The Aichi S1A Denko (Bolt of Light) was a Japanesenight fighter, intended to replace the Nakajima J1N1-SGekkou (Allied code name Irving). It was to be, like the Gekkou, equipped with radar to counter the B-29 air raids over the Japan. Development time increased while trying to overcome design shortcomings, such as the insufficient power of the Navy's requested Nakajima Homare engines, resulting in no aircraft being completed before the war ended.
Crescent with special equipment, full-service weight easily exceed ten thousand kg mark. Whether the oxygen injection means, the turbocharger is still remote rotary turret can not use a lot of problems. Navy electro-optical properties not found in the machine to make a preliminary test standards, then terminated to increase the testing machine, only manufactured two test machines used for research and test flights. (Incidentally questions, the Navy may wait until the completion of the two test machines test flight, planned in the No. 3 and No. 4 test machine installed Mitsubishi HI MK9A Ru or MK10A Ru engine)
Tonankai earthquake occurred in December 1944, and the trial as a factory badly damaged, the various factory evacuation of four, much backward making progress. 1945 June 9 Aichi Kokuki KK and Aichi Tokei Denki Seizo Co., Ltd air strikes, will be scheduled in August of the same year flight test of the No. 1 Prototypes blew up; No. 2 Prototypes evacuation to Gifu large Sadakazu factory assembled, but on July 9 with the same 1 Hao The machine is also subject to air strikes and burned. To date, the unprecedented overweight a giant fighter development stillborn Japan's naval history.