S1591 was the naval version, with its 540 hp geared and supercharged Panther IIIA engine surrounded by a Townend ring, the exhausts being of the stub type. Armament comprised two 0.303 in (7.7 mm) Vickers machineguns. Extensive tests were carried out on the machine at the A&AEE for some two years and resulted in modifications being made to S1591 which included (as seen in the photo) deletion of the horn balance on the rudder, the provision of a new fin which extended forwards and was of increased area, and the removal of the inner ring of the Townend cowling from the front of the engine.
The second (private venture) prototype, initially carrying the 'Class B' marking A-2 (c/n A.W.722), was later registered G-ABKF. It had its Panther IIIA replaced by a 565 hp Panther VII during the course of protracted trials at the A&AEE in 1933. Eventually the aircraft went to South Africa in Alan Cobham's circus. In all eighteen aircraft were produced, of which at least six were delivered to the Chinese Kwangsi Air Force, another ten were sold abroad to undisclosed customers."
Span: 33 ft 0 in (10.06 m)
Length: 25 ft 0 in (7.62 m)
Height: 11 ft 6 in (3.50 m)
Wing area: 261 sq.ft (24.24 sq.m)
Loaded weight: 3,520 lb (1,597 kg)
Max speed at 15,000 ft (4,572 m): 200 mph (322 kmh)
Max speed at 10,000 ft (6,560 m): 195 mph (314 kmh)
Climb: to 10,000 ft (3,048 m) 6 min
Endurance: 2 hour