Tsu-11 (Japan)
The Tsu-11 was produced in Japan at the close of World War II in small numbers to propel a variation of the Japanese Ohka flying bomb, a kamikaze weapon. It was somewhat primitive, consisting of a four-cylinder Hitachi Hatsukaze HA11 piston engine driving a single-stage compressor. The engine was fuel injected but engineering analysis after the war suggests that this had limited effect and that in reality the unit was little more than an afterburning ducted fan engine as the majority of the thrust came from the compressor.
The engine was developed to overcome the shortcoming of the Ohka Type 11 which needed to be carried close to their targets by specially modified bombers to overcome their limited range. This made them vulnerable to interception and large numbers were shot down before they could begin their attack runs. The engine was first tested underneath a Yokosuka P1Y bomber in 1944 which was successful enough for it to be ordered into production.
The Ohka was adapted to accommodate the engine by lengthening the fuselage with intakes on the side. This was designated the Ohka Type 22. The engine was also selected to power the Yokosuka MXY-9 Shuka ("Autumn Fire"), a trainer to prepare pilots for the Mitsubishi J8M rocket-powered interceptor, Neither of these entered service before the war ended. A single example of a Tsu-11 engine is preserved at the National Air and Space Museum in Washington DC. In 1997 it was installed in the museum's Ohka 22 during its restoration.