SUPERMARINE SEAFIRE (Merlin, fighter) - Single-seat, high-performance naval fighter initiated during 1941 as Sea Spitfire, based at first on Spitfire VB airframe fitted with 'A'-frame arrester hook and catapult spools for accelerated take-offs from carrier decks. First Spitfire VB with arrester hook (BL676) flown October 1941; two further prototypes (AB205, AD371) converted, with hooks and spools, in January/February 1942. Name Supermarine Seafire then adopted for fully-navalised version of Spitfire, as described below. In addition, from 1942 onwards, FAA received some 77 Spitfire lAs, four Spitfire IIAs, 26 Spitfire VAs, 149 Spitfire VBs and 11 Spitfire PR XIIIs. Most of these un-navalised, but including about 40 (mostly Spitfire VBs) hooked for airfield training. FAA also took on charge single Spitfire HF Mk IX in May 1945, and tested three (or more) Spitfire VIIIs fitted with 'sting' arrester hooks in April 1944.
Supermarine Seafire F Mk IB: Total of 166 Spitfire VBs converted (and given new serial numbers) by Air Service Training at Hamble (136) and Phillips & Powis or Supermarine at South Marston (30). As Supermarine Type 340, fitted with 'A'-frame arrester hooks; no catapult spools on first 48. Armament and equipment as Spitfire VB, with Merlin 45 (few with Merlin 46). Deliveries from mid-1942; principally used for training, but No 801 Sqn fully-equipped aboard HMS Furious October 1942 as second operational Supermarine Seafire squadron.
Supermarine Seafire II: First naval production variant, based on Spitfire VC airframe, with 'A'o.frame hook, catapult spools and fuselage strengthened, armament of two cannon/four mgs in 'C' wing (alternative provision for four cannon) . Provision for RATOG and, like Spitfire VC, could have tropical filter and carry bombs, and/or have 'clipped' wing tips. One original Supermarine Seafire prototype (AD371) converted to Supermarine Seafire IIC prototype, flown February 1942. Production (Supermarine Type 357) by Supermarine (262) and Westland (110); first production aircraft flown May 28, 1942. Initial Supermarine Seafire F Mk IIC had Merlin 45, 46, 50 or 55, and entered service with No 807 Sqn (first Supermarine Seafire unit in FAA) in mid-1942, operating in Operation Torch from HMS Furious with additional Supermarine Seafire squadrons. After successful testing late-1942 of Spitfire I (L1004) fitted with 1,645 hp Merlin 32 with cropped impeller for better low-altitude performance, combined with four-bladed propeller, this engine adopted for Supermarine Seafire L Mk IIC (Supermarine Type 375), with at least 60 of production total to this standard; first operational May 1943 with No 807 Sqn. About 10 aircraft were Supermarine Seafire FR Mk IIC (provisionally, PR L Mk IIC or LR Mk IIC), fitted by Heston Aircraft with one F.24 (20-in/51-cm) vertical and one F.24 (14-in/35.5-cm) oblique cameras in fuselage. First conversion flown July 1943.
Supermarine Seafire III: Developed from Supermarine Seafire II with double-folding wings (mainplanes up, tips down) for improved stowage aboard carriers. Prototype (MA970) converted from first production F Mk IIC, first flown November 1942. Basic production Supermarine Seafire F Mk III (Supermarine Type 358) normally powered by Merlin 55 (but Merlin 45, 46 and 50 also used), and four-bladed propeller; featured improved u/c for deck operations and, after first small batch, deletion of outer cannon bays in 'C'-type wing. Provision for RATOG and bombs, as Supermarine Seafire II. Major variant was Supermarine Seafire LF Mk III (often also called L Mk III) fitted for low-altitude operations with Merlin 55M. Small number of LF Mk Ills fitted with vertical and oblique cameras, as in FR Mk IIC, and designated Supermarine Seafire FR Mk III; first conversion, by Heston Aircraft, completed June 1943. Total Supermarine Seafire III production, 1,263, by Westland (913) and Cunliffe Owen (350), included about 30 initially with fixed wings, known as L Mk IIC Hybrid until converted. First production Supermarine Seafire III completed May 1943; service use began November 1943, with No 894 Sqn.
Data for LF Mk III: Max speed, 348 mph (560 kmlh) at 6,000 ft (1,830 m). Initial climb, 4,160 ftlmin (21.13 m/sec). Time to 5,000ft (1,525 m), 1.9 min. Service ceiling, 24,000ft (7,315 m). Range (with drop tanks), 513 mis (825 km). Empty weight, 6,204 Ib (2,814 kg). Gross weight, 7,640 Ib (3,565 kg). Span, 36 ft 10 in (11.23 m). Length, 30 ft 2'/2 in (9.21 m). Wing area, 242 sq ft (22.48m2).