The twin-engine combat platform proved popular with the forces of the Japanese Empire during World War 2 (1939-1945) - they offered capable bomb loads, strong performance, and the operational ranges needed to cover the vast reaches of the Pacific. One mid-war twin-engine bomber development became the Yokosuka P1Y "Ginga" (meaning "Galaxy") which was developed for the Imperial Japanese Navy (IJN) but intended for service from established land bases. Production reached 1,102 units before war's end. The Allies codenamed the bomber "Frances".
The Yokosuka Naval Air Technical Arsenal pushed for a new modern combining the operational range, firepower, and performance of the best platforms then available to the IJN. In additional to conventional level bombing, it was thought to include a capability for dive bombing and torpedo bombing to make for a more multi-faceted battlefield performer. Engineers elected for a conventional monoplane design form incorporating the two engines at each wing leading edge. The nose section of the aircraft was glazed for good vision out-of-the-cockpit and for bombing. The wing mainplanes were mid-mounted appendages and the tail given a traditional single-rudder form. A "tail-dragger" undercarriage was used. The operating crew would number three. Dimensions included a length of 49 feet, a wingspan of 65.5 feet and a height of 14 feet. Empty weight was 16,000lb against a Maximum Take-Off Weight (MTOW) of 29,765lb.
The engines were 2 x Nakajima NK9C "Homare 12" series 18-cylinder radial piston engines of 1,825 horsepower each. Performance specifications included a maximum speed of 340 miles per hour, a cruising speed of 230 miles per hour, a range out to 3,340 miles, and a service ceiling up to 30,840 feet.
Beyond the internal bombload of 2,205lb (or 1 x 1,800lb torpedo), the aircraft typically carried defensive armament in the form of 1 x 20mm Type 99 cannon in the nose and 1 x 13mm Type 2 heavy machine gun facing aft on a trainable mounting).
A first-flight of a P1Y prototype occurred during August 1943 and this led to a contract order for 1,002 aircraft which came from Nakajima factories. Twelve total prototypes were eventually constructed testing and mainly carried the Homare 11 series radial. Production yielded variants from the original P1Y1 with Homare 11 or Homare 12 engines to the thirty P1Y1 ground attack forms (these fitted 20 x 20mm Type 99 cannons to specifically target American B-29s on the ground). A non-flying ground replica for decoy purposes was also built under the "MXY10" designator. Production peaked in 1944 with 620 examples of all variants delivered and a further 434 followed during the first half of 1945.
Introduction of the P1Y was during October 1944 and the type saw combat service until the end of the war in August of 1945. By this time, the Japanese situation had deteriorated enough to showcase the P1Y bombers as kamikaze weapons against Allied warships. This proved the case during the Okinawa assault that helped pave the way for the Japanese surrender. At the end of the war, at least three P1Y examples were delivered to the United States for testing.
One notable offshoot of the P1Y program became the P1Y2 "Kyokko" ("Aurora") which was a night-fighter / night-intruder version of the original. Kawanishi handled manufacture of 96 of this aircraft which carried Mitsubishi Kasei engines (due to the growing scarcity of the Homare engines) and were fitted with radar kits. Armament included an oblique-firing system which allowed for attacking bombers from their more vulnerable bellies. However, this design failed to produce the needed performance to assail enemy Boeing B-29 Superfortresses and were therefore reconfigured to their traditional bomber roles before the end.
Over twenty IJN squadrons fielded the P1Y including the 302nd Kokutai which became the sole night-fighter group.
Status Retired, Out-of-Service
Production 1,102 Units
Yokosuka Naval Air Technical Arsenal / Nakajima / Kawanishi - Imperial Japan
- Ground Attack
49.21 ft (15 m)
65.62 ft (20 m)
14.11 ft (4.3 m)
16,017 lb (7,265 kg)
29,762 lb (13,500 kg)
(Showcased weight values pertain to the Yokosuka P1Y1a production model)
2 x Nakajima NK9C Homare 12 18-cylinder radial piston engines developing 1,825 horsepower each driving three-bladed propeller units.
342 mph (550 kph; 297 kts)
30,840 feet (9,400 m; 5.84 miles)
3,337 miles (5,370 km; 2,900 nm)
(Showcased performance values pertain to the Yokosuka P1Y1a production model; Compare this aircraft entry against any other in our database)
1 x 20mm Type 99 cannon in nose position.
1 x 13mm Type 2 heavy machine gun in rear-facing trainable position.
Up to 2.205lb of conventional drop stores OR 1 x 1,800lb torpedo.
(Showcased armament details pertain to the Yokosuka P1Y1a production model)
P1Y1 "Ginga" - Base Series Designation; medium bomber form.
P1Y1a - Nakajima Homare 12 engines; 1 x 13mm machine gun in aft-facing position.
P1Y1b - Developed from P1Y1a; Nakajima Homare 12 engines; 2 x 13mm machine guns in aft-facing position.
P1Y1c - Developed from P1Y1b; Nakajima Homare 12 engines; 1 x 13mm defensive machine gun; single example completed.
P1Y1 Model 11 - Night-fighter development based on P1Y1; 2 x 20mm Type 99 cannons.
P1Y1-S - Night-fighter development; 4 x 20mm cannons in two obliquely-angled positions, one fitted fore and the other aft of cockpit; 1 x 13mm machine gun in aft position for defense.
P1Y1 Attacker - Ground attack model; 20 x 20mm Type 99 cannons in ventral bay; 30 examples completed.
P1Y2-S "Kyokko" - Night-fighter variant; 96 examples built from the P1Y1.
P1Y2 - Developed from P1Y2-S nigth-fighter; Mitsubishi Kasei 25 engines.
P1Y2a - Developed from P1Y1a; Mitsubishi Kasei 25 engines.
P1Y2b - Developed from P1Y1b; Mitsubishi Kasei 25 engines.
P1Y2c - Developed from P1Y1c; Mitsubishi Kasei 25 engines.
P1Y3 - Developed from P1Y1; Nakajima Homare 21 engines.
P1Y4 - Developed from P1Y1; Nakajima Homare 23 engines
P1Y5 - Developed from P1Y1; Mitsubishi Ha-43 engines
P1Y6 - Developed from P1Y2; Mitsubishi Kasai 25 engines
Model 33 - Long-range bomber variant; 4-person crew and bombload of 3,000kg; not pursued.
"Tenga" - Proposed jet-powered bomber form of 1945
MXY10 - Decoy bomber; non-flying
Values are derrived from a variety of categories related to the design, overall function, and historical influence of this aircraft in aviation history.
The overall rating takes into account over 60 individual factors related to this aircraft entry. The rating is out of a possible 100.
Relative Maximum Speed
This entry's maximum listed speed (342mph).
Graph average of 300 miles-per-hour.
Yokosuka P1Y1a operational range when compared to distances between major cities.
Aviation Era Span
Showcasing era cross-over of this aircraft design.
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