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

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules

Bell believed they could get 400mph at the current weights when the engine would finally develop 1150HP at 15000' as was projected by Allison in late 1939. The weight went up drastically and the 1150HP at 15000' wasn't realized until fall of 1942 with the -85 engine. Their projections (and Allison's) were obviously off.

The British did specify a very heavy airplane at over 7600lbs, especially when their SpitfireV weighed in the neighborhood of 6600lbs. Four .30calMGs with 1000rounds per gun (almost 400lbs), nose armor and armor for the oxygen bottles etc, (about 140lbs), a fuel powered cabin heater (when heating/cooling of the cabin was actually already very good) among other items. British had to know that a plane half a ton heavier than a Spitfire had to have a performance penalty. And I have listed these items numerous times on this board.
How much did the Mustang MkI weigh with the same engine and 4 cannon plus all the other stuff, how fast did it go?
By 1941 the Spitfire MkV was introduced, some carried 4 cannon AND 4 mgs.
By the end of 1942 the MkIX was in service, the Griffon powered Mk XII was being made and the Typhoon was getting sorted. We have been through all of this before.
 
And you've been told just as many times that the additional weight added by the British was NOT useless. The requirements were levied because that's what the customer wanted. They WANTED the wing guns because they were not useless (as you keep saying). They WANTED protection for the oxygen tanks because experience showed that unprotected oxygen was a combat liability (and they levied the same requirement on the Brewster Buffalo).

Do you have evidence that the British mandated the nose armour because, from what I've seen, it was pretty much a standard fit on all P-39s?

You can blame the Brits all you like but the bottom line is that the P-39 when configured for actual combat operations wasn't a very good aircraft. Period.
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.
 
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.
Where is this armoured oxygen bottle?
 
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.
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.
 
The information and input of other eyes and ideas is worth much more than the price of one plane.

Completely agree. The use of US combat types by foreign air forces prior to the Americans joining the war gave the US forces a huge amount of valuable experience and knowledge that quite often goes unappreciated, particularly by Americans. Almost all the major US combat types in WW2 saw service with foreign air forces before the US entered the war, the PBY, P-39, P-40, P-36, F4F, B-24, B-17, P-51 etc, etc. British experience with the B-17 as the Fortress I is a good example, the B-17C was just not up to the task that the USAAC/F was expecting of it over Europe in 1941, suffering poor serviceability, high losses to enemy fighters and poor defensive armament, as well as an inability to function properly at the heights the bomber was designed to function at, with equipment routinely freezing and becoming inoperable.
 
Completely agree. The use of US combat types by foreign air forces prior to the Americans joining the war gave the US forces a huge amount of valuable experience and knowledge that quite often goes unappreciated, particularly by Americans. Almost all the major US combat types in WW2 saw service with foreign air forces before the US entered the war, the PBY, P-39, P-40, P-36, F4F, B-24, B-17, P-51 etc, etc. British experience with the B-17 as the Fortress I is a good example, the B-17C was just not up to the task that the USAAC/F was expecting of it over Europe in 1941, suffering poor serviceability, high losses to enemy fighters and poor defensive armament, as well as an inability to function properly at the heights the bomber was designed to function at, with equipment routinely freezing and becoming inoperable.
In terms of the thread, it illustrates the difference between an independent test and one done by the people who made the plane. Bell were gaming the system to their advantage, the tests didnt represent what they were selling as production models to the agreed spec.
 
The Soviets configured the P-39 without the .30cal wing guns and they thought it was a really good aircraft. Their favorite.
Since we are back in full groundhog mode, can we agree that the UK isnt Russia?

By 1941 the standard armament on UK fighters was 4 x 20mm cannon. The Spitfire was an exception because of the need for altitude performance and heating. They had a different use to that in Russia that is why they needed different armament, this is why you need to accept Russia isnt England, then we can move on, in small steps.
 
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.

