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

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Since this Setup seems to me to be for reasons of Safety, I guess that 52 and subsequently 56" were also still deemed safe, so that when the Pilot goes full throttle on a standard Day he wouldn't exceed the Limits deemed Safe. Since 56" would only be reached within a very narrow speed and altitude band it wouldn't really be reasonable to set it up as a setting on it's own.  This leads me to think that around some corners they approved of 52" and 56" for 5 Minutes, since they did put the throttle Stops at Safe Positions, which wouldn't allow the engine to exceed safe limits. 

 

When one understands the 4 types of MAP regulators all did the same thing of keeping the manifold pressure ALWAYS at 56"Hg by venting any overboost pressure there was no reason to keep the engine restricted to 52"Hg anymore for a maneuvering buffer. 

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When one understands the 4 types of MAP regulators all did the same thing of keeping the manifold pressure ALWAYS at 56"Hg by venting any overboost pressure there was no reason to keep the engine restricted to 52"Hg anymore for a maneuvering buffer. 

I'm talking about the straight throttle. I know that with Regulator the story changes. 

It doesn't matter to the topic since we don't have the regulator ingame. 

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I'm talking about the straight throttle. I know that with Regulator the story changes. 

 

Yes, you understand how it works.  I did not mean to imply that you did not.   :salute:  

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How? It's Perfectly Logical.

 

...

 

The story as I see it:

52" on the Ground Static as buffer for

56" as Maximum achievable on a standard day, Absolute Never Exceed Limit.

43.9" or 42" @ 11,200 feet as Critical Altitude guaranteed Power to the the USAAF

Sorry, that's technically impossible. You need an open throttle to achieve 42" at 12.000 feet static. You need a half closed throttle to limit the engine to 52" at sea level static. There's not regulator to gradually open it up as you go higher, it doesn't work. Farky has already explained this in more detail, including sketches.

 

Really simple, simplified engineering bit for plausibility: A compressor compresses, in goes one pressure, out comes another. Roughly, the pressure ratio in - out remains constant as long as compressor rpm don't change. On the F3R Allison it's directly linked to engine rpm, so it doesn't change as long as engine rpm don't change.

At 12000' the F3R produces ~42" from ~19" outside pressure.

At sea level we have ~29" outside pressure. Gives you ~64" pressure at the manifold.

The only way to reduce the pressure to 52" is to close the throttle, so you can't get all of the outside pressure to the compressor intake. And closing the throttle has to be done manually by the pilot, because there are no automatic devices. You cannot set up the engine to do that, without a map regulator.

If he does not manually adust it, or intentionally opens it fully, the engine runs at way above 60", static, sea level.

 

Or, if it was limited to 52" at sea level, your full throttle altitude for 42" would be ~7000". Because you couldn't open the throttle beyond what you did at sea level, since there's no automation, and you'd be hitting the same stop.

Edited by JtD

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Sorry, that's technically impossible. You need an open throttle to achieve 42" at 12.000 feet static. You need a half closed throttle to limit the engine to 52" at sea level static. There's not regulator to gradually open it up as you go higher, it doesn't work. Farky has already explained this in more detail, including sketches.

 

Really simple, simplified engineering bit for plausibility: A compressor compresses, in goes one pressure, out comes another. Roughly, the pressure ratio in - out remains constant as long as compressor rpm don't change. On the F3R Allison it's directly linked to engine rpm, so it doesn't change as long as engine rpm don't change.

At 12000' the F3R produces ~42" from ~19" outside pressure.

At sea level we have ~29" outside pressure. Gives you ~64" pressure at the manifold.

The only way to reduce the pressure to 52" is to close the throttle, so you can't get all of the outside pressure to the compressor intake. And closing the throttle has to be done manually by the pilot, because there are no automatic devices. You cannot set up the engine to do that, without a map regulator.

If he does not manually adust it, or intentionally opens it fully, the engine runs at way above 60", static, sea level.

 

Or, if it was limited to 52" at sea level, your full throttle altitude for 42" would be ~7000". Because you couldn't open the throttle beyond what you did at sea level, since there's no automation, and you'd be hitting the same stop.

 

If the supercharger FTH is sea level then it will develop power according to the reciprocal of the square root of the density ratio.

 

End of Story.

 

2wbryut.jpg

 

 

Density altitude effects....   52"Hg / SMOE 11000 feet = 52" /1.1822 = 43.9"Hg  

 

2uqd4b8.jpg

 

 

xe1ysj.jpg

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If the engine is adjusted to produce 52"Hg at sea level on a standard day...then all it will produce is 52"Hg on a standard day.

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No I can't, good for you. But you never work on this engine, just like me. I don't care about your experience or certificates. It doesn't matter here if you are 12 or 60, combat pilot or old lady working in a department store. Only shown knowledge counts here.

