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« on: March 25, 2007, 10:11:05 PM »
The Story of the Spitfire as a photographic reconnaissance aircraft starts at the end of 1939, by which time operational experience with Blenheims and Lysanders used on photographic missions had shown that an aeroplane capable of flying much faster and higher was needed.
A special flight, christened the " Heston Special Flight," was formed, and was equipped with two Spitfires specially converted at RAE. Farnborough. With one F.24 camera mounted vertically in each wing these Spitfires did not prove satisfactory. The first, unsuccessful, sortie was made from a French base against Aachen on November 18, 1939; after a few more sorties the Flight returned to Heston on January 11, 1940.
Re-named No. 2 Camouflage Unit, the Flight studied its mistakes and the shortcomings of the Spitfire as then converted, and there was evolved the first of a series of Photographic Reconnaissance Spitfires, forerunners of the Spitfire P.R.MkXI, probably the most successful photographic aeroplane in the world.
The original R.A.E. modification was designated the Spitfire A; the next model, a service conversion made at Heston was the Spitfire B. One of the disadvantages discovered with the Spitfire A was the lack of range, so a 29-gallon fuel tank was introduced into the rear fuselage, behind the pilot, on the Spitfire B. One vertical camera was carried in a fairing beneath each wing; only a few Spitfire Bs were produced. At his point, the Heston Aircraft Co., Ltd., was asked to under-take the development work on the Spitfire, and to that company must go the credit for the ground work which eventually enabled the RAF, to obtain complete photographic coverage of enemy territory.
The first Heston Aircraft conversion was the Spitfire C, which for the first time used a vertical camera in the fuselage. The wing blisters were retained, but carried two cameras under the port wing, and additional fuel under the starboard wing. Extra oxygen was carried for maximum high altitude flying, and the 29-gallon rear fuselage tank was also retained. Next in line came the first variant used in appreciable numbers.
The Spitfire D, as it was designated, incorporated several important modifications; a fuel tank of 66 gallons capacity was fitted in the leading edge of each wing, which gave a total fuel capacity of 218 gallons, there being no rear fuselage tank. No cameras were carried in the wings, but two F 8 (20-in.), F.24 (20-in.) or F.24 (14-in.) were mounted in tandem in the fuselage; these were "split,' i.e., both were slightly off vertical so that two overlapping photographs were taken simultaneously, Other features were hot air camera heaters, glycol cockpit heater and extra oxygen. The additional petrol necessitated more oil being carried, and this was provided in a 14-gallon tank in a small teardrop fairing beneath the port wing. Records of the Spitfire E are incomplete. It was a modification jointly evolved by R.A.E. and Photographic Development Unit (which the Camouflage Unit had now become) at Benson, and apparently mounted a camera in each wing, and one for oblique shots in the fuselage side behind the pilot.
Almost concurrently with the Spitfire D, Heston Aircraft produced the Spitfire F, which allowed for the installation of one vertical F.8 (20-in.) camera, or two F.8 (20-in.) vertical split cameras, or two F.24 (20-in.) vertical and one F.24 (14-in.) oblique cameras. Oxygen economizers were fitted for the first time, and additional oxygen bottles were carried, one in each wing and one behind the rear fuselage tank.
Next part to follow soon
Image is of a Spitfire PR Mk1D also known as a PRIV