P-63 Kingcobra: post-WWII service

A successor to the P-39 Airacobra, the Bell P-63 Kingcobra never saw combat in American colors but was heavily exported via Lend-Lease during WWII, and was used on three continents after the conflict.

(P-63s of three of the four air forces which operated the type.) (photo from Russian magazine World Aviation #19)

basic characteristics

The prototype P-63 first flew on 7 December 1942, the one-year anniversary of the Pearl Harbor attack. The single-seat P-63 was 33′ long with a 38′ wingspan. It was powered by an Allison V-1710 liquid-cooled engine with a two-stage turbocharger. The ceiling was 43,000′ and the average combat radius was 450 NM.

(Cockpit of a Kingcobra. The “standard” gunsight was the N-9, but as most were built for Lend-Lease, production bottlenecks of gunsights did not halt airframe completions and other types such as the N-3C seen here were readily substituted during WWII.)

Other than being larger and more sleek than the P-39, the P-63 shared it’s general shape. Improvements were the restoration of the turbocharger which had been deleted from the Airacobra, new laminar flow wings, a new tail for better stability, and a high-performance A64 11’7″ 4-bladed steel propeller. Except for the rudder, all of the P-39’s fabric surfaces were replaced by metal on the P-63.

(French air force Kingcobra during the Indochina War.)

A trait carried over from the P-39 to the P-63 was the unique automobile-style cockpit doors. To make the cockpit as compact and streamlined as possible, Bell positioned the cockpit controls in such a way that it would have been difficult for a pilot wearing a parachute to bail out the normal method. The doors could either be opened or jettisoned in an emergency.

(A WWII mechanic’s training aid showing the interrupter gear and one of the AN/M2s.)

(The removable underwing .50cal machine gun pods on an American P-63.)

The main armament was a pair of AN/M2 .50cal machine guns in the nose, firing through the propeller via an interrupter gear, each with 200 rounds. Bell also developed a “tack-on” pod for the Browning M2 .50cal. One pod could be mounted under each wing.

(The size of the 37mm rounds compared to the 50BMG cartridges ahead of them.)

The most unique weapon was the M4 37mm gun firing out of the spinner. Designed by Colt but manufactured by Oldsmobile, the M4 had a muzzle velocity of 2,000fps and a 130rpm rate of fire (only 30 rounds were carried). A hydraulic piston counteracted it’s substantial recoil. Three types of ammunition were available; the general-purpose M54, the training M55/56, and the M80 armor-piercing round. The M80 had a hefty 1½ lb bullet which could penetrate 1″ of tank armor at 500 yards. A single hit of any 37mm ammunition type would probably down all but the toughest warplanes of WWII. The effective range was 2 miles. The .50cal and 37mm rounds had greatly different ballistic arcs and typically were not fired simultaneously.

(French P-63C after WWII with drop tanks and machine gun pods fitted.)

The Kingcobra was not really intended as a bomb-delivery mount but 250 lb or 500 lb bombs could be carried on the wing pylons or centerline. Alternatively 75 gallon drop tanks could be carried, and the older 64 gallon type of the P-39 was compatible as well. A special conformal low-drag tank could be fitted to the centerline mount, further increasing the P-63’s range.

P-63A: The first version had a total build of 1,725 with production ending in December 1944. It used the Allison V-1710-95 engine. The vast bulk of these went to the USSR. There was also a planned P-63B to be powered by a Packard V-1650, the USA’s license-built Rolls-Royce Merlin. The Army cancelled this to preserve those engines for P-51 Mustangs.

(A US Army Air Corps P-63A in early 1946, several months after Japan’s surrender. Most of the A model were already out of American use by then.)

P-63C: A total of 1,227 P-63Cs were built, with most going to the USSR and some to France. Deliveries began in January 1945 and ran until the end of WWII when the contract was cancelled. It used the Allison V-1710-117 engine and had a strake under rear fuselage to improve spin recovery characteristics. The “big gun” was changed to the Oldsmobile M10, the same as the M4 but with a higher rate of fire.

(P-63C of the French fighter group II/6 “Normandie-Niemen” after WWII. The bar on the sides of the French roundel was not uncommon on Lend-Leased planes. French pilots called this marking “grosse oreilles” (big ears) and it gradually was disused throughout the late 1940s.)

