P-40 Engine Settings as I found them (a bit weird)

[Crump]

Maybe it was my experience restoring World War II warbirds, military career, friendship and flying with USAAF Mustang pilots, or my friendship with several Luftwaffe FW-190 pilots?

[JG13_opcode]

Golodnikov said they were using max RPM and higher power settings whilst cruising so as to enter combat at high speeds, and subsequently trashing the engines on the P-39/40 in 3-5 missions, he called the P-39 a dud had they been using the engine regimes in the manual.

 

Allison were overconservative with the engines until 1944 P-38L, probably the most documented being Ben Kelsey abuse testing on the P-38Gs engines and establishing an absolute CAT limit of 90 degrees C, twice as much as Allisons figure and run much higher power settings above 50 degrees for 7-8 minutes safely without engine deterioration.

Do you have a link to this, preferrably translated?  I'd love to read it but my Russian is weak.

[Crump]

 

 

s inconceivable as Golodnikov's account may be to you,

 

I say that misconception out of personal experience.  I had an FW-190 pilot tell me about "Ribbenol" as a boost system used over the Ardennes.  Ribbentrop was the Nazi foreign minister and like the USA's current John Kerry, got his fortune through marriage.  Ribbentrop married into a wine making fortune and it was a nickname to poke fun at him.  Problem is the the FW-190 did not use any alcohol boost systems such as MW-50.

 

After clarification....Oskar simply meant he used the FW-190's Erhohte Notleistung and the nickname of "Ribbenol" came from his days of fly the Bf-109G which did use MW-50.

 

Had I not known how aircraft work by convention and that the MW system was never approved for the FW-190....I might have walked away convinced I had evidence it WAS used in some unauthorized cowboy fashion in combat.

That would not have been Oskar fault for my or anyone else's misconception.

[=362nd_FS=RoflSeal]

I say that misconception out of personal experience.  I had an FW-190 pilot tell me about "Ribbenol" as a boost system used over the Ardennes.  Ribbentrop was the Nazi foreign minister and like the USA's current John Kerry, got his fortune through marriage.  Ribbentrop married into a wine making fortune and it was a nickname to poke fun at him.  Problem is the the FW-190 did not use any alcohol boost systems such as MW-50.

 

After clarification....Oskar simply meant he used the FW-190's Erhohte Notleistung and the nickname of "Ribbenol" came from his days of fly the Bf-109G which did use MW-50.

 

Had I not known how aircraft work by convention and that the MW system was never approved for the FW-190....I might have walked away convinced I had evidence it WAS used in some unauthorized cowboy fashion in combat.

That would not have been Oskar fault for my or anyone else's misconception.

So you equate someone giving a powersetting a nickname with someone saying they ran at high RPM to have a high cruise speed?

 

 

Do you have a link to this, preferrably translated?  I'd love to read it but my Russian is weak.

 

http://lend-lease.airforce.ru/english/articles/golodnikov/index.htm

Edited March 17, 2016 by RoflSeal

[Crump]

 

 

how the implementation of the P-40 by the VVS was SUPPOSED to work

 

Han already provided the VVS Operating Instructions for the P-40.  There is no speculation required and especially no fantasy of combat fairies that suddenly sprinkle pixie dust and make the physics change.

[Crump]

 

 

Are you citing these as your qualification to declare that General Golodnikov is either mistaken or lying

 

No, I am saying YOU or WHOEVER did the interview misunderstood the information General Golodnikov relates.  It is probably pretty clear in his mind what he used and did not use or at least it was at some point in his life.

[=362nd_FS=RoflSeal]

No, I am saying YOU or WHOEVER did the interview misunderstood the information General Golodnikov relates.  It is probably pretty clear in his mind what he used and did not use or at least it was at some point in his life.

Explain what is there to misunderstand here

 

 

 

When we began to use the P-40, we immediately discovered two deficiencies that reduced its value as a fighter. 1. The P-40 was a “slug” in acceleration, rather slow to acquire speed. This weak dynamic resulted in a low combat speed. It had trouble maintaining the speed required for combat. Speed is essential for a fighter. 2. It was weak in the vertical, especially the Tomahawk.

We compensated for poor acceleration by holding the engine at higher revolutions and cruising at a higher speed. We corrected the second deficiency by removing a pair of machine guns. That was all. The fighter came up to par.

