Aeroplane and Armament Experimental Establishment (A&AEE) testing of the Martlet II at a mean weight of approximately 7,350 lb showed a maximum speed of 293 mph at 5,400 ft and 13,800 ft, a maximum climb rate of 1940 fpm at 7,600 ft at 7,790 lb weight, and a time to climb to 20,000 ft of 12.5 minutes.