In the early 1950s, France was desperate for a two engine bomber. Great Britain had the English Electric Canberra, while the Soviet Union had the Ilyushin Il-28. France could not let themselves be without a comparable machine.
The SNCASO SO.4000 had disintegrated on its maiden flight in March of 1951 and there was no other design on French drafting tables that carried the same potential that it did.
Wanting something they could (more or less) call their own, rather than buying from someone else, a few SNCASO executives who had good connections to the Glenn L. Martin company were able to secure the blueprints and other technical data from the cancelled XB-51 program.
In January of 1953, a somewhat redesigned variation of the XB-51 made it's first flight in France.
Designated SNCASO SO.4050, the aircraft had slightly longer wings than the XB-51 and was powered by a pair of SNECMA Atar 101C engines. The Atars gave enough power that the third engine could be removed from the design.
The first pre-production aircraft debuted in 1954, with a pair of substantially more powerful Atar 101E engines driving them.
Aside of longer wings and a redesigned tail that replaced the original "T" tail of the XB-51 with an all moving horizontal stabilizer near the mid point of the tail fin, there wan't much to differentiate the SNCASO Vautour from the XB-51 externally.
Designing out the third engine gave the Vautour greater internal fuel volume while the Atar 101E engines gave it great speed and performance for the time.
The first French air force Vautour squadrons were active by 1956. By 1958, the aircraft was active in the Israeli air force.
