The Supermarine Seagull was a biplane amphibian, originally designed to operate as a spotter for naval gunfire at the start of the 1920s. It was then almost completely redesigned for the RAAF in 1933 as the Seagull V, and this version of the aircraft entered British service as the Supermarine Walrus.
The Seagull was first developed by R.J. Mitchell as a Commercial Amphibian, probably known as the Seal I. This aircraft was evaluated by the Air Ministry, which then ordered a single Seal II. This was a two-bay biplane, with a wingspan of 46ft. The wings folded back to reduce storage space on ships. The Seal II was powered by a single 450hp Napier Lion IB engine in a tractor configuration (propeller at the front). The hull was wooden, with an oval cross-section and two steps (to help the aircraft takeoff from water). The pilot operated from a single seat open cockpit positions well forward, and armed with a single machine gun. The radio operator was just behind the wings, with a dorsal gun position further back.
The Seal II made its maiden flight in May 1921. It was then ordered into production in July 1921, as the Seagull I. Six of these aircraft were used from the aircraft carrier HMS Eagle as spotter planes, but the Fleet Air Arm preferred the Fairey IIID in this role, and so the Seagull spent most of its service career operating as a coastal reconnaissance aircraft.
The designation Seagull I was given to the single Seal II after it was given a 480hp Napier Lion II engine and redesigned ailerons and wing floats.
The Seagull II was the main production version of the aircraft. It had a modified fuel system, but was otherwise similar to the Seagull I. Eventually twenty five Seagull IIs were ordered – two in February 1922, five later in the same year to equip 440 (Fleet Reconnaissance) Flight, five in February 1923 and the final batch of 13 in June 1923.
Six Seagull IIIs were ordered for the RAAF during 1926, where their formed No.101 Fleet Co-operation Flight. The Seagull III was similar to the Mk.II, but with a different cooling system. The Seagull IIIs were used for photographic reconnaissance over Papua, Queensland and the Great Barrier Reef, before in February 1929 they were used to equip HMAS Albatross, the first Australian seaplane carrier. In 1933 they were moved again, this time to the heavy cruisers Australiaand Canberra.
One Seagull IV was produced to test out a twin fin and rudder tail. It was also given Handley Page slots.
The Seagull V was designed in response to an Australian requirement for a single-engined amphibian, capable of being launched from catapults mounted on cruisers and larger ships. The aircraft had to be able to operate in waves of up to six feet of height, and was to be recovered by crane. The aircraft was to be used for reconnaissance, survey, communication and gun spotting duties.
Supermarine responded with a heavily modified version of the Seagull. The new aircraft had a cleaner hull, built around a light alloy monocoque and with an enclosed pilot’s cabin. The tractor engine of the earlier Seagulls was replaced with a pusher. The biplane wings were retained, but the number of struts was reduced from twelve (six pairs, three on each side) on the Seagull II to eight (four pairs), four of which also supported the engine. The prototype made its maiden flight on 21 June 1933, with Mutt Summers at the controls.
Over the next few months the aircraft passed a series of trials, including its first catapult launch at the end of January 1934, and in August 1934 the RAAF ordered 24 Seagull Vs, for use on the Leander and County Class cruisers, and on the seaplane carrier HMAS Albatross. The first production aircraft made its maiden flight on 25 June 1935, before being delivered to the Australians.
In May 1935 the British Air Ministry placed their own order for twelve Seagull Vs. The first of these aircraft made its maiden flight on 18 March 1936. Before the British Seagull Vs entered service they were renamed as the Supermarine Walrus, and under this guise would serve throughout the Second World War.
The similarity between the Seagull V and Walrus meant that as the Australian aircraft were lost in action, they could be replaced by new Walruses. The last flight of Seagull Vs to survive was that on HMAS Australia, still intact in the summer of 1943. A small number survived the war, some of which later entered civilian service.
Napier Lion IIB
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