47. There was no true prototype, instead the first production aircraft PS944 and PS945 served as trials aircraft. As the "definitive" carrier based Seafire, the Mk 47 incorporated several refinements over earlier variants. After the first four aircraft, with manually folded wings, the Mk 47 incorporated hydraulically powered wing folding, the outer wings folding upwards in one piece, without the folding wingtips of earlier marks. All Mk 47s adopted the Rotol contra-rotating propellers. The Mk 47 also featured a long supercharger air-duct, the intake of which started just behind the spinner and a modified curved windscreen, similar to that used on the Mk XVII. Other features unique to the Mk 47s were spring-loaded elevator tabs, a large inertia weight in the elevator control system and beading on the trailing edges of the elevators. These changes improved longitudinal stability, especially when the aircraft was fully loaded. The modified windscreen proved to be unpopular with pilots because of continual problems with misting and the thicker, repositioned frames obstructed visibility during deck landings. In spite of recommendations to change the windscreen back to a standard Spitfire 24 unit, this was never done. Performance tests showed that the Mk 47 was slightly slower than the Mk 46 in maximum and climbing speeds, mainly due to the long supercharger air intake, which was less efficient than the shorter type fitted to earlier Seafires. The first fourteen aircraft were powered by the Griffon 87, but the rest of the 89 production aircraft (built by Supermarine at South Marston) were powered by the Griffon 88, which used a Rolls-Royce fuel-injection system instead of the carburettor used on earlier Spitfires and Seafires. The Seafire 47 saw action with 800 Squadron on board during the Malayan Emergency of 1949 and during the Korean War in 1950. However, in 1951 all Seafires were withdrawn from front-line service. In all 90 F Mk 47s and FR Mk 47s were built, all by Supermarine. VR971, the last of the 22,000 aircraft built under the Spitfire/Seafire program, left the production line at Supermarine on 28 January 1949. The maximum level speed for this mark was: 451mph at 20,000ft or 433mph at 24,000ft, ceiling: 43,100ft, range: 405 miles plus 15 minutes combat. Assessment The Spitfire's original role, in which it proved formidable, was that of short-range land-based interceptor. As a carrier based fighter, the design was a compromise and suffered many losses through structural