Now everything depended on you, the pilot. Keep your head! And work the stick intensively.

It is true that because of our unforeseen operating regime the engines had a limit of about 50 hours, and often less. Normally an engine might last 35 hours and then it was replaced.

 

 

 

 

Not at all. Tactics has nothing to do with it. The primary difference in evaluating the combat capabilities of the P-40 arises from the fact that we and the Allies exploited the aircraft in a completely different manner. They were required to use the aircraft in accordance with written instructions [technical manuals – I.G.]. Any violation of those guidelines was a “no-no”.

In our case, as I have already mentioned, the primary rule was to get everything out of an aircraft that it was capable of and a bit more. How much is “everything” the documentation for an aircraft does not say. Often even the designer of an aircraft himself did not have even a clue. It would only be revealed in combat.

By the way, everything I have said also applies to the Airacobra. If we had flown it in those regimes that the Americans outlined in the aircraft specifications, they would have shot us down immediately. This fighter was a “dud” in its “native” [by-design] regimes. But we conducted normal combat in “our” regimes, be it with the Messer or with the Fokker. But in some cases we flew 3—4 such aerial battles and it was done. “Replace the engine.”

[Crump]

 

 

anufacturer's recommended operating limits for avoiding damage to a piece of equipment in 'normal use'

 

Normal use for a combat equipment...is combat...  

 

It is designed for combat on purpose. 

 

Of course that is without the "combat faires".  I used to love hearing those declarations, they all start out with "in combat I will do....."

 

BullS__t....

 

Human nature and physics does not change because your miserable life is in danger.   You will do what you have trained yourself to do and the equipment will only work within the same design parameters whether your miserable life is in danger or not.

 

Of course breaking your equipment on a 2 way firing range is guaranteed to end badly.

[Crump]

 

 

We compensated for poor acceleration by holding the engine at higher revolutions and cruising at a higher speed.

 

 

Where does it say they used any unauthorized rating?????

 

Some Cruise rating is 25inHg at 1950rpm or 31inHg at 2400rpm while the maximum continuous rating is 37.2inHg at 2600rpm.

 

General Golodnikov could have easily meant he flew around at any setting at or below 37.2inHg at 2600rpm and above the normal cruise ratings.  That would fit not only his anecdote but also how aircraft work by convention.  

 

YOU interpret his statement as a combat fairie appears and routinely the VVS violates the physics.

 

Not likely at all.

 

 

 

 

But in some cases we flew 3—4 such aerial battles and it was done. “Replace the engine.”

 

 

Oh in some cases engines will not last the first 2 hours of operation.  I am at a loss to find out how we get to every time the VVS used unauthorized engine settings outside of the what the manufacturer recommends?

 

I cannot find anything that leads me to that conclusion.

[Crump]

Engine life is based on following the manufacturer's instructions.  It includes proper leaning practices as well as keeping the engine within limits.

 

Proper leaning practices are not understood well by a significant number of pilots.  Doing the wrong thing with the mixture control can easily end your engines life no matter how many hours it has in operation or how well it was operated.

[Brano]

Like 5 minute military power? When every other manufacturer (Packard, RR, DB, etc) had military/combat power of 15-30minutes and Klimov didn't even engine time limits since they could support a high replacement rate.

Klimov M-105PF were optimized for given max rpm and MP that allowed exploitation of the engine within reasonable resurs. There was no forsazh. It was a rational approach ,not allowing pilot to abuse engine beyond limits. Not because they had abundance of engines lying around. Exactly opposite.

[Crump]

'Do not expect the combat fairy to come by and bonk you on the head and make you suddenly capable of doing things you never rehearsed before. It will not happen...'

 

--Warrior's Way

[Dakpilot]

Do you have a link to this, preferrably translated?  I'd love to read it but my Russian is weak.

 

See my post earlier in the thread, 

 

Cheers Dakpilot

[LukeFF]

 

 

I do not see anyone being over conservative even in the anecdotal evidence.

 

I am sure that I am a first class A__H___ to some people for pointing this out...  

 

That is really not the case.  It is just the engineering limitations of flight and complies with aviation convention.

 

At the attrition rate of replacing aircraft engines in 3-5 missions, who needs an enemy to fight?  At that rate, it will not take long for the unit to be so understrength as to be combat ineffective.

