| P-63 Kingcobra | |
|---|---|
.jpg) | |
| General information | |
| Type | Fighter aircraft |
| National origin | United States |
| Manufacturer | Bell Aircraft |
| Status | Retired |
| Primary users | United States Army Air Forces |
| Number built | 3,303 |
| History | |
| Manufactured | 1943–1945 |
| Introduction date | October 1943 |
| First flight | 7 December 1942 |
| Developed from | Bell P-39 Airacobra |
| Variants | Bell L-39 |
TheBell P-63 Kingcobra is an Americanfighter aircraft that was developed byBell Aircraft duringWorld War II. Based on the precedingBell P-39 Airacobra, the P-63's design incorporated suggestions from P-39 pilots and was superior to its predecessor in virtually all respects. The P-63 was not accepted for combat use by theUnited States Army Air Forces. However, it was used during World War II by theSoviet Air Force,[1] which had also been the most prolific user of the P-39.
While the P-39 had been introduced as aninterceptor, later in its development it was decided to reduce the cost and complexity of the engine by removing theturbocharger. High-altitude performance suffered dramatically as a result, and Bell proposed an experimental series to test out a variety of solutions.
The resultingXP-39E featured two primary changes from the earlier P-39D from which it was developed. One was a redesigned wing. The root airfoil, aNACA 0015 on other models of the P-39, was changed to a NACA 0018, to gain internal volume.[2] The other was a switch to theContinental I-1430 engine, which featured an improved overall design developed from thehyper engine efforts, as well as an improved supercharger.
Three prototypes were ordered in April 1941 with serials 41-19501, 41-19502 and 42-7164. The I-1430 had continued development problems and could not be delivered in time, so it was replaced by anAllison V-1710-47, similar to that powering the P-39. Each prototype tested different wing and tail configurations: 41-19501 had a rounded vertical tail, but squared-off tailplane tips; 41-19502, a squared-off fin and rudder and large wing fillets; and 42-7164 had all its flight surfaces squared off. The XP-39E proved faster than standard Airacobra, reaching a maximum speed of 386 mph (621 km/h) at 21,680 ft (6,610 m) during tests. However, the XP-39E was considered inferior to the stock P-39 Airacobra in all other respects,[citation needed] so it was not ordered into production.
Although the XP-39E proved disappointing, the USAAF was nevertheless interested in an even larger aircraft based on the same basic layout. Even before its first flight, the USAAF placed an order on 27 June 1941 for two prototypes of an enlarged version powered by the same V-1710-47. The new design was given the designationXP-63 and serials were 41-19511 and 41-19512. A third prototype was also ordered, 42-78015, using thePackard V-1650, the U.S.-built version of theRolls-Royce Merlin engine.
The XP-63 was larger in all dimensions than the Airacobra. The wing was redesigned again, this time with new NACAlaminar flow airfoils, 66(215)-116 a=0.6 at the root and a NACA 66(215)-216 a=0.6 at the tip. The wing taper ratio was approximately 2:1, span was 38 ft 4 in (11.68 m), and wing area was 248 sq ft (23.0 m2).[3] The engine was fitted with a second remotely mounted supercharger, supplementing the normal single-stage supercharger. At higher altitudes, when additional boost was required, a hydraulic clutch would engage the second supercharger, adding 10,000 ft (3,000 m) to the service ceiling. A larger four-bladedpropeller was also standardized. A persistent complaint about the Airacobra was that its nose armament was not easily accessible for ground maintenance; to cure this problem the XP-63 airframe was fitted with largercowling panels.
In September 1942, even before the prototype flew, the USAAF ordered it into production as theP-63A (Model 33).[4] The P-63A's armament was to be the same as the current P-39Q, a single 37 mm (1.46 in)M4 cannon firing through the propeller hub, two synchronized.50 in (12.7 mm)machine guns in the cowl, and two .50 in (12.7 mm) machine guns in underwing gondolas.
The first prototype, 41-19511, flew for the first time on 7 December 1942. It was destroyed on 28 January 1943 when its landing gear failed to extend. The second prototype, 41-19512, followed on 5 February 1943. It, too, was destroyed, this time due to an engine failure. The Merlin-engined 42-78015 (as Merlins were primarily needed for theP-51 Mustang) was delivered with another Allison instead, a -93, which had a war emergency rating of 1,500 hp (1,100 kW) at sea level, making this prototype one of the fastest Kingcobras built, attaining 421 mph (678 km/h) at 24,100 ft (7,300 m).
