Blackburn G.P., S.P. and R.T.1 Kangaroo

G.P. (General Purpose) - three-crew, three-bay biplane long-range patrol bomber seaplane. Construction of the aircraft was largely of wire-braced wood with fabric covering. The wings, of RAF34 section, were built in four sections, all with dihedral but the outer sections markedly so. The outer section upper mainplane extended past the lower mainplane and was supported by cables via kingposts, above the upper surface, over the outermost interplane struts. Ailerons were fitted to the upper wing surfaces only. To facilitate storage the outer wing sections folded to the rear. At the rear of the fuselage a biplane tail-unit with twin fins and rudders provided control and stability in pitch and yaw. Two bungee-sprung plywood-covered main floats with twelve watertight compartments supported the aircraft through a divided strut structure which left clearance for dropping torpedoes from under the fuselage. A single tail float was also strut-supported from the rear fuselage. For ground handling ashore the aircraft sat on beaching dollies under the main and tail floats.
The crew sat in open cockpits, the gunner/navigator at the nose, the pilot forward of the wing leading edges and a second gunner aft of the wings. Armament consisted of one .303 Lewis machine gun, mounted on a Scarff ring, at each of the gunners stations, plus four 230 lb bombs on racks under the wing and/or a torpedo under the fuselage. The crew also had access to Wireless Telegraphy equipment for communications with other stations. Two 150 h.p. handed Sunbeam Nubian powerplants driving four-bladed propellers were located in nacelles sitting on the upper surface of the lower mainplanes. Cooling for the engines was achieved through vertical radiator blocks attached to the rear interplane struts on either side of the engine nacelles, which also supported the oil tanks for each engine.

S.P. (Special Purpose) - a structurally stronger development the G.P. through the use of heavier gauge metal fittings and a revised structure. Other changes included four ailerons, one on each wing, engine nacelles raised clear of the lower mainplanes and scalloped trailing edges through the use of steel wire trailing edge members. Two handed 190 h.p. Rolls-Royce powerplants (later to be renamed Falcon) driving four-bladed propellers.

Three-crew, four-bay biplane anti-submarine patrol bomber, developed from the G P. seaplane. A four-wheel undercarriage was provided which was divided into twin-wheel pairs, with cross axles, all fitted beneath each engine. Accommodation for a bomb-aimer and forward gunner was provided with an exposed cockpit in the extreme nose, which was ahead of the separate open cockpit for the pilot. The rear gunner (who also served as wireless operator) was seated in a third cockpit aft of the wings. Two 250 h.p. Rolls-Royce Falcon II (first four aircraft) or 270 h.p. Falcon III powerplants.