The Fiat 4700 was developed to provide power in cold-jet driven helicopters. The 4700 was a turbo-driven air compressor driven by the primary engine, a turbojet engine based on the Fiat 4002. The compressor and primary engine are mechanically independent. The engine is mounted vertically to reducethe length of the compressed-air ducts to the rotor. The engine was used on the Fiat 7002 helicopter which first flew on 26 January 1961 where the Fiat 4700 was used to power the cold tip-jets on the two-blade rotor.