The P-39 a Zero Killer???

[tomo pauk]

The point in Western fighters, compared with Soviet, is that the Soviets viewed those as having far more equipment on-board, when compared with their A/C. So there was more to cut from. Also, the Western fighters were notably bigger than Soviet ones, while not having that much more power, or more power at all. Bigger airframe - less a performer. So they cut on the guns, ammo, radios, armor. That was good for speed, and even better for RoC.

 

[FLYBOYJ]

OK, I accept your reasoning, FLYBOYJ, and I'm sure you know more than me. I'm not even a Pilot let alone a WWII Vet (although I have ridden some WWII era aircraft - including a P-38 ).

It still seems strange to me. I spent 25 yrs in the Army, including VN. I know if in a combat situation, I wouldn't hesitate to "alter" any piece of equipment with or without approval from anyone. If it would increase my survivalability or that of any of my men (or if it just made my life a little easier).

And I think removing the .30's and ammo was easily doable and after a test flight would show no harm to the aircraft.

Our Pilots and ground staff were not dumbies and the thought must have come up at some time or another.

No I hear ya Mike, but a little different with aircraft. Removing "ammo" wouldn't be a big deal since it is something considered "expended" during the mission (in many aircraft the CG would actually change with the ammo expended, the A-10 comes to mind), but now when you start to remove items that have no maintenance instructions for removal (guns, permantely mounted armor, etc.) that's where you need approval. I've included a P-39 weight and balance chart, you could see what's calculated in the W&B as well as the vertical and horizontal CGs.

 

[muscogeemike]

Not to beat a dead horse but I'm pretty sure the guns were routinely removed for servicing and replacement. Things like armor and other equipment I can see not screwing around with.

And I have to believe someone thought of lightening the P-39, yet I've never seen any mention of it in anything I read.

I can't help but wonder why?

 

[tyrodtom]

I do know that it was just a few minutes work to install the wing 20mm cannons in a AIE, because I've been close by installing bombs on one while the armorers were installing the wing guns.
They took them out to clean and service after any mission in which they were fired.
The hardest part appeared to be for the man on the ground to lift them up to the wings.

And the armor I've seen was mounted so it could be replaced if it was ever struck. Because even if it wasn't penetrated, it still would be weak in that area thereafter.

 

[GregP]

I can tell you that when you remove guns, you bolt in lead to compensate. For instance, we are currently restoring a Canadair Sabre Mk 6. It started life with three 50-cal MG in each side of the nose. Currently the weight of the gun in lead is bolted in at the correct spot to maintain CG. We also have some lead shot in the nose ring to help out, as we have lead shot in the wing leading edge of our P-51A to ballast the removed cannons.

So if the item to be removed is far from the CG and cannot be counter-balanced by removing SOMETHING from the other side of the CG, then it has to be ballasted. If it will be the same weight, why not just leave it there to start with? That's what we did when a friend bought a MiG-15 UTI. We cut the guns (actually the BATF did) and then re-welded them back together with the parts bolted in place, then removed them, finished the welding, ground it smooth, painted it black, and bolted it back in place.

Currently, I only know of ONE guy who has a P-51 with real wings guns in it. He cannot fly outside his own property with them installed.

 

[BiffF15]

GregP,

He must have some serious property...

Cheers,
Biff

 

[GregP]

Uhhh ... yes ... he can fly an F-86 and never leave his own airspace.

 

[FLYBOYJ]

I can tell you that when you remove guns, you bolt in lead to compensate. For instance, we are currently restoring a Canadair Sabre Mk 6. It started life with three 50-cal MG in each side of the nose. Currently the weight of the gun in lead is bolted in at the correct spot to maintain CG. We also have some lead shot in the nose ring to help out, as we have lead shot in the wing leading edge of our P-51A to ballast the removed cannons.

So if the item to be removed is far from the CG and cannot be counter-balanced by removing SOMETHING from the other side of the CG, then it has to be ballasted. If it will be the same weight, why not just leave it there to start with? That's what we did when a friend bought a MiG-15 UTI. We cut the guns (actually the BATF did) and then re-welded them back together with the parts bolted in place, then removed them, finished the welding, ground it smooth, painted it black, and bolted it back in place.

Currently, I only know of ONE guy who has a P-51 with real wings guns in it. He cannot fly outside his own property with them installed.

Just about every jet warbird flying in civilian hands have ballast to make up for armament and in the case of east block aircraft, radios and nav equipment. Some of the Soviet radios I seen in L39s and MiGs I think weigh as much as lead!

