Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained)

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We'll have to disagree on the nose armor. .
You would even disagree with the Russians, maybe because you are posting on a forum, not actually fighting with it. From the very start Bell seem to have issues with giving their various clients what they wanted, North American, in part at least knew what their clients wanted better than they did themselves.
 
We'll have to disagree on the nose armor. It certainly could be removed if other adjustments were made. The 20mm cannon was 140lbs lighter than the 37mm cannon and Bell made adjustments for that. The nose armor only weighed 71-100lbs.
You still have to explain why you would want to make your aircraft so vulnerable to anyone with an LMG
You don't need IFF if your base doesn't have radar.
That isn't how radar protection works. You need a number of radars to cover an area, Just having radar at your base is a pretty futile way of using it. For example no BOB base had its own radar
Port Moresby didn't get American radar until fall 1942.
Hardly unexpected as this is only nine months after war broke out in the area and radar sets were in high demand all over the world.
I have read numerous times about the IFF radios being deleted by the Soviets
Total guess I admit, but how many US radars do you think the Russians had and what proportion of the contested area's do you think they covered? I would suggest not many and not much
. They never deleted the nose armor that I am aware of.
Why not do you think and why do you think your idea is so good?
 
We'll have to disagree on the nose armor. It certainly could be removed if other adjustments were made. The 20mm cannon was 140lbs lighter than the 37mm cannon and Bell made adjustments for that. The nose armor only weighed 71-100lbs.

So what adjustments are you going to make? And when have we stared talking about the the 20mm cannon installation? 140 pounds lighter in the nose is going to make things worse!! I have showed you on this board several times that depending on the radio installation, you're not able to remove the nose armor.
You don't need IFF if your base doesn't have radar. Port Moresby didn't get American radar until fall 1942. If you have not been detected on radar then you don't need to identify yourself as friendly. I'm only advocating removing the IFF sets in 1942.
Well then your 1942 P-39 will be without IFF but will have those huge radios in the empennage. You C/G will still be way aft and probably out of the envelope if you remove the nose armor
After then, when radar is available, the IFF radios, nose armor and 30cal wing machine guns can remain because the P-39 will have the uprated -85 engines. Again: Lighten the 1942 P-39D/F/K/L, not the more powerful 1943 M/N.
Agree on the wing machine guns but where are you installing the IFF? "Would have, could have should have"

I have read numerous times about the IFF radios being deleted by the Soviets along with the wing machine guns. They never deleted the nose armor that I am aware of.
I'm not doubting you about the Soviets removing the IFF, it would seem funny why get them if you're just going to delete them.

Nose Armor...

Now with that said, a few new things.

On this wonderful site there is a Soviet P-39 flight manual and yes, it's in Russian. Since I don't read Russian, I rely on google translator. So here is the cutaway from the Soviet flight manual (in Russian) that's been copied in English many times.

1621547851526.png


This might be hard to read so you can go in the technical section and pull up the FREE PDF copy (such a deal). Anyway I will direct you to items 15 and 16. These items "радиоприемник" translate to "radio receiver" which means that some, maybe not all Soviet P-39s kept the radios in the rear and I believe they did use American radios (correct me if I'm wrong). If they were equipped with either the SCR-522 or the SCR-274 (or a Soviet unit), you're looking at close to 100 pounds if not more as a dynamotor was probably back there too.

Operationally I KNOW they used this configuration on P-39Qs. Now how do I know that? By the one fished out of the Russian Lake.

1621548558734.png


There were many photos taken of it;

1621548622403.png


And in the empennage, guess what was sitting there?

1621548694387.png


1621548750070.png


Now I can't tell if that unit is an SCR-274 or SCR-522 (or Russian), but they look awfully close. For those warbird maintainer folks on here, would you say those are at least 50 pound looking cathode-tube storage units? ;)

Photos courtesy Air & Space magazine for the photos and story - according to those folks this was an operational aircraft and had already seen action near Murmansk .

