The Gazelle was the result of research performed to create a more modern version of the Alouette II. It was the work on the Gazelle that led to many technological advances, such as the NAT Main Rotor Head assembly with no bearing on the drag hinge, visco-elastic drag dampers, low frequency landing gear, and the shrouded Fenestron® tail rotor. We owe all three of these inventions to René MOUILLE, who added these three patents to the more than forty others that he registered during his career.
The first prototype (SA 340) had a traditional tail rotor and performed its first flight on 7 April 1967. It was equipped with a new semi-rigid rotor with composite blades developed in a cooperative effort with Bolköw. But just one year later, the version that took to the air was the first to be equipped with the now-famous Fenestron® shrouded tail rotor.
The Gazelle was the response to military invitations for bids issued by France and Great Britain, and would be built by Aerospatiale and Westland. It would be used mainly as a liaison and observation helicopter, and is currently used mostly for training. The Gazelles would be armed with guns or anti-tank weapon systems.
One of the major advantages of the Gazelle was its tremendous speed. On 13 May 1971, Denis PROST and Jean Marie BESSE broke two speed records in the Gazelle helicopter class: 307km/h over 3 km and 296km/h over a100 km closed course.
After the Gazelle had obtained the civil certifications in 1972, civil versions were used by law enforcement agencies and private customers for transport missions. A total of 1267 Gazelles were built in France and the United Kingdom. It was also produced by licensed manufacturers in Yugoslavia.
In December 1972, a Gazelle known as the SA 349 was equipped with two small wings and was used to fly experimental flights to test the "compound rotor craft" concept, but this development program would never go any further.