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Note: This is a sub-section of Supermarine.
The Supermarine-Napier S.4 monoplane was entered for the Schneider Trophy contest in America 1925. The designer was Mr Mitchell.
"Instructions to proceed with the construction of this machine were issued by the Air Ministry on March 18th. 1925, and the first flight was carried out on August 25th, 1925. The machine was of an entirely new design and embodied a number of very novel features. The machine is a cantilever monoplane in which entirely new methods of construction were incorporated. These methods, made it possible for the design to be carried out.
The wing itself was built all in one piece and the wing section is one which has been recently developed at the Royal Aircraft Establishment, Farnborough. The wing form was not adopted until a trial wing had been constructed and tested to destruction at Farnborough. The tail unit, including the fin and tail plane, was built in one piece with the fuselage.
The cantilever chassis was made flexible by the use of high-tensile steel members which absorb the landing shocks very efficiently. Flap gears were fitted to reduce the landing speed and wooden floats were employed. Cleanliness of design was the first consideration. To this end all the controls, &c., are internally operated, thus reducing head resistance. Every component is covered either with wood or with metal and no fabric whatever is used. Wing radiators are fitted and the propeller is of metal. A special lubricating oil cooler of a new design particularly developed for high-speed aircraft is employed.
The engine is a special form of direct-drive Napier Lion. A Bristol gas starter is used for starting up the engine.
On September 13th, over a 3-kilometres course on Southampton Water, it achieved a speed of 226.752 miles per hour. This figure has been accepted officially as a world's record. How great is the advance it represents will be understood when it is remarked that the previous record speed for seaplanes was 188.118 miles per hour, established just a year ago at Baltimore on a Curtiss-Navy racing machine."
Unfortunately the S.4 was lost in an accident prior to the competition.