Oh - and here are a couple of photos that clearly show no radios installed behind the pilot, yes, older units.
1621549256391.png


1621549326147.png


1621549347857.png

I think you might recognize a few of these guys -

So as you say, the Soviets DID NOT remove the nose armor? Can you guess why?

Well My theory is as we know (an mentioned by you many times) they removed the wing guns, IFF (oh that pesky IFF) and maybe a few other things. Well I did a W&B calculation based on Greg's chart (once again thanks Greg!) and found that with the IFF, no wing guns and all ammo exhausted on 1/4 tank the C/G is at 135.9/ 30.19 % of MAC. Within limits but waaay aft.

Fully loaded, the same calculation - 134.2 - 28.07% of MAC

NOW - Remove the IFF at station 274 (I used 110 pounds) fly off your ammo and return with 1/4 gas and now that C/G is at 133.58 about 27-28% of MAC (I/m almost ready to do spins!) A way better place to be in this aircraft.

NOW - Fully loaded? C/G 132.06 C/G Range? 130.1072 - 136.5584 Nice! Let's do spins!

It's quite obvious WHY the Soviets didn't remove the nose armor, especially if they were flying around with radios in the "empennage"
 
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the stars need to perfectly align.

Yup, nailed it. That they didn't for the p-39 and P-63 is more on the aircraft themselves rather than the conditions though, otherwise, there wouldn't have been better aircraft, which brings us to this next thing...

P-39N was competitive with late 1942 P-38F/G, P-47B/C and P-51A. Yes it was.

The FW190A-6 vs P-39N graphs are graduated by altitude. Better climb and ceiling.

According to charts, which your entire argument is based around, not even real-world comparisons, which granted, between the Fw 190 and P-39 couldn't have happened in 1942 at any rate, but as you know, P-39 Expert, but steadfastly refuse to acknowledge and accept, charts present only a portion of aircraft performance and capability demonstration and do not reflect real-world conditions. You can present as many charts as you like saying the P-39 was 'superior' in climb or what have you compared to the P-51A etc, etc, but it isn't backed up by what actually happened nor the course of action the US military took in its aircraft procurement program.

If it was so good, why did they give so many of them to the Russians and kept the P-38s, the P-47s and the P-51s, and the P-40s, which, taking Commonwealth service into consideration, outlived and saw greater proliferation than the P-39? Why did Bell build a replacement that required a bigger engine, better cooling, etc, but looked almost identical to it? Because the P-39, over time could not match the expectations of the militaries that operated it. Even the Russians, who did get much out of it were able to build better fighters that were a better match to the local conditions than it.

Those other aircraft could. As has been said here already, the P-39 was just not capable of meeting the modern combat environment from 1943 onwards, after all, why would Bell build the P-63 if it was? Take the example of the Bf 109 and Spitfire, both saw remarkable transformation in their performance throughout the war and both remained relevant right through to the end because of the changes that were made to them, yet they predate the P-39 by a few years. The Mustang had a new engine installed which transformed its role in the war into an arguably war-winning one, the Fw 190, potent from the outset had new engines and armament fit that turned it into one of the most versatile and capable single-seat fighters of the war.

So, those charts you keep referring to as evidence of the P-39's greatness, against all the evidence that is being presented on this site alone, as well as the evidence that isn't, do not reflect how great the P-39 is and that collectively, we are just not seeing it, but rather your inability to grasp the situation and your refusal to accept the evidence being presented to you.
 
So what adjustments are you going to make? And when have we stared talking about the the 20mm cannon installation? 140 pounds lighter in the nose is going to make things worse!! I have showed you on this board several times that depending on the radio installation, you're not able to remove the nose armor. The cannon is just an example of how the plane could be ballasted when 140lbs is removed from the nose.