Deliveries of production P-63As began in October 1943. The USAAF concluded the Kingcobra was inferior to the Mustang, and declined to order larger quantities. American allies, particularly theSoviet Union, had a great need for fighter aircraft, however, and the Soviets were already the largest users of the Airacobra. Therefore, the Kingcobra was ordered into production to be delivered underLend-Lease. In February 1944, the Soviet government sent a highly experienced test pilot, Andrey G. Kochetkov, and an aviation engineer, Fyodor P. Suprun, to the Bell factories to participate in the development of the first production variant, the P-63A. Initially ignored by Bell engineers, Kochetkov's expert testing of the machine'sspin characteristics (which led to airframe buckling) eventually led to a significant Soviet role in the development. Afterflat spin recovery proved impossible, and upon Kochetkov's making a final recommendation that pilots should bail out upon entering such a spin, he received a commendation from theIrving Parachute Company. The Kingcobra's maximum aftCG was moved forward to facilitate recovery from spins.[5]
P-63A-8, SN269261, was extensively tested atTsAGI in what was then the world's largestwind tunnel. Soviet input was significant. With the Soviet Union being the largest buyer of the aircraft, Bell was quick to implement their suggestions. Most of the changes in the A sub-variants were a direct result of Soviet input, e.g. increased pilot armor and fuselagehardpoint on the A-5, underwing hardpoints and extra fuel tanks on the A-6, etc. The Soviet Union even experimented with ski landing gear for the P-63A-6, but this never reached production. Most significantly, Soviet input resulted in moving the main cannon forward, favorably changing the center of gravity, and increasing its ammunition load from 30 to 58 rounds for the A-9 variant. The P-63 had an impressive roll rate, besting the US P-47, P-40, and P-51—and the Japanese Navy'sKawanishi N1K2Shiden-Kai fighter—with a rate of 110° per second at 275 mph (443 km/h).[6]
After the war, two war surplus P-63Cs were modified by Bell under Navy contract for flight testing of low-speed and stall characteristics of high-speed wing designs. The aircraft received new wings with adjustable leading edge slats, trailing edge flaps and a pronounced sweep of 35 degrees. The wings had no wheel wells; only the nose gear was retractable.[7] L-39-1 first flew 23 April 1946, demonstrating a need for extra tail surface and rear fuselage length to balance the aircraft in flight—the wing repositioning reducedempennage effectiveness and moved the center of lift aft. A lighter three-bladed propeller from aP-39Q-10 was mounted and the necessary changes to the empennage were made. L-39-2 incorporated these adjustments from the start. L-39-1 later went toNACA atLangley for wind tunnel testing, where much valuable data was gathered.[8] L-39-2 also served as a testbed for theBell X-2 40-degree wing design.[9]
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One of the enduring myths regarding the P-39/P-63 in Soviet use is that because of its armament, in particular the 37mm nose cannon, it excelled as a ground-attack aircraft, even a "tank buster". In translating and preparing this manuscript ... I have had the opportunity to peruse several Russian-language sources. Mentions of ... this aircraft in the ground-attack role are so rare ... as to be exceptional... The "tank buster" myth has its roots in the misunderstanding of the general wartime role of the Red Air Force and in the imprecise translation of specific Russian-Language terms... The specific ... term most often used to describe the ... role of the Airacobra-equipped Red Air Force fighter units ... isprikrytiye sukhoputnykh voysk [coverage of ground forces]... Frequent misunderstanding ... as to the combat role of the P-39 in Soviet use is based in part on imprecise translation of the termprikrytiye sukhoputnykh voysk to "ground support". The latter term ... suggests the attacking of ground targets in support of ground troops, also called "close air support". Did a Soviet Airacobra pilot ever strafe a German tank? Undoubtedly. But this was never a primary mission or strong suit for this aircraft.
In general, official Soviet histories played down the role of Lend-Lease supplied aircraft in favor of local designs, but it is known that the P-63 was a successful fighter aircraft in Soviet service. There has been a common misconception that both the P-39 and P-63 were used mainly as ground attack aircraft. As historian James F. Gebhardt pointed out in a translation of one Soviet memoir (see quote box, right), this was likely a result of mistranslations of Soviet military terminology. The role known asprikrytiye sukhoputnykh voysk literally "coverage of ground forces" was essentially the same asclose air support in other air forces.