 

Which you haven't shown much except to try and advance a gamers theory for some fantasy overboost system for your Allison engine.

 

Let decide someone else than the self-proclaimed expert how much knowledge I showed so far, shall we?

 

 

 

I am fascinated by your idea of limitation movement of throttle so that it can NEVER be fully open. Madness.

 

 

MMMmmm

 

Go check any engine....throttle movement is not infinite so why are you trying to make a case that is somehow infinite in the Allison V-1710-39 series?

 

It is not.  The throttle linkage is fixed by the settings it is adjusted too and will only open so far.  It opens to the manifold pressure the mechanic adjust's it too IAW with Type Certificate and Engine Maintenance instructions.

 

Are you out of your mind ? You know what, tell any FAA inspector that you adjusted (limited) maximum movement of the throttle in engine (in engine, not in cockpit) . Friendly advice - kiss your certificate goodbye before you do that.

 

You didn't extrapolate power table I posted, let me do this "rocket science" for you then. Maybe now is the right time to do your math again.

 

power_chart_allison_extrapolated_new.jpg

Allison_memo_66.jpg

 

 

 

Now lets see what Allison says the Full Throttle Height of the V-1710F3R engine is at 52"Hg without a MAP regulator.....

 

2lldon8.jpg

 

 

The rated Altitude is Sea Level on a standard day.  That kind of eliminates the entire thought process of it develops any more manifold pressure than the 52"Hg that is set by the linkage to produce at the throttle stops.

 

With the same logic, V-1710-39 (-F3R) was at the same time able to produce 45.5"Hg/3000rpm ONLY at sea level. Rated Altitude in this case do not mean what you think, this is NOT Full Throttle Height. Yes, I know definition of Rated Altitude, but in this table is this term clearly used for something different. I know for what, but you don't care what I am saying so why wasting my time with explanation.

 

sea_level.JPG

 

Btw - 52"Hg/3000rpm was rating for engines WITH automatic MAP regulators. Manuals are dealing with setting this MAP on automatic regulators. What manuals don't? They do NOT say a word about adjusting throttle on engines without automatic MAP regulator. Isn't it strange that there are no instructions for this adjusting in manuals at all ?

 

 

With regard to Technical Order No. 02-5A-47 - you don't know what this Technical Order says, so how do you know it means instalation of automatic MAP regulators into P-40E? I don't know what it says neither, but I am sure that this T.O. do NOT approve or order instalation of automatic regulator into airplane. It probably approve instalation of automatic MAP regulator on engine, which is NOT the same thing. How i know that? Because Technical Orders with first number 02 are always ONLY about engine, not the airplane. If you need approve anything on airplane, you need Technical Order with first number 01. No exceptions. Instalation of engine equipped with automatic MAP regulator into P-40E was approved by T.O. No. 01-25C-112, issued autumn 1943. 

 

Separate discussion that has NOTHING to do with what your Allison V-1710F3R engine should produce or how it produces power nor is it applicable to your game.

 

I will simply point out that you are taking the instructions for the PC-1 regulator...ONE of FOUR different regulators that can be mounted and attempting to apply the fact SOME PC-1 regulators were fitted at the factory and SOME PC-1 regulators were fitted IAW the Technical Order at service or Depot Level maintenance as applying to ALL four MAP regulator designs.

...

Your theory that the V-1710F3R engines did not recieve a MAP regulator in USAAF service is not factual.  The Technical Order is very clear, all V-1710F3R engines will receive a MAP regulator when they undergo service or depot level maintenance.

 

I never said that " the V-1710F3R engines did not recieve a MAP regulator in USAAF service ", stop making up things. Your theory with four types of regulators is wrong and it comes from your head, not from manuals. You don't even know what manual you quote, you are just using picture posted by me.

 

Technical Order AN 02-5AB-2 - SERVICE INSTRUCTIONS V-1710-29, -39, -49, -51, -53, -55, -73, -81, -87, -89, -91, -99, -111, -113 and -115 AIRCRAFT ENGINES (issued February 1945) - "The PC-1 model is the ONLY control of this series used on engines covered in this handbook." You can clearly see, that other three types of regulator (PC-2, PC-3 and PC-4) were NOT installed in V-1710-39. For this reason, I was talking only about PC-1.

 

regulators_1945.JPG

 

Erection and Maintenance instructions for P-40E-1 (Technical Order No. 01-25CJ-2, issued January 1944) do NOT mention any inspection of automatic MAP regulator in this airplane. Other P-40 maintenance manuals (for variants of P-40 with MAP regulator) ALWAYS mention check of this device as part of 25-Hour Inspection. I am NOT saying that P-40Es never get automatic regulators, they do, but not all of them and not before they were withdrawn from combat units to training units.

