Kamov Ka-20
The Kamov Ka-20 (NATO reporting name Harp) was a Soviet twin-engined prototype helicopter designed and built by Kamov that led to the Ka-25 family of helicopters, it was developed, during the early Cold War to counter United States Navy submarines. == Design and development == Developed from the earlier Ka-15 to meet a 1958 Soviet Navy requirement for a heavy shipborne helicopter, the Ka-20 had the similar twin contra-rotating, three-blade rotors of the earlier Ka-15 design and was powered by two 670 kW turboshaft engines.