 

[gjs238]

Not to beat a dead horse but I'm pretty sure the guns were routinely removed for servicing and replacement. Things like armor and other equipment I can see not screwing around with.<SNIP>

I think by "remove" he means permanently remove.

 

[FLYBOYJ]

Not to beat a dead horse but I'm pretty sure the guns were routinely removed for servicing and replacement. Things like armor and other equipment I can see not screwing around with.

If it's within the aircraft maintenance manuals, absolutely. In the tech section there is a P-39 armament manual that describes servicing and routine maintenance .

And I have to believe someone thought of lightening the P-39, yet I've never seen any mention of it in anything I read.

I can't help but wonder why?

A few thoughts...

Without removing vital factory equipment or risking structural failure, there might have been limitations in trying to make it any lighter than the Soviets did. Additionally Bell was already developing the P-63, so I don't think the interest was there.

 

[tyrodtom]

I realize removing the guns of a F-86, or Mig-15, is going to have a pretty big effect on the CG.

But the wing guns, and ammo on most WW2 aircraft are pretty close to the CG, you might be able to remove them and get the CG back into limits with some fairly light weights further from the CG. Am I wrong ?

 

[GregP]

We had lead shot in the leading edges of our P-51A.

Of course, they were cannons with heavy breeches. I don;t believe we have any lead in the P-51D's, but am not really sure. I will check!

 

[Shortround6]

Somethings to consider when comparing the P-39 (several different models), P-40s (also several different models) in combat vs Japanese fighters ( also several different models), is different tactical situations.

In Regards to the AVG they were fighting the Japanese Army with Ki 43 and some Ki 27s for fighters. The majority of the Ki 43s had one 12.7mm and one 7.7mm machine gun and had much less firepower than the Navy Zeros, at least for the first 6-8 seconds.
Some of the AVG tactics involved only fighting when they had an advantage, preserving their own aircraft was a a very important consideration. This is something that may not have been a high priority in other areas, (perhaps it should have been?)
Japanese Army cooperated by flying strikes at altitudes the P-40s could operate at and/or the AVG had more advanced warning than some the South Pacific bases.
Germans co-operated with the Russians flying P-39s by NOT flying bombers at 23-28,000ft like the Japanese Navy often did in the SP.

You also have the climate differences. A lot of the "book" figures for aircraft performance are done at standard temperature and pressure (usually 59-60 degrees F or 15 degrees C for temp) and performance falls off with increasing temperatures. Higher air temps mean lower air density and both less lift from the wing and less engine power. Throw in less the perfect aircraft condition (it is one thing to change spark plugs when suffering from Dysentery and Malaria, it is another thing to wash and wax the aircraft) and aircraft in tropical conditions maybe operating at less than "book" figures. Less lift means a higher stalling speed even in a 2 "G" turn and more power needed to maintain minimum flying speed.
It can get hot in Russia but not tropical hot for weeks/months on end.

Please also remember that average combat height is exactly that, an average. One fight at 5,000ft, one at 10,000ft, one at 20,000ft and one at 25,000ft average 15,000ft. However if you are flying P-39s you are at a distinct disadvantage in two of those fights.

 

[buffnut453]

Some of the AVG tactics involved only fighting when they had an advantage, preserving their own aircraft was a a very important consideration. This is something that may not have been a high priority in other areas, (perhaps it should have been?)

Sometimes it's impossible to manage the fight to ensure you only fight on advantageous terms. Lack of early warning often means having to respond when the attacks come which can result in engaging at a tactical disadvantage. The alternative of having fighters constantly airborne is only practical if you have sufficient aircraft available - standing patrols are notoriously costly from the maintenance and availability perspectives.

 

[varsity07840]

I'm always amused at how these woulda, coulda, shoulda threads, especially about the P-39 and P-40 vs the Zero eventually go off on a tangent, probably becasue there's not much left to say. Having said that, I'll through in my two cents worth. The P-39 was a fighter designed around a gun, not a fighter with a gun designed for it. As such it was doomed to be a pre-war design to pre war standards with no growth potential save perhaps the use of the 2 stage engine used in the P-63, which suffered from the same range limitations, poor armament/design philosophy. It was not a Zero killer or even a potential Zero killer. It was Zero food.

