POWER PLANT: One Rolls-Royce “Merlin” 55 liquid-cooled engine, rated at 1,470 hp
PERFORMANCE: 352 mph at 12,250 ft
COMMENT: The Supermarine “Seafire” was a naval version of the Supermarine “Spitfire” adapted for operation from aircraft carriers. The name “Seafire” was arrived at by abbreviating the longer name “Sea Spitfire”.
In late 1941 and early 1942, the Admiralty assessed the “Spitfire” for possible conversion. In late 1941, a total of 48 “Spitfire” Mk Vb were converted to become “hooked Spitfires”. This was the “Seafire” Mk Ib and would be the first of several “Seafire” variants to reach the Royal Navy’s Fleet Air Arm. The second semi-naval variant of the “Seafire” and the first to be built as such, was the “Seafire F Mk IIc which was based on the “Spitfire” Mk Vc. The IIc was the first of the “Seafires” to be deployed operationally in large numbers. Although developed for aircraft carrier use, this version still lacked the folding wings needed to allow them to be used on board some Royal Navy carriers, some of which had small aircraft elevators unable to accommodate the full wingspan of the “Seafires”. The “Seafire” F Mk III was the first true carrier adaptation of the Spitfire design. It was developed from the “Seafire” Mk IIC, but incorporated manually folding wings allowing more of these aircraft to be spotted on deck or in the hangars below. Supermarine devised a system of two straight chordwise folds; a break was introduced immediately outboard of the wheel-wells from which the wing hinged upwards and slightly angled towards the fuselage. A second hinge at each wingtip join allowed the tips to fold down (when the wings were folded the wingtips were folded outwards). This version used the more powerful Merlin or Merlin 55M, driving the same four-bladed propeller unit used by the IIC series; the Merlin 55M was another version of the Merlin for maximum performance at low altitude. This Mark was built in larger numbers than any other “Seafire” variant; of the 1,220 manufactured Westland built 870 and Cunliffe Owen 350 aircraft. (Ref.: 24).
POWER PLANT: Two de Havilland Gipsy Major IC inline piston engine, rated at 140 hp each
PERFORMANCE: 102 mph
COMMENT: In 1941 the Air Ministry issued specification B.11/41 calling for a fast bomber operating from aircraft carriers. Beside high speed and bomb load main requirement was a lay out of the aircraft to give the pilot the best view possible for landing on aircraft carriers. Miles proposed a tandem wing experimental aircraft based on its M.39 design. To prove the concept Miles designed and built a 5/8th scale version, the M.39B Libulella which flew for the first time on July 1943. Flight evaluation showed no “undesirable handling” characteristics and its design coincided with interest by the authorities in unorthodox designs for large aircraft. The rear wing was higher than the forward one to avoid downwash and give ground clearance for the propellers. The M39B design had inboard flaps and outboard ailerons on the rear wing and the front wing had an auxiliary aerofoil/flap/elevator device, which could vary the wing area without changing lift coefficient. Miles continued testing, generating more flight data and submitted an improved M.39 design in early 1944. Meanwhile, the sole M.39B passed to the Royal Aircraft Establishment at Farnborough in 1944, where it was damaged and repaired after two accidents, only to be broken up with the full-sized bomber project’s cancellation (Ref.: 24).