P-63D: Only one prototype was built, which crashed resulting in the design’s cancellation.

(The doomed YP-63D prototype. It omitted the “car doors” with the airscoop repositioned to let the canopy slide back.)

P-63E: The final production version, entering service in the late summer of 1945. It incorporated all improvements of all previous versions. Of the 2,943 ordered, only 13 had been delivered before the end of WWII and the immediate cancellation of the contract.

(A lone P-63E sits in front of a forest of P-40 Warhawks at the US government’s Walnut Ridge, AR disposal airbase in 1947.)

P-63F: Only two P-63Fs were built. This version was specifically to counter Luftwaffe fighters, and when Germany surrendered in May 1945, the entire project was immediately cancelled as existing fighters were superior to anything Japan could develop before the planned final invasion of the home islands.

(One of the two YP-63F prototypes in early 1945.)

American use

No Kingcobra ever saw combat with an American unit. The vast bulk of production was Lend-Leased; and what remained was held for training or reserve. The most memorable contribution in American service was the “Pinball” manned live-fire target project. These “Pinballs” (the name painted on the first prototype) were one of the most amazing stories of WWII.

Early in WWII it was considered desirable to have a manned target for defensive bomber gunners to train against. Key to this was development of a frangible .30-06 Springfield round, which fired a bullet made of bakelite (plastic) and brittle lead alloy.

Contrary to most accounts today, this .30-06 ammo wasn’t developed exclusively for the Pinball effort, but rather to go in rifles of watchstanders at fuel refineries and other places where it was desirable for bullets to not penetrate walls or ricochet. In any case, it allowed the idea of a manned live-fire target to come to fruition.

Obviously, even with frangible bullets, the target would have to be heavily armored. A-20 Havoc bombers were proposed but rejected as too easy of a target. It was suggested that a turbocharged P-63 Kingcobra, stripped of all equipment but burdened with the armor, would end up having similar traits to a Messerschmitt Bf-109. It was approved.

One hundred P-63As were converted to the RP-63 model, along with two hundred P-63Cs. All guns, combat equipment, and anything unnecessary for basic flight was removed. A total of 2,164 lbs of armor was applied all over the airframe, mostly aluminum but steel over the exhaust and airscoop. The propeller blades were wider. The earliest models had a big red lightbulb in the spinner which lit when the plane was struck (hence the “pinball” name), most RP-63s however had smaller shatterproof red lights set into the fuselage and upper wings. Internally, a network of microphones tied into an analog counter recorded the number of hits and where they occurred.

Pinballs served as targets for the US Army’s Flexible Gunnery School. This training was done at Buckingham Army Airfield, FL, and served to train the waist, chin, ball, and tail gunners of American bomber crews. After ground instruction, pupils advanced to air-to-air firing, first at towed target sleeves and finally at the Pinballs.

(Before shooting from aircraft at the Pinballs, future gunners practiced on the ground vs clay pigeons. Remington Model 11 shotguns were cosmetically modified to resemble a machine gun, and trainees shot from moving trucks to simulate the difficulty.)

Even with frangible ammunition, there was obviously still danger involved. In particular, when RP-63s peeled off to present their belly to the gunners, their small radiator slats could be struck by bullet fragments. This was not sufficient to down the plane but would result in an overheated engine and forced landing. More worrisome was normal ammunition accidentally getting mixed in with frangible rounds, which seriously damaged several RP-63s.

(RP-63G with the airscoop retracted. The black discs helped make the lights stand out.)

The RP-63G Pinball was the last Kingcobra version of any type. These 30 planes were post-WWII rebuilds of unused P-63C airframes. A more powerful engine was used, and the airscoop could be completely retracted inside the fuselage. They served from 1946 until the termination of the Pinball project.

After WWII

From a technical perspective, the Kingcobra was highly rated by the US Army Air Corps in WWII. From a practical perspective, it was “in the wrong place at the wrong time” and had no future. After Japan’s surrender, it was decided that the P-40 Warhawk would be withdrawn immediately, and the P-38 Lightning and P-47 Thunderbolt no later than 1949, leaving only the P-51 Mustang as a long-term piston-engined fighter as jets entered service. The Kingcobra simply had no niche to fill.

