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

[pbehn]

"why don't you chaps ask Bell to put four 7.5 machine guns out in the wing so the plane will be heavier, this is so that after Germany beats you and we take over the contract we can get out of the contract when America comes up with lend lease over a year in the Future."

Then instead of being given P-39s we will be given something better.

The whole argument of cost is a nonsense, there were and still are more aircraft on the Atlantic sea bed than and UK order of P-39s.

 

[Peter Gunn]

Any way the title of this thread could be renamed "P-39 Continuing Thread" or something like that?

No.

 

[Peter Gunn]

And I have replied at least as many times that no other fighter plane had an armored reduction gear or armored oxygen bottles (except the Brewster Buffalo). I never said the British mandated the nose armor, I just said the plane would improve without it.

And the .30cal wing guns were as close to worthless/redundant as you can get. Little hitting power, wide convergence and (the main reason) their effective range was only 200yds (AHT). 200yds is pretty darn close to be getting to a bomber that is shooting back. No P-38, P-40, P-47, P-51, F4F, F4U, F6F, B-17, B-24, B-25, B-26, or B-29 fought for the AAF/USN with .30cal MGs. Especially since the plane already had a 20mm cannon and twin .50cal MGs. Plenty of armament.

The Soviets configured the P-39 without the .30cal wing guns and they thought it was a really good aircraft. Their favorite.

I'm sorry, did I miss the memo on the early Mustangs not having 4 .30's and 4 .50's?

 

[pbehn]

I'm sorry, did I miss the memo on the early Mustangs not having 4 .30's and 4 .50's?

And later ones having 4 20mm cannon. Unlike Bell, North American just put in, or on or under what the client told them to. Camera sir, in the back sir? certainly sir, will look lovely! Or would sir like a tail warning radar?

 

[Clayton Magnet]

The P-40B or C must, surely, have flown in combat, some of those being at Pearl Harbor when teh Japanese attacked. They had 2 0.50" hmgs in the cowl and 4 0.30"lmgs in the wings.




Plenty of armament to fight against?

What was the firing time for each of those weapons? 6 seconds for the 20mm?

It would be handy to have smaller calibre weapons available when the main guns ran out of ammunition.

Did the P-400 pre-date the belt fed Hispano?
I would agree with the resident expert, that 2 .50's and a central 20mm cannon was plenty of firepower, BUT, only assuming they could get a reasonable rate of fire out of the synchronized Brownings and a belt feed for the 20mm

Trying to supply three different ammunition types to the aircraft seems like it would be a logistical issue

 

[33k in the air]

BUT, only assuming they could get a reasonable rate of fire out of the synchronized Brownings and a belt feed for the 20mm

I think the ill-fated XP-75 wins there: four nose-mounted .50-cal guns firing through contra-rotating props. The rate of fire couldn't have been great. But at least is still had its six wing-mounted .50 cal MGs.

 

[pbehn]

Did the P-400 pre-date the belt fed Hispano?
I would agree with the resident expert, that 2 .50's and a central 20mm cannon was plenty of firepower, BUT, only assuming they could get a reasonable rate of fire out of the synchronized Brownings and a belt feed for the 20mm

Trying to supply three different ammunition types to the aircraft seems like it would be a logistical issue

He is actually talking about late 1942 for most things but projecting onto the first P-39s delivered to UK in August 1941, obviously the XP39 was tested in USA long before that (Aug 1940 I think) If a fully functioning 20mm cannon was available in 1940, the British would have been using it. If the 0.5" MG worked in 1940 as it did in 1943/44 the British may also have used that, but they didnt and werent.

 

[Clayton Magnet]

If we are talking about an early drum fed Hispano, with 6 seconds of ammunition and liable to jam on the first shot, combined with early synchronized Browning M2's, firing at 450 rounds per minute and liable to jam under slight g-loading, then yes, the wing mounted 30 caliber (.303?) machine guns would probably be a welcome addition.

 

[pbehn]

If we are talking about an early drum fed Hispano, with 6 seconds of ammunition and liable to jam on the first shot, combined with early synchronized Browning M2's, firing at 450 rounds per minute and liable to jam under slight g-loading, then yes, the wing mounted 30 caliber (.303?) machine guns would probably be a welcome addition.

This is why it is a groundhog thread, jumping endlessly though space and time.

 

[33k in the air]

This is why it is a groundhog thread, jumping endlessly though space and time.

Well, time travel is the best travel!

 

[SaparotRob]

The British do indeed believe in traveling well.

 

[pbehn]

The British do indeed believe in traveling well.

With lots of rifle calibre guns and ammo.

