Spitfire PR Mk Ia serial N3071 at Lilly, France 1939
In August 1939, Flying Officer Maurice Longbottom of the RAF submitted a groundbreaking proposal to the Air Ministry. His paper outlined innovative ideas for the future of aerial photographic reconnaissance. Longbottom advocated for the use of a “single small machine” that relied on speed, climb, and ceiling to avoid detection, suggesting that fighter aircraft, like the Spitfire I, could be adapted for long-range reconnaissance missions. By removing armament and non-essential equipment, he argued that significant weight savings could be achieved, allowing for additional fuel to be carried. This adaptation would potentially triple the aircraft’s range, extending it to 1,500 miles (2,414 km) even with the installation of cameras and extra tanks.
Initial Reception and Early Adaptations
Initially, the Ministry was not enthusiastic about Longbottom’s proposal. However, the heavy losses experienced by Blenheims and Lysanders in early war reconnaissance missions quickly changed their perspective. The urgent need for a more effective solution led to the release of two Spitfire Is (N3069 and N3071) for conversion to reconnaissance standards. These aircraft were delivered to the secret Heston Flight reconnaissance unit, commanded by Wing Commander Sidney Cotton.
Sidney Cotton’s Contributions
An Australian, Sidney Cotton played a crucial role in establishing the Heston Flight. Prior to the war, he had covertly photographed various strategic locations in Germany, including the Ruhr Valley and numerous military installations, using a pair of Lockheed 12A aircraft. Operating under the guise of a businessman for the ‘Aeronautical Research and Sales Corporation’, Cotton’s activities laid the groundwork for the reconnaissance capabilities that would be developed further during the war.
Modifications and First Missions
The initial modifications to the Spitfires included the installation of a 5-inch (12.7 cm) focal length vertical camera in each wing. Although no additional fuel capacity was added, the aircraft were streamlined (e.g., gun ports sealed, joints filled) to enhance their speed by an extra 10-15 mph (16-24 km/h). Maurice Longbottom, now a Flight Lieutenant, flew the first reconnaissance mission in one of these modified Spitfires on 18 November 1939.
Evolution of the Reconnaissance Unit
The Heston Flight was soon renamed No. 2 Camouflage Unit, a title reflecting the unique bluish-green ‘Camotint’ color scheme initially applied to the aircraft. However, as the unit evolved, it became known as the Photographic Development Unit (PDU) in early 1940, and later, in July of the same year, it was re-designated as the Photographic Reconnaissance Unit (PRU). The Camotint was eventually replaced by the more effective ‘PR Blue’ for high-altitude operations.
The adaptations and innovations initiated by Maurice Longbottom and Sidney Cotton laid the foundation for the Spitfire’s role in photographic reconnaissance. Their work transformed the Spitfire into a crucial asset for the RAF, providing vital intelligence throughout the war and setting the stage for future developments in aerial reconnaissance technology.