 

Your opinion does not square at all with this piece of evidence: http://www.raafwarbirds.org.au/targetvraaf/p40_archive/pdfs/Allison%201710-39%20abuse.pdf

[LukeFF]

I cannot find anything that leads me to that conclusion.

 

What, you mean this? (bolded and in large text, so you don't miss it this time):

 

The primary difference in evaluating the combat capabilities of the P-40 arises from the fact that we and the Allies exploited the aircraft in a completely different manner. They were required to use the aircraft in accordance with written instructions [technical manuals – I.G.]. Any violation of those guidelines was a “no-no”.

 

and

 

If we had flown it in those regimes that the Americans outlined in the aircraft specifications, they would have shot us down immediately. This fighter was a “dud” in its “native” [by-design] regimes. But we conducted normal combat in “our” regimes, be it with the Messer or with the Fokker. 

 

Geez man, come on. It's right there in front of you, as plain as day.

'Do not expect the combat fairy to come by and bonk you on the head and make you suddenly capable of doing things you never rehearsed before. It will not happen...'

 

...said no Medal of Honor or Victoria's Cross recipient, ever. 

Edited March 17, 2016 by LukeFF

[LukeFF]

This whole talk about engine limits reminds me of the official, "legal" limits put forth by the manufacturers of American fleet submarines, concerning their crush depth. Anyone who's conducted some research on WWII American subs knows that the officially rated crush depth numbers were laughably below their true max limits, and many a patrol report confirms this. It's just that the builders had to give the Navy a safe value that would guarantee the sub's structural integrity. It was no different with aviation engines.

[MiloMorai]

This whole talk about engine limits reminds me of the official, "legal" limits put forth by the manufacturers of American fleet submarines, concerning their crush depth. Anyone who's conducted some research on WWII American subs knows that the officially rated crush depth numbers were laughably below their true max limits, and many a patrol report confirms this. It's just that the builders had to give the Navy a safe value that would guarantee the sub's structural integrity. It was no different with aviation engines.

 

And many examples of Merlins running at max for long past the 5 minute limit.

[Crump]

You are attacking a straw man here with this 'combat fairy' nonsense. Nobody here is talking about expecting magic out of a man or machine just because a fight is on.

 

We're talking about steadily and deliberately consuming engine service life at a higher rate than what the manufacturer projected or promised to the government when they signed the contract. Which is what drives operating limitations to begin with (as well as avoiding sudden catastrophic failure, obviously).

 

Even if I'm wrong about the feasibility of doing this in practice I'd appreciate you at least criticizing an accurate version of my argument instead of a false one that makes you look clever at my expense.

 

 

 

And I suppose if my aunt had balls she would be my uncle. Frankly I'm just thrilled that you finally read the material in question and provided a coherent case based on details.

 

For what it's worth, what led me to the conclusion about power settings is the fact that the engines wore out in relatively few hours. I find it hard to believe, but if the engines really did wear out in 3-5 missions when running max continuous power then so be it.

 

 

No straw man and there is no basis for believing the VVS used anything but the published limitations out their own manuals.

 

 

You simply read the anecdotal account and believed what you wished to hear instead of what was actually said in the context of how airplanes work.  It is not my fault you did that.

[Crump]

 

 

Geez man, come on. It's right there in front of you, as plain as day.

 

There is nothing that says they used unauthorized engine limitations.

[Venturi]

Nominal values are NOMINAL - this is the mentality for civilian aviation, peacetime military too

 

Allison was covering its a$$, keep in mind the prewar mentality of a tight-budget US army and viciously-fought contract acquisitions. Easy to lose a contract and companies were out to make $

 

Again, nominal published limits are one thing, but the pilots obviously when in need, discovered the equipment was capable of much more. There are period documents clearing the same Allison engine for higher manifold pressure, later...?

 

The problem lies in CODING ENGINE FAILURE AS A STANDARD TIME LIMIT

 

1. Nominal should always be safe

2. Then have a variable, semi-random timer if above nominal for failure, based on how much abuse

3. Time limit changes for each engine (allison maybe MUCH LONGER??)

 

=FIXED

Edited March 17, 2016 by Venturi

[Crump]

 

 

..said no Medal of Honor or Victoria's Cross recipient, ever. 

