The Ishikawajima Ne-20 (Japanese: 石川島 ネ-20) was Japan's first turbojet engine. It was developed during World War II in parallel with the nation's first military jet, the Nakajima Kikka.
The decision to manufacture this engine came about because of the unsuitability of two earlier powerplants selected for the Kikka, the Tsu-11 and the Ne-12. The Ne-20 was made possible by Imperial Japanese Navy engineer Eichi Iwaya obtaining photographs and a single cut-away drawing of the German BMW 003 engine.
In July 1944, the Japanese military attache stationed in Germany returned home with a few photocopies, including a cross-section of the BMW 109-003 turbojet and some general materials concerning the Me-262 fighter and Me-163 interceptor. The important data such as the schematic drawings, however, were being transported by a submarine which was sunk.
When details, breaf as they were, of the BMW 19-003 reached Japan, the Army and Navy held a joint conference at which it was decided that a Japanese version of this turbojet held more promise in the short term than Japanese work still in its early stage. This resulted in 4 projects.
The Ne-20 was the navy project headed by Osamu Nagano assisted by Tanegashima at Kugisho in Yokosuka. The Ne-20 was to become the Japan's most successul turbojet and the other 3 projects were not fully developped in the time available.
It was the Tokyo Ishikawajima Shipyards that was chosen by the navy to be in charge of trial-manufacture and mass production of jet engines (for commercial use also).
Koichi Ichida, chief of the Business Planning Department, National Aerospace Development Agency, says that reciprocal engines were the main power during the war, but Ishikawajima made steam turbine engines for ships.
It was close to a jet engine because of the rotating mechanism. That is why turbo engines were researched for automobile engines as well.
Only a small number of these engines, perhaps fifty, were produced before the end of the war. Two of them were used to power the Kikka on its only flight on August 7, 1945. Only a few of the engines under construction survived. It was also planned to use the engine to power a version of the Ohka kamikaze weapon, but this was not implemented before the end of the war.
Nakashima Aeroplane and Mitsubishi Heavy Industries also were directed to do trial-manufacture with the same one-page diagram from Germany, but both were unable to realize it.
Everything concerning aircraft, including the Ne-20, was either destroyed by the Allied Powers or brought back to the United States.
Three Ne-20s have been preserved:
One at Ishikawajima-Harima's internal company museum in Tanashi,
Two at the National Air and Space Museum in Washington, DC.