Several Doves were used in Holland as business aircraft or by air charter companies. Around 1960 Martin Air Charter Doves became popular for joy flights at Schiphol. The Sikorsky S-55 was one of the first large helicopters, it made its first flight in 1949. Equipped with a winch many S-55's were used for rescue operations. The rotor blades are driven by small ramjet engines attached to the blade tips.
Ramjets are jets without moving parts, burning cheap fuel like paraffin oil.
Because the propulsion forces act at the blades the fuselage is hardly effected by reaction torque, consequently a small tail rotor is sufficient. Since 1958 Kolibris were used for agricultural crop spraying. During the second half of the 1950's the Hawker Hunter flew in most West European air forces. Many hunters were built by Fokker's at Schiphol. In the Dutch Air Force the Hunter was succeeded by the supersonic Lockheed F-104G Starfighter, capable of flying twice the speed of sound.