(P-63 Kingcobra acting as chase plane for a P-59 Airacomet, the USA’s first jet fighter.)

(P-63 Kingcobra at Wright Field (today Wright-Patterson AFB), OH shortly after the end of WWII. The ski kit was being shown as part of an open house on the base for nearby civilians. This P-63 was already disarmed.)

Despite the money put into the Pinball project, it was slow to get going and only in full swing for the last five months of WWII. After WWII, cuts to the Army budget resulted in the Flexible Gunnery School closing on 1 October 1945. There was limited need for it in the postwar military anyways. The B-17 Flying Fortress, B-24 Liberator, B-26 Marauder, and B-32 Dominator were all being withdrawn from service. The standard bomber going forward would be the B-29 Superfortress, which (with the exception of the tail gun) had an automated gunfire control system. The first jet bomber, the B-45 Tornado, had nothing but a tail gun position, which was semi-automated.

(QF-63s at a US Air Force base in the late 1940s.)

In September 1947, remaining Pinballs were redesignated QF-63 by the newly independent US Air Force. They were assigned to a subunit of Strategic Air Command, to train gunners on the now rapidly-shrinking number of planes with manual or semi-automated defensive guns.

Even this limited effort was beyond the need or budget of the US Air Force, and the Pinball program was terminated at the end of 1948. For the planes that remained, the Air Force proposed to convert them into unmanned targets, however Congress did not fund the idea and they were used as test planes then scrapped.

(One of the former Pinball planes after all the target equipment had been removed, being used as a research plane.)

During WWII, a lone Kingcobra had been completed with a vee-type tail. The results were not encouraging and nothing more was done with it. With the war’s end, the test pilot Robert Stanley (the first American to fly a jet) felt that this style would be optimal for high-performance fighters of the future, and lobbied the military to once again investigate it. In 1948, a surplus Kingcobra was modified with an exotic 45° butterfly tail, and redesignated XF-63N by the US Air Force.

(The XF-63N test plane.)

Tests showed the tail gave slightly increased maneuverability but poor crosswind effects during takeoff and landing. The project ended and the plane was scrapped.

The most extreme experimental model was the Bell L-39, of which a pair were completed on the US Navy’s behalf in 1946.  The purpose was to explore low-speed characteristics of swept wings. The US Navy was at the time concerned how swept-wing jets would behave on the final approach to an aircraft carrier’s deck. The Kingcobra airframes were grotesquely modified with swept wings, a ventral fin, a new rear fuselage, and an instrumentation package behind the pilot.

(One of the two Bell L-39 test planes of the US Navy.)

(The final configuration of the wing with a controllable 80% leading edge and wingtip pitot rod.)

The landing gear in the wings could not retract, which was fine with the Navy as the project was for low-speed trials anyways.

(The array of fabric tufts allowed airflow over the wings to be photographed.)

As the tests went on, it was decided that the high-performance propeller was causing problems and a 3-bladed propeller from the P-39 was substituted. The wings were modified several times during the tests, which ran until mid-1949. This odd program was actually highly valuable and proved the feasibility of swept-wing planes aboard carriers.

(Bell L-39 in flight, showing the fixed main landing gear.)

The final Kingcobra modification was a pair of  P-63Es which transferred back to Bell from the US Army after WWII. They were given civilian registrations by the FAA and used in the Regulus project, which resulted in the Cold War-era RGM-15 Regulus cruise missile.

(One of the two Regulus planes at Bell’s company airport.)

The two Kingcobras were modified by Bell with a second crew position in the fuselage. All weapons were removed, and instrumentation added. The purpose was to test remote control of aircraft, specifically the upcoming Regulus missile. The nuclear-tipped Regulus was obviously a one-way affair, but during it’s design, Bell incorporated rudimentary landing gear so that an expensive missile would not have to be expended for every single flight test.

(The optical lens being tested was housed in an underwing pod. The antenna atop the wing is a TV transmitter.)

(One of the Regulus-modified Kingcobras with a P-51 Mustang chase plane.)