Duane

 

[FLYBOYJ]

I'm always amused at how these woulda, coulda, shoulda threads, especially about the P-39 and P-40 vs the Zero eventually go off on a tangent, probably becasue there's not much left to say. Having said that, I'll through in my two cents worth. The P-39 was a fighter designed around a gun, not a fighter with a gun designed for it. As such it was doomed to be a pre-war design to pre war standards with no growth potential save perhaps the use of the 2 stage engine used in the P-63, which suffered from the same range limitations, poor armament/design philosophy. It was not a Zero killer or even a potential Zero killer. It was Zero food.

Duane

Duane;

While I cannot disagree with anything you say, there's a broader picture here that is continually danced around. I could bring the same old rant about "How come the Soviets did so well with the P-39," but I think we already know the P-39 was at its' best element where the Soviets were operating it (at low level, close to home), but despite being "Zero Food" it seems the units operating the aircraft just soiled on and I think we have found that although the P-39 was shot down in numbers perhaps 3 fold in what they dished out, it was the Japanese who suffered the high pilot attrition rate that eventually led to a loss of air superiority over the Solomons, this happening during the final days of the P-39 in that region. It would be an amazing task (but all ready recognized as virtually impossible) if we could really determine how well (but in reality how lousy) the P-39 REALLY did against the Zero. Folklore leads us to believe that this aircraft was swept from the skies and all who flew her eventually became shark food, but the P-39 did enable some outstanding fighter pilots to gain combat experience and live to tell about it (Tommy Lynch for one).

I'm not trying to re-write history or paint a better picture of this aircraft than what it's combat record actually reveals, but I think we should look at the P-39 experience as using "the wrong tool for the wrong job" unfortunately at the time no one in the AAF wanted to admit to that even though I think they knew the limitations of this aircraft. It was all that was available and like the grunts on the ground using their 1910 Enfields, AAF pilots had to go with the P-39 (or P-400).

Even at an actual 1:3 kill ratio (if you want to believe the most extreme numbers) this "dog" of an aircraft did succeed in at least holding the line at places like Henderson until late 1942 when the real game changer entered the fray, and at that point I think the Zero (and other Japanese aircraft) became a common snack.

 

[tomo pauk]

The Zero wasn't ideal fighter itself, and the growth potential was limited there, too.
The location of fuel tanks (in the wings) was similar to the P-39. In case one wants to have those in self-sealing variety, it will have to pay the price, exactly as the P-39 did - serious degradation of fuel tankage, along with weight increase. The XP-39 started with 200 US gals, decreased to 170 gals from YP-39, and further down to 120 gals when P-39C was superseded with P-39D, due to introduction of s-s tanks.
The Zero have had around 150 US gals, and never received s-s tanks; how much had they bother to install them - 100-110? Even the Oscar introduced them, mid-war. Zero was a better climber, especially above 15000 ft, the P-39 was better protected. P-39 rolled better as speed went up, the Zero rolled better at lower speeds.
The fastest Zero was making 350+ mph, the fastest P-39(-Q) was at 380+ mph, and a 390+ without external guns. I'm not sure that USAF ever used those against Zeroes. Installation of the belt-fed 20mm in P-39 should be a trivial exercise.

 

[Shortround6]

The P-39 did help "hold the line" in the South Pacific but it seems more like a situation in which the Allies could afford to loose P-39s/P-40s (and some pilots) while delaying/stopping the Japanese and the Japanese could NOT afford to loose the planes and more importantly, the pilots, they were loosing fighting the P-39s and P-40s. It might have been very hard for the Allies to over to the offensive using P-39s and P-40s though without a much longer and costlier battle of attrition. The P-39/P-40 offered a higher survival rate for the pilots if operated close to home bases, too.

 

[gjs238]

In Guadalcanal would the P-40 have performed any better than the P-39?

 

[GregP]

I looked at our P-51A. There are plugs in the cannon holes, but they are wood plugs, not lead. So the CG change MUST be minor for the wing cannons. We MAY have also moved some items in the fuselage to restore CG of which I am not aware.

Interesting aside, our P-51A is the only flyable one in the world at this time as far as I am aware ... and it has been "down" for about 3 - 4 years since the last time we flew it. It has been a source of great trouble and it all centers around the radiator. They finally "had enough" and designed a new radiator from scratch, actually radiator /oil cooler, and have installed it in the plane. Last Saturday, we pulled it out for a first engine run since the last flight.

After sitting for 3 - 4 years, John Hinton turned the Allison over 3-blades and it fired right off and ran smoothly. Looks like it will be flying again for our airshow in 2 weeks (May 3 - 4)!

Glad to see it flying again.