Sud-Ouest SO 9000 Trident

Stemming from the lightweight fighter philosophy that emerged from the Korean conflict, the SO 9000 Trident single-seat interceptor developed by a team led by Lucien Servanty was of unusual concept in employing turbojets for auxiliary power and a rocket motor for primary thrust. Two prototypes of the Trident were ordered on 8 April 1951, the first of these flying on 2 March 1953 solely on the power of two wingtip-mounted Turbomeca Marbore II turbojets each rated at 400kg. The second prototype was destroyed on its first flight on 1 September 1953, but development continued with the first example, which, on 4 September 1954, flew for the first time with its primary power plant, a triple-barrel SEPR 481 liquid rocket motor providing a total thrust of 4500kg. As the aircraft could not take-off on the power of the Marbores at fully loaded weight, these gave place to Dassault MD 30 (Viper ASV 5) turbojets of 745kg, with which it flew on 17 March 1955. Although conceived as a combat aircraft, the SO 9000 had meanwhile been overtaken by a more advanced development, the SO 9050, and its test programme was terminated on 10 December 1956, the prototype having achieved a speed of Mach=1.63 - the highest speed attained by any piloted aircraft in Europe at that time - and an altitude of 15,000m.