SHOULD the P39 have been able to handle the Zero? Was it training or performance?

[Shortround6]

Just which Luftwaffe plane(s) were so superior to the P-39?
Regarding lend lease, how could the British take the P-39 under lend lease when they had so publicly derided them as inferior under the hard money contract? "Oh these P-39s suck, but we'll take them for free"? They no longer needed them after winning the BoB and their internal fighter production was then adequate. They didn't need them and couldn't pay for them. Bell had the last laugh though. They got a $2million cash advance from the British in the original order. Bell was a relatively new company struggling under depression era economics and although $2mil doesn't sound like much today, in 1940 dollars it was a fortune and put them in the black for the rest of the war. And the Army took over the British order and had P-39s available from 1941 on.

Oh boy........
The British took delivery of 80 P-39s. The US took over 179. 212 are sent to Russia and 53 are lost at sea en-route. The British may have sent some of their P-39s on to Russia. This all takes some time and it takes until June 30th 1942 to get 93 P-400s to the Russians, this may be different than Aircobra Is

British P-39s had lethal concentrations of carbon monoxide in the cockpit after the nose guns fired. Firing the nose guns knocked the compass out of action. There were other faults.

 

[Shortround6]

Sorry I don't understand how a supercharger works. I thought it compressed intake air to provide more power to the engine. Whether the power is reduced at lower altitudes because of a lower gear or because of a lower throttle setting on a single gear seems irrelevant to me. The sole purpose of low gear is to keep from overboosting the engine at takeoff. The same protection against overboosting at takeoff in a single speed engine is provided by reduced throttle. The Allison's single speed was high gear, it didn't have a low gear. It reduced boost at takeoff and low altitude by reduced throttle. Simple operation, lighter weight, more reliable.

try reading it again. use of a lower gear meant better fuel economy at low altitude, it meant less of a cooling problem, it meant lower stress on the whole engine.
The advantages of a lower gear are not just for take-off but at any time the plane is operating at pretty much under 10,000ft.

I would note that Wright built 2 speed R-1820s, 2 speed R-2600s, 2 speed R-3350s. Pratt and Whitney built 2 speed R-1830s, two speed R-2800s and they even built a few 2 speed R-4360s and some variable speed ones.
Rolls-royce built a lot ot two speed Merlins and Bristol built 2 speed Pegasus engines and 2 speed Hercules and 2 speed Centaurus engines.

Allison built a few two speed prototypes at the end of the war or just after.

I guess they were all wrong along with the Russian, German and Japanese engine builders who all built 2 speed or variable speed superchargers.

 

[P-39 Expert]

Not even close.
I asked where the British added weight to get out off the contract. They took out over 100lbs compared to an American P-39 with 37mm gun. The P-39c had a pair of 30 cal guns in the fuselage
View attachment 485844
weight figures may be suspect. The speed sure is, British got 359mph out of the ones they got.
Basically Larry Bell sold the British and French an imaginary aircraft. When the British took delivery it would not come close to meeting the promised performance. The XP-39 when delivered to Wright field in 1939 was 10% overweight and the prototype had no guns let alone armor or self sealing tanks.
Yanking a cabin heater wasn't going to save it.
Nobody says you have to fill the ammo boxes completely full.

Spitfire Vb went a bit over 6500lbs, cutting 500lbs out of an Aircobra still leaves you over 500lbs heavy and several hundred hp short.

Okay, look at your photo of the P-39C. Says it weighed 7075# and made 379mph at 13000'. The British only got 359mph from theirs because they weighed 7850#. That's 775# lighter. But the real performance gain was in climb. That little P-39C at 7075# would climb at 3720fpm up to 12000'. How fast would the SpitV climb at that altitude? About 3000fpm or 750fpm less. The P-39C was faster and climbed faster than the SpitV.
Now, that P-39C didn't have self sealing tanks or armor plate/glass necessary for combat. The tanks added 260# and the armor added 240# so now we're up to 7575#. But wait, we can deduct 300# because the self sealing tanks reduced fuel capacity by 50 gallons, 100# by removing the two .30 caliber MGs in the nose and another 100# by deleting the nose armor (too far from pilot for protection) leaving us back at the original 7075# that gave the 379mph/3700'climb. Now the P-39C is faster than the SpitV, climbs faster, carries 20 gallons more gas, easier to land and is heavily armed/armored. This plane was available from July 1941 and was the plane the Army should have purchased.

