The Armstrong Siddeley Python was an early British

turboprop A turboprop is a turbine engine that drives an aircraft propeller. A turboprop consists of an intake, reduction gearbox, compressor, combustor, turbine, and a propelling nozzle. Air enters the intake and is compressed by the compressor. ...

engine designed and built by the

Armstrong Siddeley Armstrong Siddeley was a British engineering group that operated during the first half of the 20th century. It was formed in 1919 and is best known for the production of luxury vehicles and aircraft engines. The company was created following t ...

company in the mid-1940s. Its main use was in the

Westland Wyvern The Westland Wyvern was a British single-seat carrier-based multi-role strike aircraft built by Westland Aircraft that served in the 1950s, seeing active service in the 1956 Suez Crisis. Production Wyverns were powered by a turboprop engine dri ...

, a

carrier-based Carrier-based aircraft, sometimes known as carrier-capable aircraft or carrier-borne aircraft, are naval aircraft Naval aviation is the application of military air power by navies, whether from warships that embark aircraft, or land base ...

heavy fighter. The prototypes had used the

Rolls-Royce Eagle The Rolls-Royce Eagle was the first aircraft engine to be developed by Rolls-Royce Limited. Introduced in 1915 to meet British military requirements during World War I, it was used to power the Handley Page Type O bombers and a number of oth ...

piston engine, but Pythons were used in production aircraft. In this application, the Python was rated at 4,110 equivalent shaft horsepower (eshp).

Design and development

The design started as an experimental pure-turbojet known as the ASX, which commenced testing 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 by the addition of a reduction gearbox to drive a propeller. The turboprop thus formed was named ASP.

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'': in each aircraft Pythons replaced the two outboard

Rolls-Royce Merlin The Rolls-Royce Merlin is a British liquid-cooled V-12 piston aero engine of 27-litres (1,650 cu in) capacity. Rolls-Royce designed the engine and first ran it in 1933 as a private venture. Initially known as the PV-12, it was late ...

s. Lincoln B.2 ''RF403'' had two Pythons similarly installed and was used for high-altitude bombing trials at Woomera, South Australia. These trials were principally of the ballistic casings for the Blue Danube

atomic weapon A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bom ...

: the Lincoln was the only available aircraft that could accommodate the large weapon casing, measuring 62 inches diameter x in length. The Pythons were fitted to increase the

height Height is measure of vertical distance, either vertical extent (how "tall" something or someone is) or vertical position (how "high" a point is). For example, "The height of that building is 50 m" or "The height of an airplane in-flight is ab ...

from which tests could be carried out. Maximum release height and speed for the first eleven tests was 275 mph and with a bombing error of 61 ft.The National Archives, London, file ES 1/44 E4C Appendix 3 page 1.

Python Engine on public display

An Armstrong Siddeley Python is on display at the

East Midlands Aeropark East Midlands Airport is an international airport in the East Midlands of England, close to Castle Donington in northwestern Leicestershire, between Loughborough (), Derby () and Nottingham (); Leicester is () to the south and Lincoln () no ...

Castle Donington.

Variants

;ASP.1 (Python 1):reduction gear ratio 0.127:1 ;ASP.2 (Python 2):reduction gear ratio 0.135:1 ;ASP.3 (Python 3):

Applications

Avro Lancaster The Avro Lancaster is a British Second World War heavy bomber. It was designed and manufactured by Avro as a contemporary of the Handley Page Halifax, both bombers having been developed to the same specification, as well as the Short Stir ...

- (test only) *

Avro Lincoln The Avro Type 694 Lincoln is a British four-engined heavy bomber, which first flew on 9 June 1944. Developed from the Avro Lancaster, the first Lincoln variants were initially known as the Lancaster IV and V; these were renamed Lincoln I and I ...

- (test only) *

Specifications (ASP.3)

References

Notes

Bibliography

* * *

External links

Image of the Python-engined Lancaster B.Mk.I (FE) ''TW911''
a 1949 ''Flight'' article on the Python {{ASaeroengines 1940s turboprop engines Python Axial-compressor gas turbine engines