 

Let me remind you who start this off topic about automatic MAP regulators. YOU, when you was talking that nonsence about throttle control and MAP control. Now you act like someone else brought this topic to debate.

 

------------------------------------------------------

 

 

I think I'm done with this thread (at least for some time). I have better things to do than walk in circles on forum. I have to admit Crump, that how you convince some people here about your knowledge and infallibility is pretty impressive. They do not see your old cheap discussion tactics like "change of the subject when I realize that I am wrong", "no respond to direct questions", " if I have no rational argument, so I declare myself an expert, so I must be right", " use complex calculations for simple things, so only a few people can reveal that I'm wrong" or "constant and regular misrepresentation of views of your opponents"... Well, I know what are your doing, I've seen this tactics on the internet forums many times.

 

This thread is all yours now Crump, I just hope you will not do any damage to the game with your incompetent mess. Nothing personal.

 

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You didn't extrapolate power table I posted, let me do this "rocket science" for you then. Maybe now is the right time to do your math again.

 

You can extend and extrapolate certain things in aircraft performance...but that is not one of them!

 

260g20g.jpg

 

 

Oh look!  I can get 30 inches of manifold pressure out of a Lycoming O-360!  Let me see how that works out!!  It does not.  The linkage that opens those butterflies and the limiting fuel to air mixtures only goes so far....

 

 

 

"The PC-1 model is the ONLY control of this series used on engines covered in this handbook."

 

Covered in that particular handbook.

 

If you look in the V-1710-39 overhaul manual it tells you how to install the other regulator types...

 

Totally not relevant though to the basics of how the engine operates and the fact it does not produce anything more than 52"Hg at sea level.

 

 

 

Yes, I know definition of Rated Altitude, but in this table is this term clearly used for something different

 

Obviously you do not as you continue to argue it.

 

 

 

With the same logic, V-1710-39 (-F3R) was at the same time able to produce 45.5"Hg/3000rpm ONLY at sea level.

 

No, that is a take off rating and could very well be below maximum manifold pressure in a ground boosted engine.  That is something you would know with some experience flying!

 

In fact, you see the answer to your question in the P-40 Training Manual....

 

sltap3.jpg

 

 

 

I think I'm done with this thread (at least for some time).

 

I would withdraw too because only one explanation aligns the rated altitude and the physics....

 

 

Density altitude effects....   52"Hg / SMOE 11000 feet = 52" /1.1822 = 43.9"Hg  

 

If the supercharger FTH is sea level then it will develop power according to the reciprocal of the square root of the density ratio.

 

End of Story.

 

2wbryut.jpg

 

 

 

2uqd4b8.jpg

 

 

xe1ysj.jpg

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For the last time, I promise.

 

 


You can extend and extrapolate certain things in aircraft performance...but that is not one of them!

 

260g20g.jpg

 

 

Oh look!  I can get 30 inches of manifold pressure out of a Lycoming O-360!  Let me see how that works out!!  It does not.  The linkage that opens those butterflies and the limiting fuel to air mixtures only goes so far....

 

 

You are trying to make a fool of me? Of course you cannot extend things in sea level performance part of power chart, this data are already for FULL THROTTLE. Why you don't show right part of the power performance chart, Altitude Performance chart? Because everyone than can see how complete chart looks like (no extrapolation need or possible here) and everyone can see that chart for V-1710-39 I posted is obviously not complete and therefore need to be extrapolated to get complete power performance?

 

Let's say you you decide limit maximum MAP obtainable by Lycoming O-320 at Sea Level to 25"Hg at 2700 rpm (by adjusting throttle linkage as your theory say). Take a look what happens to your Altitude Performance, you unavoidably shift whole 2700 rpm line in chart to much lower altitude. Basics and common sense -  if you open throttle only partially (because stops do not allow you to use full throttle), you get only partial power.

 

lycoming.JPG

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Why you don't show right part of the power performance chart, Altitude Performance chart?  
 

 

Because it is not required to answer the question "What is the highest manifold pressure the V-1710F3R will produce at sea level on a standard day?"  That is 52:Hg as per the Type Certificate.

 

 

 

You are trying to make a fool of me?

 

No but you are doing it all on your own.

 

Great explanation of what happens if you do not touch the throttles on fixed pitch propeller and climb to altitude but that is not the question.

 

In fact I have to wonder what is your entire point because the discussion is the maximum manifold pressure the engine produces at sea level under standard conditions and I think the P-40E has a Constant Speed Propeller.  We all know it changes with density altitude and propeller load.

 

 I used that chart is such a sneaky way because the question is, "What is the highest manifold pressure the V-1710F3R will produce at sea level on a standard day?" 

