Developed as an all-weather version of the Douglas F4D, the F5D Skylancer first flew on 21 April 1956. It used a more powerful engine (Pratt & Whitney J57 – the first 45kN thrust class turbojet engine). Compare to the F4d, the wing was thinner, but more reinforced, the fuselage was area-ruled, reducing transonic drag and was 2.4m longer.
Originally nine test aircraft were ordered, with a 51 production run to follow, although only four of the test aircraft were built. During testing, the US Navy decided that the Skylancer was too similar to the Vought F8U Crusader that was already in service and canceled the contract.
The F5Ds continued as test aircraft, being passed on to NASA in the early 1960s, two were grounded and used for spare parts. One was used as a testbed for the American supersonic transport program, fitted with an ogival wing platform (the type eventually used on Concorde). Data from the program was shared with the European designers.
Both of the aircraft used by NASA were used to support the Dyna-Soar project. One was retired in 1968 followed by the second in 1970.
The Supermarine Seagull II was developed as an amphibious aircraft for the RAF for operation from the Royal Navy’s aircraft carriers. At the time, the RAF controlled all flying activities for the Royal Navy. Developed from the Supermarine Seal, the two prototypes (N158 and N159) were designated as the Seagull I.
A total of 25 Seagull IIs were built, with one going to Japan along with the Seal II for evaluation. The Seagull II proved unpopular in use, with slow speed and poor sea keeping. It was replaced by the Fairey III.
An improved Mk III version was ordered by the Royal Australian Air Force for use on the Royal Australian Navy seaplane tender HMAS Albatross.
Supermarine Seagull prototype N-158Supermarine Seagull N-9563Supermarine Seagull N-9605Supermarine Seagull N-9642Supermarine Seagull N-9643Supermarine Seagull G-EBXH on the civil register
Based on the Supermarine Commercial Amphibian which achieved second place in an Air Ministry competition in 1920, the Supermarine Seal II prototype first flew on 21 May 1921. The designation Seal II is presumed to come from the Commercial Amphibian which was briefly named Seal before it crashed and was written off.
Testing by the RAF of the Seal II resulted in several changes, including a more powerful engine and relocation of the fuel tanks to the upper wing. Two additional prototypes were ordered, but were renamed Seagull before delivery. See these pages for photos and a brief history of the resulting Seagull IISeagull III and Seagull V (which became the Supermarine Walrus).
The Seal II and one of the prototypes were sold to the Imperial Japanese Navy Air Service for evaluation.
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