The Kuznetsov NK-4 is a turboprop engine, designed by the Kuznetsov Design Bureau.
Development
Development of the NK-4 began on September 27, 1955 at the Kuznetsov Design Bureau. Factory tests were passed on April 17, 1956 and state tests were passed in 1957. At the time, the NK-4 was considered an economical and technologically advanced engine. A modified version of the NK-4 that improved in terms of service life and efficiency, the NK-4A, passed factory tests in October 1957. State tests of the NK-4A were passed in June 1959. ==Applications==