Turbomeca Astazou - Design and Development

Design and Development

The Astazou IIA version was derived from the original Astazou powerplant for use in helicopters. By 1993, 2,200 had been built. As of 2007, it was still in production. However, many aircraft initially equipped with it, especially the heavier ones, have since been upgraded with more powerful engines.

The basic design of the single shaft Astazou has a two-stage compressor, with the first stage an axial and the second stage a radial design. It has an annular combustion chamber, after which the hot exhaust enters a three-stage axial turbine. Maximum rpm was later raised to 43,500.

Production turbines have a reduction gear in front of the air inlet, reducing propeller speed to 1,800, 2,080, 2,200, 0r 2,400 rpm, or 6,000 rpm in the helicopter version. The engine controls itself automatically, so the pilot only needs to set the desired rpms.

As of the Astazou X, the engine received a second axial compressor stage. This was the engine for the Potez 840. The Astazou XIV and XVI were also marketed by Rolls-Royce Turboméca International Ltd under the names AZ14 and AZ16, respectively.

Power was steadily increased over the years, with the Eurocopter Dauphin's dual Astazou XVIII developing 783 kW each. The Astazou XX received a third axial stage, raising compression even further to achieve aprojected output of 1075 kW in the turboprop application. The XXB derivative, used in the single engine SA 361H Dauphin, has 1043 kW.