 

And you have never met those that died awaiting the miracle of the combat fairey!!

 

 

Nominal values are NOMINAL - this is the mentality for civilian aviation, peacetime military too

 

 

Ahh....so in combat physics will change just because your miserable life is in danger?  Right?

[Venturi]

 

 

 

Ahh....so in combat physics will change just because your miserable life is in danger?  Right?

 I'm sorry, are you confusing Newton's laws with Published Operating Guidelines?

[Venturi]

This whole talk about engine limits reminds me of the official, "legal" limits put forth by the manufacturers of American fleet submarines, concerning their crush depth. Anyone who's conducted some research on WWII American subs knows that the officially rated crush depth numbers were laughably below their true max limits, and many a patrol report confirms this. It's just that the builders had to give the Navy a safe value that would guarantee the sub's structural integrity. It was no different with aviation engines.

Not just American subs, but German as well. It's a truism that nominal has to be a conservative value plus a safety factor, to cover manufacturing variables. The reality is that for intelligent men at risk of being killed, the safety factor and conservative values of "nominal" were ignored WHEN NECESSARY AS PART OF A RISK ASSESSMENT. 

Edited March 17, 2016 by Venturi

[=362nd_FS=RoflSeal]

There is nothing that says they used unauthorized engine limitations.

Dude it was like LITERALLY  in front of you

 

 

If we had flown it in those regimes that the Americans outlined in the aircraft specifications, they would have shot us down immediately. This fighter was a “dud” in its “native” [by-design] regimes. But we conducted normal combat in “our” regimes, be it with the Messer or with the Fokker. 

 

If that doesn't read like exceeding published engine limits to you, I diagnose you as selectively blind.

Edited March 17, 2016 by RoflSeal

[Venturi]

To be honest, this is the same issue with the db601e power limits... the only difference is that the factory "rated" it as higher after a period of time... with significant ramifications for power delivery

 

Here's a quote on this forum from Kurfurst on this subject (different engines, same issue) 

 

http://forum.il2sturmovik.com/topic/4706-question-about-db-601e-start-und-notleistung-start-and-emer/

 

 

German standards were similar - Jumo 211 endurance tests I have show iirc 170 hours at max. rating (stressing the engine several hp less than in case of the M66, for fairness).

 

Even early batches of DB 605D, that had early troubles with faulty sized pistons delivered by subcontractors and valve assembly deficiencies, and as a subsequent result of temporarily ban om their 2000 HP rating, could run in cases at 2000 HP for 40 minutes straight (in contrast to 10 minutes in the manual).

 

Because of mass production tolerances and because practical use stress is usually much worse then bench testing, there is plenty of reserve before approval of a new rating. Also keep in mind that the 601E emergency power was producing only 1350 PS, which was subsequently cleared for 30 mins on the 605 series due to improvements in the design.

Edited March 17, 2016 by Venturi

[LukeFF]

There is nothing that says they used unauthorized engine limitations.

 

Oh my word...

 

Crump, if you cannot use basic logic to deduce from those quotes that the Soviets were using their Allisons way differently than prescribed in the American manuals, then this discussion is DOA. 

[6./ZG26_Klaus_Mann]

Does it really matter what the russian pilots did or not? All we are trying to show is that the Allison could run higher settings for longer than stated in the Training Manuals and subsequent Russian translations. 

We have the Combat Power of 44" for 15 Minutes in the Engine Specs and 56" for 5 Minutes, which would put the P-40 back on the map at least below 3500m. 

I think we can add the Take-Off power which is basically the same and suddenly we get 45" for 20 Minutes and that is a compromise we should all be able to live with. 

And we can still have the 70" if we have to get out of harms way as quickly as possible. 

 

 

As we will most likely never see a "Permanent Wear" System implemented we have to argue for Meaningful Limits, not bicker and moan about completely unrelated topics. 

If you don't stop, this topic will fail. 

[Venturi]

As we will most likely never see a "Permanent Wear" System implemented we have to argue for Meaningful Limits, not bicker and moan about completely unrelated topics. 

If you don't stop, this topic will fail. 

 

I assume you are referring to my suggestion.