Well then your 1942 P-39 will be without IFF but will have those huge radios in the empennage. You C/G will still be way aft and probably out of the envelope if you remove the nose armor
Agree on the wing machine guns but where are you installing the IFF? "Would have, could have should have" If the 110lb IFF is removed from the aft fuselage it will offset the removal of the 71-100lb nose armor.


I'm not doubting you about the Soviets removing the IFF, it would seem funny why get them if you're just going to delete them. Same reason they deleted the wing guns, less weight equals better performance.

Nose Armor...

Now with that said, a few new things.

On this wonderful site there is a Soviet P-39 flight manual and yes, it's in Russian. Since I don't read Russian, I rely on google translator. So here is the cutaway from the Soviet flight manual (in Russian) that's been copied in English many times.

View attachment 624064

This might be hard to read so you can go in the technical section and pull up the FREE PDF copy (such a deal). Anyway I will direct you to items 15 and 16. These items "радиоприемник" translate to "radio receiver" which means that some, maybe not all Soviet P-39s kept the radios in the rear and I believe they did use American radios (correct me if I'm wrong). If they were equipped with either the SCR-522 or the SCR-274 (or a Soviet unit), you're looking at close to 100 pounds if not more as a dynamotor was probably back there too.

Operationally I KNOW they used this configuration on P-39Qs. Now how do I know that? By the one fished out of the Russian Lake.

View attachment 624065

There were many photos taken of it;

View attachment 624066

And in the empennage, guess what was sitting there?

View attachment 624067

View attachment 624068

Now I can't tell if that unit is an SCR-274 or SCR-522 (or Russian), but they look awfully close. For those warbird maintainer folks on here, would you say those are at least 50 pound looking cathode-tube storage units? ;)

Photos courtesy Air & Space magazine for the photos and story - according to those folks this was an operational aircraft and had already seen action near Murmansk .

Oh - and here are a couple of photos that clearly show no radios installed behind the pilot, yes, older units.
View attachment 624069

View attachment 624070

View attachment 624071
I think you might recognize a few of these guys -

So as you say, the Soviets DID NOT remove the nose armor? Can you guess why?

Well My theory is as we know (an mentioned by you many times) they removed the wing guns, IFF (oh that pesky IFF) and maybe a few other things. Well I did a W&B calculation based on Greg's chart (once again thanks Greg!) and found that with the IFF, no wing guns and all ammo exhausted on 1/4 tank the C/G is at 135.9/ 30.19 % of MAC. Within limits but waaay aft.

Fully loaded, the same calculation - 134.2 - 28.07% of MAC

NOW - Remove the IFF at station 274 (I used 110 pounds) fly off your ammo and return with 1/4 gas and now that C/G is at 133.58 about 27-28% of MAC (I/m almost ready to do spins!) A way better place to be in this aircraft.

NOW - Fully loaded? C/G 132.06 C/G Range? 130.1072 - 136.5584 Nice! Let's do spins!

It's quite obvious WHY the Soviets didn't remove the nose armor, especially if they were flying around with radios in the "empennage". Flyboy: Exactly my point, if you have nose armor then you need the radios in the tail. Without the nose armor the radios in the tail need to be removed or moved up behind the pilot for balance. The nose armor could be removed if other balance adjustments were made. Sorry about the italics, I can't make them go away. :)
Yup, nailed it. That they didn't for the p-39 and P-63 is more on the aircraft themselves rather than the conditions though, otherwise, there wouldn't have been better aircraft, which brings us to this next thing...



According to charts, which your entire argument is based around, not even real-world comparisons, which granted, between the Fw 190 and P-39 couldn't have happened in 1942 at any rate, but as you know, P-39 Expert, but steadfastly refuse to acknowledge and accept, charts present only a portion of aircraft performance and capability demonstration and do not reflect real-world conditions. You can present as many charts as you like saying the P-39 was 'superior' in climb or what have you compared to the P-51A etc, etc, but it isn't backed up by what actually happened nor the course of action the US military took in its aircraft procurement program.

