This little jet engine has an amazing (if short) history. After the 1944 Battle of the Marianas demonstrated Japan’s loss of air superiority, the Japanese military hurriedly decided to build their own jet fighter — based on what they’d seen of the German twin-engine Me-262. Working from only a few photos and a cut-away drawing of a BMW 003 jet engine, Japanese engineers were able to design, build, and test the Ne-20 within months.
Ne-20s went into production in order to power the Nakajima Kikka, Japan’s first jet-powered aircraft. But the prototype of the Kikka itself (looking much like a smaller variant of the Me-262) only flew once before the second World War ended in Japan. As a result, only 3 Ne-20 engines have survived to this day.