Alvis Leonides Major
{{short description|1930s British piston aircraft engine}}
{{Use dmy dates|date=February 2018}}
{{Use British English|date=February 2018}}
| {{Infobox Aircraft Begin
|name= Leonides Major |image= Alvis Leonides Major.JPG |caption= }}{{Infobox Aircraft Engine |type= Radial engine |manufacturer= Alvis |national origin= United Kingdom |first run= |major applications= Westland Whirlwind |number built = |program cost = |unit cost = |developed from = Alvis Leonides |variants with their own articles = |developed into = }} |
The Alvis Leonides Major is a British air-cooled 14-cylinder radial aero engine developed by Alvis from the earlier nine-cylinder Leonides.{{cite book|last1=Gunston|first1=Bill|title=World encyclopaedia of aero engines|date=1989|publisher=P. Stephens|location=Wellingborough|isbn=1-85260-163-9|page=13|edition=Fully rev. 2nd}}
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 {{convert|875|hp|abbr=on}} and the 751/1 for helicopters at {{convert|850|hp|abbr=on}}. 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.Lumsden 2003, pp.60-61.
Variants
Data from:British Piston Engines and their Aircraft.{{cite book |last=Lumsden |first=Alec |title=British Piston Engines and their Aircraft |year=2003 |publisher=Airlife Publishing |location=Marlborough, Wiltshire |isbn=978-1-85310-294-3 |pages= 60–61}}
;Leonides Major 702/1
:{{cvt|850|-|875|hp}} for aeroplanes, also known as A.LE.M.1-1 in Air Ministry
;Leonides Major 751/1
:{{cvt|850|hp}} for helicopters, also known as A.LE.M.1-2
;Leonides Major 755/1
:{{cvt|780|hp}} 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
:{{cvt|780|hp}} for helicopters in a vertical mounting, also known as A.LE.M.1-6 and as Mk.160 in civil aircraft
Applications
- Bristol Type 173 Mk3 – 2x 755/1 (Mk.155) {{cvt|780|hp}}; 2x 755/2 (Mk.160) {{cvt|780|hp}}
- Handley Page HPR.5 Herald – four {{cvt|850|hp}} 702/1
- Westland Whirlwind 1x 755/1 (Mk.155) or 1x 755/2 (Mk.160) {{cvt|780|hp}}
Specifications (Leonides Major 702/1)
{{pistonspecs|
|ref=Jane's All the World's Aircraft 1956-57.{{cite book |title=Jane's all the World's Aircraft 1956–57 |editor1-last=Bridgman |editor1-first=Leonard |year=1956 |publisher= Jane's all the World's Aircraft Publishing Co. Ltd. |location= London |pages= 417–419}}
|type= 14-cylinder twin-row air-cooled radial piston engine, geared down and supercharged
|bore={{cvt|4.80|in|mm}}
|stroke={{cvt|4.41|in|mm}}
|displacement={{convert|1,118|cid|L|abbr=on}}
|length={{cvt|70.9|in|cm}}
|diameter={{cvt|38.9|in|cm}}
|height=
|weight= {{convert|1,200|lb|abbr=on}} (dry)
|valvetrain=2 sodium cooled valves per cylinder, driven by 2 cam discs
|supercharger=Single speed single stage driven at 6.5:1
|turbocharger=
|fuelsystem=Fuel injection, low pressure via Hobson or SU pump
|fueltype=100/130 octane
|oilsystem=Dry sump, pressure and scavenge pumps
|coolingsystem=Air-cooled
|power=(international rating) 860 hp (642 kW) at 1,500 ft (457 m)
|specpower=
|compression=6.8:1
|fuelcon={{convert|60|impgal|usgal l|abbr=on}} per hour (at maximum continuous power)
|specfuelcon=
|oilcon=6-12 pint/h (3.4-6.8 L/h)
|power/weight=
|designer=
|reduction_gear=Farman type epicyclic, ratio 0.533:1
|general_other=
|components_other=2 spark plugs per cylinder, twin BTH C.14.C/1 magnetos
|performance_other=
}}
See also
{{aircontent
|see also=
|related=
|similar engines=
|lists=
}}
References
{{Commons category|Alvis Leonides Major}}
{{Reflist}}
{{Alvis aeroengines}}
Category:Aircraft air-cooled radial piston engines