 

A permanent wear system is not what I posted, read more closely

The problem lies in CODING ENGINE FAILURE AS A STANDARD TIME LIMIT

 

1. Nominal should always be safe

2. Then have a variable, semi-random timer if above nominal for failure, based on how much abuse

3. Time limit changes for each engine (allison maybe MUCH LONGER??)

 

=FIXED

 

It is a simple change in the code, nothing more complex than something like

 

Time to failure at power setting Y = (time constant) + (variable time interval, X)

 

X = power setting Y multiplier * (random time interval (0-10min))

 

 

Example possible result from such a system: 

 

Time to failure at WEP = 5min + (1/2 [WEP multiplier] * RNG 0-10) = 5min + (1/2 * 7.23) = 8.615 min

 

 

 

You could even add an exponential decay function if you wanted, that is easy enough. I'm just posting something very simple, above, that is already infinitely better than what we already have.

Edited March 18, 2016 by Venturi

[JG13_opcode]

Folks, don't forget that there is a survivorship bias.  When running for their lives I'm sure many pilots pushed the engines harder than authorized.  How many of those pilots were lost to history because they pushed their engines past the operating limits and those engines failed (or even just began to suffer from significant performance degradation) at a bad time?  Not an easy question to answer.

 

We only tend to hear about the ones that came back.

 

Never forget that any value, particularly aircraft performance data, exists as the nominal value plus/minus some uncertainty.

 

If you measure 600 km/h TAS at 3000m, what you're really measuring is 600 km/h plus or minus the uncertainty in the speed measurements, compounded by the conversion from indicated to true airspeed which is subject to errors in altitude measurements, etc. etc. etc. etc.  Furthermore, that's just one point on a continuous statistical distribution.

Edited March 18, 2016 by 13GIAP_opcode

[Venturi]

If you look above, you will see a period document FROM ALLISON representatives TO ALLISON, an internal document, regarding widespread use of higher power settings amongst the Allied Forces utilizing the P40.

 

The guiding principle here should be History, when it is documented in detail or sufficiently shown to be true via multiple consistent historical accounts. Certainly that is the case here.

[6./ZG26_Klaus_Mann]

If you look above, you will see a period document FROM ALLISON representatives TO ALLISON, an internal document, regarding widespread use of higher power settings amongst the Allied Forces utilizing the P40.

 

The guiding principle here should be History, when it is documented in detail or sufficiently shown to be true via multiple consistent historical accounts. Certainly that is the case here.

No. We have to stay precise and create arguable Limits based on Paper. 

Every Fighter could run high power settings for considerable amounts of time without negative effects and that is something we can only fix with a constant wear mechanic I SUGGESTED halfheartedly, because mostly I don't really mind, more DED style and historical:

http://forum.il2sturmovik.com/topic/20768-lets-stop-1min-engine-limitation-madness-manu-my-silly-ideas/

[Venturi]

K. I. S. S.

[JG13_opcode]

If you look above, you will see a period document FROM ALLISON representatives TO ALLISON, an internal document, regarding widespread use of higher power settings amongst the Allied Forces utilizing the P40.

 

The guiding principle here should be History, when it is documented in detail or sufficiently shown to be true via multiple consistent historical accounts. Certainly that is the case here.

 

How many historical accounts does it take to establish a trend?  "Multiple" means "more than one", so are you saying if I can find 2 historical accounts saying that the P-51 could out-run the Me 262, we should change it even if we know the performance data?

 

Historical accounts aren't infallible either, just like test data, but the problem with anecdotes is that they often lack crucial info.

Edited March 19, 2016 by 13GIAP_opcode

[Venturi]

Every position in the world, no matter how sensible, can be changed to ridiculous statements by extreme reductionism.

 

Your statement is also a red herring, debate 101

 

Maybe straw man argument as well.

 

If I had a Daimler Benz period internal document stating the Db601e could withstand 1.42ata for 45 min or more and furthermore that diverse groups of pilots were using it widely on the front lines in this manner without ill effect, then I submit that I there would be much consideration of incorporating revised timelines for db601e failure. Why should Allison be any different? I mean, if History is the basis of all this, I am not sure how much more you need than Period Orginal Allison Documents describing the widespread method of use of these engines. There are additional documents floating around as well regarding this. Check my post history if you like. Some are even regarding Allison-powered Mustangs (same engine).

