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P-39 engine protection


GrendelsDad
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I would imagine the engine will be more susceptible to rear gun attacks due to it being in the middle of the plane. Is there any evidence for or against this. Maybe there is extra armor? Thanks guys.

Edited by II./ZG1_GrendelsDad
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Y29.Layin_Scunion

If you really look at a cutaway from the aircraft, you can see there was a lot of equipment behind the engine.  There was a flame resistant bulkhead directly behind the engine as well.

2021bc925595707e910e4e962c79e9ca.jpg

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216th_Lucas_From_Hell

Nice cutaway!

 

The placement should make it tougher against small calibre weapons fired from the front though (i.e. rear gunners and the likes).

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"With all the machinery up front, there was little to be damaged in a rear attack, whereas the P-39, with all of its plumbing in back, was very vulnerable to a stern attack."

 

http://www.aerofiles.com/p400.html

 

"The rear-mounted engine made the aircraft ideal for ground attack since fire would be coming from the front-bottom quarter and was less likely to hit the engine and its cooling systems. The arrangement proved to be very vulnerable to attacks from above and behind and nearly any hit on the fuselage from an attacking enemy fighter was virtually guaranteed to disable the cooling system and lead to the prompt demise of the engine and thus the aircraft. Flying at its upper altitude limits, the Airacobra was extremely vulnerable to any enemy fighter with decent high altitude performance."

 

http://www.warbirdsresourcegroup.org/URG/p39_design.html

Edited by FuriousMeow
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=362nd_FS=Hiromachi

I remember from my readings on 1942 operations in New Guinea that this was one of the major complains from P-39/P-400 pilots - vulnerability of the engines. Despite added armor to provide protection tail was still the most exposed section of an aircraft and so engine damage was very common. On the other hand any pilot must have appreciated a solid block of steel right behind his back. I mean if there is a choice between loosing engine or loosing life, the latter one is more important for any pilot. 

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Hi all,

some infos found about armor plates and skin thickeness of fuselage of P-39/P-400 (and previously posted on the "wrong" thread) :

post-481-0-32824000-1475095636_thumb.png

post-481-0-01419600-1475095666_thumb.png

Edited by Pierre64
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216th_Lucas_From_Hell

I remember from my readings on 1942 operations in New Guinea that this was one of the major complains from P-39/P-400 pilots - vulnerability of the engines. Despite added armor to provide protection tail was still the most exposed section of an aircraft and so engine damage was very common. On the other hand any pilot must have appreciated a solid block of steel right behind his back. I mean if there is a choice between loosing engine or loosing life, the latter one is more important for any pilot. 

 

I guess the preference will come from how far away the pilot is from their lines. Over Kuban for example the P-39 was considered a blessing because it could take a lot of damage and still come home, while also being very safe and steady to crash-land, but over there and overall in the Eastern Front the action was mostly close to the front lines or over friendly territory.

 

The flip side of the coin was that, in the few situations where it could not be brought back or landed on its belly, bailing out was almost as unsafe as staying with a burning crate. Many Soviet aces survived by landing Airacobras that were on fire, missing parts of wings, control surfaces, leaking fuel, smoking and the likes. Gaidaenko from 19 GIAP for example was involved in the first P-39 loss, bringing it down safely in the Murmansk frozen wasteland. Klubov also landed a P-39 that was reduced to Swiss cheese once, Konstantin Sukhov had to repeat the feat twice with a burning crate.

 

Evgenii Mariinskiy in particular not only brought back destroyed P-39s but once survived a high speed crash from thousands of metres straight into the ground, suffering no more than a light hand injury. After being hit in combat, his P-39 entered a nose dive, the elevators jammed and though he tried to recover using the trim it didn't work. Impact happened at a very high speed, with an angle of about 30º, and the cockpit section was the only bit that was left. The rest of the Cobra was reduced to bits.

 

Hopefully we will be able to enjoy the structural integrity in this game, I already have a bad habit of staying with the plane too long so this will come handy in, you know, not dying :biggrin:

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I'm not sure any water-cooled planes are much better/worse than others, frankly, regarding vulnerability. 

 

On a related note:  Hopefully, the bail-out animation will show the pilot properly bailing out of the right door.  1946 incorrectly showed a left door bail-out. 

