Armstrong Siddeley Python

The Armstrong Siddeley Python was an early British turboprop engine designed and built by the Armstrong Siddeley company. Its main use was in the Westland Wyvern carrier-based heavy fighter, the turboprop engine replacing the Wyvern prototype's original Rolls-Royce Eagle piston engine in production aircraft. In this application, the Python was rated at 4,110 EHP (Effective Horsepower).

Design and development

The design started as an experimental pure-turbojet known as the ASX, which started running in 1943. By this point other engine designs were already entering pre-production, and it seemed there was little need for the ASX in its existing form. The design was then modified into the turboprop layout with the addition of a second turbine stage, which was geared to the propeller and was named ASP at that stage.^[1]

Flight testing

Early flight-testing of the Python was carried out using the Lancaster B.1 (FE) TW911 and the Lincoln B.2 RE339/G, each aircraft having the two outboard Rolls-Royce Merlins replaced by Pythons. Lincoln B.2 RF403 also had two Pythons similarly installed and was used for high-altitude bombing trials at Woomera, South Australia, the Pythons being used to increase the height from which tests could be carried out.