The Miles Master was a tandem-seat low-wing cantilever monoplane, powered by a single reciprocating engine. Initial models used the Kestrel XXX engine; capable of providing up to 745 hp (555 kW), this powerplant enabled the aircraft to achieve a maximum speed of 296 mph (477 km/h), which reportedly made the Master as fast as the single-seat biplane fighters of 1935. The "inverted gull"-shaped wing of the Master was a major distinguishing factor of the aircraft and was adopted, despite higher production costs, due to its performance benefits, permitting the stowage of both the retractable undercarriage and fuel tanks; aside from this shaping, the wing's design largely conformed with traditional approaches. It features hydraulically-actuated split flaps along its trailing edge, their position being indicated electronically on the cockpit's instrumentation planel. The wing's center-section also accommodates a machine gun.