Seversky Reborn - Late-Model Radial-Engined SF200s With Sea Legs
The Mercury-Serval series was not the end of the radial-engined Seversky SF200 series. British Fleet Air Arm interest in the stillborn Cyclone-Serval was transferred to the more promising X-100-powered version as that project matured. Pratt & Whitney was finally able to begin delivering production R-2000 engines in late 1942. By that time, Seversky had already improved its original engine installation.
To take full advantage of the extra powered delivered by the R-2000, Seversky had lengthened the fuselage. This pushed the cockpit rearward leaving space for an additional fuselage fuel tank behind the firewall. Less obvious changed included the strengthened the main gear (along with the undercarriage door revisions introduced on the
inline-engined SF250 series). Compared with its X-100 installation, Seversky revised the exhaust outlets, replacing a single pipe on each side with multiple exhaust thrust augmenter tubes. An updraught Bendix-Stromberg PD12 carburettor was used and twin oil cooler intakes were let in to the wing leading edges.
The driving force behind the R-2000-powered SF225 was the British Fleet Air Arm. But, ironically, the FAA released the first SF225s for use by the Royal Netherlands East Indies Army. But the NEI fell to the Japanese for a single SF225 had been completed for the ML-KNIL. Eight airframes near completion were taken over by the US Navy. The remainder were converted on the line into FAA Sea Horse F.Mk.Is.
(Top) A Seversky YF2N-1 of the US Navy's Fleet Air Combat Training Unit (Fighter) using dissimilar air combat training to familiarized Naval Aviators with Japanese fighter tactics. Note 'shipping out' style buzz codes.
Although the Seversky Sea Lion had not been an impressive performer, the FAA had appreciated its cannon armament. At the time, Sea Hurricanes were considered interim equipment and the FAA was very interested in more powerful, radial-engined fighters. The SF225 Sea Horse was seen as a potential Marlet replacement. Unfortunately, R-2000 deliveries were never a wartime priority for Pratt & Whitney. High numbers of Sea Horses were never attained. Despite this, the Sea Horse was one of the most highly regarded FAA fighters until the advent of the Hawker Sea Fury.
(Bottom) A Seversky Sea Horse F.Mk.IA of No.804 Squadron on convoy duty aboard HMS Emperor, Oct-Nov 1943. Note 'carrier' tailwheel, catapult spools, and belly arrestor hook. The F.Mk.IA introduced a bulged canopy and eliminated wing-mounted machine guns.