 

[P-39 Expert]

Apparently you're forgetting that the Brits had already fought BoB with Hurricanes and Spitfires armed with .30 caliber machine guns, and did "fairly well" with them. The US .30/06 is a bit better cartridge than the British .303, too. The Germans had 7.92 machine guns in their aircraft, which might as well be .30s (okay, they are .32s, not that it matters).

The Russians were fighting a different war than were the Brits, that cannot be emphasized enough, they were fighting a different war. You always seem to gloss over that, but the needs/wants were completely at odds with one another. The Russians weren't paying for P-39s and didn't give a crap about wearing out motors, either.
Just because "the Russians liked them" doesn't mean, by any stretch whatsoever, that the aircraft was worth a tinker's damn anywhere but on the Eastern front. And it wasn't much count anywhere EXCEPT the Russian front, either, as many others here have shown you, many, many times.

Yes, the Brits fought the BoB with .30s but they upgraded to 20mm cannons as soon as they could. Many stories of Spitfires/Hurricanes emptying their magazines into German bombers just to see them fly on unimpeded.

The Soviets were certainly fighting about the same war as the BoB. Intercepting medium altitude bombers and higher altitude fighters. The Soviets with the P-39 fought the LW at all altitudes in all conditions.

 

[FLYBOYJ]

The Soviets were certainly fighting about the same war as the BoB. Intercepting medium altitude bombers and higher altitude fighters. The Soviets with the P-39 fought the LW at all altitudes in all conditions.

Except over the North Sea

 

[pbehn]

Yes, the Brits fought the BoB with .30s but they upgraded to 20mm cannons as soon as they could. Many stories of Spitfires/Hurricanes emptying their magazines into German bombers just to see them fly on unimpeded.

The Soviets were certainly fighting about the same war as the BoB. Intercepting medium altitude bombers and higher altitude fighters. The Soviets with the P-39 fought the LW at all altitudes in all conditions.

No they were not, how can you make and continue to make that assertion, it is beyond ridiculous.

 

[33k in the air]

The Soviets were certainly fighting about the same war as the BoB. Intercepting medium altitude bombers and higher altitude fighters. The Soviets with the P-39 fought the LW at all altitudes in all conditions.

What are the actual altitude bands? What is low altitude, what is medium altitude, and what is high altitude? In feet or metres.

 

[P-39 Expert]

Well, adding guns will certainly increase the weight of an unarmed prototype.
Bell should have paid more attention to the air intake, P-40s with the -39 engine could hold 1150hp to over 14,000ft in level flight even if not in a climb.
Was Allison promising 1150hp at 15,000ft with or without RAM?
The failed Allison engines with the too narrow 9.60 gears didn't show up until around Dec of 1941. Two years after Allison was promising 1150hp at 15,000ft?

As for the British specifying the weight, They didn't.
The P-39C was already heavier than the Spitfire V.
Was the USAAC trying to get out of the contract by specifying useless stuff?
P-39 had about 50lbs worth of drive shaft that the Spitfire didn't.
P-39 had a heavier, stiffer fuselage than the Spitfire. Around 50lbs more than a conventional fuselage according to one account.
P-39 had about 128lbs worth of nose landing gear, Much heavier than the tail wheel of the Spitfire.
The P-400 was built to US strength/stress standards, not British standards.


as to the .30 cal gun thing, well covered by others except the fact is that the British were NOT the ones who ordered the wing guns, The French did. Were the US fell in I don't know. Last 60 P-39Cs on the initial order were completed as P-39Ds with the two worthless .30 cal cowl guns moved out to the wings and another gun added in each wing. Did the British "order" the wing guns or just fall in line with French and Americans?

For your allegation to be true we would have to have some British agent talking to the French in late 1939, very early 1940 ad telling them
"why don't you chaps ask Bell to put four 7.5 machine guns out in the wing so the plane will be heavier, this is so that after Germany beats you and we take over the contract we can get out of the contract when America comes up with lend lease over a year in the Future."

As an historic note the British also ordered 620 Mustang Is with Allison engines and four .50 cal guns and four .303s.
The Curtiss P-46 prototype had two.50s and eight .303s.
The Hurricane IIB had twelve .303s as did the early Typhoon.
The Fulmar defended the Med convoys using eight .303s. Many Italian and German aviators would be really discouraged to find out they were shoot down by worthless guns/ammo.

In 1940 the 20mm Hispano and the US .50 were both immature weapons systems.

Another historic note, The Japanese used the very same 7.7/.303 cartridge in their version of a Vickers gun (licensed) in the Zero, the Ki-43, the Ki 27, the A5M, the Val and a host of other aircraft, they seemed to do pretty well with it in 1941/42, perhaps they mostly held their fire until the were within 200yds?