 

If you want to answer that question on a ground boosted or normally aspirated engine you simply follow the green line until it reaches the sea level point (yellow circle) or you just use the other side of the chart for sea level performance.

 

qs5z48.jpg

 

The green line correspond to the power reduction due to density altitude effects on a standard day.  I highlighted it so you can find it.  You can keep a constant RPM with a constant speed propeller.  That is the beauty of them!

 

 

 

 


The green line varies with the reciprocal of the square root of the density ratio.


What that chart definitely tells us is I cannot extend the lines to create my own manifold pressure settings.

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Thank you for your excellent and very correct posts Farky.

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http://www.askacfi.com/24117/manifold-pressure-gauge-requirement.htm

 

Thank you for your excellent and very correct posts Farky.

Not only was his hypothesis incorrect, it is just plain nonsense for the discussion, Venturi.

 

Constant Speed Propellers maintain a constant RPM. In his example, the rpm is reduced which is correct for a fixed pitch propeller.

 

That is why most fixed pitch propeller aircraft do not even have a manifold pressure gauge. It is just useless information in a fixed pitch propeller aircraft.

 

That farky shows the rpm reducing and does not understand rpm is constant pretty much is a solid case for being "lost in the sauce". The argument has become a point of ego for him...and you.

 

Take a deep breath...step back...and use your brain not your feelings!

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Constant Speed Propellers maintain a constant RPM. In his example, the rpm is reduced which is correct for a fixed pitch propeller.

...

That farky shows the rpm reducing and does not understand rpm is constant pretty much is a solid case for being "lost in the sauce". The argument has become a point of ego for him...and you.

 

Bad news. If you think I let you say everything you want about me or informations I posted here, you are wrong, Altough I said that I am done here, I will be reacting on you manipulations and misinterpretations. Now back to the topic - 

 

In my example with Lycoming rpm is NOT reduced, remains on maximum 2700 rpm in both cases (red lines). We can all see that, look at the picture. Stop lying or start properly read. 

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Bad news. If you think I let you say everything you want about me or informations I posted here, you are wrong, Altough I said that I am done here, I will be reacting on you manipulations and misinterpretations. Now back to the topic - 

 

In my example with Lycoming rpm is NOT reduced, remains on maximum 2700 rpm in both cases (red lines). We can all see that, look at the picture. Stop lying or start properly read.

 

Oh...so when you accuse me of cutting off a portion of a chart that is simply not applicable...it is not a misunderstanding and you have misread nothing. Yeah I see you have the rpm. Frankly, you totally mucked that chart up. You have one line between 2100 rpm and the other at 2700 rpm with arrows going towards your 2100 rpm line. You invented your own way to read the thing and it is simply confusing without illustrating any real point.

 

It certainly does not explain the fact the critical altitude for 52"HG in the V-1710F3R is sea level nor does it explain how the other maximum power ratings follow the physics of a ground boost engine. If the linkage is adjusted for 52"HG at sea level...it is only going to put out 52"HG at sea level. The manifold pressure will drop over altitude at the rate of the reciprocal of the square root of the density ratio.

 

That is a quite a large stumbling block in your theory.

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For the last time, I promise.

 

 

 

 

You are trying to make a fool of me? Of course you cannot extend things in sea level performance part of power chart, this data are already for FULL THROTTLE. Why you don't show right part of the power performance chart, Altitude Performance chart? Because everyone than can see how complete chart looks like (no extrapolation need or possible here) and everyone can see that chart for V-1710-39 I posted is obviously not complete and therefore need to be extrapolated to get complete power performance?

 

Let's say you you decide limit maximum MAP obtainable by Lycoming O-320 at Sea Level to 25"Hg at 2700 rpm (by adjusting throttle linkage as your theory say). Take a look what happens to your Altitude Performance, you unavoidably shift whole 2700 rpm line in chart to much lower altitude. Basics and common sense -  if you open throttle only partially (because stops do not allow you to use full throttle), you get only partial power.

 

lycoming.JPG

 

Even though Crump does not get it, Farky is correct. He is showing that limiting the engine to part throttle effectively reduces its altitude performance.

 

Crump, you are supposed to read that graph left to right. Of course even though it is his own graph, he does not get it. Typical Crump.  :rolleyes:

 

By arbitrarily limiting throttle movement (aka your "rods" analogy, earlier, Crump) one also limits the engine's power output at altitude. That's why the bottom red line on the right is parallel to the top red line.... the engine is also at 2700 RPM on the left, just that it's at part throttle. What Farky is showing is that you reduce the output of the engine by several thousand feet equivalence.

 

To add an additional wrinkle for the advanced reader... (mea culpa) the Lycoming O-320 is a naturally-aspirated engine. Comparing it to a supercharged engine like the Allison V-1710 its kinda apples to oranges.