(A prototype Regulus missile comes in for a remote-control landing.)

Bell cleverly did the modifications so that, despite the drastic appearance, they could be “undone” after the project. One was indeed undone and sold to Honduras as a regular fighter.

French use

Late in WWII, a contract was signed with the Free French air force for 300 P-63C Kingcobras. This was quickly trimmed to 250, of which only 114 had been delivered by the time of Japan’s surrender. The rest of the contract was voided as the USA itself had cancelled all Kingcobra production after V-J Day and it would be unprofitable to fill the remainder of the French order.

(French P-63C)

It had initially been envisioned that the reforming French air force would use their Kingcobras to defend liberated port cities, specifically Le Havre, against V-1 buzz bombs. There is nothing to indicate this was ever done. The first French unit to convert to P-63s was the fighter group II/9 “Auvergne” which was based in France’s African colonies.

After WWII

Three French fighter groups had fully converted to Kingcobras by the time of the contract cancellation, and more planes were still in the pipeline. During the summer of 1945, a Kingcobra detachment of the group I/5 “Vendee” was briefly assigned to the French occupation zone in Germany. Most remained in France’s north African possessions.

(Kingcobra of the fighter group I/5 “Vendee” based in the French occupation zone of Germany in 1945.) (artwork via Wings Palette website)

This itself was starting to become a political irritation to the USA. The order had been subsidized by American tax dollars, with the intention that the P-63s would fight the Luftwaffe, not sit out the war then enforce overseas colonialism.

By the end of 1947, six French air force groups were operating Kingcobras: I/5 “Vendee”, I/9 “Limousin”, II/5 “Ile-de-France”, II/6 “Normandie-Niemen”, II/9 “Auvergne”, and III/6 “Roussilon”. These were by no means second-rate units; for example “Normandie-Niemen” was considered the best group in the French air force.

(Insignia of III/6 “Roussilon” on a P-63 Kingcobra after WWII.)

Indochina war

As France’s problems in it’s Indochina colonies picked up in 1946 and 1947, more air power was requested there to fight the communist insurgency. In 1948, the French floated plans to station P-47 Thunderbolts in Indochina.

The USA’s attitude towards the Indochina war changed only gradually. In the mid-1940s, opinions in Congress were still against the French colonial war. It was relayed to Paris that any reassignment of P-47s from defending Europe to crushing a colonial rebellion would result in curtailment of American military aid. Instead, France sent the P-63s, which were already based largely outside of the French homeland. The USA was not keen on this either but did not stop it.

(P-63 Kingcobras of II/6 “Normandie-Niemen” after WWII.)

The first Kingcobras arrived in French Indochina in April 1949. They replaced WWII-era Spitfires donated by the RAF, which themselves had replaced Ki-43 “Oscar”s left behind by the Japanese in 1945.

(French P-63 being serviced in Indochina.)

Always one, often two, sometimes more fighter groups flew P-63s in Indochina. A total of five different groups operated in Indochina, rarely all at the same time however.

(P-63 Kingcobras of  II/6 “Normandie-Niemen” during the Indochina War at Tan Son Nhut airbase, a facility which would expand and become more famous during the Vietnam War.)

As the Viet Minh had no aircraft, French P-63s were used exclusively for ground attack missions, either with WWII-surplus 250 lbs bombs or (more effectively) finless napalm bombs.

(Arming a Kingcobra’s .50cal guns prior to a mission against the Viet Minh.)

Meanwhile the Viet Minh, which had in 1946 been limited to WWII machine guns left behind by the Japanese, by 1949 had begun to receive 12.7mm and 37mm anti-aircraft guns from China and the USSR.  French Kingcobra losses in Indochina were extremely high (as much as a 25% total annual average attrition rate) with 30 planes being lost between 1949-1951. Obviously none were downed in aerial combat, the most common cause being write-offs due to AA gunfire damage. Others were lost due to landing accidents, which is not surprising as many of the airbases in Indochina were dirt runways left behind by the Japanese or unimproved facilities built by France before WWII.

(French P-63 takes off for a reconnaissance mission during the Indochina War.)

(A French Kingcobra which suffered a landing accident in Indochina. Many of the airbases were still dirt or grass.)

