S.6B

The Supermarine S.6B is a British racing seaplane developed by R.J. Mitchell for the Supermarine company to take part in the Schneider Trophy competition of 1931. The S.6B marked the culmination of Mitchell's quest to "perfect the design of the racing seaplane" and represented the cutting edge of aerodynamic technology for the era. The S.6B was last in a line of racing seaplanes to be developed by Supermarine, following the S.4, S.5 and the S.6. Despite these predecessors having previously won the Schneider Trophy competition twice, the development of the S.6B was hampered by wavering government support, which was first promised then withdrawn, and then given once more after a high-profile public campaign encouraged by Lord Rothermere and backed by a substantial donation by Lady Houston. Once government backing had been secured, there were only nine months before the race, so Mitchell's only realistic option was to refine the existing S.6, rather than attempting a new design. The principal differences between the S.6 and the S.6B were the increased power of the Rolls-Royce R engine and redesigned floats: minor aerodynamic refinements typically aimed at drag reduction were also made. A pair of S.6Bs, serials S1595 and S1596, were built for the competition. Flown by members of RAF High Speed Flight, the type competed successfully, winning the Schneider Trophy for Britain. Shortly after the race, S.6B S1596, flown by Flt Lt. George Stainforth, broke the world air speed record, attaining a peak speed of 407.5 mph (655.67 km/h).

Summary from Wikipedia, photo via Wikimedia Commons, licensed under CC BY-SA.