Spitfire prototype during the service trials at the Aeroplane and Armament Experimental Establishment in Martlesham Heath. This is also where this excellent photo was taken, probably in the last days of May 1936.

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Like many RAF aircraft before and after, the Spitfire prototype went through a series of service trials at the Aeroplane and Armament Experimental Establishment (A&AEE) in Martlesham Heath in Suffolk. This is also where this excellent photo was taken, probably during the last days of May 1936.

During the two-plus months since its initial flight on 6 March 1936, the Spitfire prototype was brought to a more “final” state, although a lot of refinement work was still remaining. It now had wheel well covers and a rebuilt cowling with proper air-tight sealing. The carburettor air intake underneath the nose was redesigned and shortened. A reflector gunsight was installed. The rudder received a “squared” balance horn. All rivet indentations and panel joints were filled and sanded to a smooth surface to minimize drag, and the aircraft was painted in a glossy light grey-blue finish, allegedly based on automotive lacquer. The tail skid was still remaining, as was the long pitot tube mounted in the port wing’s leading edge.

The prototype also underwent a series of high-speed trials, which lead to the conclusion that the selected propeller did not get the best out of it in terms of level speed. Indeed, the prototype was at best clocked at 349 mph at 16,800 feet, whereas later series-production Spitfires Mk. I, would be achieving as much as 364 mph with full equipment.

Last but not least, the aircraft was now officially named the Spitfire. Its previously used designation was Supermarine F 37/34 after the Air Ministry specification number to which it was designed.

K5054 was delivered to Martlesham on 26 May 1936. Amazingly, already on 3 June Supermarine received their first order from the Air Ministry for 310 Spitfires to the value of £1.25million. Such was the urgency assigned to the RAF rearmament programme that the huge contract – one of the largest in the history of British aviation, and certainly the largest ever for Supermarine – was awarded solely on the basis of A&AEE test pilots’ first assessment of the type, which related by the telephone to the Air Ministry in London. War was looming at the horizon.

The full report entitled “Handling Trials of the Spitfire K5054” emerged only in September, but luckily it only reinforced the favourable impression. Summarising the flying qualities, it concluded:

“The aeroplane is simple and easy to fly and has no vices. All controls are entirely satisfactory for this type and no modification to them is required, except that the elevator control might be improved by reducing the gear ratio between the control column and the elevator. The controls are well harmonised and appear to give an excellent compromise between manoeuvrability and steadiness for shooting. Take-off and landing are straightforward and easy.”

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