Kawanishi KX-03

Kawanishi KX-03 Very-Heavy Flying Boat Project

By 1943, the military situation in the Pacific Ocean began to develop not in favor of the Japanese Empire. The Japanese transport fleet has become an easy target for allied ships and submarines. Considering the loss of aircraft carriers in 1942 during the Battle of Midway Atoll and the inability of Japanese industry to recover the losses in a short time, the transport convoys found themselves practically without protection from air strikes. The resulting situation jeopardized the supply of the numerous garrisons of the Japanese army on the islands of the Pacific Ocean. It also became impossible to transfer troops between the metropolis and theaters of operations. In connection with the inability to change the current situation, the Japanese authorities considered any unconventional technical solutions that could prevent the complete defeat of the army outside the metropolis. One of these solutions was the project of a giant flying boat, capable of solving the problem of supplying even a large garrison in one flight. At the end of 1943, the Kawanishi Aircraft Company was commissioned by the Imperial Japanese Navy to develop a 500-ton flying boat capable of supplying cargo to garrisons throughout the Pacific region. The project received the designation - "KX-03". To speed up the development, the serially produced and well-proven flying boat H8K "Emily" was taken as the basis for the aircraft design. In addition to size, the new project was supposed to have more advanced wing mechanization to ensure good takeoff and landing characteristics. Also, the engines were moved to the upper part of the wing and installed on pylons, which protected the propellers from water during takeoffs and landings in the open ocean. The aircraft was supposed to have a wingspan of 180m, a fuselage length of 162m. The height reached 35.5 m. The main problem for the designers was the choice of engines. The engine required in terms of power and fuel consumption was not available in Japan. It was decided to equip the project with twelve turboprop engines Rikugun Kokugijutsu Kenkyuuju (RKK) Ne 201, each of which was supposed to produce 1870 hp. Additionally, four Mitsubishi Ne 330 turbojet engines were to be used during takeoff and landing (licensed copy of German BMW engines) ... However, technical problems did not allow the creation of turboprop engines even by the end of the war. In addition, the general scarcity of resources in the blockade of Japan would certainly not have allowed the construction of such gigantic aircraft. In view of this, the KX-03 project was doomed from the very beginning of development and the aircraft, which could become the largest of all built in the world, remained one of the unrealized projects of the Second World War. .

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