 

[P-39 Expert]

try reading it again. use of a lower gear meant better fuel economy at low altitude, it meant less of a cooling problem, it meant lower stress on the whole engine.
The advantages of a lower gear are not just for take-off but at any time the plane is operating at pretty much under 10,000ft.

I would note that Wright built 2 speed R-1820s, 2 speed R-2600s, 2 speed R-3350s. Pratt and Whitney built 2 speed R-1830s, two speed R-2800s and they even built a few 2 speed R-4360s and some variable speed ones.
Rolls-royce built a lot ot two speed Merlins and Bristol built 2 speed Pegasus engines and 2 speed Hercules and 2 speed Centaurus engines.

Allison built a few two speed prototypes at the end of the war or just after.

I guess they were all wrong along with the Russian, German and Japanese engine builders who all built 2 speed or variable speed superchargers.

I think that having to operate in single stage, two stage turbo (P-38) and two stage mechanical (P-63) may have had something to do with keeping the single speed for simplicity. But I still maintain it was no disadvantage vs. the two speed.

 

[Graeme]

Basically Larry Bell sold the British and French an imaginary aircraft. When the British took delivery it would not come close to meeting the promised performance.

I've read (Ray Wagner) Bell promised the RAF the Model 14 (Airacobra I) to have a top speed of 383 mph at 14,400 ft, an altitude that should have been reached in 5 minutes 30 seconds. The American support group could not explain the speed loss and believed the company had greatly exaggerated their product's virtues.

Other authors deride the British for believing Bell - knowing the turbo-supercharger had now been removed.

 

[tomo pauk]

Please accept my apology if you think I threw mud on you. Message boards are for debate and everyone always doesn't agree with everyone else. I'm just trying to explain to you what the numbers on the engine chart mean.

I'm from Croatia, not from UK, the country that was trying to 'weasel out' from P-39 contract, per your words. The term can mean " To back out of some situation or commitment in a selfish or sly manner:" by this on-line dictionary.
It is one thing to debate and discuss about numbers, that above was not about the numbers.

 

[pbehn]

The British operated almost every major type of aircraft made by the USA, they operated the P-39 on one mission of four aircraft, if the P-39 was any use they would have taken it, many were ordered and diverted under lend lease. By the time the P-39 was operational in UK the FW-190 was on the other side of the channel, the British needed something superior to the MkV both in UK (for offense) and Malta (for defence) and the P-39 wasn't, if it had been it would have been put into service with begging letters for more as happened with the P51A (Mustang I).

 

[P-39 Expert]

I've read (Ray Wagner) Bell promised the RAF the Model 14 (Airacobra I) to have a top speed of 383 mph at 14,400 ft, an altitude that should have been reached in 5 minutes 30 seconds. The American support group could not explain the speed loss and believed the company had greatly exaggerated their product's virtues.

Other authors deride the British for believing Bell - knowing the turbo-supercharger had now been removed.

View attachment 485848

Look at your SpitV speed of 364mph. Now look at the photo in post #119. P-39C speed of 379mph. Weight was the issue.

 

[pbehn]

Look at your SpitV speed of 364mph. Now look at the photo in post #119. P-39C speed of 379mph. Weight was the issue.

There were many issues, most of them embodied in the FW190.

 

[Graeme]

Look at your SpitV speed of 364mph. Now look at the photo in post #119. P-39C speed of 379mph. Weight was the issue.

Yes, post No.119 shows the P-39C with 379mph.
As I understand it the British received only 3 P-39C versions in July 1941 - but under test were capable of only 359 mph. Why?
However the bulk of the order were for the export version - the Airacobra I which according to Wagner was promised to the British as capable of 383 mph and their was even a claim that 392 mph had been attained on April 29 1941.
I get the weight issue - but then why were Bell telling the British speeds that weren't attainable?

In the end this is what they got...

 

[Peter Gunn]

Just which Luftwaffe plane(s) were so superior to the P-39?

