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| At a fairly early stage in the development of the Bell P-39 Airacobra, work had been carried out to enhance the performance of this aircraft by the introduction of aerodynamic improvements. Three experimental aircraft were built, each utilising the basic fuselage of the P-39D, to which were added a new laminar-flow wing with square wingtips and a revised tail unit. In fact, each of the three XP-39Es, as these aircraft were designated, had a different tail unit. It was planned originally to power the prototypes with the Continental Aviation and Engineering Corporation's IV-1430 12-cylinder inverted-vee piston-engine, which had demonstrated a power output in excess of 1491kW. However, Allison V-1710 engines of little more than half of that power output were installed, presumably because of unreliability of the Continental engine. Testing of the XP-39Es began in February 1942 and, proving satisfactory, the type was ordered into production under the designation P-76. Some 4,000 aircraft were to be built at Bell's Marietta, Ohio, facility but were cancelled only three months later.
It was decided, instead, to build a larger and more powerful version for utilisation in a close-support fighter/fighter-bomber role, and the research and design development which had been carried out for the XP-39E were used in finalising the design of what was to become known as the Bell Model 33, or P-63 Kingcobra. In its layout this latter aircraft was generally similar to the P-39, but apart from being larger and with, the V-1710 engine more powerful than those installed in all but the P-39K and P-39L production aircraft, efforts had to be made to render this new development more suitable for the close-support role regarded as its primary mission.
Two prototypes were ordered by the US Army Air Corps in June 1941 under the designation XP-63, and these made their first flights on 7 December 1942 and 5 February 1943, both powered by
the 988kW Allison V-1710-47 engine. Both aircraft were lost in an early stage of their test programme, resulting in the construction of a third prototype, the XP-63A, first flown on 26 April 1943 and powered by a V-1710-93 engine with a war emergency rating of 1119kW. It was planned subsequently to flight-test this prototype with a Packard-Merlin V-1650-5 engine installed, under the designation XP-63B, but this did not happen.
The performance of the XP-63A was found to be satisfactory, and the type was ordered into production in September 1942. Initial deliveries of the P-63A began in October 1943, and by the time production ended in 1945 more than 3,300 Kingcobras had been built in several versions. By far the majority, something in excess of 2,400, were supplied to the USSR under lend-lease, and about 300 went to the Free French Armee de I'Air. Very few of the total production of P-63 close-support fighters/ fighter-bombers were delivered to the USAAF, and so far as is known no King-cobras were used operationally by that service.
Equipment of production batches varied considerably, resulting in many sub-types. The first production P-63A-1s had V-1710-93 engines, a nose-mounted 37mm M4 cannon and two 12.7mm machine-guns in underwing fairings; other sub-types had two additional 12.7mm guns mounted in the fuselage nose. P-63A-1s and P63A-5s could accommodate a 284-litre or 662-litre drop tank, or a 237kg bomb beneath the wing centre-section; P-63A-6s had underwing racks for two similar bombs or additional fuel; and P-63A-10s could mount three air-to-surface rockets beneath each wing. The weight of defensive armour, intended primarily to give protection from ground weapons, increased progressively from 39.8kg on the P-63A-1 to 107.2kg on the P-63A-10.
The P-63A was succeeded on the production line by the P-63C with the V-1710-117 engine, this offering with water injection an emergency war rating of 1342kW. A distinctive identification feature of the P-63C was provided by the introduction of a small ventral fin. Other variants included a single P-63D with V-1710-109 engine, a bubble canopy, and increased wing span; 13 of the P-63E (or Bell Model 41), all that had been produced of 2,930 on order when contracts were cancelled at the war's end, and which were generally similar to the P-63D except for a reversion to the standard cockpit canopy; and two P-63Fs, a version of the P-63E with a V-1710-135 engine and modified tail surfaces.
One other unusual version of the Kingcobra was built extensively (in excess of 300) for use by the USAAF in a training programme involving the use of live ammunition. Developed from the P-63A, all armour and armament was removed, and the external surface of the wings, fuselage and tail unit were protected externally by the addition of a duralumin alloy skin weighing some 680kg. Other protection included the installation of bulletproof glass in windscreen and cockpit side and upper windows, the provision of a steel grille over the engine air intake and steel guards for the exhaust stacks, and the use of a propeller with thick-walled hollow blades. All of these precautions were to make it possible for the aircraft to be flown as a target that could withstand, without significant damage, the impact of frangible bullets. When a hit was made by an attacking aircraft a red light blinked to confirm the accuracy of the weapon being fired against it.