The first version to be supplied in quantity to the Soviet Union was the P-63A-7 with a higher vertical tail, and reinforced wings and fuselage. The fuselage proved to need strengthening; consequently, in October 1944 a reinforcement kit for operational P-63s was developed.[10]
Air Transport Command ferry pilots, including pilots of theWASP program, picked up the planes at the Bell factory atNiagara Falls, New York, and flew them toGreat Falls, Montana and then onward via theNorthwest Staging Route through Canada toAlaska, where Soviet ferry pilots, many of them also women, would take delivery of the aircraft atNome[11] and fly them to the Soviet Union over theBering Strait via the Alaska-Siberia route (ALSIB). A total of 2,397 (2,672, according to other sources)[12] aircraft were delivered to the USSR, 72.6% of the overall 3,303 production aircraft.[13]
P-63s were allegedly supplied to the Soviet Union only on the condition that they be reserved forfuture operations against Japanese forces, under a 1943 agreement with the US.[citation needed] As such, all P-63 units were supposedly based in theSoviet Far East. However, according to anecdotal accounts, from both Soviet and German sources, some P-63s saw service against theLuftwaffe. A Soviet pilot who served underA. I. Pokryshkin, reported that the entire4th Guards Fighter Aviation Regiment (4 GvIAP) secretly converted to P-63s in 1944.[citation needed] Stuka pilotHans Rudel stated in his memoirs that, over theCourland pocket, in early 1945, he and other German pilots had often encountered "American types of aircraft, especially Airacobras, Kingcobras andBostons"..[14] One account states they were in action atKönigsberg, in Poland and in thefinal assault on Berlin.[citation needed] There are German reports of P-63s shot down by both fighters andflak.[citation needed] Nevertheless, official Soviet records do not record P-63s being used in Europe.[citation needed]
The Soviets developed successful group aerial fighting tactics for the Bell fighters and scored a surprising number of aerial victories over a variety of German aircraft. Low ceilings, short missions, good radios, a sealed and warm cockpit and ruggedness contributed to their effectiveness. To pilots who had once flown the trickyPolikarpov I-16, the aerodynamic quirks of the mid-engined aircraft were unimportant. In the Far East, P-63 and P-39 aircraft were used in theSoviet invasion ofManchukuo and northern Korea. In the Pacific theatre, the Kingcobras flew escort, close air support and ground attack missions. The Soviet P-63s achieved their first air victory on 15 August 1945, whenLejtenant I. F. Miroshnichenko from 17th IAP/190 IAD, shot down aNakajima Ki-43HayabusaIJAAS fighter off the coast of North Korea.[12]
Sufficient aircraft continued in use after World War II for them to be given thewestern reporting name of "Fred". By 9 May 1945, operational units still had 1,148 Kingcobras on strength.[12] On 8 October 1950, two USAFF-80Cs from the49th Fighter Group breached the USSR's border and attacked Sukhaya Rechka airfield 19 mi (31 km) south-west ofVladivostok and 62 mi (100 km) from the Soviet-Korean border,[15] making two strafing runs before returning to their home base. Soviet sources say the attack was intentional, but the pilots claimed it was a result of a navigational error.[16] The airfield belonged to theAir Forces of the Pacific Fleet (VVS TOF), but it was occupied by the821st Fighter Aviation Regiment (821 IAP) of the190th Fighter Aviation Division (190 IAD). Mostly aircraft of the 1st Squadron of 821 IAP were hit with 12 P-63s damaged, one P-63 burned to the ground while the other damaged aircraft were able to be repaired. There were no human losses.[17]
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In 1945, 114 later models were delivered to theFrench Air Force (Armée de l'Air), but they arrived too late to see service in World War II. They did see service during theFirst Indochina War before being replaced in 1951.