*SNIP*

I'll venture to say the Bf-109 and the Fw-190 to name just two. I'd wager the Bf-110 and the Ju-87 and 88 would be tough nuts to crack. I'm a dyed in the wool lover of the P-39, mostly for it's looks and the whole tricycle landing gear forward thinking behind it, but in no way do I ever think it was going to be competitive anywhere but low down and overboosting the engine like the VVS pilots used it.

Visually for me, it's one great looking ship, right next to the Mustang, Macchi 202, Reggiane 2005, the Ki-61 just to name a few.

Unfortunately, no matter how good I think it looks, it still doesn't help it's real world performance.

 

[Graeme]

A 1943 assessment - British of course....

 

[Elmas]

Problems with the airplanes with central engines were the same in the world over: see

Piaggio P-119

 

[P-39 Expert]

I'll venture to say the Bf-109 and the Fw-190 to name just two. I'd wager the Bf-110 and the Ju-87 and 88 would be tough nuts to crack. I'm a dyed in the wool lover of the P-39, mostly for it's looks and the whole tricycle landing gear forward thinking behind it, but in no way do I ever think it was going to be competitive anywhere but low down and overboosting the engine like the VVS pilots used it.

Visually for me, it's one great looking ship, right next to the Mustang, Macchi 202, Reggiane 2005, the Ki-61 just to name a few.

Unfortunately, no matter how good I think it looks, it still doesn't help it's real world performance.

Okay, pick one. FW190 or Me109. Either one. Which version of each so we know we are comparing the correct version of the P-39.

 

[drgondog]

Cost was the big issue, especially for the British. They had stood alone against Germany since the fall of France and they were dead broke. They had to order those planes before France fell not knowing how long the war would run. After they were safely past the Battle of Britain and a German invasion was no longer possible, they moved to cut their losses and weasel out of not only the P-39 contract but a similar contract for P-38s that were ordered without turbochargers. Those were hard money contracts and payment was demanded. The British knew that if the Battle of Britain had not gone their way and they needed the P-39s that they could have quickly stripped the excess weight (.30 cal MGs, heater, unnecessary radio equipment) from those planes to make them competitive.

Where in the world are you drawing facts from?

The Brits were desperate to augment their own production capacity with aircraft equal to, or better than their own. The NA-73/Mustang I was accepted because it promised And Delivered the performance estimates NAA provided and it was better than the P-40 (and P-39) and P-38 at the altitudes RAF engaged in for most ops.

The P-39C was Not Ever competitive in combat ops because they did not come equipped with Required modifications such as self sealing tanks, etc. It was not even better than the Hurricane, certainly not as good as Mk 5 Spit or A6M or FW 190A-1 introduced into Operations 9/41. There was a reason the P-39D and subsequent were relegated to CAS as quickly as P-40E and P-38F could replace the P-400 in SWP and Africa. The AAF thought so much of the P-39, that the P-39 trained 52nd and 31st FG sent pilots only to England to be replaced by Spit V on reverse Lend Lease. The P-39D and subsequent, when stripped of wing armament & 20mm (mostly) replacing the 37mm, were 'almost' competitive at low altitude but still suffered appalling losses to BF 109F and FW 190A-2 and -3.

You will Never find a US or Commonwealth survivor of the Iron Dog experience against A6M, Tony, 109 or 190 that wished they could get the P-39 after they graduated to P-40F/N or 38E/F or P-47C/D.

 

[P-39 Expert]

Yes, post No.119 shows the P-39C with 379mph.
As I understand it the British received only 3 P-39C versions in July 1941 - but under test were capable of only 359 mph. Why?
However the bulk of the order were for the export version - the Airacobra I which according to Wagner was promised to the British as capable of 383 mph and their was even a claim that 392 mph had been attained on April 29 1941.
I get the weight issue - but then why were Bell telling the British speeds that weren't attainable?

In the end this is what they got...

View attachment 485858

THE REASON WAS WEIGHT. WEIGHT per your photo says the P-400 gross weight was 7845#. The P-39C weighed 7075#, that extra 770# is the difference in the 355mph vs the 379mph. Everything about the P-39C and the P-400 was exactly the same (engine, propeller, aerodynamics) except the additional 770#. To put this in perspective, you know the performance benefits of dropping your external tank for combat, it is quite substantial or the pilots would not have dropped them. A 75 gallon external tank only weighed 500# FULL OF FUEL. We're talking about 770# here. This is the same reason that the Russian P-39s outperformed the Luftwaffe, they discarded the useless 30 caliber wing guns and one of the radios (didn't use their frequency) and got much better performance.