The first five of these target aircraft were designated RP-63A-11; the 95 RP-63A-12s which followed had increased fuel tankage; the next production version, with the V-1710-117 engine, became designated RP-63C (200 built); and the final version was the RP-63G (32 built), this having the V-1710-135 engine. Although never flown as pilot-less drone aircraft, the designations of these three versions were changed subsequently to QF-63A, QF-63C and QF-63G respectively.
| MODEL | P-63A |
| CREW | 1 |
| ENGINE | 1 x Allison V-1710-93, 988kW |
| WEIGHTS |
| Take-off weight | 4763 kg | 10501 lb |
| Empty weight | 2892 kg | 6376 lb |
| DIMENSIONS |
| Wingspan | 11.68 m | 38 ft 4 in |
| Length | 9.96 m | 33 ft 8 in |
| Height | 3.84 m | 13 ft 7 in |
| Wing area | 23.04 m2 | 248.00 sq ft |
| PERFORMANCE |
| Max. speed | 660 km/h | 410 mph |
| Cruise speed | 608 km/h | 378 mph |
| Ceiling | 13110 m | 43000 ft |
| Range w/max.fuel | 3540 km | 2200 miles |
| Range w/max payload | 724 km | 450 miles |
| ARMAMENT | 1 x 37mm cannon, 4 x 12.7mm machine-guns, 3 x 237-kg bombs |
 | A three-view drawing (752 x 1113) |
| Aaron, e-mail, 19.08.2010 04:20 Ron,
I have been studying and researching WW2 fighter A /C on and off since 1968. I love the subject and compiled tons of material. I would love to share the little I have put together with you or anyone who is interested. There is so much I haven't learned yet and would like to know. I have very limited time to use a computer, job, wife and life, but would be glad to pass on what I can. reply | | Ron, e-mail, 21.04.2010 08:50 No sooner do I finish the last post, behold: I find Bell's P-52 design. Never produced of course, but a design just like I was thinking of and better looking than the P-54, 55, and 56. Wish it followed through to compete, at least a flying prototype would have been nice.
Anyway, even with the existing P-63, the prospect of replacing the Allison with a P&W R-2800 would have been an improvement in power and reliability (though heavier). Chances are it could have given the P-51 a bit more competition despite there not being enough Packard Merlin engines to share with Bell. I like to think it would be fast like the P-47 or F4U rather than slower like the F6F that all had the R-2800 radial, my favorite powerplant for WW 2 fighters. reply | | Ron, e-mail, 20.04.2010 23:32 The P-56 Black Bullet was a pusher with an R-2800 radial, but was short and unstable. It had no canard elevator like the J7W of Japan (or Allison powered Curtis P-55) had.
The longer Vultee P-54 pusher with the tailplane P-38 style, was probably most stable.
Thought I had to mention the American pushers especially the radial powered one after my last post. reply | | Ron, e-mail, 20.04.2010 20:19 If the underpowered and unreliable Allison was the only inline engine available to the Kingcobra, what if a radial was tried?
It worked in the Kyushu J7W Shinden with a Mitsubishi radial engine behind the pilot.
The Pratt and Whitney 2800 was reliable and powerful in time for the P-63.
Of course it need not be a pusher like the Shinden but actually that might have worked even better: No synchronized limit for guns to 300 rpm through the prop;
No more gearset and extension shaft to a distant motor.
Imagine a clean nose for efficient Russian guns and you have a kick-butt Bell fighter by mid-war!
Unconventional, maybe. But Bell was never otherwise. reply | |
| | Ron, e-mail, 19.04.2010 20:15 I misspoke about the Chrysler powered P-47H.
It was a couple of D-15s not P-47Cs.
Most often the published speed is 490 mph.
Now I just read that was the hoped for speed.
The actual speed was a disappointing 414 mph!
It seems the super charger designed for it turned into a dead end so a 2nd choice was a turbo-supercharged installation that got those results and the expensive project was understandably dropped. Too bad. reply | | Ron, e-mail, 16.04.2010 23:59 Can you imagine 2,500 hp at 25,000'!!
No wonder the P-47H did 490 mph with the Chrysler V-16.
The P-63 could have made room for it better than most.
Luftwaffe bombers might fly above other Soviet interceptors, but not this one. reply | | Ron, e-mail, 16.04.2010 23:29 Want a true fighter-bomber /bomber destroyer, and leave the dogfights to the lightweights?
