The Ancestors

The British aircraft constructor Reginald J. Mitchell, who started at Supermarine in 1917 and became chief designer and managing director 10 years later, had designed and built several splendid aircraft. Among these seaplanes like the Supermarine Sea Lion II, Supermarine S4 and S6B, which secured Britain the Schneider trophy. This trophy was set up for grasps by the Frenchman Jacques Schneider. The winner of the 150 nautical mile (277.8 km) long speed competition for seaplanes could if he won the race for his country 3 times make the trophy the country's permanent property. The S6B did the "race track" at an average speed of approximately 407 mph (651 km/h) and thus secured the trophy in front of the noses of the Italians, who were also pacesetting in regards to seaplanes. The S6B was equipped with a liquid cooled 12 cylinder Rolls-Royce R25R engine which had an output of 2,600hp at 3,400 rpm. The R25R was purpose designed - a big output and a short life - only a 5 hours TBO (time between overhaul). The engine ran on a mixture of petrol, methanol, benzole and tetra-ethyl lead.

The S6B could carry 378 litres of fuel of which the 252 were contained in starboard (right) float. You can imagine that this imbalance in weight would give the aircraft some interesting flying characteristics, however, the torque of the propeller compensated for this.

The Italians were still the main opposition at later races and they also beat the S6B, but contrary to Supermarine the Italians never succeeded in transferring the race results to something useful and durable in later civil and military aircraft. Supermarine, however, gathered invaluable experience about construction and work with all-metal constructions.

Later Mitchell and Supermarine designed a fighter aircraft meeting the specification F7/30. It was called Type 224. This was a low set winged tail wheel aircraft with an open cockpit and faired main undercarriage. This aircraft was far from a success, because it only achieved an quite unimpressive top speed of 238 mph (380 km/h), which was about 12 mph below what was asked for in the specification. The problems were a drag caused by the thick wings and the fixed and faired undercarriage. The engine, the Rolls-Royce Goshawk, suffered from overheating. The engine overheat warning light came on all the time. The coolant evaporated in the engine, condensed in the wings leading edges and was returned to the engine. The system was not good enough. The project was scrapped and 224 was used for gunnery practice.

It was the Gloster Gladiator (a biplane) that won the contract.

In 1934 Hawker Aircraft and Supermarine both submitted a project meeting the specification F37/34. This specification contained elements from earlier specifications e.g. F7/30, so the aircraft should be a low wing monoplane. The important thing was that the new 1000 hp Rolls-Royce PV12 engine was a part of the project. Both of these projects were accepted and the result was 2 of the most well known aircraft in the world: Sidney Camm's Hawker Hurricane and Mitchell's Supermarine Spitfire.
 

 

Rolls-Royce R25R

 

The Supermarine S6B

 

The unsuccessful Type 224 fighter.

 

R.J. Mitchell