I don't

You are continuing with the circular argument here. We've discussed this many times before and you keep bringing it up.

The .30 wing guns were added to the P-400 in March 1940. France had not yet capitulated but who was running the P-400 contract at that time? France or Britain? The P-400 would weigh 7850lbs after the British got finished with it, as compared with a Spitfire V at 6600lbs. The British knew full well the weight penalty on performance involved.

Either way, the P-39C was being produced Jan-March 1941 and was on the right track to be a very potent warplane for 1941. It grossed 7075lbs and would go 379mph and climb at 3720fpm, both better than a Spitfire V. The P-39-C did not have self sealing fuel tanks or pilot armor. Adding the self sealing tanks (240lbs), armor plate (120lbs as in the P-39N without the nose armor) and an additional 15 rounds of 37mm ammo (30lbs) should have been offset by removing the two .30s in the nose (100lbs) and the 50gal fuel not available after installation of the self sealing tanks (300lbs) for a net reduction of 10lbs.

The P-39D which began production in April 1941 could easily have weighed 7150lbs, only 75lbs more than the P-39C. Empty Weight 5523lbs, Pilot 160lbs, 37mm cannon and two .50calMGs with ammunition and gun sight 580lbs, Fuel (120gal) 720lbs, Oil 71lbs, armor plate and glass (as above) 120lbs, oxygen 8lbs. Total 7182lbs. Deduct 32lbs for the wing .30cal gun mounts, chargers, heaters and ammunition boxes and you have 7150lbs. Substitute the more reliable (at that time) 20mm cannon and deduct 130lbs for a new gross weight of 7020lbs. Both versions about the same performance as the 7075lb P-39C, 379mph and 3720fpm climb. A heavily armed and armored warplane available from April 1941.

 

[P-39 Expert]

What are the actual altitude bands? What is low altitude, what is medium altitude, and what is high altitude? In feet or metres.

I haven't seen actual numbers, but I always use 0-10000ft for low altitude, 10000-20000ft for medium altitude, and over 20000ft for high altitude.

 

[P-39 Expert]

No they were not, how can you make and continue to make that assertion, it is beyond ridiculous.

Only difference between air combat in western Europe and eastern Europe was there were no high altitude bombers in Eastern Europe. And those weren't really a force in the west until mid '43. Soviets standard combat formation was the "Kuban Stairs" or "Flying Bookshelves" with a flight (4 planes) at 5000meters (16500ft), a flight at 6000meters (20000ft) and the top flight at 7000meters (23000ft). P-39s could match the LW fighters up to 8000meters (26400ft) with neither side willing to go much higher than that.

Turbocharged B-17s and B-24s flew at 25000ft with their escorts a little higher. Not much difference.

 

[Glider]

You are continuing with the circular argument here. We've discussed this many times before and you keep bringing it up.

The .30 wing guns were added to the P-400 in March 1940. France had not yet capitulated but who was running the P-400 contract at that time? France or Britain? The P-400 would weigh 7850lbs after the British got finished with it, as compared with a Spitfire V at 6600lbs. The British knew full well the weight penalty on performance involved.

Either way, the P-39C was being produced Jan-March 1941 and was on the right track to be a very potent warplane for 1941. It grossed 7075lbs and would go 379mph and climb at 3720fpm, both better than a Spitfire V. The P-39-C did not have self sealing fuel tanks or pilot armor. Adding the self sealing tanks (240lbs), armor plate (120lbs as in the P-39N without the nose armor) and an additional 15 rounds of 37mm ammo (30lbs) should have been offset by removing the two .30s in the nose (100lbs) and the 50gal fuel not available after installation of the self sealing tanks (300lbs) for a net reduction of 10lbs.

The P-39D which began production in April 1941 could easily have weighed 7150lbs, only 75lbs more than the P-39C. Empty Weight 5523lbs, Pilot 160lbs, 37mm cannon and two .50calMGs with ammunition and gun sight 580lbs, Fuel (120gal) 720lbs, Oil 71lbs, armor plate and glass (as above) 120lbs, oxygen 8lbs. Total 7182lbs. Deduct 32lbs for the wing .30cal gun mounts, chargers, heaters and ammunition boxes and you have 7150lbs. Substitute the more reliable (at that time) 20mm cannon and deduct 130lbs for a new gross weight of 7020lbs. Both versions about the same performance as the 7075lb P-39C, 379mph and 3720fpm climb. A heavily armed and armored warplane available from April 1941.

And yet no one made these simple changes. Strange that isn't it.