Just after the advent of aircraft and submarines during World War I, the combined procedure among these two tools had been considered by many nations. But wound up being just the Imperial Japanese Navy that may put it to practical usage. At outbreak the Pacific War, numerous large-sized submarines associated with the Imperial Japanese Navy was loaded with catapult and small observation-type aircraft made to strike harbors and also to bomb the U.S. mainland. Acknowledging the success of previous assaults by the Imperial Japanese Navy, it made a decision to prepare surprise attack missions toward Panama canal by unique submarineborne aircraft at the start of 1942. The airplane was the Aichi M6A1 Seiran, created entirely with this particular one exceptional goal. It was in-may 1942 when the Aichi Aircraft company received specifications to create and create a special attack bomber. Initially, the employment of the then new Suisei bomber with customizations was in fact proposed, even so the discussion was discovered not practical because of the trouble to own interchangeability of major assemblies. On November 1943, first prototype made its maiden trip. Undergoing a few improvements, the Aichi Aircraft Company received an order for limited manufacturing from Navy in 1944. The engine finished up being a 12-cylinder liquid-cooled Atsuta 32, which was based on the German Daimler-Benz DB603. A 12.7mm, type-2 flex mounted device tool finished up being equipped on back, and a torpedo or a 250kg/800kg bomb could be carried. The Seiran is always to be carried by the I-400 program submarine inside hanger pipeline of 4.2m in diameter and 30.5m long. The hanger pipe ended up being capable of holding three Seirans. They certainly were conserved on catapult launching vehicles with armaments for fast ejection after surfacing. To cope with the location limitation, the Seiran was built to save your self area by folding the wings. The wings was in fact pivoted concerning the main spar where it joined up with the fuselage. By rotating the best edge downward, the wing could lie straight back flat despite the sides regarding the fuselage. The external portions of each and every stabilizer and elevator hinged on 90cm through the fuselage centerline and folded downward. Vertical approval had been acquired by folding the tip associated with fin to your right. 28 Seirans including a Nanzan, its ground-take-off-and-landing equivalent, had been manufactured in total by 1945, and submersible providers for them, the I-400 and I-401, had been finished almost at the same time. Getting the target changed from Panama Canal on U.S. Navy aircraft carriers staged at Ulithi Atoll because of the improvement in priorities the war demanded, the very first Submarine Flotilla including the I-400 and I-401 with three Seirans each departed Japan on 23 July 1945 with regards to their 1st and final mission. On 15 August, the flagship I-401 monitored a radio message from headquarters, informing them of Japan's surrender even though the flotilla ended up being bought to return towards nearest slot in Japan. For this reason the chance to show the Seiran's worth was missed forever.
