that's not expectations, it's wishful thinking.

[Barnacles]

Although I generally agree with these limits, we need to be careful here. If we accept limits for engines with non-standard or late war modifications, we will open the Pandora's box. In that case, it will be fair to give Bf 109G-2 maximum MAP 1.42 ata for example.

Not quite the same, as the G2 was mechanically restricted when the 1.3 ata restriction was in force. Physically the p40 engine was not limited. I think that they should add a modification with various planes to have different engine limits. Eg 1.3 ata g4/f4, 1.42 ata g2 etc. P40 engine damage criteria should reflect ,as best they can, objective historical documentation of what that engine could take, ie the most recent war time engine limits are the 'best'. That is of course if nothing actually changed physically in the engine to prompt the change in limits. Edited August 2, 2017 by 71st_AH_Barnacles

[Stig]

I'm a fan of the aircraft and I have different expectations to it's performance and capability when compared to what we're currently offered in game. I wouldn't consider my expectations optimistic, though.

 

I wish we'd have the P-40 on the +5% side of things, like several other aircraft in game. But that's not expectations, it's wishful thinking.

 

I would not consider you one of the fans with optimistic expectations either. 

[Farky]

Not quite the same, as the G2 was mechanically restricted when the 1.3 ata restriction was in force. Physically the p40 engine was not limited.

 

 

If we will talk strictly about that 1944 table, P-40E's engine was also mechanically restricted, by automatic manifold pressure regulator. My point is - this table is for different configuration of P-40E, we don't have such airplane in game. Using this 1944 table without proper and clear explanation can lead to dangerous precedent.

 

But if we will talk about P-40E we have in game, you are of course right, this is not the same as "G-2 situation" at all. As I said, I generally agree with limits in that table. Safe maximum for V-1710-39 should be 56 inHg@3000 rpm, everything over this settings should be very dangerous. Not impossible, dangerous.

 

P.S. - I assume that we will be soon talking about "real" limits of R-2600-11 (A-20B engine) and V-1710-63 (P-39L).

[Barnacles]

If we will talk strictly about that 1944 table, P-40E's engine was also mechanically restricted, by automatic manifold pressure regulator. My point is - this table is for different configuration of P-40E, we don't have such airplane in game. Using this 1944 table without proper and clear explanation can lead to dangerous precedent.

 

But if we will talk about P-40E we have in game, you are of course right, this is not the same as "G-2 situation" at all. As I said, I generally agree with limits in that table. Safe maximum for V-1710-39 should be 56 inHg@3000 rpm, everything over this settings should be very dangerous. Not impossible, dangerous.

 

P.S. - I assume that we will be soon talking about "real" limits of R-2600-11 (A-20B engine) and V-1710-63 (P-39L).

 

Yes I 100% agree with you there. I was thinking about the situation where the manufacturer's engine limits are amended without a change in configuration. I believe there is a difference between 1941 and 42 engine limits for the same airframes, in the case of the P40.

[19//Moach]

it would make sense then, for a practical implementation, to raise the tolerances such that "combat mode" starts at 45"@3000rpm, and "emergency mode" would set in just above 56"@3000, extending* all the way to 70"

 

* the time limit to a given "mode" seems to be governed by a factor which lerps across the minimum and maximum power for said mode. - I suspect the stated max time would apply at 100% of that factor, such that being half-way into "combat mode" would give you twice the stated limit 

 

that would make (a bit more) sense with the current timer-based consequences we get from operating within these modes...

 

 

 

it's not perfect, but I think I can live with it disassembling in a few seconds at 70", or 5~10 minutes running above 56" -- it would be more or less adequate if it were this way

Edited August 2, 2017 by 19//Moach

[Barnacles]

it would make sense then, for a practical implementation, to raise the tolerances such that "combat mode" starts at 45"@3000rpm, and "emergency mode" would set in just above 56"@3000, extending* all the way to 70"

 

* the time limit to a given "mode" seems to be governed by a factor which lerps across the minimum and maximum power for said mode. - I suspect the stated max time would apply at 100% of that factor, such that being half-way into "combat mode" would give you twice the stated limit 

 

that would make (a bit more) sense with the current timer-based consequences we get from operating within these modes...

 

 

 

it's not perfect, but I think I can live with it disassembling in a few seconds at 70", or 5~10 minutes running above 56" -- it would be more or less adequate if it were this way

 

The system in the game already lerps.

[19//Moach]

The system in the game already lerps.

