The Theseus was the Bristol Aeroplane Company's first attempt at a gas-turbine engine design. A turboprop delivering just over 2,000 hp (1,500 kW) was chosen rather than compete with companies that were already developing turbojets. A heat exchanger to transfer waste heat from the exhaust to the compressor exit was necessary to meet a requirement for a fuel consumption comparable to a piston engine. However, the heat exchanger was abandoned after tests showed that it had a high pressure loss and only produced a fuel saving of 8%. Furthermore overall performance was reduced [1] [2]
| Theseus | |
|---|---|
| |
| Preserved Bristol Theseus | |
| Type | Turboprop |
| Manufacturer | Bristol Siddeley |
| First run | 18 July 1945 |
| Major applications | Handley Page Hermes |
As well as being one of the first engines to feature a free propeller turbine, the Theseus was the first turboprop in the world to pass a type test in January 1947.[3] Following 156 hours of ground runs and the receipt of a test certificate from the Ministry of Supply on 28 January 1947, two Theseus engines were fitted in the outer positions of a four-engined Avro Lincoln for air tests.[4] After ground and taxying test the Lincoln first flew on 17 February 1947.[4]
The engine was also installed in two Handley Page Hermes 5 development aircraft.[5]
It was soon superseded by the Proteus design with more power.
Applications
editBristol Theseus on public display
editEast Midlands Aeropark Castle Donington.
Variants
edit- Theseus Series TH.11
- Variant without heat exchanger. Ran for first time July 18, 1945
- Theseus Series TH.21
- Variant with heat exchanger. Ran for first time in December, 1945
- Theseus 502
Specifications (Theseus Th.21)
editData from Aircraft Engines of the world 1946[7]
General characteristics
- Type: Mixed compressor turboprop with matrix heat exchanger
- Length: 106 in (2.69 m)
- Diameter: 48 in (1.22 m)[8]
- Dry weight: 2,310 lb (1,050 kg)
Components
- Compressor: 8-stage axial + 1-stage centrifugal compressors feeding the combustion chambers through a heat exchanger
- Combustors: 8 x stainless steel can combustion chambers
- Turbine: 2-stage axial + 1-stage axial free turbine driving the propeller
- Fuel type: Kerosene (R.D.E. / F / KER)
- Oil system: pressure feed to bearings, dry sump, 40 S.U. secs (13 cSt) (Intavia 620) grade oil
Performance
- Maximum power output: 1,950 bhp (1,450 kW)@Sea Level Static, ISA plus 500 lbf (2.22 kN) residual thrust[8]
- Overall pressure ratio: 5:1[9]
- Air mass flow: 30.0 lb/s (13.61 kg/s)[9]
- Specific fuel consumption: 0.57 lb/equiv. hph (kg/equiv. kWh)@ Max Power, 300mph, Sea Level, ISA[8]
- Specific Fuel Consumption : 0.5 lb/equiv. hph (kg/equiv. kWh)@ Max Power, 300mph, 20000ft, ISA [8]
- Thrust-to-weight ratio:
- Maximum flight rating: 2,350 hp (1,750 kW) equivalent at Max Power, 300mph, Sea Level,ISA[8]
- Maximum flight rating: 1,500 hp (1,100 kW) equivalent at Max Power, 300mph, 20,000 ft (6,100 m),ISA NOTE:Equivalent Power defined as Propeller Shaft Power plus (Jet Thrust * Flight Velocity/Propeller Efficiency) [8]
- Power-to-weight ratio: 1.02 equiv. hp/lb (1.677 equiv. kW/kg) [clarification needed]
See also
editReferences
editNotes
edit- ^ Making Jet Engines in World War II: Britain, Germany, and the United States', Hermione Giffard 2016,University of Chicago,p.114-115
- ^ Turbojet History And Development 1930-1960 Volume 1, Antony Kay2007, ISBN 978 1 86126 912 6, p.139
- ^ http://www.flightglobal.com/pdfarchive/view/1947/1947%20-%200602.html [dead link]
- ^ a b "Theseus Air Testing - First Bristol Airscrew Turbines Fly in a Lincoln : Some Features Discussed". Flight: 270. 27 March 1947.
- ^ Gunston 1989, p.34.
- ^ Test bed only
- ^ Wilkinson, Paul H. (1946). Aircraft Engines of the world 1946. London: Sir Isaac Pitman & Sons. pp. 284–285.
- ^ a b c d e f Practical Mechanics, February 1947, p.172
- ^ a b Practical Mechanics, January 1947, p.116-118
Bibliography
edit- Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9
External links
edit
- "Bristol Theseus I" a 1945 Flight article
- Development of the turboprop Flight 30 November 1950