Forget about saving weight. Take a P-63 powered by an inverted Chrysler XIV-2220 V-16, swap out the Olds 37mm cannon for the NS-37 for triple the firepower. swap out the 4 Browning .50s for UB 12.7mm for a denser pattern, or 5 B-20s instead (maybe even put one in the tail as a stinger defense too). 3 bomb load or drop tanks. It would be like an Il-10 with more speed and endurance. reply | | Rusty Hatten, 01.04.2010 19:52 This aircraft is amazing and beautiful, I wish I had one (; reply | | Ron, e-mail, 29.03.2010 19:55 That's the spirit. Art you got that right, but remember the extra 1,000 hp too!
The P-47H was a razorback D from 1943. The Chrysler v-16 engine was slow in coming together. Too bad.
Meantime Allison put out 70,000 units in WW2. reply | | Art Deco, 28.03.2010 02:17 Recall that the chrysler engine was a yard longer and a thousand pounds heavier and then add the turbocharger plus inter and after-coolers and didn't fly until after VE Day. Apart from that, just as you say. reply | | Ron, e-mail, 28.03.2010 01:06 Recall the experimental Thunderbolt with the long pointy nose?
That was the 490 mph P-47H with the Chrysler XIV-2220 liquid cooled inverted-v engine. Imagine that long power plant in the P-63 where it could fit without looking so goofy. That was 1943. The 16 'hemi' cylinder motor could have put the Allison on the trailer, and perhaps reached production in the P-63. Maybe that would have given the Mustang a run for it's money. At the least, it would have given the Soviets an even better impression of American mettle. Just a thought. reply | | Ron, e-mail, 18.03.2010 00:45 To reduce the weight, what could be done?
With that engine behind the pilot, he doesn't need much armor.
drop the wing .50 cal. mgs and swap out the nose guns for more efficient Russian weapons.
Those are no-brainers. reply | | Aaron, e-mail, 03.09.2010 22:38 I have a real hard time believing the published figures of the P-63A having a 408-410mph. maximum speed and the P-63C with water injection as have a maximum speed of 410mph. also, especially at close to the same weights. I am only guessing here but I would say the 410 figure is probably at military power, not combat or war emergency power. Now that opens a can of worms. reply | | Ron, e-mail, 19.02.2010 08:20 The visiting Russian test pilot and engineer had the new P-63 nose guns moved forward at the Bell factory to help the c /g. They were also helpful in strengthening the fuselage to eliminate distortion from spin forces.
But their ideas for mounting ski landing gear didn't make it into production.
When I read of Pokryshkin's squadron of P-39s converting to P-63s by late 1944, I tend to believe it from what I heard about him. If you had his talents, would you stay with old P-39s while all these improved P-63s were being delivered?
I don't think the Germans that shot them down were misidentifying them just to endorse the rumors of Soviet pilots. When the Germans mention the loop antenna behind the cockpit, I think it was a P-63 they identified. They didn't sign the 1943 lend-lease agreement prohibiting P-63s from fighting in Europe (officially).
I can't believe more Russian Kobra ace leaders didn't do the same as Pokryshkin. Besides, I think it was more comfy than the Russian types. You could see through the clear glass, the radio and heater worked, and it packed plenty of ammo. It was not so limited by altitude like the P-39 and most Russian fighters. reply | |
| | Ron, e-mail, 09.02.2010 09:00 I like the fact that the P-63 was testing a teardrop canopy and a swept wing (I didn't care for the V tail though).
I also appreciate the injected engine and ventral fin that made it into production. I would like to have seen all of these improvements and more developed and fielded in a more timely manor.
Why did I say 'and more'?
I like the idea of the P-63B succeeding with the Merlin engine. If Packard couldn't spare any, Allison or someone else like Klimov or Mikulin could do the same as Packard and install them when they get uncrated off the ship in Russia. Why couldn't the stupid turbo be refined by Allison and added the the injected engine before all that. Inver the darn engine like a Daimler-Benz if you want better view over the sloped cowl and also put the guns under the nose to avoid the flash blinding the pilot especially at night.
More also means put the fuel and ammo close to the center of gravity and the pilot and engine on either end of that.
As ammo and fuel are lost the balance would remain: stall and spin trouble solved!
Am I carried away yet?
Put all B-20 cannons in the nose. More than 3 if you want - they're so light. They synchronize well too. Voila, harmonized ballistics!
