 The Parnall G.4/31 was a 1930s general purpose aircraft which could operate as a day and night bomber as well as the reconnaissance, torpedo and dive-bombing roles.It was a large angular biplane powered by a 690 hp (515 kW) Bristol Pegasus IM3 with a Townend ring.The Parnall Heck was designed by Basil B. Henderson as a single-engined, conventional low-wing cabin monoplane, built of spruce with a plywood covering, initially a two-seater in tandem layout.