Yokosuka P1Y Ginga Frances
The Yokosuka P1Y Ginga — Frances to the Allies — was a twin-engined land-based bomber designed by the Yokosuka Naval Air Technical Arsenal for the Imperial Japanese Navy and built mainly by Nakajima, with a night-fighter batch from Kawanishi. First flown in August 1943, it was fast and handled well, but its unreliable Homare engines and difficult maintenance delayed its entry into combat until the spring of 1945. Production totalled about 1,100 aircraft. A single P1Y1 survives, in the National Air and Space Museum's collection in the United States.
Why It Mattered
The P1Y Ginga, which the Allies called Frances, was designed at the Naval Arsenal at Yokosuka to a 1940 specification for a fast low-altitude bomber that could also dive-bomb and carry a torpedo. In the air it delivered on that promise: it was fast, handled well, and was popular with its pilots. On the ground it did not, because its untested engines dragged down its reliability and delayed its entry into combat until the spring of 1945. The Smithsonian's National Air and Space Museum judges the finished aircraft mediocre beside more successful twin-engined bombers such as the Mosquito and the B-25 Mitchell.
Design Notes
The design team, led by Tadanao Mitsuzi and Masao Yamana, produced a clean twin-engined aircraft with a narrow circular fuselage, tapered mid-mounted wings and a glazed nose. Power came from two Nakajima Homare eighteen-cylinder radial engines, a design still under development when it was chosen for the P1Y. A crew of three flew it. Defensive armament was light, two flexibly mounted machine guns, because speed was meant to be the aircraft's protection, and the airframe was almost entirely un-armoured apart from a plate of armour behind the pilot's head. The bomb bay took a torpedo carried partly recessed into it, or two 1,102-pound bombs, and fourteen fuel tanks in the wings gave the aircraft its long range.
Operational History
Work on a production line at Nakajima's Koizumi factory began in February 1943, before the prototype had flown; the prototype made its maiden flight that August. Production built up slowly while the reliability problems were worked on: forty-five aircraft were produced in 1943, and 453 had been completed before the Japanese Navy finally accepted the type for service in October 1944. The Ginga was finally ready to enter combat in the spring of 1945, when it could outrun most Allied fighters at low level, but it suffered from low serviceability levels that limited what its units could achieve. Two night-fighter versions were tried, the Nakajima-based P1Y1-S Byakko and Kawanishi's P1Y2-S Kyokko, which replaced the Homare engines with Mitsubishi Kasei radials and carried obliquely mounted cannon. At altitude the Kyokko performed poorly, and most of the batch ended up converted back into bombers. In the war's last months P1Ys were also used to carry out kamikaze attacks against American warships. Production ended with the war: History of War's accounting gives 1,098 aircraft in all, 996 of them built by Nakajima and 96 by Kawanishi, besides six prototypes.
Afterlife
Three P1Y1s were captured at the end of the war and sent to the United States. The Smithsonian's aircraft was flown and evaluated by guest pilots at Olmstead Field, Pennsylvania, from February to July 1946. The U.S. Air Force transferred it to the Smithsonian Institution in September 1948, and it remains in the National Air and Space Museum's collection, where the museum reports it is not on display. It spent the intervening decades in store, first at Park Ridge, Illinois, and later at Suitland, Maryland. It is recorded as the single P1Y1 preserved, at that museum.