To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
Live Statistics
English Articles
Improved in 24 Hours
Added in 24 Hours
Show all languages
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.

Alvis Leonides Major

From Wikipedia, the free encyclopedia

Leonides Major
Alvis Leonides Major.JPG
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 (652 kW) and the 751/1 for helicopters at 850 hp (630 kW). 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]


Data from:British Piston Engines and their Aircraft.[3]

Leonides Major 702/1
850–875 hp (634–652 kW) for aeroplanes, also known as A.LE.M.1-1 in Air Ministry
Leonides Major 751/1
850 hp (630 kW) for helicopters, also known as A.LE.M.1-2
Leonides Major 755/1
780 hp (580 kW) for helicopters in a 35° canted mounting, also known as A.LE.M.1-6 and as Mk.155 in civil aircraft
Leonides Major 755/2
780 hp (580 kW) for helicopters in a vertical mounting, also known as A.LE.M.1-6 and as Mk.160 in civil aircraft


Specifications (Leonides Major 702/1)

Data from Jane's All the World's Aircraft 1956-57.[4]

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)


  • Valvetrain: 2 sodium cooled valves per cylinder, driven by 2 cam discs
  • Supercharger: Single speed single stage driven 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


  • 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

Comparable engines

Related lists


  1. ^ Gunston, Bill (1989). World encyclopaedia of aero engines (Fully rev. 2nd ed.). Wellingborough: P. Stephens. p. 13. ISBN 1-85260-163-9.
  2. ^ Lumsden 2003, pp.60-61.
  3. ^ Lumsden, Alec (2003). British Piston Engines and their Aircraft. Marlborough, Wiltshire: Airlife Publishing. pp. 60–61. ISBN 978-1-85310-294-3.
  4. ^ Bridgman, Leonard, ed. (1956). Jane's all the World's Aircraft 1956–57. London: Jane's all the World's Aircraft Publishing Co. Ltd. pp. 417–419.
This page was last edited on 24 March 2021, at 22:21
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.