Alvis Leonides Major

Country of origin: UK
Built: Coventry, c. 1960
Manufacturer: Alvis Engineering
Engine: 14 cylinder air-cooled radial engine

Type: Radial Piston engine

Note: Used in Westland Whirlwind Mks. 5, 6, 7 and 8.

Details: Air-cooled radial engines were a popular choice to power helicopters in the 1940-1960 period, despite their bulk, and were usually adapted from fixed-wing installations.

The Leonides family powered several British helicopters, culminating in the 14 cyclinder 750hp Leonides Major which engined the Westland Whirlwind and the experimental Bristol Type 173.

In 1951 Alvis started development of a 14-cylinder, two row radial of 1,118 cu in (18.3 L) displacement, based on the earlier 9-cylinder 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

You can see a Whirlwind Mk7 here in the Helicopter Museum.