Nakajima C6N Saiun
The Nakajima C6N was designed as the successor of the Aichi D4Y. The Saiun was a fast carrier-based, long-range reconnaissance airplane, almost immune to Allied interception. Airframe structure was very light, with six unprotected fuel tanks located inside the wings, features that made it very vulnerable to battle damage.With the same maximum speed than the Hellcat and 12,500 m of absolute ceiling, the Saiun could travel 3,000 nautical miles with a ventral fuel tank of 762 litres, eluding all Allied fighters except for the Mustang. The C6N was too valuable for the IJN intelligence services, for its ability to locate Allied fleets, and only intervened in the kamikaze offensive marginally.
The structural weakness of the aircraft did not allow the installation of a bomb under the fuselage and had to be renovated according to the existing plans for the future version of bombardment C6N1-Ko Mod.21. The wings were probably strengthened, eliminating the external tanks of 1,921 litres and installing one 800 kg bomb that was bolted under the centre section of the wing.
Two C6N were also modified as C6N1-S night fighters, with Type 5, a 30 mm cannon mounted in 30 degrees Schräge Musik configuration, installed behind the pilot.
In July-August of 1945 the two prototypes performed operational tests with the 302 Kokutai-3rd Hikotai based in Atsugi. The night of 1 August 1945 one of the airplanes intercepted a B-29, without shooting it down. The IJN concluded that the maximum speed and ceiling of the C6N1-S were insufficient to fight the B-29s.
Nakajima decided to improve the performances of the Saiun using a NK9K-2 Homare 24 Ru engine, with Hitachi 92 (Ru 212) turbocharger, driving a four-bladed, constant-speed, VDM C6P10 propeller. The prototype, known as C6N2 Model 12, proved capable of flying at 12,500 m, but its maximum speed was not considered enough.
The C6N3-KAI Model 22 was a night fighter project powered by a Mitsubishi Ha-43-11 radial engine, with Hitachi Model 10 turbocharger and two Type 99-2, 20 mm cannon mounted in 30-degree Schräge Musik configuration.
C6N1-S technical data
Wingspan: 12.5 m, length: 11.15 m, height: 3.96 m, wing area: 25.5 sq.m, max weight: 4,500 kg, estimated max speed: 600 kph, estimated service ceiling: 10,800 m.