In order to counter the introduction of German turbojet-powered aircraft, the Soviet Union in 1944 began a crash program to develop a high-performance fighter which resulted in the Mikoyan-Gurevich I-250(N).
Although the aircraft was largely conventional in layout, it featured a novel propulsion system which consisted of a Klimov VK-107R V-12 piston engine (mounted conventionally and driving a tractor propeller) which was connected, via an extension shaft, to a compressor with seven fuel burners. This produced a propulsive jet which was directed, and accelerated, through a variable rear nozzle (compare thermojet). This mixed powerplant configuration enabled the I-250(N) to reach a maximum speed of 513 mph (825 km/h).
The I-250(N) was produced in small numbers from late 1945, and served with the Baltic Fleet and some Northern fighter units until 1950 under the designation MiG-13.