If it was so good, why did they give so many of them to the Russians and kept the P-38s, the P-47s and the P-51s, and the P-40s, which, taking Commonwealth service into consideration, outlived and saw greater proliferation than the P-39? Why did Bell build a replacement that required a bigger engine, better cooling, etc, but looked almost identical to it? Because the P-39, over time could not match the expectations of the militaries that operated it. Even the Russians, who did get much out of it were able to build better fighters that were a better match to the local conditions than it.

Those other aircraft could. As has been said here already, the P-39 was just not capable of meeting the modern combat environment from 1943 onwards, after all, why would Bell build the P-63 if it was? Take the example of the Bf 109 and Spitfire, both saw remarkable transformation in their performance throughout the war and both remained relevant right through to the end because of the changes that were made to them, yet they predate the P-39 by a few years. The Mustang had a new engine installed which transformed its role in the war into an arguably war-winning one, the Fw 190, potent from the outset had new engines and armament fit that turned it into one of the most versatile and capable single-seat fighters of the war.

So, those charts you keep referring to as evidence of the P-39's greatness, against all the evidence that is being presented on this site alone, as well as the evidence that isn't, do not reflect how great the P-39 is and that collectively, we are just not seeing it, but rather your inability to grasp the situation and your refusal to accept the evidence being presented to you.
Right, those performance tests, who needs them? They certainly didn't mean anything.
 
For the love of God, stop with the obsession with the nose armor.
You CANNOT delete the nose armor because it was there to protect the gearbox.
We've been over this countless times - it was an integral part of the aircraft as much as the nose-gear was.
And as I have said countless times: No other fighters had armored gearboxes. None.
 
The cannon is just an example of how the plane could be ballasted when 140lbs is removed from the nose.
If the 110lb IFF is removed from the aft fuselage it will offset the removal of the 71-100lb nose armor.

These are all "would have, could have, should have." And all this was not going to happen without a "customer" buying in. Why is that?

Exactly my point, if you have nose armor then you need the radios in the tail. Without the nose armor the radios in the tail need to be removed or moved up behind the pilot for balance. The nose armor could be removed if other balance adjustments were made.
No, you once again you MISSED THE POINT!!! It's obvious for one reason or another the Soviets were flying P-39s WITH THE RADIOS IN THE TAIL. They may have had some aircraft configured with the radios behind the pilot but I'd stick my neck out to say that most of their Cobras kept the radios in the tail. With the armor in the nose I HAVE CLEARLY SHOWN the aircraft it sits in a better W&B configuration, is no longer tail heavy and will have better spin and stall characteristics!!!

IMO THAT IS ONE OF THE REASONS WHY I BELIEVE THE SOVIETS HAD SUCCESS WITH THEM!!!!

I've told you months ago that sometimes removing weight does not make the aircraft fly better, this is a perfect example!!!!
 
Divide the length of the eastern front by the number of fighters in service there, then divide the length of the reachable areas across the channel and the number of fighters. It is a completely different conflict.
 
OK guys, I went into the museum today to work on the Grumman Mallard cowling and looked at both the P-39 and the P-63 while I was there.

There is a virtual plug in the P-63A behind the wing root training edge where the auxiliary supercharger goes and it has a cross member in it on which to mount the aux-stage supercharger. The area has plenty of room for the aux-stage A/C. The wing is moved back on the fuselage to balance the CG. The aux-stage supercharger is almost as wide as the engine itself. The P-39 does not have the plug and there is no room for the auxiliary-stage supercharger since the fuselage is more narrow than the auxiliary-stage supercharger itself.

A 2-stage Allison just will NOT fit. The engine compartment is virtually the same since both of them mounted the same engine block, but there is simply not room on the P-39 for the second stage and coupling. Granted, you could MAKE room, but you'd have to insert a plug to make room and then move the wing aft to make the CG possible ... and you'd have a P-63.

