The Nakajima J5N1 Tenrai (Heavenly Thunder) was a design for a single-seat twin-engine interceptor that reached the prototype stage during 1944 but that didn't enter production.
The J5N1 was designed in response to an 18-Shi specification of 1943 for an interceptor with a top speed of 414mph at 19,685ft. Nakajima decided to base their new aircraft on the Nakajima J1N, a low-wing monoplane with a clean fuselage that had disappointed as a fighter when first tested in 1941, but that had entered production as a reconnaissance aircraft. In April 1943 production began of the J1N1-S night fighter, the most successful version of the design, so the concept had some validity.
The J5N1 was a mid-wing monoplane, with a all-round vision canopy for the pilot's cockpit, mounted above the leaded edge of the wings. It was armed with two 30mm and two 20mm cannon.
The J5N1 had a loaded weight of 16,094lb, only 650lb heavier than the J1N1-S. Despite this its two 1,990hp Nakajima Homare 21 radial engines still only gave it a top speed of 371mph it trials, well below the specified top speed.
Six prototypes were completed. The last two were converted to test the design out as a two-seat fighter, but neither version was judged to be good enough and the type didn't enter production.
Engine: Two Nakajima Homare 21 radial engines
Power: 1,990hp each
Span: 47ft 2 15/16in
Length: 37ft 7 3/16in
Loaded weight: 16,094lb
Max speed: 371mph
Armament: Two 20mm cannon and two 30mm cannon