Firstly, the RAF did not specify 30cals. They specified the ability to fit .303s which would be Government Furnished Equipment installed when the aircraft were erected in the UK. Different weapon, different capabilities. Again, it's YOUR assessment that the 30cals were useless. The fact that the RAF continued with .303s even after the introduction of 20mm cannon as the main fighter armament suggests that they weren't useless. The fact that the USAAF operating the P-400s and P-39s under combat conditions also didn't remove the wing 30 cals suggests rather strongly that they were beneficial. Just because the Russians removed the wing guns does not mean that was a workable solution in other theatres. You have been told this DOZENS of times and yet you still persist in your belief that the 30cal/.303 was useless. Sorry but you can't use your own incorrect statement as evidence of malfeasance by the Brits.

(Yet) again, the RAF was using .303s when the P-39 was ordered and they were still using them in fighters long after they, rightly, shit-canned the P-39 as a waste of time. The RAF was the customer. They had the combat experience in the theatres where they were fighting. No amount of armchair generalling, particularly from someone who is so intent on not listening to anyone else, will convince me that they were wrong to specify the .303s. As to your long list of American aircraft that didn't use 30 cals...that's ENTIRELY irrelevant because the CUSTOMER was the RAF.

You said "I never said the British mandated the nose armor, I just said the plane would improve without it" and yet in post 1589 you said "The British did specify a very heavy airplane at over 7600lbs, especially when their SpitfireV weighed in the neighborhood of 6600lbs. Four .30calMGs with 1000rounds per gun (almost 400lbs), nose armor and armor for the oxygen bottles etc, (about 140lbs), a fuel powered cabin heater (when heating/cooling of the cabin was actually already very good) among other items" which clearly suggests that the RAF specified all those items, including the nose armour. And, YET AGAIN, people have explained why it was necessary for both weight and balance and because of the P-39's unique configuration which meant that damage to the gearbox would result in a whiplashing drive shaft that ran between the pilots legs. And you ask why this is the groundhog day thead?

As to the oxygen tank, was it actually armour-plated or simply afforded greater protection? Looking at the location, I can't help wondering if there were concerns about oxygen leaking from a damaged tank being ignited by the guns firing. Certainly, most other fighter aircraft of the period had the oxygen tank aft of the cockpit. Again, the P-39s unique configuration forced the tank to be moved forward...so perhaps putting it the gun bay wasn't the brightest idea?
 
The British did specify a very heavy airplane at over 7600lbs, especially when their SpitfireV weighed in the neighborhood of 6600lbs. Four .30calMGs with 1000rounds per gun (almost 400lbs), nose armor and armor for the oxygen bottles etc, (about 140lbs), a fuel powered cabin heater (when heating/cooling of the cabin was actually already very good) among other items. British had to know that a plane half a ton heavier than a Spitfire had to have a performance penalty. And I have listed these items numerous times on this board.

US aircraft seemed to have heavier structures than their UK counterparts.

And note that the Spitfire at 6,600lb had two 20mm cannon and 4 0.303" lmgs, plus armour and self sealing fuel tanks. So the extra weight of the P-39 is likely not totally due to the items you list, particulalry when some of those items were also on the Spitfire.
 
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.

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.


Especially since the plane already had a 20mm cannon and twin .50cal MGs. Plenty of armament.

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.
 
Re: .30 caliber MGs
USAAF aircraft equipped with this weapon at the end of 1941
P-26
P35A
P-36A
P-39D/P-400
P-40B and C
A-20A
A-24
Most bombers at this date (B-17, B-18, B-24, B25, B-26) carried a mix of .50 and .30 caliber guns for defense.

And the supreme irony in his bringing up all those aircraft without 30cals is that the P-39D WAS equipped with 30cals. The comedy value is priceless.
 
Bell believed they could get 400mph at the current weights when the engine would finally develop 1150HP at 15000' as was projected by Allison in late 1939. The weight went up drastically and the 1150HP at 15000' wasn't realized until fall of 1942 with the -85 engine. Their projections (and Allison's) were obviously off.

The British did specify a very heavy airplane at over 7600lbs, especially when their SpitfireV weighed in the neighborhood of 6600lbs. Four .30calMGs with 1000rounds per gun (almost 400lbs), nose armor and armor for the oxygen bottles etc, (about 140lbs), a fuel powered cabin heater (when heating/cooling of the cabin was actually already very good) among other items. British had to know that a plane half a ton heavier than a Spitfire had to have a performance penalty. And I have listed these items numerous times on this board.

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
 

Users who are viewing this thread

Back