 

And the P-39 bellied-in extremely well due to the low wings, curved belly and bridge-like construction.  Not that this characteristic will ever be needed - lol.

Edited by chuter
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Evgenii Mariinskiy in particular not only brought back destroyed P-39s but once survived a high speed crash from thousands of metres straight into the ground, suffering no more than a light hand injury. After being hit in combat, his P-39 entered a nose dive, the elevators jammed and though he tried to recover using the trim it didn't work. Impact happened at a very high speed, with an angle of about 30º, and the cockpit section was the only bit that was left. The rest of the Cobra was reduced to bits.

 

 

Though (if I remember correctly) he crashed at a high angle onto a slope :) Still, structural integrity of the p-39 is unquestionable after such a feat.

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With actual german 20mm you dont have to worry about your engine.

Not sure what that means. But anyaway, in "Red Star airacobra" Evgenii MariinskiY flying p-39, gets hit by anothers p-39 37mm cannon, damaging large parts of the tail-section. He does manage to land. They can't know for sure, but suspect it was their kill-hungry group leader that did it. They do however easily conclude it must have been a 37mm as a German 20mm hit would not do a hole as nearly as big as that. I'm guessing these guys had seen good amounts of battle damage.

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216th_Lucas_From_Hell

I think he was going down along the slope then crashed once the ground leveled up, but I could be wrong. Either way, as you said, it's some feat.

 

I'd forgotten about the friendly fire snippet, thanks for bringing it back! Overall the book is full of anecdotes about the P-39 and its reliability, durability and so on. Anyone interested in reading, please send me a PM so I can share the book.

 

Not that it affects the game modelling since the P-39s received in Kuban were all brand spanking new, with new airframes arriving every couple of weeks and major repair workshops right by the supply lines within easy reach, but a major complaint throughout Red Star Airacobra was the engine of older machines. One would think the units would refit them with newer engines once they started giving in but apparently they kept some P-39s flying with old spiffy engines, which led to incidents such as aircraft ending up into the river by the end of the airfield during take-off.

 

I think the major aspects which will take getting used to will be handling (how much manoeuvring is too much, and stalls and spins), and engine management. The official restrictions for the P-39L were quite lax, and you could get a decent amount of power out of the crate without using WEP ratings, but in the middle of a dogfight it's easy to forget and then have your engine blow up in your face (or back in this case).

 

Does anyone know if the P-39L-1's engine feature manual or fully automatic RPM control?

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-=PHX=-SuperEtendard

Why they put L version? I think it was in few numbers comparing with other p39s

 

Could it be because the P-39D was kinda oldish for this theater, and the P-39N too new? Other thing could be the performance differences between the variants (D too bad, N too good?) Would really like to know the performance differences between the D, the L and the N.

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I think he was going down along the slope then crashed once the ground leveled up, but I could be wrong. Either way, as you said, it's some feat.

 

I'd forgotten about the friendly fire snippet, thanks for bringing it back! Overall the book is full of anecdotes about the P-39 and its reliability, durability and so on. Anyone interested in reading, please send me a PM so I can share the book.

 

Not that it affects the game modelling since the P-39s received in Kuban were all brand spanking new, with new airframes arriving every couple of weeks and major repair workshops right by the supply lines within easy reach, but a major complaint throughout Red Star Airacobra was the engine of older machines. One would think the units would refit them with newer engines once they started giving in but apparently they kept some P-39s flying with old spiffy engines, which led to incidents such as aircraft ending up into the river by the end of the airfield during take-off.

 

I think the major aspects which will take getting used to will be handling (how much manoeuvring is too much, and stalls and spins), and engine management. The official restrictions for the P-39L were quite lax, and you could get a decent amount of power out of the crate without using WEP ratings, but in the middle of a dogfight it's easy to forget and then have your engine blow up in your face (or back in this case).

 

Does anyone know if the P-39L-1's engine feature manual or fully automatic RPM control?

 

Your probably right. Another interesting thing mentioned in it: Among modellers painting plastic scale models, wear and tear, or also called weathering has always been a hot topic. Some argue these things were replaced before looking to shabby and until, were maintained very well by groundcrew. While others say field conditions were very harsh and so all dirt/grime and paint chipping is justified. This same book mentioned Evgenii Mariinskiy one evening walking down to his aircraft and finding his mechanic cleaning the plane with towels. In an attempt at getting all dust/mud off to decrease overall drag of the airframe. That was an eyeopener for me. Well maintained yes, But this must have been a sandpaper treatment. Scuffing and thinning away lot's of paint.