Throughout 1950 the USA had a change of heart and began to actively support the French effort against the communists. In early 1951 the USA agreed to directly supply warplanes direct to Indochina, and the first shipments of WWII-surplus fighters arrived in March 1951. The detachment from I/5 “Vendee” dispersed it’s planes to other groups at the end of 1950, and it’s personnel returned to France. The group I/9 “Limousin” switched to F6F Hellcats in March 1951, and II/9 “Auvergne” to F8F Bearcats at the same time. The group II/5 “Ile-de-France” dispersed it’s remaining Kingcobras to other Indochina units at the end of 1950, as it’s personnel returned to France to retrain on Vampire jets. The last two operational Kingcobra units in Indochina were II/6 “Normandie-Niemen” which switched to F6F Hellcats in March-April 1951, and III/6 “Roussilon” which changed over to the F8F Bearcat at the same time. The final French combat missions in Kingcobras were flown during the last week of April 1951. By September 1951, there were no P-63 in inventory in Indochina.

(P-63s of I/9 “Limousin” in Indochina.)

(The mount of the Squadron Commander in Indochina.)

(Nose-on view of a French P-63 in Indochina.)

None of the Kingcobras sent to Indochina ever returned, as it was uneconomical to ship them as sea cargo. As Bearcats and Hellcats arrived, P-63s were flown one at a time to a collection airfield at Bach Mai where they were scrapped. During the early stages of the Vietnam War, American GIs found a pair of P-63 carcasses still there, which was probably quite perplexing at the time.

There were still a small number of French Kingcobras which had not been sent to Indochina. These served with a unit at Sidi-Ahmed in French North Africa (today Tunisia) until 1956. A handful of disarmed P-63s were assigned to the Center d’Essais en Vol (Flight Test Center) at Brétigny in France, and one of them was still in use until 1962. By then, this lone Kingcobra was the last P-63 still in any sort of military use anywhere on Earth.

(P-63 Kingcobra of I/9 “Limousin” at Sidi Ahmed airbase in French North Africa after the Indochina War. This airbase protected the French naval base at Bizerte, which was at that time one of France’s largest overseas naval bases.) (artwork by Pierre-Andre Tilley)

Honduran use

Honduras was the only Kingcobra operator not to receive the type during WWII. In October 1948, three WWII-surplus P-63s were delivered by the USA, one of which crashed on it’s first flight in Honduran markings. A replacement was delivered in July 1949, along with another which had been one of the Regulus planes at Bell. The latter was rarely flown and kept as a backup.

The Honduran Kingcobras were numbered in the 400 series, and operated in a joint squadron with seven WWII-surplus P-38 Lightnings delivered at the same time.

The four P-63s, and occasionally the fifth, were kept in active use as fighters and ground attack planes until October 1960 when they were finally retired. Honduras was by then the last country on Earth operating the P-63 as a frontline fighter. Several were sold back to the USA, another was installed as a monument outside the officer’s club at Tegucigalpa airbase.

During the 1990s this displayed P-63 was allowed to deteriorate. It was later moved to a small aviation museum, and in 2013-2014 the plane was restored.

Soviet use

Of the 3,303 Kingcobras built, 2,421 (roughly 73%) were delivered to the USSR during WWII. Another 23 either crashed in transit or were withheld in the USA after Japan’s surrender. The role of the P-63 in the Soviet military is often incorrectly described as either an interceptor or ground attack plane. The Soviets actually tasked their Kingcobras with a mission called PSV (prikritiy’y sukhoputnykh voysk, literally ‘defense of land forces’). This tactic didn’t really have a direct equivalent in the American military, and called for P-63s to screen advancing ground units from enemy dive bombers and reconnaissance planes, while leaving air superiority to other fighters, battlefield support to the Il-2, and tactical bombing missions to twin-engine types.

(USSR-marked P-63s over Niagara Falls during a test flight from Bell’s factory airfield near Buffalo, NY during WWII.)

(Soviet P-63s had two unique features; a directional ring radio antenna and this nub on the spinner. The cold in Siberia would often cause battery failure and this attachment allowed an army truck to ground-start the engine.)

(Soviet P-63A in Alaska during it’s WWII transit flight.)

