it confirmed Britain as the outright and final winner of the Schneider trophy. Following the contest a S6b, flown by Flt Lt G. H. Stainforth went on to set a new world air speed record of 407.5 mph. Walrus and Stranraer In response to a 1929 Royal Australian Air Force (RAAF) requirement for an aircraft to replace their Seagull IIIs, but with the ability to be catapult-launched from cruisers, the company in 1931 designated the Type 223 Seagull V as a private venture and built a prototype. This eventually led to the RAAF placing an order in 1934 for 24 production versions which were designated Type 228 Seagull V. The Royal Navy was impressed by the new design and placed an order for 12 aircraft which were virtually identical except for a more powerful engine. Given the designation Type 236, they entered service as the Walrus. More orders were to follow until a total of 740 were built in all by Supermarine and other firms. Following on from the Southampton Mk II the company developed the biplane twin-engined Southampton IV in response to specification R.20/31 for a general reconnaissance flying boat. Featuring all-metal construction with fabric covered flying surfaces, it had an enclosed cockpit. The prototype first flew in July 1932. Renamed the Scapa fifteen were built. Soon after the design of the Scapa was finalised, the Air Ministry issued specification R.24/31 for a twin-engined general purpose flying boat, in response to which Supermarine developed the Stranraer. The prototype first flew in July 1934 and they entered service from April 1937, with the last being delivered to the RAF in 1939. Vickers in Canada also built them for the Royal Canadian Air Force. Supermarine Spitfire In 1930, the Air Ministry began formulating the requirements for an advanced high-performance fighter which were spelled out in specification F.7/30, which was in turn issued in the autumn of 1931 to a number of aircraft manufacturers. Among them was Supermarine, who were keen to broaden its product range from seaplanes and flying boats. In response to the specification, Mitchell designed the Type 224, an all-metal monoplane design, with an open cockpit, un-braced cranked wing and fixed undercarriage. A single prototype was built and first flew in February 1934. Flight testing however identified that it had only average performance and so Supermarine received no production contract. Unhappy at how the Type 224 had turned out