Whirlwind HAS.7

Westland WS-55 Whirlwind powered by Alvis Leonides Major engine and a 3 degree droop of the tail boom for increased main rotor clearance. 120 built for Royal Navy and some used as Commando transports for Royal Marines.

Early individuals of the HAS.7 were plagued by engine problems, principally with the centrifugal clutch mechanism of the Alvis Leonides Major Mk.155 engine. Failure rates became so high that the type was withdrawn from service for several months while intense work was put into solving the problem. In the meantime the type was grounded between Apr and Nov 1959 and some Units re-equipped with the older HAR.3 until they could be replaced with rectified HAS.7s.