A frustration to the Soviets were the limits of the Oldsmobile gun. The USA refused to release the M80 AP round for Lend-Lease, and in shipments of regular M54 rounds, there was often an absurdly high amount of unwanted M55/56 training rounds.

(Not all of the Lend-Leased Kingcobras were delivered. After Japan’s surrender in 1945, further deliveries were halted by the Truman administration. This P-39E had already been painted in Soviet markings by Bell but instead was flown to Davis-Monthan AFB, AZ where it was stored until scrapping in the early 1950s.)

Per a 1943 agreement with the USA, Soviet P-63s were mandated to be based east of the Ural mountains and reserved only for combat against Japan, which was to commence no more than 3 months after Germany was defeated. None the less, it appears that Stalin ignored the directive. One regiment of P-63s was used for point defense of Moscow in 1945.

(Soviet P-63C just prior to the end of WWII in Europe.)

A handful of Kingcobras may have been mixed into a P-39 Airacobra unit during the East Prussia offensive. This is not unreasonable as the two planes looked similar and the P-63 wouldn’t have stuck out. In May 1945, immediately after Germany’s surrender, a Kingcobra detachment from the 1st Guards Air Division was announced as operational at Neuhausen Ost, a Luftwaffe airbase in the part of northern East Prussia which the USSR annexed. Kingcobras flew out of this base for only a year or two before the airfield was decommissioned.

(The Third Reich-era former control tower at Neuhausen Ost in Russia’s Kaliningrad exclave, still standing in the early 1990s. The base’s hangars and runways had been demolished in the late 1940s after the P-63s departed.)

Likewise, it’s possible that some Soviet Kingcobras took part in the May 1945 Berlin offensive that ended WWII in Europe. In the 1950s, West German pilots who had served in the WWII Luftwaffe felt certain they had encountered the type at the end of WWII. Irregardless of appearance, a fighter pilot in the air would notice the difference of the P-63’s turbocharged engine compared to the P-39. No existing Russian records indicate that the P-63 ever fought over Berlin.

(Soviet Kingcobra in the markings used during the August 1945 Manchurian offensive against Japan.) (artwork via Wings Palette website)

For certain the P-63 took part in the USSR’s brief but intense attack on Japan in August 1945. A massive flight of fifty P-63s out of Dalnerechensk, USSR was used to attack the Japanese-manned Hutou South fortification on the Manchukuo border. The 190th and 245th Fighter Divisions of the Trans-Baikal Front both flew P-63s and supported five Soviet army groups (along with practically the entire Mongol military) which advanced eastward out of Mongolia. Japanese air opposition in this area was minimal. However it was here that the Kingcobra scored it’s first (official) Soviet victory, against a Ki-43 “Oscar”.

(Soviet P-63C returning from a mission against the Japanese.)

The 888th and 410th Fighter Regiments took part in both the Manchuria operation, and the attack on South Sakhalin and the amphibious assault on the Kuril Islands. Here the P-63s were assigned to cover the invasion fleet, which was actually a ramshackle assortment of converted torpedo boats and freighters. Several Japanese planes were claimed as shot down by P-63s in this area. For the most part these claims were withdrawn after WWII. One Japanese aircraft that slipped through was responsible for the minesweeper KT-152, the only Soviet warship sunk by a kamikaze during WWII.

Thirty more P-63s were assigned to the Soviet navy’s Pacific fleet but saw no combat.

After WWII

The USA ceased deliveries of the Kingcobra immediately after WWII’s end. The last one, which had been in transit when the war ended, arrived in the Soviet Union on 29 September 1945.

The USSR had no intention of either returning it’s P-63s to the USA nor phasing them out. For one, it was simply a good fighter compared to the rest of the 1945 Soviet air force. It was clearly superior in every regard to the MiG-3 and LaGG-3. At most flight profiles it was superior to the Yak-3 and Yak-7. It was comparable to the La-5 in all criteria except rate-of-climb. Below 22,500′, the P-63’s performance was inferior to the La-7 but above the planes were comparable. The only Soviet propeller fighter clearly superior to the P-63 in every regard was the La-11, the USSR’s last piston-engined fighter which didn’t enter service until after WWII.

