The Aérospatiale Gazelle (company designations SA 340, SA 341 and SA 342) is a French five-seat helicopter, commonly used for light transport, scouting and light attack duties. It is powered by a single Turbomeca Astazou turbine engine and was the first helicopter to feature a fenestron tail instead of a conventional tail rotor. It was designed by Sud Aviation, later Aérospatiale, and manufactured in France and the United Kingdom through a joint production agreement with Westland Aircraft. Further manufacturing under license was performed by SOKO in Yugoslavia. and the Arab British Helicopter Company (ABHCO) in Egypt. Since being introduced to service in 1973, the Gazelle has been procured and operated by a number of export customers. It has also participated in numerous conflicts around the world, including by Syria during the 1982 Lebanon War, by Rwanda during the Rwandan Civil War in the 1990s, and by numerous participants on both sides of the 1991 Gulf War. In French service, the Gazelle has been supplemented as an attack helicopter by the larger Eurocopter Tiger, but remains in use primarily as a scout helicopter. Originally developed as a replacement to Aérospatiale's Alouette helicopter, some aspects of the Gazelle such as its purpose and layout were based on the previous model. The Gazelle featured several important innovations. It was the first helicopter with a fenestron or fantail; this is a shrouded multi-blade anti-torque device housed in the vertical surface of the Gazelle's tail, where it replaces a conventional tail rotor. The fenestron, while requiring a small increase in power at slow speeds, has advantages such as being considerably less vulnerable to damage, safer for people working around the helicopter and with low power requirements at cruising speeds, and has been described as "far more suitable for high-speed flight". The fenestron is likely to have been one of the key advances that allowed the Gazelle to become the world's fastest helicopter in its class. The main rotor system was originally based upon the rigid rotor technology developed by Messerschmitt-Bölkow-Blohm for the MBB Bo 105; however, due to control problems experienced while at high speeds upon prototype aircraft, the rigid rotor was replaced with a semi-articulated one on production aircraft. The difficulties experienced with the early design of the main rotor was one of the factors contributing to the lengthy development time of the Gazelle. The individual rotor blades were made from composite materials, primarily fiberglass, and had been designed for an extremely long operational lifespan; composite rotor blades would become common on later helicopters. The main rotor maintains a constant speed in normal flight, and is described as having a "wide range of tolerance" for autorotation. For more details of development, design, operational history and variants, click here.
