The Bristol Orion aero engine was a two-shaft turboprop intended for use in later marks of the Bristol Britannia and the

Canadair CL-44 The Canadair CL-44 was a Canadian turboprop airliner and cargo aircraft based on the Bristol Britannia that was developed and produced by Canadair in the late 1950s and early 1960s. Although innovative, only a small number of the aircraft were ...

. Although the engine was built and underwent a development program, the BE.25 Orion project was cancelled in 1958 by the British

Ministry of Supply The Ministry of Supply (MoS) was a department of the UK government formed in 1939 to co-ordinate the supply of equipment to all three British armed forces, headed by the Minister of Supply. A separate ministry, however, was responsible for aircr ...

in favour of the

Rolls-Royce Tyne The Rolls-Royce RB.109 Tyne is a twin-shaft turboprop engine developed in the mid to late 1950s by Rolls-Royce Limited to a requirement for the Vickers Vanguard airliner. It was first test flown during 1956 in the nose of a modified Avro Linc ...

.Turbojet History And Development 1930-1960 - Volume 1 Great Britain and Germany, Antony L. Kay 2007, The Crowood Press Ltd., , p.149 In addition, interest in turboprop-powered aircraft was beginning to wane, because of the successful introduction of the

Boeing 707 The Boeing 707 is an American, long-range, narrow-body airliner, the first jetliner developed and produced by Boeing Commercial Airplanes. Developed from the Boeing 367-80 prototype first flown in 1954, the initial first flew on December 20, ...

and

Douglas DC-8 The Douglas DC-8 (sometimes McDonnell Douglas DC-8) is a long-range narrow-body airliner built by the American Douglas Aircraft Company. After losing the May 1954 US Air Force tanker competition to the Boeing KC-135, Douglas announced in Ju ...

jetliners into airline service. The Orion gas generator had been chosen by French aircraft designer Wibault to power a vectored thrust aircraftPegasus The Heart of the Harrier, Andrew Dow, Pen & Sword Aviation 2009, , p.71/73 which ultimately became the

Hawker Siddeley P.1127 The Hawker P.1127 and the Hawker Siddeley Kestrel FGA.1 are the British experimental and development aircraft that led to the Hawker Siddeley Harrier, the first ''vertical and/or short take-off and landing'' ( V/STOL) jet fighter-bomber. Devel ...

but with a Bristol Siddeley Orpheus gas generator which had a compressor derived from the Orion low pressure compressor.

Design and development

A single-stage HP turbine drove a five-stage all-axial HP compressor, while a three-stage LP turbine drove both the seven-stage LP compressor and the propeller, via a reduction gearbox. Thus the Orion used a shared-load LP turbine (like the

), whereas its predecessor, the

Bristol Proteus The Bristol Proteus was the Bristol Engine Company's first mass-produced gas turbine engine design, a turboprop that delivered just over 4,000 hp (3,000 kW). The Proteus was a reverse-flow gas turbine. Because the second turbine drov ...

, had a free-power turbine. The

combustor A combustor is a component or area of a gas turbine, ramjet, or scramjet engine where combustion takes place. It is also known as a burner, combustion chamber or flame holder. In a gas turbine engine, the ''combustor'' or combustion chamber is fed ...

used separate

flame can A flame (from Latin '' flamma'') is the visible, gaseous part of a fire. It is caused by a highly exothermic chemical reaction taking place in a thin zone. When flames are hot enough to have ionized gaseous components of sufficient density they ...

s. One novel feature of the Orion was a derate from a thermodynamic rating of 9,000 shp at sea level, to enable a constant 5,150 ehp power level to be maintained up to 15,000 ft altitude. The Orion project was cancelled in January 1958, at a reported total cost of £4.75 million ().

Applications

* Bristol Britannia *

Specifications (BOn.1 Orion)

Design and development

Applications

Specifications (BOn.1 Orion)

See also

References

Further reading