Another advantage was the Kingcobra’s tricycle landing gear. Home-grown Soviet fighters of WWII were all tail-draggers, but the first post-WWII Soviet jets, the Yak-15 and MiG-9, were tricycles. The Kingcobra made an ideal choice for transitioning pilots to this arrangement.

(Soviet 63UTI conversion trainer.)

A two-seat conversion trainer of the P-39 Airacobra, the TP-39, had been built during WWII with some delivered to the USSR. Bell had proposed a similar model of the P-63 but the USA did not order it. To keep it’s Kingcobras flying, the Soviets converted several into a two-seat model called the 63UTI with a second cockpit replacing the weapons chassis forward. These ugly planes were very useful and actually safer than a regular P-63, as the centre-of-gravity shift reduced the tendency to enter a spin.

After WWII, with Lend-Lease ended, the Soviets modified a P-39 with USSR-made weapons and engine. Some thought was given to doing this to the P-63s but it was not proceeded with. However, as no more American ordnance would ever be coming, the Kingcobra’s bomb pylons were modified to accept the FAB-100M 226 lbs bomb.

(FAB-100M general-purpose bomb)

(Soviet P-63 after the end of WWII. The dot over the exhaust was possibly a photo calibration marking for some sort of tests.)

Spare parts were another concern. After 1948, a speed governor was installed on Soviet P-63s to limit engine wear.

NATO intelligence was aware that the Lend-Leased P-63s were still in use, and in 1949 the ASCC reporting code-name “Fred” was assigned to the type. Most Kingcobras remained along the USSR’s Pacific coast. There, they provided a good counter to American warplanes in occupied Japan. This was not uniformly adhered to, for example in the late 1940s two fighter regiments of Soviet naval aviation flew Kingcobras for defense of Leningrad in the Baltic, and another P-63 detachment was assigned air defense of the Black Sea.

the Korean War

Today, now six decades past the Korean War which began in 1950, military historians are often perplexed as to why Stalin did not forward the WWII-vintage Kingcobras to the North Koreans or Chinese. Many were already in the area, and compared to the garbage the North Koreans flew in the war’s first weeks, they would have been highly competitive. As the USSR never paid for them, the financial cost was none, and they were nearing obsolescence anyways.

(Soviet P-63 “Fred” as the type was painted during the Korean War era.) (artwork from Avions magazine)

There was an incident that may have influenced Stalin’s thinking. On 4 September 1950, a WWII Lend-Leased Douglas DB-7 (which NATO had assigned the reporting name “Box”) was shot down over the Pacific by F4U Corsairs off USS Valley Forge (CV-45). In the USA, it was feared that the incident might antagonize the USSR as the attack was difficult to explain or justify. Meanwhile in Moscow,  there was concern that the presence of a Soviet bomber of American origin needlessly aggravated the American pilots. Both concerns were out of proportion and the incident faded.

None the less, as Soviet aid to China and North Korea picked up, there may have been legitimate apprehension in the Kremlin about forwarding P-63s; in that encountering enemy Kingcobras which the USA’s taxpayers had funded five years previous would further enrage the American public.

More pragmatic (and much more more likely the real reason) was the fact that the USA was rushing F-80 Shooting Stars and F-86 Sabres to South Korea. Sending P-63s up against these jets was not likely to end well, and the North Korean and Chinese bullpen of trained fighter pilots was being rapidly depleted.

The P-63 Kingcobra did play a role in one incident during the Korean War. On 8 October 1950, a pair of US Air Force F-80 Shooting Stars of the 49th Fighter Group strafed Sukhaya Rechka airbase, fairly deep (about 60 NM) inside the USSR’s Pacific Maritime Province, near the junction of the Soviet, Chinese, and North Korean borders. This airbase belonged to the Soviet navy but at the time was being loaned to the air force’s 821st Fighter Regiment, a Kingcobra unit.

(Location of Sukhaya Rechka airbase) (map via Google)

The F-80s approached Sukhaya Rechka from the north, hugging a hill, and made two strafing runs on the 821st’s 1st Squadron, which was nominally the peacetime ready-reaction unit of the regiment, and as such, had it’s Kingcobras full of aviation fuel. One P-63 was destroyed, three heavily damaged, and another three lightly damaged. A Soviet veteran present that day said many years later that the loss was more substantial, and more than a quarter of the unit’s planes were damaged.