 

The reason why is that on a naturally-aspirated, non-supercharged engine, manifold pressure increases with increased throttle not because there is a supercharger pressurizing the air, but because the airflow entering the intake runners must move at a faster and faster velocity as RPM increases. Because that air has mass it thus has inertia. So the pistons suck a column of air in at faster and faster velocities, but then they can only suck a certain amount of that air into the cylinder when the intake valves are open. Because the intake runners contain more air than what the pistons can suck, and this air has a higher and higher velocity (due to a more open butterfly removing an intake restriction and increased RPM), it results in a pressure that more and more closely resembles ambient atmospheric pressure. It is called "the scavenging effect" and operates both in exhaust and intake tracts. I won't mention the other name. ;) Regardless of MP increasing as RPM increases, on a naturally-aspirated engine which is not experiencing ram-air effects, the manifold pressure can never appreciably rise above ambient atmospheric, whatever that is at that altitude.

 

Regardless, Farky is correct in his assertion.  :salute:

The Allison V-1710 and really any engine, is designed to have full capability of the complete range of butterfly valve movement. 

My car does, your car does, and any piston-engined aircraft does. 

The only exception are the go-karts that you used to drive at the local kiddie park. THOSE used throttle restrictions like Crump is suggesting. 

Edited by Venturi
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Crump, you are supposed to read that graph left to right. Of course even though it is his own graph, he does not get it. Typical Crump.  :rolleyes:

 

 

 

 

Well...I guess instruction step one is all wrong on the chart.....if you read the instruction!!

 

 

The rest of your post is kind of drivel mixing correct information with incorrect assumption about power development over altitude. Most of it has already been covered.

 

I encourage you to retread it. The entire throttle butterfly argument is a great point. Farky is arguing with himself on that one and I find it funny you have picked up the banner. Both of you misunderstand what the fixed distance rods meant. Completely irrelevant to the discussion. It is beyond the scope of this thread to give an A&P level fuel metering class.

 

Just stop for a second and set all these rabbit holes aside.

 

 

 

It certainly does not explain the fact the critical altitude for 52"HG in the V-1710F3R is sea level nor does it explain how the other maximum power ratings follow the physics of a ground boost engine. If the linkage is adjusted for 52"HG at sea level...it is only going to put out 52"HG at sea level. The manifold pressure will drop over altitude at the rate of the reciprocal of the square root of the density ratio.

That is a quite a large stumbling block in your theory.

Answer the following very simple question

 

Explain the maximum power output of the engines Critical Altitude is sea level?

 

 

No more silly rabbit holes....I think that is a very reasonable request and gives you, Venturi and Farky, the opportunity to enlighten us all with your knowledge!

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Sry for little off topic but i think you all miss that main problem with BOM P40 is wing polar and critical angle of attack not with engine settings. Russian test result in sustained turn time at 1000m was 19.2 sec so better then Bf 109 F4. In Bos is over 20 sec and got only 14 deg cAoA. So P40 E at low alt should better turn then 109 F

Edited by 303_Kwiatek

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The P-40 should most certainly turn better than the Bf109 at the stall line. I did not know that it did not. The engine question is valid because of the aircrafts thrust limited performance but I agree....BOS has the engine settings correct for the time period in VVS service.

 

The discussion is relevant to future development as I understand the P-40E remained in VVS service as a fighter for most of the war.

 

Do you have 2D data on the NACA 2215/NACA 2209 airfoils?

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It's really simple. You can extrapolate given data. 52" max, LMAO. Clueless, and that's polite for it.

 

Thanks Farky, good posts.

post-20105-0-66386600-1472494653_thumb.jpg

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Oh...so when you accuse me of cutting off a portion of a chart that is simply not applicable...it is not a misunderstanding and you have misread nothing.

 

Yes, my bad. I thought you are smart enough to understand what I want from you when I tell you "extrapolate this chart". Therefore, I thought that you deliberately used a different portion of the power performance chart as part of manipulation . Now when you clarified that you did not understand what I want at all, I have to apologize. Sorry.

 

 

Answer the following very simple question

 

Explain the maximum power output of the engines Critical Altitude is sea level?

 

 

No more silly rabbit holes....I think that is a very reasonable request and gives you, Venturi and Farky, the opportunity to enlighten us all with your knowledge!

 

Challenge accepted. You wanna play? All right, game on ...

 

Ladies and gentlemen, sit back and relax, open your mind and let yourself be amazed by my knowledge...

 

Answer on this question will by shocking - Critical Altitude (also known as Full Throttle Height) for the maximum allowed power output of V-1710-F3R(-39) is NOT, I repeat NOT, sea level.

