During the 1940s, as part of a wider effort to re-built French military power, particularly the French Air Force, and to furnish it with advanced, new domestically-produced designs, a request for a supersonic-capable point defence interceptor aircraft to equip the French Air Force was issued to SNCASO.
French aircraft company SNCASO received a request from the Air Staff to conduct activities upon the development of a capable and advanced point defence interceptor aircraft. In response, the firm designed the mixed-propulsion Trident, powered by a single SEPR rocket engine, which was augmented by wing-tip mounted turbojet engines.
On 2 March 1953, the first prototype Trident I conducted its maiden flight. Subsequently, refitted with Dassault-built MD 30 Viper ASV.5 wing tip engines, the prototype soon exceeded Mach 1 during a shallow dive even without the rocket motor installed.
The first Trident II exploded on 21 May 1957 during a test flight due an uncontrolled mixing of its fuels resulting in the loss of the aircraft and the death of its pilot, Charles Goujon.
Despite having reached a late stage of development and achieving promising performance in April 1956 it was decided to end flight testing with the sole remaining Trident I and to terminate all work on the Trident programme. The Trident I had completed over 100 flights, having eventually reached a maximum recorded speed of Mach 1.8 and a peak altitude of 20,000 metres (65,000 ft) and setting a new time-to-height and altitude record of 24,300 metres (79,700 ft). A total of 24 of these flights had been flown using the rocket engine. A more developed and even faster version, the Trident III was never built.
Photo MikaŽl Restoux/commons.wikimedia.org
While having achieving promising results during testing, including the establishment of several world records during flight tests, the French Government chose to cancel its order for the Trident, leaving it as a development programme only.