Bristol Types 73 and 83

Three seat, single bay light biplane. It was constructed predominantly of wood with fabric covering. The fuselage was a plywood covered box from the engine bulkhead to the rear cockpit, aft of which it was a fabric covered structure of four ash longerons, spruce struts, and steel wire bracing. The pilot sat in an open front cockpit, ahead of his passengers, who were accommodated side by side in a second open cockpit. The passenger cockpit was provided with a hinged entry door on the port side, together with a small baggage compartment with a separate access door. The heavily staggered upper and lower wings were identical to reduce the number of spares required, constructed of I-section spruce spars and light spruce ribs, and were fitted with N-type interplane struts. Ailerons were fitted on all four mainplanes. The struts, both inter-plane and centre-section, were formed of streamline steel tubes, welded together to form a letter N. The tail plane and elevators were built of steel tubes. One 118 h.p. Bristol Lucifer III powerplant, provided with a hinged mounting, to allow ready access to the rear of the engine, and its accessories when required.

Type 73 Taxiplane Specification
Span	Length	Height	Wing Area	Empty Wt	Max AUW	Cruise Speed	Maximum Speed	Range	Service Ceiling
31 ft 1 in	23 ft 3 in	8 ft 10 in	284 sq ft	1210 lb	1840 lb		90 mph/ 78 kn
9.47 m	7.09 m	2.69 m	26.38 m2	549 kg	835 kg		145 km/h

(Also known as the Primary Training Machine, or PTM) Two seat training variant of the Type 73, using the same wings, tail and undercarriage as the Taxiplane, but with a new, narrower fuselage containing two cockpits in tandem and fitted with dual controls. One 118 h.p. Bristol Lucifer III powerplant, but without the hinged mounting of the Taxiplane.

Type 83A with enlarged rudder and elevators. 140 h.p. Bristol Lucifer IV powerplant.

Single seat variant, streamlined for competition. Modifications to the aircraft included a more streamlined cowling and spinner, fuselage fairings and increased chord interplane struts. It was also fitted with a comma-shaped, all-moving rudder. It was later modified as a three-seater. 140 h.p. Bristol Lucifer IV powerplant.

Strengthened version for 220 h.p. Bristol Titan engine test bed, featuring a larger, horn balanced rudder and the increased chord interplane struts of the Type 83C.

Type 83A Specification
Span	Length	Height	Wing Area	Empty Wt	Max AUW	Cruise Speed	Maximum Speed	Range	Service Ceiling
31 ft 1 in	24 ft 4 in	8 ft 10 in	284 sq ft	1340 lb	1900 lb		96 mph/ 83 kn
9.47 m	7.42 m	2.69 m	26.38 m2	608 kg	862 kg		154 km/h