 

I know where it comes from, source is this table in Allison's Operations and Maintenance handbook for V-1710 "F" type engines (ALD-3F2) on page 34 -

 

sea_level_rated~0.jpg

 

As we can see, maximum allowed MAP/RPM for V-1710-F3R is 56.0"Hg/3000 RPM and Rated Altitude for this War Emergency Rating is Sea Level. It looks like this engine is SEA LEVEL RATED, but let's cross-check it out, that is always good thing to do. What Allison says about this engine on page 9 in same handbook (ALD-3F2) ?

 

altitude_rated~0.JPG

"The V-1710-F3R, F4R and F20R Model engines are ALTITUDE RATED ENGINES" ... Allison handbook itself is contradictory here.

 

So now what? I'm so glad you asked. Now we need other source to find correct answer. Luckily, V-1710-F3R was installed also in North American Mustang and we have this transcription of RAF report located at http://www.wwiiaircraftperformance.org/mustang/ap222.html . Here is a table from this report -

 

Full_throttle_height_RAF.jpg

 

As you can see, Full throttle height for 56"Hg MAP  (well, 55.8"Hg) was in this test 7900 ft under rammed flight condition. This fully agrees with the data from the book "Vee's For Victory!" (ISBN: 0-7643-0561-1), where on page 167 author states that Full throttle height for 56"Hg/3000 RPM on V-1710-39(-F3R) without ram is 4300 ft (1490 bhp). Source for this data in "Vee's For Victory!" are Allison Performance Curves.

 

Conclusion - Critical Altitude (also known as Full Throttle Height) for the maximum allowed power output of V-1710-F3R is NOT, I repeat NOT, sea level.

 

 

So, here is you answer Mr.Crump. My turn ...

 

Every mechanic need specific instructions for his work, he find them in handbooks. You are saying, that on airplanes without automatic MAP regulator " the throttle linkage was adjusted for 52"Hg maximum at sea level". Here is my simple question -

 

Where in handbook ALD-3F2 are specific instruction for linkage adjustment for 52"Hg maximum at sea level on engine without automatic regulator, page number?

 

Your time to shine Mr. Crump.

 

 

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It's really simple. You can extrapolate given data. 52" max, LMAO. Clueless, and that's polite for it.Thanks Farky, good posts.

It is not valid. It is different airplane installation and you are drawing the same lines as Farky on a P-51 Operating Instructions chart.

 

 

 

You understand that you can run the math on the points for a V -1710F3R that is cleared for 52"HG and it will do the same thing because a ground boost engine will vary power at the reciprocal of the square root of the density ratio.

 

It is entirely possible that at some point later than 01 Apr1943 that the engine in the P-51 was cleared but that is not applicable to the P-40E or the V-1710F3R as of 01April 1943.

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It is the same engine Crump. Just like a Lycoming O-360 is the same engine even if installed in two different aircraft.

Sry for little off topic but i think you all miss that main problem with BOM P40 is wing polar and critical angle of attack not with engine settings. Russian test result in sustained turn time at 1000m was 19.2 sec so better then Bf 109 F4. In Bos is over 20 sec and got only 14 deg cAoA. So P40 E at low alt should better turn then 109 F

This could very well be the case too. The plane should be able to be competitive with a 109 E-7.

 

The engine is a valid topic because not only is the airframe performance (too) poor, but the engine cannot hold even 56" / 3000 for 5min.

 

Maybe we should make a new topic.

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Farky, It is an altitude engine with a MAP regulator fitted by definition. That does not mean it is an altitude engine without one. In fact I think that is mentioned in the Aircraft Engine Historical Society article on Allison supercharger development.

 

That would explain several things in fact. I will take a closer look at things when I off work.

 

Llooking at the P-51 in which ALL V-1710F3R were factory equipped with a MAP regulator tells you nothing about a P-40E V-1710F3R engine NOT equipped with a MAP regulator.

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It is the same engine Crump. Just like a Lycoming O-360 is the same engine even if installed in two different aircraft.

 

.

Engines Operating Instructions are installation specific. For example, my aircraft has the same engine as a Mooney M20 but the Mooney has power limitations that mine does not. Neither installation violates Lycomings O-360 Type Certificate.

 

In the case of the V-1710F3R, all P-51 installations came with a MAP regulator. The P-40E did not and a closed manifold system with a single stage single speed supercharger is by definition a ground boost or sea level engine.

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Engines Operating Instructions are installation specific. For example, my aircraft has the same engine as a Mooney M20 but the Mooney has power limitations that mine does not. Neither installation violates Lycomings O-360 Type Certificate.

 

In the case of the V-1710F3R, all P-51 installations came with a MAP regulator. The P-40E did not and a closed manifold system with a single stage single speed supercharger is by definition a ground boost or sea level engine.