 

yes, that is what I meant... I believe it was you that found that out by experiments, wasn't it?

 

my point was, given that it does indeed lerp, if the "modes" were set as I mentioned, I believe it would make for a satisfactory enough solution for the time being... at least until they get around overhauling the much lacking engine simulation aspect of the whole game (one day, we hope)

[TheJay13]

yes, that is what I meant... I believe it was you that found that out by experiments, wasn't it?

 

my point was, given that it does indeed lerp, if the "modes" were set as I mentioned, I believe it would make for a satisfactory enough solution for the time being... at least until they get around overhauling the much lacking engine simulation aspect of the whole game (one day, we hope)

Team Fusion has recently announced that it is revamping how engine damage will work in TF 4.5 https://theairtacticalassaultgroup.com/forum/showthread.php?t=25578 (they discuss how it works a little ways down) so perhaps we will eventually see a similar system of engine damage in BOX although a pretetonation feature to indicate when we are close to breaking the engine would be really nice.

 

I have to say, reading through these comments I am a bit confused as to what is actually required to "fix" the P-40s engine. It seems like some people want the P-40 to be able to run around on emergency power all the time? or am I misreading what is being said? Should the engine not work similarly to any other aircraft? The higher the engine power, the faster and more likley you are to mess up your engine? 

Edited August 2, 2017 by TheJay13

[6./ZG26_Klaus_Mann]

 

I have to say, reading through these comments I am a bit confused as to what is actually required to "fix" the P-40s engine. It seems like some people want the P-40 to be able to run around on emergency power all the time? or am I misreading what is being said? Should the engine not work similarly to any other aircraft? The higher the engine power, the faster and more likley you are to mess up your engine? 

The Problem is that the current Engine Limitations System is quite Autistic. It's a bit like Political Islam. It's too literal in it's interpretation of the Handbook Recommendations. 

 

I think the Guys here all want it to be revamped to a Degree that is more Liberal in allowing for Higher Power Settings, an Opinion I agree with. A System that more closely resembles the Real World. 

[ACG_KaiLae]

Safe maximum for V-1710-39 should be 56 inHg@3000 rpm, everything over this settings should be very dangerous. Not impossible, dangerous.

 

 

And not for very long, either at 56...certainly not more than 5 minutes. Speaking of engine limits, I have a question about engine design. Right now if you move up to 3000 RPM, that is combat power, regardless of your boost. Is this a realistic limit? 

[Barnacles]

Team Fusion has recently announced that it is revamping how engine damage will work in TF 4.5 https://theairtacticalassaultgroup.com/forum/showthread.php?t=25578 (they discuss how it works a little ways down) so perhaps we will eventually see a similar system of engine damage in BOX although a pretetonation feature to indicate when we are close to breaking the engine would be really nice.

 

I have to say, reading through these comments I am a bit confused as to what is actually required to "fix" the P-40s engine. It seems like some people want the P-40 to be able to run around on emergency power all the time? or am I misreading what is being said? Should the engine not work similarly to any other aircraft? The higher the engine power, the faster and more likley you are to mess up your engine? 

 

You are right I think. The p40's limitations are treated the same way as all the other planes, insofar as and when you get engine damage. This system is an arbitrary measure designed to stop just what you said. 1946 chose to do that by making the engine overheat, this game chose to do it by making your engine get damaged terminally if you continue to run beyond the timer. The only point that is specific to the p40 is that the system they have chosen renders the p40 a lot more ineffective because of what they have chosen (ie catastrophic damage rather than something less terminal). If they chose something different then the p40 I belive would benefit far more than some of the other planes. I don't think anyone wants p40s tearing around on 56" mp more than a few seconds, as if that were to be the case, it would be a monster.

 

I think the current system is a good compromise but I recognise it is arbitrary and not 'realistic' per se.

 

Another point, the spitfire for has a much faster recovery rate for it's emergency boost than other planes (about a 1 for 1 ratio with the time limit). It actually explodes the engine a lot quicker than the manual's limit though, (3min vs 5min) so from one persons point of view it is limiting the Spitfire better than the other planes but from another person's point of view the spit is being treated worse. However appying the same recovery ratio to the p40 would transform it I think and you could do it to the other planes to make it 'fair'.

Edited August 2, 2017 by 71st_AH_Barnacles

[ACG_KaiLae]

I have to say, reading through these comments I am a bit confused as to what is actually required to "fix" the P-40s engine. It seems like some people want the P-40 to be able to run around on emergency power all the time? or am I misreading what is being said? Should the engine not work similarly to any other aircraft? The higher the engine power, the faster and more likley you are to mess up your engine? 

