Nakajima J5N1 Tenrai (Heavenly Thunder)

Twin-engine, conventional layout with tailwheel-type landing gear. Parts only.

Nakajima conceived the Tenrai as a high-performance interceptor but the experimental fighter never met its expected performance and was not produced. The Japanese Navy assigned Nakajima the task of developing a single-seat, twin-engine aircraft to meet requirements set fourth early in1943. The design goals called for a top speed of 667 kph at 6,000 m (414 mph at 19,685 ft). The navy wanted this fighter to carry heavy guns so Nakajima installed two 30 mm and two 20 mm cannons. Katsuji Nakamura and Kazuo Ohno, the same team that designed the Nakajima J1N1 Gekko IRVING (see NASM collection), also laid out the Tenrai and both designs had numerous features in common.

Nakajima built only six prototypes (two two-seat aircraft) before the navy decided to end the program. NASM has the last remaining Tenrai prototype, but it is incomplete. Only the aft fuselage and fin, a left wing panel, and some of the fuel cells remain. The origin of the Museum's Tenrai parts is unknown. They probably came to the U. S. for evaluation aboard aircraft carriers, part of a group of 145 Japanese planes brought here for technical evaluation. Whether the interceptor was actually flown and why it was reduced to pieces remains a mystery.

Nakajima designed the Tenrai as a high-performance interceptor but the experimental fighter never met its expected performance and the firm did not build any production airplanes. The Japanese Navy instructed Nakajima to develop a single-seat, twin-engine aircraft to meet requirements set fourth early in 1943. The design goals called for a top speed of 667 kph at 6,000 m (414 mph at 19,685 ft). The navy wanted this fighter to carry heavy guns, so Nakajima installed two 30 mm and two 20 mm cannons. Katsuji Nakamura and Kazuo Ohno, the same team that designed the Nakajima J1N1 Gekko IRVING (see NASM collection), also laid out the Tenrai. Both designs had numerous common features. One visible difference was the smaller, all-round-vision canopy that enclosed a Tenrai pilot.

In July 1944, the first prototype was ready. Flight trials were disappointing and the fighter managed a maximum speed of only 597 kph (371 mph), well below navy specifications. Nakajima built only six prototypes (two were two-seat variants) before the program was cancelled.

NASM has the last remaining Tenrai prototype, but it is incomplete. Only the aft fuselage and fin, a left wing panel, and some of the fuel cells remain. The origin of the Museum's Tenrai parts is unknown. They probably came to the U. S. for evaluation aboard aircraft carriers, part of a group of 145 Japanese planes brought here by the United States Navy for technical evaluation. Whether anyone actually flew the interceptor and why it was reduced to pieces remains a mystery.