Armstrong Siddeley Python

Python
An Armstrong Siddeley Python during NACA wind tunnel testing in 1949
Type	Gas turbine turboprop
National origin	United Kingdom
Manufacturer	Armstrong Siddeley
First run	April 1945
Major applications	Westland Wyvern

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.

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.

Specifications (ASP.3)

Data from:

General characteristics

• Type: Turboprop
• Length: 123.2 in (3129 mm)
• Diameter: 54 in (1372 mm)
• Dry weight: 3,450 lb (1565 kg)

Components

• Compressor: 14 stage axial
• Combustors: 11 combustion chambers
• Turbine: Two-stage turbine

Performance

• Maximum power output: 4,110 ehp (3,065 kW), sea level at 8,000 rpm including 1,180 lbf (535 kgf) exhaust thrust
• Overall pressure ratio: 5.35:1
• Air mass flow: 52.5 lb/sec (23.8 kg/sec)
• Specific fuel consumption: 0.805 lb/hr/eshp
• Power-to-weight ratio: 1.2:1

See also

• List of aircraft engines

References

Bibliography

• Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9