Alvis Leonides Major

The Alvis Leonides Major is a British air-cooled 14-cylinder radial aero engine developed by Alvis from the earlier nine-cylinder Leonides.

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.

Variants
Data from:British Piston Engines and their Aircraft.
 * Leonides Major 702/1
 * 850 - 875 hp for aeroplanes, also known as A.LE.M.1-1 in Air Ministry


 * Leonides Major 751/1
 * 850 hp for helicopters, also known as A.LE.M.1-2


 * Leonides Major 755/1
 * 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
 * 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) 780 hp; 2x 755/2 (Mk.160) 780 hp
 * Handley Page HPR.5 Herald – four 850 hp 702/1
 * Westland Whirlwind 1x 755/1 (Mk.155) or 1x 755/2 (Mk.160) 780 hp