 

As it is my suggestion of a increased but semi random failure time based on an engine design by engine design case takes all this into account.

 

AGAIN it all boils dow to RISK ASSESSMENT. By making the pilot choose to RISK his engine by pushing it past nominal output, with semi random failure interval, then the devs would be RECREATING decisions real pilots had to make, being more realistic in the timeframe for failure on different a/c, while still utilizing nominal guidelines as a starting point for failure. It also allows the devs to introduce uncertainty in engine failure modeling and to also change the parameters in a realistic manner from engine design to engine design.

Edited March 19, 2016 by Venturi

[JG13_opcode]

I don't think you are reading what I am actually writing.

[JtD]

I think the first sentence in Venturis reply is a perfect summary of your statement, so I guess he was reading. If you didn't just want to take a sensible statement and reduce it to a ridiculous level, maybe you can find another, better way express your point of view?

[Crump]

 

 

When we began to use the P-40, we immediately discovered two deficiencies that reduced its value as a fighter. 1. The P-40 was a “slug” in acceleration, rather slow to acquire speed. This weak dynamic resulted in a low combat speed. It had trouble maintaining the speed required for combat. Speed is essential for a fighter. 2. It was weak in the vertical, especially the Tomahawk. We compensated for poor acceleration by holding the engine at higher revolutions and cruising at a higher speed. We corrected the second deficiency by removing a pair of machine guns. That was all. The fighter came up to par. Now everything depended on you, the pilot. Keep your head! And work the stick intensively. It is true that because of our unforeseen operating regime the engines had a limit of about 50 hours, and often less. Normally an engine might last 35 hours and then it was replaced.

 

I do not see where there is any claim by the VVS pilots of using unauthorized settings.  While some aircraft do have restrictions for vibrational harmonics issues for specific power settings below the maximum continuous power setting.  Most aircraft engine/propeller combinations do not have such restrictions.

 

There is nothing that prevents using a higher cruise rpm/manifold pressure up to and including maximum continuous power setting.  All it does is increase your speed, gas consumption, and wear on the engine.

[Crump]

 

 

Historical accounts aren't infallible either, just like test data, but the problem with anecdotes is that they often lack crucial info.

 

Absolutely and that missing crucial information leads to misinterpretation.

[=362nd_FS=RoflSeal]

I do not see where there is any claim by the VVS pilots of using unauthorized settings.  While some aircraft do have restrictions for vibrational harmonics issues for specific power settings below the maximum continuous power setting.  Most aircraft engine/propeller combinations do not have such restrictions.

 

There is nothing that prevents using a higher cruise rpm/manifold pressure up to and including maximum continuous power setting.  All it does is increase your speed, gas consumption, and wear on the engine.

Confirmed diagnosis of selective blindness

 

Also if you are willing to believe that they got 3-4 missions out of an Allison which was the first US engine to complete the 150 hour type test at 1,000 horsepower in 1937 (albeit it was the C model not F) then be my guest.

Edited March 22, 2016 by RoflSeal

[Crump]

 

 

So you equate someone giving a powersetting a nickname with someone saying they ran at high RPM to have a high cruise speed?

 

No, I am saying you are making the same mistake that we did when first hearing a pilot anecdote that was contrary to the norms.

 

We were researching the BMW801D series engine ADI and boost systems to determine what the aircraft was equipped with and what we needed to restore.  The BMW801D series was never authorized MW-50 as an ADI to increase knock limited performance.  We had clear and overwhelming documented evidence of that.  BMW did research it and tested it on the engine.  The simple fact was other systems were better.

 

On the surface, Oskar's account was contrary to the evidence we had gathered but after further investigation, it was simply our misinterpretation of the slang just as you are now misinterpreting the VVS pilots anecdote.  

 

If you were a pilot and understood how operating instructions compliance works, it would be much clearer to you.  You would not see it as evidence of using some wonder boost system that will miraculously save the day in combat.

 

I think you underestimate the importance of a high cruise speed and the fact the VVS P-40E was by losing 250lbs of weight. 

 

 

Also if you are willing to believe that they got 3-4 missions out of an Allison which was the first US engine to complete the 150 hour type test at 1,000 horsepower in 1937 (albeit it was the C model not F) then be my guest.

 

Much more to do with the oil they were using than any power setting......