Great Design… the Supermarine Spitfire

Thoroughbred lineage: Supermarine S series airframes and the Rolls-Royce R series engines


My grandfather George Garrett was designer of the floats for the Supermarine Spitfire shown below.

Proudly I hope you enjoy the article.

Nick Garrett


The S Series

Supermarine S5
Supermarine S5

Designed by Supermarine ‘s brilliant Chief Designer Reginald J. Mitchell the Type 300 Spitfire was a thoroughbred design whose lineage can be traced back through Mitchell’s ‘S’ series of high-speed racing floatplanes of the late 1920’s that competed for the ‘Coup Schneider’ (‘Schneider Cup’) seaplane contests after the first World War.

These popular sea-plane races attracted aviations elite designers and pilots, spurring phenomenal advances in aerodynamic technology and high speed engine development during the years between the two world wars.

Advanced aerodynamics and airframe engineering were mated to unbridled horse power when Henry Royce developed a special R (R for racing) series of the Rolls Royce Kestrel engine for Mitchell’s new S6B seaplane, and the union secured the Schneider Cup for Britain in 1931. The R series trippled the original output of the Kestrel to over 2000 horse power.Mitchell ‘s Supermarine S6B was one of the major technical achievements in British aviation between the two world wars, and set an absolute speed record of 656 km/h (407.5 mph) on 29 September 1931, alarmingly almost twice the speed of Britain’s fastest service fighter aircraft at that time!

the Rolls Royce R Series engine is shown here being lowered into the Supermarine S6B during its construction.
Supermarine S6B General characteristics
Crew: 1
Length: 28 ft 10 in (8.79 m)
Wingspan: 30 ft 0 in (9.14 m)
Height: 12 ft 3 in (3.73 m)
Wing area: 145 ft? (13.5 m?)
Empty weight: 4,590 lb (2,082 kg)
Loaded weight: 6,086 lb (2,760 kg)
Max takeoff weight: lb (kg)
Powerplant: 1? Rolls-Royce R , 2,350 hp (1753 kW)

Maximum speed: 354 knots (407.5 mph, 655.8 km/h) (world speed record)
Wing loading: 42lb/ft? (205 kg/m?)
Power/mass: 0.386 hp/lb (0.635 kW/kg)

[more: Legacy of the R series engines]


Supermarine S6B
This Supermarine S6B raised the world absolute speed record to 656 km/h (407.5 mph) in Sept 1931.
Rolls Royce R Series engine being lowered into the Supermarine S6B during construction

Supermarine Type 224

The first Supermarine ‘Spitfire’ (the Type 224 design) first flown in 1934 didnt satisfy expectations. After their success with the the high speed S Series of monoplane racers, Mitchells team thought that designing a fighter to Air Ministry specification F.7/30 would be a relatively simple affair. The design was also hampered by the evaporative cooling design of the 660 horse power Rolls Royce Goshawk engine. The fighter contract was eventually awarded to the Gloster SS 37 (Gladiator) biplane because of it’s climb rate advantage over the monoplane designs.

In 1934 the Supermarine 224 design was subsequently cleaned up and succesive specifications sought from the air ministry to cover the refinements, eventually leading to the superb Type 300 that followed.

Type 224
The first Supermarine ‘Spitfire’ – the gull winged Type 224 was not a success, but should be considered a valuable stepping stone to the Type 300 that followed.


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