In fact the FTH for the P-40D Kittyhawk I with V-1710-F3R without a MAP regulator was 11,400 ft, according to an A&AEE report dated 27/5/42

 

http://www.wwiiaircraftperformance.org/P-40/AK572.pdf

 

 

This aeroplane is an early 4-gun model and has neither the various American modifications and improvements, nor any British modifications.

 

A slightly later test on a different Kittyhawk I has a FTH of 12,000 ft

 

http://www.wwiiaircraftperformance.org/P-40/AL229.pdf

 

same Kittyhawk with flame damping exhausts has a FTH of 14,400 ft

 

http://www.wwiiaircraftperformance.org/P-40/AL229-flame-damping-exhaust.pdf

 

while another report gives a FTH of 13,500 ft (this time with a modified cowling)

 

http://www.wwiiaircraftperformance.org/P-40/ET573-Modified-Cowling.pdf

 

American operational instructions from November 1941 give a Military Rated Power of 1150 hp @ 3,000 rpm @ 43.9" @ 15,000 ft

 

http://www.wwiiaircraftperformance.org/P-40/P-40E_Operation_Instructions.jpg

 

To claim that the V-1710-F3R without MAP was a "sea-level rated engine" is plainly wrong. (Unfortunately, this last comment will, no doubt, precipitate yet another of Crump's condescending lecture series, with lots of diagrams, red herrings and diversions, so the ignore feature will probably be needed. ;) )

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In fact the FTH for the P-40D Kittyhawk I with V-1710-F3R without a MAP regulator was 11,400 ft, according to an A&AEE report dated 27/5/42

 

http://www.wwiiaircraftperformance.org/P-40/AK572.pdf

 

 

 

A slightly later test on a different Kittyhawk I has a FTH of 12,000 ft

 

http://www.wwiiaircraftperformance.org/P-40/AL229.pdf

 

same Kittyhawk with flame damping exhausts has a FTH of 14,400 ft

 

http://www.wwiiaircraftperformance.org/P-40/AL229-flame-damping-exhaust.pdf

 

while another report gives a FTH of 13,500 ft (this time with a modified cowling)

 

http://www.wwiiaircraftperformance.org/P-40/ET573-Modified-Cowling.pdf

 

American operational instructions from November 1941 give a Military Rated Power of 1150 hp @ 3,000 rpm @ 43.9" @ 15,000 ft

 

http://www.wwiiaircraftperformance.org/P-40/P-40E_Operation_Instructions.jpg

 

To claim that the V-1710-F3R without MAP was a "sea-level rated engine" is plainly wrong. (Unfortunately, this last comment will, no doubt, precipitate yet another of Crump's condescending lecture series, with lots of diagrams, red herrings and diversions, so the ignore feature will probably be needed. ;) )

How is it condescending when stuff like this keeps getting added to the thread.

 

None of those reports show or have a thing to do with 52"HG. In a ground boost engine, only the maximum manifold pressure will be achieved at sea level. Any power setting below that will have a FTH at altitude. You understand that, right?

 

 

 

It is just white noise that does not add a thing to the conversation.

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None of those reports show or have a thing to do with 52"HG

 

Doesn't matter; the reports clearly show the rated altitudes for the V-1710-F3R as fitted to P-40Ds and Es without a MAP Regulator.

 

 In a ground boost engine, only the maximum manifold pressure will be achieved at sea level. Any power setting below that will have a FTH at altitude. You understand that, right?

 

Allison disagrees with Crump; Allison Service School Handbook, 1 April 1943:

 

Allison%20V-1710%20Service%20School%20Ma

 

V-1710-F3R was rated at 10,800 ft Normal, 12,000 ft Military.

 

The F2R/L  and  F5R/L, as fitted to the P-38, needed a separate turbocharger to be rated at 25,000 ft, otherwise they were S/L rated.

 

Allison%20V-1710%20F%20Series%20handbook

Allison%20V-1710%20F%20Series%20handbook

 

I will take the engine manufacturer's word over a self-proclaimed "expert" such as Crump.

 

Wasn't there already a thread on ground and altitude engines. Didn't it get locked?

 

http://forum.il2sturmovik.com/topic/465-sea-level-engine-vs-altitude-engine/

 

Plenty of white noise, red herrings and diversions from Crump in that thread.  ;)

Edited by NZTyphoon

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NZ, you don't have a degree from the premier aeronautical education college/university in the USA, so can not understand all this aeronautical 'talk'. :rolleyes:

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NZ, you don't have a degree from the premier aeronautical education college/university in the USA, so can not understand all this aeronautical 'talk'. :rolleyes:

 

No, that can’t be the problem because I have an MSc in aeronautics and I still don’t get it. I mean, what Farky, NZ and the others are saying makes sense to me but what Crumpp is posting simply flies over my head……

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Holt, you got your aeronautics MSc from a 2 bit university. :biggrin:

Well, the Royal Institute of Technology in Stockholm ain't all that bad. I mean a lot of the guys who went there went on to design planes at SAAB so we can't all be dummies right? Ya know I even worked on parts of the AJ37, JA37 Viggen and JAS39 Gripen systems myself. ;)

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Farky, It is an altitude engine with a MAP regulator fitted by definition.

