The Schneider Prize was a trophy awarded to the winner of a race for seaplanes and flying boats. It was financed by Jacques Schneider, a balloonist and aircraft enthusiast and was intended to take place annually and latter biannually. If an aero club won three races in five years, they would retain the trophy. The competition offered a prize of approximately £1,000. The first contest took place in April 1913 which the French won with a French Deperdussin at a speed of 45.75 mph.
The Supermarine company, founded in 1913, entered the race in 1922 with the Supermarine Sea Lion II developed by the company’s chief designer and chief engineer, Reginald Mitchell. Competing against the French and Italians it won with an average speed of 145.72 mph.

For the seventh contest at Baltimore, USA in October 1925 Supermarine built a racing floatplane the S.4. It’s clean, cantilever mid-wing, wood-built monoplane construction with fabric-covered wings and a 700hp Napier engine uprated for racing caused quite a sensation and on 13 September 1925 it gained the seaplane world speed record in England at 226.6 mph. However, when flying over Chesapeake Bay, before the contest it developed wing flutter, went out of control and dived into the sea two miles off-shore and was therefore not able to compete – the pilot Captain Biard was lucky to be rescued. The race winner was America with a C.2 floatplane flying at 232.57 mph.

When the Italians won in 1926 with a Macchi Mono-seaplane at 246.44 mph the British Government was realising the technical important of this competition. They established an experimental High Speed Flight at Felixstowe air station with pilots drawn from the elite of Service test pilots. Mitchell started work on improving the S.4, but the design of the new S.5 was not ready until the 1927 competition for which it now sported low fabric-covered wings wire braced to counter the flutter problem, a narrower fuselage and fuel stored in the floats. The fuselage and float were made from duralumin, one of the earliest types of age-hardenable aluminium alloys.

At the Lido, near Venice, on 26 September Flight Lieutenant Webster piloted the S.5 with a geared-down propeller to victory at 281.65mph. Flight Lieutenant Worsley came second in the slower direct-drive S.5. 1927 was the last annual competition, the event then moving onto a biannual schedule to allow for more development time. However, in November 1928, Flight Lieutenant D’Arcy Greig raised the British speed record to 319.57mph in Webster’s winning S.5.
For the 1929 competition Supermarine entered the S.6 now of all metal construction and with the 1,900hp Rolls-Royce R engine which was designed specifically for racing. Flying Officer Waghorn won in his S.6 at 328.63mph.
Two years later the country faced a financial crisis and, although another win would enable Britain to retain the trophy outright, the government decided to withdraw support for further development. Following a public outcry and a campaign supported by Lord Rothermere, a substantial donation by Lady Houston of £100,00 saved the day and enabled Mitchell of Supermarine to upgrade the existing S.6 airframes that participated in the 1929 race and to boost the Rolls Royce engine to 2,300hp.

When Britain was ready there were no challengers and on 12 September Flight Lieutenant Boothman piloting the S.6B averaged 340.08mph round the course thereby gaining a technical victory and winiing the trophy outright with a third straight win. Later that month the S.6B, flown by Fligh Lieutenant Stainforth, became the first aircraft in the world to exceed 400mph when setting a new record of 407mph – all at a time when the air was dominated by biplanes!
Mitchell was to apply much of the knowledge acquired in designing his racing floatplanes to the development of the Supermarine Spitfire fighter, but one which was to have radically different design elements.