Put an NS-37 cannon in the tail to discourage rear attackers. This also could deliver the unexpected parting shot when pulling out of a strafing run. The recoil would speed your climb, not stall the plane.
That would be a Bell Kobra fighter worthy of 1944-5. reply | | Ron, e-mail, 31.01.2010 08:00 At altitudes above 7,500 meters, the Kingcobra overtook the English Spitfire Mk. IX and Soviet Lavochkin La-7 in Russian tests. reply | | Ron, e-mail, 24.01.2010 08:25 Other 'unofficial' P-63 action ranged from Poland to Berlin. The 4 GvIAP for example, converted from 1944 to new P-63s. But officially these were 'P-39s' on paper.
By official agreement all P-63s were strictly to fight Japan in the East. One downed a Nakajima fighter (likely an Oscar) in August 1945 when Russians attacked to seize territory held by Japan. That would have been it for the P-63 but for the unofficial action in the stuggle to defeat Hitler with these 'P-39s' so called. Certainly it spices things up a bit, with high powered Soviet regunning for double the rate of fire and all. It was good enough to serve as late as the Korean War too. reply | | JOHN E. BOEING, e-mail, 08.09.2010 00:20 JACK BOEING, CAPTAIN, CLASS 43A, BLYTHEVILLE, ARK. WE WERE FLYING ACCEPTANCE CHECKS FOR THE RUSSIANS LEND-LEASE PROGRAM IN 1944 AND 45 IN FAIRBANKS, AK - THEY WERE GETTING P=39, P-63, A=20, B-25, C-47 AND AT=6'S, I ALSO HASD A CHANCE TO FLY A P38, BUT THE KINGCOBRA WAS MY FAVORITE, AND I THINK THE BEST FIGHTER WE PRODUCED..THE RUSSIANS SENT THEIR ACES TO FAIRBANKS FOR R & R AND THEY FLEW THE PLANES BACK TO RUSSIA. ONCE A WEEK, THEY HAD A PARTY TO WHICH WE WERE INVITED. MAN COULD THEY PUT AWAY THE VODKA reply | | John L. Fritz, e-mail, 06.10.2009 05:23 I worked at Bell from Nov 1945 to April 1959. I was an Project Engineer /Test Pilot anf flew one of two P-63s that had an extra cockpit behind the engine. I would love to see a picture of this plane. I engineered the modification of an F80 as a simulated Rascal Missile with cruciform fins at mid-wing spans. I remember the number being 484. It was the forerunner of six such aircraft used by an airforce training cadre. At 89 years of age I now live in Sebring, Florida-Jack Fritz reply | | Ronald, e-mail, 18.09.2009 07:07 Roll rate was 110 degrees /second @ 275 mph vs the P-39D which did 75 d /s @ 235 mph. The fighters that could do better could be counted on your fingers. Even the F4U-1D was edged out at 108 d /s @ 300 mph. What was the rate for the Bf 109G - 80 @ 200 mph (sans wing cannon gondolas)?
I'd like to read more about the Merlin plans for the P-63 too.
Anyway, it's good to know that the P-63 was utilized by the USSR not just against the Japanese in the end, but unofficially against the German wermacht beforehand (officially still P-39s). Many King Cobras had the new light weight B-20 cannon replace the slow U.S. 37 mm, and fast firing UBS 12.7 mm cowl guns. Just those 3 Russian guns put out 2.72 kg vs 2.77 kg for all 5 U.S. guns. The ballistics were a better match and the pattern of fire was more dense (40+ r /s vs 37 r /s), not to mention the weight savings without wing gun gandolas and the B-20 (lightest cannon in the world) replacing the much heavier Olds 37mm (one of the slowest). Even with original 5 guns the P-63 outclimbed the P-39 (the new motor gave the P-63 another 10,000' of combat altitude). With the King Cobra re-armed, the Luftwaffe faced a far more agile if not more leathal P-63 than expected. Oh I'm sorry, "P-39". The battle of Koenigsburg was one such highly suspected clandestine confrontation. It turned out badly for the Luftwaffe.
Also, get a load of that maximum range! On the Eastern front no less. If Bell addressed the weaknesses of the P-39, the USSR soon replaced the slowest cowl guns (5 r /s each) with some of the fastest (about 14 r /s each) and retired the (2 r /s) 37 mm M4 with poor ballistics, for a high velocity, rapid fire 20 mm cannon (13 r /s). A worthy dogfighter out of a heavier close-support fighter-bomber.
-Ron reply |
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