The Supermarine Sea Urchin was an unbuilt British racing biplaneflying boat designed by the Supermarine Aviation Works to compete in the 1924 Schneider Trophy. It was to be a single seat biplane, powered by a Rolls-Royce CondorV-12 water-cooled engine buried in the fuselage, driving a pusher propeller mounted on the upper wing via geared shafts. It was abandoned without being built owing to problems with the engine and the transmission required to drive the propeller.[1]
Powerplant: 1 × Rolls-Royce Condor V-12 water-cooled piston engine, 600 hp (450 kW) driving the propeller through bevel gearboxes and a transmission shaft