Bristol Orion
- For the 1920s piston 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 the 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, 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 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 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