This carrier-borne torpedo-bomber was designed to Specification Ml/30. The aircraft had one 825 hp Rolls-Royce Buzzard engine enclosed in a smooth cowling, with a large chin radiator hung underneath. The upper wing was mounted flush with the fuselage top, giving the pilot and observer a good upward and forward view at least. Slats were fitted over the outer leading edge of the top wing. The lower wings had a very steep anhedral over the inner section and the spatted pairs of mainwheels were mounted at the joint where the changeover to dihedral occurred. The undercarriage was to have had single main wheels originally and was very similar in appearance to that of the Heyford. The wings folded to reduce aircraft carrier stowage requirements. A single fin and rudder were to be fitted and the tailplane had vee-strut bracing.
The prototype was allocated the serial number S1642 and possibly made just one flight on 25th October, 1932.
Span 50ft 0 in. Length 39 ft 5 in. Height 13 ft 0 in. All-up weight 10,600 lb.
Two other aeroplanes were built to the M1/30 Specification were the Vickers 207, S1641, and the Blackburn M1/30, S1640. This specification had superseded Specification M5/28 to which the HP41 had been designed. This was to have been a two-seat all metal machine of 7,350 lb all-up weight.