 

That is correct.

 

 

In the case of the V-1710F3R, all P-51 installations came with a MAP regulator. The P-40E did not and a closed manifold system with a single stage single speed supercharger is by definition a ground boost or sea level engine

 

 

Well, incorrect and correct at the same time, it's little complicated.

 

Incorrect - if pilot strictly follows maximum engine limits in manual (green line in picture), it is by definition altitude rated engine. I know you will disagree because you still think that on airplanes without MAP regulator was throttle restricted to give only 52"Hg at sea level. It did not happen, this theory is wrong and I'll get to this topic later.

 

SUPERCHARGING_V-1710_Altitude_rated.jpg

 

Correct - but only if we bend definition of ground boosted (= sea level rated) engine a little. If we put aside what was allowed and we will work with what was POSSIBLE, than yes, V-1710-39(-F3R) without automatic MAP regulator is ground boosted engine. This is exactly the reason why we need extrapolate that engine performance chart from Mustang manual to get performance of V-1710-F3R at sea level/3000 rpm without ram. You think that this engine (without regulator) is ground boosted engine for different reason - your theory of restricted throttle, which is incorrect.

 

SUPERCHARGING_V-1710_Ground_boosted.jpg

 

------------------------------------------------------------------------------------------------------

 

Attempt at least once open your mind to other opinions and just think about this -

 

If you restrict throttle so that you never get FULL THROTTLE (throttle fully open), how you can get FULL THROTTLE HEIGHT? Simple logic is obviously against your "restricted throttle" theory.

 

Try transfer your theory into chart for Lycoming O-320 I posted before (I will post you clear picture at the end of this post). Try same thing I did, "adjust" engine to maximum 25"Hg/2700 rpm at sea level, calculate with use of constant speed propeller of course.

 

------------------------------------------------------------------------------------------------------

 

I will not let you ignore that question, it would be fair from you answered it, I answer yours -

 

Every mechanic need specific instructions for his work, he find them in handbooks. You are saying, that on airplanes without automatic MAP regulator " the throttle linkage was adjusted for 52"Hg maximum at sea level". Here is my simple question -

 

Where in handbook ALD-3F2 are specific instruction for linkage adjustment for 52"Hg maximum at sea level on engine without automatic regulator, page number?

 

------------------------------------------------------------------------------------------------------

 

Clear Lycoming O-320 chart -

post-13312-0-08147900-1472589454_thumb.jpg

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[Edited]

 

You and Venturi (who upvoted this post) are treading into a bad place.  I know where you're going with this and I think you should just drop it.

 

This is a fscking thread about a niche engine on a video game forum.  You don't need to let your desire for Crump to be wrong consume you the way it seems to.  

 

Why else would you be perusing a list of ERAU Daytona MSc theses going back to the 80s?

Edited by Bearcat

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I'd also appreciate if we got back to the Allison, even if everything that can be said on the matter has been said. A Lycoming mini engine is really not that interesting.

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You and Venturi (who upvoted this post) are treading into a bad place.  I know where you're going with this and I think you should just drop it.

 

This is a fscking thread about a niche engine on a video game forum.  You don't need to let your desire for Crump to be wrong consume you the way it seems to.  

 

Why else would you be perusing a list of ERAU Daytona MSc theses going back to the 80s?

 

I think the point here is if someone is consistently being patronising and condescending claiming that other people’s opinion does not count since they lack formal aerodynamic education or alternatively cannot possibly have an MSc because they disagree with you then you should not be surprised if your own claims to academic credentials come under scrutiny.

 

But that being said then yes, by all means return to the Allison discussion but I think continuing to beat on that long dead horse is futile.

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I think the point here is if someone is consistently being patronising and condescending claiming that other people’s opinion does not count since they lack formal aerodynamic education or alternatively cannot possibly have an MSc because they disagree with you then you should not be surprised if your own claims to academic credentials come under scrutiny.

 

But that being said then yes, by all means return to the Allison discussion but I think continuing to beat on that long dead horse is futile.

 

I understood the point.  This forum has rules about personal info, and this is rapidly moving from a disagreement to a witch hunt.  That's all I'm saying.

 

:salute:

Edited by JG13_opcode
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