I have some pics of the P-63 and will come back here and insert same within a few days, but there is no way to mount a 2-stage Allison in the P-39 in a stock airframe. There is room for the engine, but not for the aux-stage S/C. If you disagree with that, I suggest you come look at them both in Chino, CA for yourself. If you come to see, let me know and I'll happily show you around so you see for yourself. If you are close then, by all means, PM me and I'll show you around. If you aren't close, you are welcome anyway but you'll be wasting your money if the trip is just to address this subject. The engine package for the 2-stage Allison just will not fit and, if it did, the resulting airplane would be out of CG aft without lead ballast in the nose or moving the wing aft to compensate.

I do NOT have too many pics of the P-39 because, to get the pics I need, I'd have to take off several panels from the P-39, and it is in a very good display and there is no real reason to do any disassembly when there is useful work to be done. There are enough P-39 pics available already. The cross-section of the P-39 fuselage just aft of the engine compartment narrows very quickly to the point where is simple to observe that the aux-stage will not fit. Casey Wright (currently working on the P-63) said that he has looked and said: 1) there are things in the way where the aux-stage would go, 2) there is no way to mount the aux stage, and 3) the fuselage is just too small where the aux stage would physically need to be.

Here is a P-39:
oCfLrLIpv_F_qQ5H39x-ne-JcfbxAt2YsonEtlXaZe2ZFd8NYGZgMPzl3q95nHyxROg8Cv9CKdpGyFBvEBgJygVasQSRJe76.jpg


Look at the relative length of the nose in front of the wing versus the tail behind the trailing edge. The leading edge of the fin is about the same distance as the nose from the trailing edge. Note the insignia star has no bars and is behind the scoop just a small amount. If the insignia star HAD bars, the bars would extend ahead of the scoop rear edge. Note the engine exhaust manifolds stop just in front of the point where the wing trailing edge would intersect the fuselage. If it HAD an aux-stage supercharger, it would extend past the wing trailing edge to about the rear of the airscoop. The fuselage aft of the exhaust manifolds narrows quickly. Note if you extend the wing leading edge, it intersects the fuselage right about where the windscreen starts.

avp39_15.jpg


Here is a P-63. Note the insignia star has bars and the bars are still aft of the scoop rear edge. The tail is longer because there is more room behind the wing trailing edge and the engine exhaust manifolds are farther forward from the wing trailing edge. The aux supercharger stage would end about at the wing trailing edge. The fuselage at the end of the exhaust manifolds is about as wide as the engine compartment since the aux-stage goes in there. Note if you extend the wing leading edge to the fuselage it intersects right about the windscreen rear frame is. The wing has been moved aft about a foot or so from where it is on the P-39.

OK, here are some P-63 pics:

P63_3.JPG


I apologize for the orientation, it's correct in my phone. I don't know how to rotate the pic in this forum. This is looking down into the "plug" at the rear of the engine bay, where the auxiliary supercharger would be if the engine were to be a 2-stage Allison. The engine installed is NOT a 2-stage, but CAN put out 1,600 hp if asked to do so. This empty space is NOT present in a P-39 and the rear bulkhead is up right against the aft end of the engine block.


P63_2.jpg


Above is at least oriented correctly. You can see there is plenty of room behind the single-stage engine for the auxiliary-stage supercharger. This space is not present in the P-39.

All for now; cheers!
 
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OK guys, I went into the museum today to work on the Grumman Mallard cowling and looked at both the P-39 and the P-63 while I was there.

There is a virtual plug in the P-63A behind the wing root training edge where the auxiliary supercharger goes and it has a cross member in it on which to mount the aux-stage supercharger. The area has plenty of room for the aux-stage A/C. The wing is moved back on the fuselage to balance the CG. The aux-stage supercharger is almost as wide as the engine itself. The P-39 does not have the plug and there is no room for the auxiliary-stage supercharger since the fuselage is more narrow than the auxiliary-stage supercharger itself.