 

That's not what people (well most people) want at all. Right now putting the engine over about 42" will blow it out in very short order, because the engine chart being used was developed before the entry into war by the USA. It was developed with reducing engine wear in mind. Allison engines were somewhat notorious for being underrated by the manufacturer, in both the case of this engine and also the one used in the P-38. Many are advocating using a chart from later in the war with higher limits, where the engine was effectively identical to the one in game.

[Multimetal]

Just thought I'd add some interesting passages I just read in the P-40 section of Stackpoles Flying American Combat Aircraft of WW2-(great book btw if you guys haven't read it).  The P-40 section was written by General Bruce Holloway, who later went on to command the SAC in Nebraska.  He flew approximately 100 combat missions with 300+ hours in the P-40, so I would trust his judgement!

 

"The P-40 was not a spectacular performer.  It was, however, except for the very early models, a rugged, simple, reliable aircraft which would take more punishment and get home safely more often than any other fighter of its era except possibly the P-47."

 

On the P-40 E vs. earlier models-"The only real disappointment about the E was that it had no improvement in service ceiling and only slightly more speed. Climb performance was infinitesimally better, but-like speed-was achieved only because the newer model engines could be operated at considerably higher power settings."

 

On the E and K series-Both of these series would go straight down and hang together at speeds of over 450 miles per hour (with both feet on the left rudder pedal)

 

On the P-40K-"Horsepower ratings were then up to 1,350"

 

On the Allison 1710-"The P-40's Allison 1710 was just plain sturdy....once, while strafing trucks, I recieved a hit in the scavenge oil pump and immediately lost all oil pressure.  Power was reduced to a low setting, and the engine ran for nearly 4 minutes with no oil!  A post-mortem, as best as I could conduct it, showed that actually failure had occured in the reduction gear box rather than in the engine proper-a finding that tallies with the fact that an internal engine failure would probably have resulted in a fire.  In 300 hours of combat flying, the only problems I had with the 1710 were a broken throttle linkage and a sheared distributor rotor.  This was in spite of a fair amount of operation well over red-line limitations.

 

 

I found this article really interesting, and it lends support to the idea that the P-40 was routinely operated at well over the "book" limitations and still maintained a reputation as a workhorse.

[TheJay13]

That's not what people (well most people) want at all. Right now putting the engine over about 42" will blow it out in very short order, because the engine chart being used was developed before the entry into war by the USA. It was developed with reducing engine wear in mind. Allison engines were somewhat notorious for being underrated by the manufacturer, in both the case of this engine and also the one used in the P-38. Many are advocating using a chart from later in the war with higher limits, where the engine was effectively identical to the one in game.

Ah I see, I am not familiar with the operational perameters of Allison engines, I had seen a few people throwing around wildly different numbers, some as high as 70in, i believe which seemed ridiculous to me. So if we are aware of what the engines nominal operating threshold and have established what the issue is, why is everyone still arguing about it? Is it not the case that the devs said they were looking to fix the P-40 both in FM and engine limits?

[Gambit21]

That's not what people (well most people) want at all. Right now putting the engine over about 42" will blow it out in very short order, because the engine chart being used was developed before the entry into war by the USA. It was developed with reducing engine wear in mind. Allison engines were somewhat notorious for being underrated by the manufacturer, in both the case of this engine and also the one used in the P-38. Many are advocating using a chart from later in the war with higher limits, where the engine was effectively identical to the one in game.

 

I for one appreciate the time and effort you've put in on this.

[ACG_KaiLae]

Ah I see, I am not familiar with the operational perameters of Allison engines, I had seen a few people throwing around wildly different numbers, some as high as 70in, i believe which seemed ridiculous to me. So if we are aware of what the engines nominal operating threshold and have established what the issue is, why is everyone still arguing about it? Is it not the case that the devs said they were looking to fix the P-40 both in FM and engine limits?

 

Because the developers are using russian provided documentation and it uses the pre-war settings. Also, depending on when you look, you get very different numbers. Also, there's the issue where people think that allowing increased engine power will suddenly let the aircraft start spewing rainbows out the exhaust stacks. There's a lot more problems than that. Just going off my head (these are as of right now):

 

In game dive speed is above the 485 MPH VnE listed in the flight manual

Aircraft appears to stall about 5 mph early (though some confusion over this due to PEC data) suggesting possibly wrong CLmax used. Very inconclusive data/lack of data severely impeding investigation in this area.

