Safran, April 07, 2017 - "Initial testing for what became the Astazou family took place in August 1958 with Turbomeca planning it as a turboprop.
However, it was not long before interest in turboshafts variants for helicopters materialized. The 523-hp Turbomeca Astazou IIA ran in 1960 and an Alouette II variant equipped with that engine first flew on January 31, 1961.
This new version quickly replaced the earlier model on the assembly lines at Marignane, with Turbomeca producing 615 Astazou IIA until 1978.
The Aerospatiale SA 340 Gazelle was conceived by Sud-Aviation to replace the Alouette II. Its prototype, which had an Alouette tail rotor, first flew on April 7, 1967, on the power of 523-hp Astazou IIN.
After a few flights, the tail rotor was replaced by a "fenestron", an enclosed ducted fan which has become a Eurocopter trademark.
The Gazelle, along with the Puma, and the Westland Lynx, became part of a Franco-British helicopter program. The Gazelle thus was adopted on both sides of the Channel.
Initial production Gazelles were powered by the 529-hp Astazou III, the increased power being obtained by raising operating temperatures and using new construction materials for the turbine."
Extract from Turbomeca Uplifting Experience (Editions Larivière)