Initially, the French Kingcobras were deployed to Algeria. Fighter squadron (Groupe de Chasse) 2/6 "Travail", previously equipped with P-39 Airacobras, received their Kingcobras on 18 July atCasablanca; the pilots were surprised by the higher landing speed of their new aircraft.[18] The Kingcobra were scrambled to Indochina when the insurgency broke. Only 60 Kingcobras were operational in Indochina in January 1950, mainly because the Americans refused to supply spare parts.[19] Starting in February 1951, the squadrons equipped with Kingcobra started to receiveGrumman F8F Bearcats as replacements. Most Kingcobras were mothballed by July. The last flight of a Kingcobra in Indochina took place on 6 September 1951.[20]
Its main use in American service was the unusual one of a manned flying target for gunnery practice.[21] The aircraft was generally painted bright orange to increase its visibility. All armament and the regular armor was removed from these RP-63 aircraft, and over a ton of armored sheet metal was applied to the aircraft. This was fitted with sensors that would detect hits, and these hits were signaled by illuminating a light in the propeller hub where the cannon would have been. This earned the aircraft the unofficial nickname ofPinball.[21] Specialfrangible rounds made of alead/Bakelite combination were developed that would disintegrate upon impact.[21] These were known as the "Cartridge, Caliber .30, Frangible, Ball, M22". In 1990, veteran Pinball pilot, Ivan L. Hickman, wroteOperation Pinball about the training flights.[22]
British engineers, like the Americans, had a growing interest during World War II in the application of laminar flow airfoils. In an effort to learn more about the practical application of laminar flow airfoils, in 1945 theRoyal Aircraft Establishment (RAE) undertook a flight test program with one of the two P-63As that the United Kingdom had received.[23][page needed] The aircraft was equipped with a wake rake array mounted outboard, behind the wing, to allow the momentum deficit, and thus section drag, to be measured.
The RAE first tested it in an "as delivered" configuration. The wing airfoil was designed to support laminar flow to 60% of chord. In the "as delivered" configuration, a profile drag was measured which was representative of the wing section with boundary layer transition at the leading edge (0% laminar flow). Reducing the surface roughness reduced the drag at low lift coefficients to a level representative of laminar flow to 35% of chord.[23] Measurements were made of the surface waviness. This showed peak wave amplitudes, above the mean, of approximately 0.011 inches (0.28 mm) over a two-inch (5.1 cm) span. The standard waviness criteria[24] shows the critical wave height to be 0.0053 inches (0.13 mm) for this application.[25] To reduce the waviness, RAE personnel stripped the wing to bare metal. The wing was then sprayed with two coats of primer paint and a coat of paint type filler. After the paint was dry, it was sanded in a chordwise direction, using sanding blocks whose curvature matched the local surface curvature. This was repeated several times. Surface waviness was then measured and found to be no more than 0.005 inches (0.13 mm). In flight, this configuration was found to have a profile drag representative of boundary layer transition at 60% of chord.[23] This gave researchers an idea of what level of wing surface quality was required to actually get the benefits of laminar flow airfoils.
Numerous surplus P-63s ended up on theair racing circuit in the immediate postwar era. Charles Tucker purchased two P-63s from the disposal facility atKingman, Arizona just after the war. He entered one of them, theTucker Special as Race 28 with the nameFlying Red Horse emblazoned on the nose (civilian registerN62995) in the 1946Thompson Trophy race. He had clipped the wings by 12 ft 9 in (3.89 m) in an attempt to improve its speed, reducing the span to 25 ft 9 in (7.85 m). The second one (44-4126 (XN63231 Race 30)) was intended for the 1946Bendix cross country race. It was initially fitted with two wingtipdrop tanks. In 1947, the drop tanks were removed and the wings were clipped to 28 ft 6 in (8.69 m).
Two other significant racers were flown later.Tipsy Miss, John Sandberg's clipped-wingtip P-63 unlimited racer, was identified as "Race 28," and painted in bright orange, white and black race numbers with a chromespinner. Later sold to a European pilot, this P-63 was destroyed in a fatal accident in 1990[26][27]Crazy Horse Campgrounds was the most radically modified P-63 Kingcobra ever. Larry Haven's "Race 90" clipped-wing unlimited racer had a tiny bubble canopy installed; it appeared in all silver (unpolished aluminum) finish with a white rudder and black trim. The aircraft later crashed into the ocean on a test flight in 1972.[28]
On 3 June 2001, a Bell P-63A crashed during theBiggin Hill International Air Fair in London, England, killing the pilot. The pilot was at the top of a vertical maneuver when he appeared to have lost control of the plane. This was the second plane accident in 24 hours at Biggin Hill following the crash of ade Havilland Vampire that killed both pilots.[45][46][47]
On 12 November 2022, P-63F 43-11719, owned by theCommemorative Air Force and piloted by Craig Hutain,collided withBoeing B-17G Flying FortressTexas Raiders at an airshow in Dallas, Texas. 43-11719 was one of only five remaining airworthy P-63s and was the only surviving P-63F of the two that were built.[48] Six people were killed, one in the P-63 and five in the B-17.[49]
Data fromJane's Fighting Aircraft of World War II.[50]
General characteristics
Performance
Armament
Related development
Aircraft of comparable role, configuration, and era
Related lists
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