Bell P-63 Kingcobra

https://en.wikipedia.org/wiki/Bell_P-63_Kingcobra

The Bell P-63 Kingcobra is an American fighter aircraft developed by Bell
Aircraft during World War II. Based on the preceding Bell 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 the United States Army Air Forces. However, it was deployed during World War
II by the Soviet Air Force, which had also been the most prolific user of the
P-39.

Design and development

XP-39E

While the P-39 had originally been introduced as an interceptor, later in its
development it was decided to reduce the cost and complexity of the engine by
removing the turbocharger. High-altitude performance suffered dramatically as a
result, and Bell proposed an experimental series to test out a variety of
solutions.

The resulting XP-39E featured two primary changes from the earlier P-39D from
which it was developed. One was a redesigned wing. The root airfoil, a NACA 0015
on other models of the P-39, was changed to a NACA 0018, to gain internal
volume. The other was a switch to the Continental I-1430 engine, which featured
an improved overall design developed from the hyper 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 was having continued development problems and could not be
delivered in time, so it was replaced by an Allison V-1710-47, similar to that
powering the P-39. Each prototypes 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, so it was not ordered into production.

XP-63

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
designation XP-63 and serials were 41-19511 and 41-19512. A third prototype was
also ordered, 42-78015, using the Packard V-1650, the U.S.-built version of the
Rolls-Royce Merlin engine.

The XP-87897 was larger in all dimensions than the Airacobra. The wing was
redesigned again, this time with new NACA laminar 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). 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-bladed propeller was also standardized. A persistent complaint against the
Airacobra was that its nose armament was not easily accessible for ground
maintenance, and in order to cure this problem, the XP-63 airframe was fitted
with larger cowling panels.

Swept-wing L-39

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. 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 reduced empennage effectiveness and moved the
center of lift aft. A lighter three-bladed propeller from a P-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 to NACA at Langley for wind tunnel
testing, where much valuable data were gathered. L-39-2 also served as a testbed
for the Bell X-2 40-degree wing design.

Role
Fighter aircraft

National origin
United States

Manufacturer
Bell Aircraft

First flight
7 December 1942

Introduction
October 1943

Status
Retired

Primary users
United States Army Air Forces
Soviet Air Force
French Air Force

Produced
1943–1945

Number built
3,303

Unit cost

US$65,914 (1945)


Developed from
Bell P-39 Airacobra

Operational service

Soviet Union

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.

Air Transport Command ferry pilots, including U.S. women pilots of the WASP
program, picked up the planes at the Bell factory at Niagara Falls, New York,
and flew them to Great Falls, Montana and then onward via the Northwest Staging
Route through Canada to Alaska, where Soviet ferry pilots, many of them women,
would take delivery of the aircraft at Nome and fly them to the Soviet Union
over the Bering Strait via the Alaska-Siberia route (ALSIB). A total of 2,397
(2,672, according to other sources) such aircraft were delivered to USSR, out of
the overall 3,303 production aircraft (72.6%).

By a 1943 agreement, P-63s were disallowed for Soviet use against Germany and
were supposed to be concentrated in the Soviet Far East for an eventual attack
on Japan. However, there are many unconfirmed reports from both the Soviet and
German side that P-63s did indeed see service against the Luftwaffe. Most
notably, one of Pokryshkin's pilots reports in his memoirs published in the
1990s that the entire 4th Guards Fighter Aviation Regiment (4 GvIAP) was
secretly converted to P-63s in 1944, while officially still flying P-39s. One
account states they were in action at Königsberg, in Poland and in the final
assault on Berlin. There are German reports of P-63s shot down by both fighters
and flak. Hans Rudel, highest decorated pilot of the Luftwaffe, states in his
memoirs, "We often encounter American types of aircraft, especially Airacobras,
Kingcobras and Bostons." This was in the Courland front towards the end of the
war. Nevertheless, all Soviet records show nothing but P-39s used against
Germany.

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. A common Western misconception is
that the Bell fighters were used as ground attack aircraft.

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 for publication, I have had the opportunity to peruse several
Russian-language sources. Mentions of the employment of this aircraft in the
ground-attack role are so rare in these sources 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 that describe this role. The specific Russian-Language
term most often used to describe the mission and role of the Airacobra-equipped
Red Air Force fighter units, in this manuscript and other Russian-language
sources, is prikrytiye sukhoputnykh voysk [coverage of ground forces]...
Frequent misunderstanding in this country as to the combat role of the P-39 in
Soviet use is based in part on imprecise translation of the term prikrytiye
sukhoputnykh voysk to 'ground support'. The latter term as it is understood by
many Western military historians and readers, 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.

—?Soviet Army Colonel Dmitry Loza, Commanding the Red Army's Sherman Tanks: The
World War II Memoirs of Hero of the Soviet Union, Dmitriy Loza, Loza and
Gebhardt 2002, pp. 15–16.

Postwar air racers

Numerous surplus P-63s ended up on the air racing circuit in the immediate
postwar era. Charles Tucker purchased two P-63s from the disposal facility at
Kingman, Arizona just after the war. He entered one of them, the Tucker Special
as Race 28 with the name Flying Red Horse emblazoned on the nose (civilian
register N62995) in the 1946 Thompson Trophy race. He had clipped the wing 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
1946 Bendix cross country race. It was initially fitted with two wingtip drop
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 chrome spinner. Later sold
to a European pilot, this P-63 was destroyed in a fatal accident in 1990 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.

Specifications (P-63A)

General characteristics
Crew: 1
Length: 32 ft 8 in (9.96 m)
Wingspan: 38 ft 4 in (11.68 m)
Height: 12 ft 7 in (3.84 m)
Wing area: 248 sq ft (23.0 m2)
Airfoil: root: NACA 66-116; tip: NACA 66-216
Empty weight: 6,800 lb (3,084 kg)
Gross weight: 8,800 lb (3,992 kg)
Max takeoff weight: 10,700 lb (4,853 kg)
Powerplant: 1 × Allison V-1710-117 V-12 liquid-cooled piston engine, 1,800 hp
(1,300 kW) driving propeller through extension shaft and gearbox
Propellers: 4-bladed constant-speed propeller

Performance
Maximum speed: 410 mph (660 km/h, 360 kn) at 25,000 ft (7,620 m)
Range: 450 mi (720 km, 390 nmi)
Ferry range: 2,200 mi (3,500 km, 1,900 nmi)
Service ceiling: 43,000 ft (13,000 m)
Rate of climb: 2,500 ft/min (13 m/s)
Wing loading: 35.48 lb/sq ft (173.2 kg/m2)

Armament

Guns: ** 1× 37 mm M4 cannon firing through the propeller hub. From the A-9
version of the aircraft onward, the M4 gun was replaced with the slightly
improved M10 37 mm cannon, which used a disintegrating link ammunition belt,
increasing the ammo capacity to 58 rounds; the M10 also had a slightly higher
rate of fire. 4× 0.50 in (12.7mm) M2 Browning machine guns (two synchronized in
the nose, two in the wings)

Bombs: 1,500 lb (680 kg) bomb load on wing and fuselage




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