The Short R.24-31 (or Short S.18 and nicknamed the Knuckleduster) was a British twin-engined high-wing cantilever gull winged monoplane flying-boat designed and built by Short to Air Ministry specification R.24-31 for a General Purpose Open Sea Patrol Flying Boat. The contract also specified the use of the experimental Rolls-Royce Goshawk engine. The Saunders-Roe London and the Supermarine Stranraer competed successfully for this contract.
Made by Short Brothers.