A 2-stage Allison just will NOT fit. The engine compartment is virtually the same since both of them mounted the same engine block, but there is simply not room on the P-39 for the second stage and coupling. Granted, you could MAKE room, but you'd have to inset the plug to make room and then move the wing aft to make the CG possible ... and you'd have a P-63.

I have some pics of the P-63 and will come back here and insert same within a few days, but there is no way to mount a 2-stage Allison in the P-39 in a stock airframe. There is room for the engine, but not for the aux-stage S/C. If you disagree with that, I suggest you come look at them both in Chino, CA for yourself. If you come to see, let me know and I'll happily show you around so you see for yourself. If you are close then, by all means, PM me and I'll show you around. If you aren't close, you are welcome anyway but you'll be wasting your money if the trip is just to address this subject. The engine package for the 2-stage Allison just will not fit and, if it did, the resulting airplane would be out of CG aft without lead ballast in the nose or moving the wing aft to compensate.

I do NOT have too many pics of the P-39 because, to get the pics I need, I'd have to take off several panels from the P-39, and it is in a very good display and there is no real reason to do any disassembly when there is useful work to be done. There are enough P-39 pics available already. The cross-section of the P-39 fuselage just aft of the engine compartment narrows very quickly to the point where is simple to observe that the aux-stage will not fit. Casey Wright (currently working on the P-63) said that he has looked and said: 1) there are things in the way where the aux-stage would go, 2) there is no way to mount the aux stage, and 3) the fuselage is just too small where the aux stage would physically need to be.

Here is a P-39:
View attachment 624074

Look at the relative length of the nose in front of the wing versus the tail behind the trailing edge. The leading edge of the fin is about the same distance as the nose from the trailing edge. Note the insignia star has no bars and is behind the scoop just a small amount. If the insignia star HAD bars, the bars would extend ahead of the scoop rear edge. Note the engine exhaust manifolds stop just in front of the point where the wing trailing edge would intersect the fuselage. If it HAD an aux-stage supercharger, it would extend past the wing trailing edge to about the rear of the airscoop. The fuselage aft of the exhaust manifolds narrows quickly. Note if you extend the wing leading edge, it intersects the fuselage right about where the windscreen starts.

View attachment 624075

Here is a P-63. Note the insignia star has bars and the bars are still aft of the scoop rear edge. The tail is longer because there is more room behind the wing trailing edge and the engine exhaust manifolds are farther forward from the wing trailing edge. The aux supercharger stage would end about at the wing trailing edge. The fuselage at the end of the exhaust manifolds is about as wide as the engine compartment since the aux-stage goes in there. Note if you extend the wing leading edge to the fuselage it intersects right about the windscreen rear frame is. The wing has been moved aft about a foot or so from where it is on the P-39.


Thanks Greg for taking the time, we appreciate it.

Hope it scores.

Cheers,
Biff
 
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Hello Nuuumannn
the fact is that Soviets demanded more Spitfires and P-39s and asked why Allies sent Hurricanes and P-40s instead of Spitfires and P-39s which they wanted. They got 10 very early Mustangs and appr. 200 P-47Ds. They don't like them and simply did not understand what to do with "monster" size P-47s, in the end Naval Aviation used them as fighter bombers very late of the war or just after the war. They definitely did not want more of them.
Three of the five top Soviet aces (Grigori Rechkalov, Nikolai Gulaev and Dmitri Glinka) got most of their kills while flying P-39s and Rechkalov and D. Glinka ended the war in May 1945 still flying P-39s with Guards units operating inside Germany. Gulaev was badly wounded in Aug 44 while flying P-39 with 129 GIAP. Stalin asked more P-39s and Spitfires, not P-40s and Hurricanes. And Valentine tanks not Churchills, another thing what put British wondering reason why.
Most of their fighters were rather small with short range and were low- and medium altitude fighters like P-39s and had centrally mounted armament. So P-39 suited their tactical thinking and the environment on the Eastern Front.
 