Critical AoA of wings in game is unusually low, and a very similar wing design we have data on that strongly suggests it should be greater

Above engine issues

Rudder on the plane is so bad it's likely the upcoming flight model changes were put in to address it. It's possible to put the plane into a spin with rudder only. At slow speeds the nose hunts back and forth around the axis of flight

Aircraft manual states that as RPM increases, the manifold pressure on the engine will actually do down, not up. Then at "high altitude" this operation will reverse. While uselessly inexact, strongly suggests engine modeling is deficient in some basic way

RL aircraft required you to use rudder trim and/or a capton of rudder during dives, like full rudder to keep the A/C moving straight and not yaw off. In game aircraft gives no you-know-whats and does not have this behavior

Cooling system is ludicrously effective compared to RL plane. Would overheat on the ground in RL, will never do that in game. Obviously incorrectly modeled.

Devs may have used bad data to determine how much rudder you can apply to the aircraft before it becomes unstable (Farky can explain better than I can)

Aircraft might be too fast at high altitude. Max speed should be about 352 MPH at about 15k. Took it for a test spin at something like 18k and turned on trackview, observed listed TAS, showed the A/C doing 373 MPH. Information depends on how reliable trackview reporting is, which I'm not sure on at all. 

 

There are more things but that's what I can recall. They did get around to fixing the fuel gauges so they now indicate correctly, so that isn't an issue any longer. 

I for one appreciate the time and effort you've put in on this.

 

Yet IMO, there's not enough data to actually change anything, because we don't have anything conclusive. That's frustrating. I was unable to speak to a RL pilot at EAA too, which was also frustrating. 

[Gambit21]

Because the developers are using russian provided documentation and it uses the pre-war settings. Also, depending on when you look, you get very different numbers. Also, there's the issue where people think that allowing increased engine power will suddenly let the aircraft start spewing rainbows out the exhaust stacks. There's a lot more problems than that. Just going off my head (these are as of right now):

 

In game dive speed is above the 485 MPH VnE listed in the flight manual

Aircraft appears to stall about 5 mph early (though some confusion over this due to PEC data) suggesting possibly wrong CLmax used. Very inconclusive data/lack of data severely impeding investigation in this area.

Critical AoA of wings in game is unusually low, and a very similar wing design we have data on that strongly suggests it should be greater

Above engine issues

Rudder on the plane is so bad it's likely the upcoming flight model changes were put in to address it. It's possible to put the plane into a spin with rudder only. At slow speeds the nose hunts back and forth around the axis of flight

Aircraft manual states that as RPM increases, the manifold pressure on the engine will actually do down, not up. Then at "high altitude" this operation will reverse. While uselessly inexact, strongly suggests engine modeling is deficient in some basic way

RL aircraft required you to use rudder trim and/or a capton of rudder during dives, like full rudder to keep the A/C moving straight and not yaw off. In game aircraft gives no you-know-whats and does not have this behavior

Cooling system is ludicrously effective compared to RL plane. Would overheat on the ground in RL, will never do that in game. Obviously incorrectly modeled.

Devs may have used bad data to determine how much rudder you can apply to the aircraft before it becomes unstable (Farky can explain better than I can)

Aircraft might be too fast at high altitude. Max speed should be about 352 MPH at about 15k. Took it for a test spin at something like 18k and turned on trackview, observed listed TAS, showed the A/C doing 373 MPH. Information depends on how reliable trackview reporting is, which I'm not sure on at all. 

 

There are more things but that's what I can recall. They did get around to fixing the fuel gauges so they now indicate correctly, so that isn't an issue any longer. 

 

Yet IMO, there's not enough data to actually change anything, because we don't have anything conclusive. That's frustrating. I was unable to speak to a RL pilot at EAA too, which was also frustrating. 

 

There's a few real pilots here

http://www.flyingheritage.com/Explore/The-Collection/United-States/Curtiss-P-40C-Tomahawk.aspx

 

I'll bet they could shed some light on this.

[TheJay13]

Because the developers are using russian provided documentation and it uses the pre-war settings. Also, depending on when you look, you get very different numbers. Also, there's the issue where people think that allowing increased engine power will suddenly let the aircraft start spewing rainbows out the exhaust stacks. There's a lot more problems than that. Just going off my head (these are as of right now):

 

In game dive speed is above the 485 MPH VnE listed in the flight manual

Aircraft appears to stall about 5 mph early (though some confusion over this due to PEC data) suggesting possibly wrong CLmax used. Very inconclusive data/lack of data severely impeding investigation in this area.