There were no personnel losses as all the pilots were in their barracks. The commander of the 821st did not scramble the remaining Kingcobras as there was little to no chance of propeller fighters taking off, climbing, and chasing down faster jets.

The USA stated that the attack was accidental. The 49th Fighter Group was at the time, operating out of the K-2 airfield near Daegu. The Air Force stated that the F-80s had been assigned to strafe Chonjin airbase in North Korea, about 40 miles away from the Soviet border and 68 miles southwest of Sukhaya Rechka. The mission originally started with three Shooting Stars, of which one (the lead) aborted due to engine problems. The remaining two said they became disoriented when climbing above a cloud bank in strong winds.

According to the US Air Force’s account, as the F-80 pilots made their approach against Sukhaya Rechka, they immediately realized it was not Chonjin but thought it maybe was Najin, a different North Korean airbase. They also recognized the parked planes as Kingcobras, which was confusing, but attacked anyways. All three air forces in the region (China, USSR, North Korea) used a variation of a red star emblem and the North Koreans were flying a bizarre assortment of aircraft, including WWII Japanese types, so it wasn’t unthinkable that they had obtained P-63s somehow.

The official Soviet account said the F-80s penetrated the USSR’s airspace over distant Lake Khanka on the Manchurian border, which would have been a remarkable flight path, requiring the American fighters to cross all of North Korea, then about 100 miles of Chinese airspace, then another 80 miles of Soviet airspace in the opposite direction. This is highly unlikely.

The USSR claimed to have shot down one of the attacking F-80s, a claim later retracted. Less the one which blew up, all of the damaged Kingcobras were later repaired. The Soviets filed a diplomatic protest and the USA accepted responsibility and promised that the pilots would be court-martialed. A court-martial was indeed later held, with the pilots being quietly acquitted.

The political ramifications did not go away. In the USA there was already increasing animosity between Gen. Douglas MacArthur and the Truman administration, which increasingly saw MacArthur as “going rogue” as to his oversight of the Korean War. Fanciful rumors circulated that the mission had been a “staged accident” on MacArthur’s behalf, to illustrate to the Soviets that Vladivostok was within reach should they choose to intervene in the war. For certain, the Kingcobra incident wasn’t a main cause of President Truman relieving MacArthur six months later, but it didn’t help.

In 1990, one of the pilots gave an interview and stated that the Air Force’s 1950 explanation was accurate, and the attack was indeed an accident, not any intrigue by MacArthur or deliberate provocation.

Staring in September 1950, Soviet P-63 Kingcobra units along the Pacific were kept at “Alert-1”, the highest level, meaning the pilots had to sit in or alongside the planes at all times. None the less, they were never committed to combat. Throughout the final months of 1950 and early 1951, American pilots repeatedly claimed to have encountered Kingcobras near the USSR/North Korea border, but there is no evidence of this happening.

(Soviet fighter pilot Vladimir Zabelin just prior to the Korean War. A biplane pilot during WWII, he flew Kingcobras throughout the late 1940s until the P-63’s retirement in 1951. He then moved on to MiG-15 and MiG-17 jets before retiring in 1971.)

In January 1951, fighter units transitioned from the P-63 to Yak-17 or MiG-15 jets. That was the end of the Kingcobra’s run in the USSR. For some years, MiG-15 squadrons typically retained one or two P-63s “off the books” as a training aid, as if the flaps were not extended, the Kingcobra’s landing run was very similar to the MiG-15’s.

Legacy

In the USA, France, and Honduras; the Kingcobra is largely forgotten today. It was as the US Army had stated in 1945, a good plane which was simply in the wrong place at the wrong time.

In the USSR, the role Lend-Leased weapons played in WWII was often swept under the rug during the Cold War. Because of it’s popularity with pilots, the P-63 was often displayed more than other America-made equipment. In the 1950s and 1960s, it was fondly recalled by a generation of Soviet fighter pilots as it was usually the last piston-engined type they flew before advancing to jets.

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