Hi Dash 119,

The nose armor, for some reason, seems to have a life of its own. I'm still not sure why.

We have shot it several times and it refuses to die. I was thinking of asking my congressman to introduce a bill banning any mention of nose armor in public without a mask on. But the weight of the documentation would be more than the nose armor itself, so the exercise would seem to be full of greenhouse gases and thus would not be carbon-neutral.
 
OK guys, I went into the museum today to work on the Grumman Mallard cowling and looked at both the P-39 and the P-63 while I was there.

There is a virtual plug in the P-63A behind the wing root training edge where the auxiliary supercharger goes and it has a cross member in it on which to mount the aux-stage supercharger. The area has plenty of room for the aux-stage A/C. The wing is moved back on the fuselage to balance the CG. The aux-stage supercharger is almost as wide as the engine itself. The P-39 does not have the plug and there is no room for the auxiliary-stage supercharger since the fuselage is more narrow than the auxiliary-stage supercharger itself.

A 2-stage Allison just will NOT fit. The engine compartment is virtually the same since both of them mounted the same engine block, but there is simply not room on the P-39 for the second stage and coupling. Granted, you could MAKE room, but you'd have to insert a plug to make room and then move the wing aft to make the CG possible ... and you'd have a P-63.

I have some pics of the P-63 and will come back here and insert same within a few days, but there is no way to mount a 2-stage Allison in the P-39 in a stock airframe. There is room for the engine, but not for the aux-stage S/C. If you disagree with that, I suggest you come look at them both in Chino, CA for yourself. If you come to see, let me know and I'll happily show you around so you see for yourself. If you are close then, by all means, PM me and I'll show you around. If you aren't close, you are welcome anyway but you'll be wasting your money if the trip is just to address this subject. The engine package for the 2-stage Allison just will not fit and, if it did, the resulting airplane would be out of CG aft without lead ballast in the nose or moving the wing aft to compensate.

I do NOT have too many pics of the P-39 because, to get the pics I need, I'd have to take off several panels from the P-39, and it is in a very good display and there is no real reason to do any disassembly when there is useful work to be done. There are enough P-39 pics available already. The cross-section of the P-39 fuselage just aft of the engine compartment narrows very quickly to the point where is simple to observe that the aux-stage will not fit. Casey Wright (currently working on the P-63) said that he has looked and said: 1) there are things in the way where the aux-stage would go, 2) there is no way to mount the aux stage, and 3) the fuselage is just too small where the aux stage would physically need to be.

Here is a P-39:
View attachment 624074

Look at the relative length of the nose in front of the wing versus the tail behind the trailing edge. The leading edge of the fin is about the same distance as the nose from the trailing edge. Note the insignia star has no bars and is behind the scoop just a small amount. If the insignia star HAD bars, the bars would extend ahead of the scoop rear edge. Note the engine exhaust manifolds stop just in front of the point where the wing trailing edge would intersect the fuselage. If it HAD an aux-stage supercharger, it would extend past the wing trailing edge to about the rear of the airscoop. The fuselage aft of the exhaust manifolds narrows quickly. Note if you extend the wing leading edge, it intersects the fuselage right about where the windscreen starts.

View attachment 624075

Here is a P-63. Note the insignia star has bars and the bars are still aft of the scoop rear edge. The tail is longer because there is more room behind the wing trailing edge and the engine exhaust manifolds are farther forward from the wing trailing edge. The aux supercharger stage would end about at the wing trailing edge. The fuselage at the end of the exhaust manifolds is about as wide as the engine compartment since the aux-stage goes in there. Note if you extend the wing leading edge to the fuselage it intersects right about the windscreen rear frame is. The wing has been moved aft about a foot or so from where it is on the P-39.

Thanks for doing this Greg. Question for one of the pilots (Steve H?) The shelf behind the pilot, how hot does it get from the engine?
 

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