Bristol Orion
- For the 1920s engine of the same name, see Bristol Jupiter
| Orion | |
|---|---|
 | |
| Type | Turboprop |
| Manufacturer | Bristol Siddeley |
| First run | 1956 |
| Major applications | Bristol Britannia |
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The Bristol Orion aero engine was a two-shaft turboprop intended for use in later marks of the Bristol Britannia and Canadair CL-44. 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. At that time, interest in turboprop powered aircraft was beginning to wane, because of the successful introduction of the Boeing 707 and Douglas DC-8 jetliners into airline service.[1]
Design and development
A single stage HP turbine drove a five stage all-axial HP compressor, whilst 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 Rolls-Royce Tyne), whereas its predecessor, the Bristol Proteus, had a free-power turbine. The combustor used separate flame cans.
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 all the way up to 15,000 ft altitude.
The Orion project was cancelled in January 1958, at a reported total cost of £4.75 million.[2]
Applications
Specifications (Orion)
Data from: Flightglobal archive[3]
General characteristics
- Type: Twin-spool turboprop
- Length: 112.3 in (2,852 mm)
- Diameter: 41 in (1,041 mm)
- Dry weight: 3,150 lb (1,429 kg)
Components
- Compressor: 7 stage low pressure, 5 stage high pressure
- Combustors: Annular combustor with 10 flame tubes
- Turbine: Single stage high pressure, 3 stage low pressure
- Fuel type: Kerosene
Performance
- Maximum power output: 5,150 eshp (3,840 kW) (maximum takeoff)
- Overall pressure ratio: 10:1
- Air mass flow: 82 lb/sec (37 kg/s)
- Specific fuel consumption: 0.64 lb/eshp/hr
- Thrust-to-weight ratio: 1.63 eshp/lb (2.68 kW/kg)
See also
- Related development
- Comparable engines
- Related lists
References
Notes
- ↑ Gunston 1989, p.35.
- ↑ "Cancelled projects: the list up-dated" (PDF). Flight: 262. 17 August 1967.
- ↑ Flightglobal archive, 1956. Retrieved: 31 December 2008
Bibliography
- Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9
External links
- "The Supercharged Turboprop" a 1955 Flight article on the B.E.25 Orion by Stanley Hooker
- "Orion" a 1956 Flight article on the design of the Orion
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