Critical AoA of wings in game is unusually low, and a very similar wing design we have data on that strongly suggests it should be greater

Above engine issues

Rudder on the plane is so bad it's likely the upcoming flight model changes were put in to address it. It's possible to put the plane into a spin with rudder only. At slow speeds the nose hunts back and forth around the axis of flight

Aircraft manual states that as RPM increases, the manifold pressure on the engine will actually do down, not up. Then at "high altitude" this operation will reverse. While uselessly inexact, strongly suggests engine modeling is deficient in some basic way

RL aircraft required you to use rudder trim and/or a capton of rudder during dives, like full rudder to keep the A/C moving straight and not yaw off. In game aircraft gives no you-know-whats and does not have this behavior

Cooling system is ludicrously effective compared to RL plane. Would overheat on the ground in RL, will never do that in game. Obviously incorrectly modeled.

Devs may have used bad data to determine how much rudder you can apply to the aircraft before it becomes unstable (Farky can explain better than I can)

Aircraft might be too fast at high altitude. Max speed should be about 352 MPH at about 15k. Took it for a test spin at something like 18k and turned on trackview, observed listed TAS, showed the A/C doing 373 MPH. Information depends on how reliable trackview reporting is, which I'm not sure on at all. 

 

There are more things but that's what I can recall. They did get around to fixing the fuel gauges so they now indicate correctly, so that isn't an issue any longer. 

 

Yet IMO, there's not enough data to actually change anything, because we don't have anything conclusive. That's frustrating. I was unable to speak to a RL pilot at EAA too, which was also frustrating. 

Thank you for taking the time to explain the whole situation there I appreciate it.

 

Have they confirmed that they are going to perform a complete overhaul of the aircraft like they did with the Fw-190? If they do I would presume it would be included with the FM patch thats coming.

[ACG_KaiLae]

The only word is that there isn't even time to look into it until kuban is complete. That, of course, assumes we have better data for them to base a change to, which we don't have enough right now IMO.

[JtD]

I'd wait for the changed FM's and update the to-do list then. Maybe some issues are already gone.

 

On the other hand, they don't want to change the P-40 engine model, because this means they'd have to adjust all engines from 'transcribed manual' to something mirroring physics and historical performance. Same way the Allison could take far more than 40" without falling apart, the German engines lasted for more than a minute with Notleistung.

 

So what the devs need is not more data on P-40 and Allison, but more time (and possibly a change of heart) to globally revamp the engine model the same way they are doing it with the FM.

Edited August 3, 2017 by JtD

[TheJay13]

I'd wait for the changed FM's and update the to-do list then. Maybe some issues are already gone.

 

On the other hand, they don't want to change the P-40 engine model, because this means they'd have to adjust all engines from 'transcribed manual' to something mirroring physics and historical performance. Same way the Allison could take far more than 40" without falling apart, the German engines lasted for more than a minute with Notleistung.

 

So what the devs need is not more data on P-40 and Allison, but more time (and possibly a change of heart) to globally revamp the engine model the same way they are doing it with the FM.

I can easily understand their hesitation to deviate from the transcribed values though. It is almost impossibly difficult to determine how hard an engine could generally be flown. How would you know exactly how far beyond the listed value an engine could run without actually having access to one which you can most likely destroy? It is far safer and more precise for them to use the listed data.

 

As for the P-40, who says that if they acknowlege that the source they are using is underrating the engine and they increase its power to a commonly reported value that they must completely redesign every engine in the game? As far as I am aware the P-40 is the only one in the sim with such a serious lack of performance due to its listed data, the rest of the aircraft generally have reasonably good engine representations taken from transcribed values in official manuals. If they have a wartime manual for the P-40 which provides evidence of a higher pressure setting then I am sure they will have no qualms about changing the engine tolerances. 

 

As for luftwaffe aircraft only having one minute of boost, I understand that this is based off of conservative estimates to ensure engine longevity, how much longer are you purposing we allow the engine to run at such high settings? Do you or anyone actually know how long a 190's engine could run in emergency power? Now I suppose that this could be solved by creating an accurate simulation of the engine itself within the aircraft with its own thermodynamic model and whatnot but that is a pretty ridiculous thing to ask of the developers. 

Edited August 3, 2017 by TheJay13