 

Highly recommend this book Lucas is talking about.

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I./ZG1_Dutchvdm

Could it be because the P-39D was kinda oldish for this theater, and the P-39N too new? Other thing could be the performance differences between the variants (D too bad, N too good?) Would really like to know the performance differences between the D, the L and the N.

 

These are from http://www.aviation-history.com/bell/p39.html. Don't know how accurate they are.

 

Edited by I./ZG1_Martijnvdm
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216th_Lucas_From_Hell

Why they put L version? I think it was in few numbers comparing with other p39s

It was the most numerous individual model during the Kuban battles, I think.

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/CSAR/kirumovka

I can see people complaining about its handling like the fockewulf when it comes out... you can sort of already tell where the CoG would be

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216th_Lucas_From_Hell

MP servers on the day it's out will be comic. Just a bunch of Bf-109s circling around, watching P-39s spinning helplessly. Whoever doesn't stall on the first day wins a BoK copy  :biggrin:

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From the beginning of mass exploitation reports about exposed hidden defects began to emerge from the horn of plenty. In most cases the engine failed, either upon takeoff or during combat. For example, in the 19th Guards IAP, there was one catastrophic failure and four accidents in the first two weeks; in the 153d IAP, one catastrophic failure and one accident. At first everyone blamed the Allison, in general a decent, light, and powerful engine that did not, however, want to work on Soviet-refined oils. It was real "picky", however, only at the beginning, and not without reason. After filtration, which removed dross and other debris, the Allison stopped "self destructing". Another defect required a great amount of investigation, the so-called "throwing of rods". This allegedly occurred when because of frequent running at the engine's operating limits (without which, of course, aerial combat was unthinkable) the aforementioned parts broke loose, came through the crankcase and destroyed everything in their path, in particular the control rods. A number of flight and laboratory tests were undertaken which enabled the test engineers to recommend the most favorable operating regimes of the engine to combat pilots, and succeeded in reducing the level of this type of failure.

 

These anecdotes are regarding the Allison-engined early lend-lease P-39s, without MAP regulator (the same setup as on the P40E).

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Why they put L version? I think it was in few numbers comparing with other p39s

 

Why not. P-39L represents Airacobras over Kuban pretty well - P-39D-2, P-39K and P-39L were basically the same.

 

 

The P39L would have the automatic manifold pressure regulator.

 

P-39s with V-1710-63(E6), including P-39L, were not equipped with automatic manifold pressure regulator. So, in the future we will talk about "right" engine limits again, just like in case of P-40E.

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E69_geramos109

Why not. P-39L represents Airacobras over Kuban pretty well - P-39D-2, P-39K and P-39L were basically the same.

 

 

 

P-39s with V-1710-63(E6), including P-39L, were not equipped with automatic manifold pressure regulator. So, in the future we will talk about "right" engine limits again, just like in case of P-40E.

When was the auto pressure regulator put in to the P39? 

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When was the auto pressure regulator put in to the P39?

 

With V-1710-83(E16) engine, i.e. since P-39M. Before this, there was 25 aircraft rather trial series equipped with a automatic regulator designated P-39J, basically P-39F with "improved" Allison V-1710-59(E12).

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=362nd_FS=RoflSeal

P-39 gonna get whacked by the same hammer as the P-40 considering their engines are in similar situations.

 

Either way the engine could be refit with a pressure regulator, don't know whether the devs will add it, (though my guess is it won't)

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I like the idea of a more complex engine management ala P40 (if corrected).

 

However a simplistic method of modeling engine blow-ups probably won't "feel right" with it.

 

My thoughts on control translations to the PC are that control curves should be allowed ala ROF.

 

Don't compromise on CoG, control sensitivity or authority, just allow the user to dial in whatever compensation they need for their setup. Some have 2' long joystick extensions, some have mini joysticks. The abstraction is what needs to be allowed for here, so go ahead and provide an outright abstraction via control curves. Don't try to hide it and don't compromise the actual simulation. Again, RoF did it right.

Edited by Venturi
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