Alvis Leonides Major

Leonides Major
Type	Radial engine
National origin	United Kingdom
Manufacturer	Alvis
Major applications	Westland Whirlwind
Developed from	Alvis Leonides

The Alvis Leonides Major was a British air-cooled 14-cylinder radial aero engine developed by Alvis from the earlier nine-cylinder Leonides.^[1]

Design and development

In 1951 Alvis started development of a 14 cylinder, two row radial of 1,118 cu in (18.3 L) displacement, based on the Leonides. Certification covered the Mk. 702/1 for aeroplanes at 875 hp and the 751/1 for helicopters at 850 hp. The only numerous model of the Major was the Mk. 755/1, a medium supercharged, de-rated, obliquely mounted direct-drive and fan cooled engine fitted to the Westland Whirlwind Mks. 5, 6, 7 and 8.^[2]

Applications

• Bristol Type 173 Mk1,2 & Mk3 – 2x 755/1 Mk 155, 780 hp, 755/2 Mk 160, 780 hp or 2x 850 hp
• Handley Page Herald – four 870 hp
• Handley Page H.P.R.1 Marathon – two
• Westland Whirlwind 1 x 755/1 Mk 155, 780 hp

Specifications (Leonides Major, geared, fixed wing version)

Data from Jane's All the World's Aircraft 1956-57 pp.417-9

General characteristics

• Type: 14-cylinder twin-row air-cooled radial piston engine, geared down and supercharged
• Bore: 4.80 in (122 mm)
• Stroke: 4.41 in (112 mm)
• Displacement: 1,118 cu in (18.32 l)
• Length: 70.9 in (180 cm)
• Diameter: 38.9 in (99 cm)
• Dry weight: 1,200 lb (540 kg) (dry)

Components

• Valvetrain: 2 sodium cooled valves per cylinder, driven by 2 cam disks
• Supercharger: Single speed single stage diven at 6.5:1
• Fuel system: Fuel injection, low pressure via Hobson or SU pump
• Fuel type: 100/130 octane
• Oil system: Dry sump, pressure and scavenge pumps
• Cooling system: Air-cooled
• Reduction gear: Farman type epicyclic, ratio 0.533:1
• 2 spark plugs per cylinder, twin BTH C.14.C/1 magnetos

Performance

• Power output: (international rating) 860 hp (642 kW) at 1,500 ft (457 m)
• Compression ratio: 6.8:1
• Fuel consumption: 60 imp gal (72 US gal; 270 l) per hour (at maximum continuous power)
• Oil consumption: 6-12 pint/h (3.4-6.8 L/h)

See also

Related development

• Alvis Leonides

Comparable engines

• Pratt & Whitney R-1535

Related lists

• List of aircraft engines

References

Notes

1. Gunston 1989, p.13.
2. Lumsden 2003, pp.60-61.

Bibliography

• Bridgman, Leonard. Jane's All the World's Aircraft 1956-57. Jane's All the World's Aircraft Publishing Co. Ltd, London, 1956.
• Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9.
• Lumsden, Alec. British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing, 2003. ISBN 1-85310-294-6.

External links

• http://www.helicoptermuseum.co.uk/westland.htm