 

[buffnut453]

THE REASON WAS WEIGHT. WEIGHT per your photo says the P-400 gross weight was 7845#. The P-39C weighed 7075#, that extra 770# is the difference in the 355mph vs the 379mph. Everything about the P-39C and the P-400 was exactly the same (engine, propeller, aerodynamics) except the additional 770#. To put this in perspective, you know the performance benefits of dropping your external tank for combat, it is quite substantial or the pilots would not have dropped them. A 75 gallon external tank only weighed 500# FULL OF FUEL. We're talking about 770# here. This is the same reason that the Russian P-39s outperformed the Luftwaffe, they discarded the useless 30 caliber wing guns and one of the radios (didn't use their frequency) and got much better performance.

And where did much of that extra weight come from? Armour plating probably made up a fair amount of it. Per Shortround6's Post #110, the P-39C did not have armour plating. Given that armour was considered vital in ALL combat aircraft engaged in operations from mid-1940 onwards, we cannot consider the P-39C to be a truly combat-capable platform.

 

[Shortround6]

The P-39C did have armor, at least some and had BP glass, it didn't have self sealing tanks.
I would not use the Ray Wagner figures as gospel however. I used the photo to show the British aircraft only had 2 more RCMGs than the P-39C.

SOme of the disparity in figures come from different test conditions.
http://www.wwiiaircraftperformance.org/P-39/P-39C_40-2988.pdf
A P-39C that did do 379mph, however it was at 6689lbs, roughly 400lbs lighter than the figure Ray Wagner used. One wonders what was left out, ammo or fuel? A bit of both?
Please note the comments where under no circumstance was the oil cooling satisfactory to USAAF standards and in both high speed level flight and in climb both oil and prestone cooling did not meet USAAF standards.
Please note that Larry Bell & company were promising a LOT more than they could deliver.
Company performance chart.
http://www.wwiiaircraftperformance.org/P-39/P-39C_Chart-Bell_Aircraft-1400.jpg
Dated feb of 1940 which is well before the YP-39s flew.
I would note that the British had 675 Aircobras on order about 4 months before the first YP-39 flew let alone any P-39Cs

British test
http://www.wwiiaircraftperformance.org/P-39/AH573.pdf

I would note that while the US tested climb at 3000rpm for the first 5 minutes the British used 2600rpm for the entire climb but this was British procedure. ALL british climb figures are done at max continuous or a 30 minute rating and not at a 5 minute rating.

 

[pbehn]

Where did the USA use the P-39 with any success? Wiki states it was good at ground straffing and recon,

 

[drgondog]

Okay, pick one. FW190 or Me109. Either one. Which version of each so we know we are comparing the correct version of the P-39.

The P-39D-2 was operational as the first 'combat ready' P-39 (self sealing tanks/uprated engine) and introduced into combat ops in Spring 1942.

Combat experience shows that they are ineffectual at interception (the original design Purpose) at altitudes at or above 20,000 feet against Japanese. It was so bad that the P-39 and P-400 are relegated to CAS as USMC Wildcats take over air defense until P-38F arrive. At MP, the P-39D-2 climb rate = max at 2400fpm at 7,000 feet, declines to 1900 fpm at 15000 at GW=7631 # (ref A100K by Dean, pg 191 Top speed at MP= 371mp at ~12K, at SL = 310mph.

The P-40E had peak ROC at 2400fpm @15,000 ft, Top speed at 310mp at SL/365 at 15K at 8,400# and MP w/200 hp less.(than 39-D-2).

The Bf 109F-2/G-1 at same period had 3,427 fpm at SL; 2,644 at 19,000 feet; Top speed 314mph at SL; 391mph 22,000 feet -----------> at all altitudes a better climb rate and top speed than the P-39 and P-40.

The FW 190A-2 earlier - Digging now for same reference data, but greater in all respects except turn rate vs Spit V.

For the A-5, Peak ROC at SL=2950fpm; 2000fm @20,000. Top speed = 352mph; 408mph @21000.

The question is" what 1st line fighter - US, RAF, LW, IJN was Not superior combat a/c than any P-39?