The G.42 was designed by Gloster to the specification E.1/44 as a fighter, and was of all-metal construction, except for the wooden upper fin. It featured a mid-positioned wing, had an exceptionally broad fuselage and an landing gear with an unusually wide track. It was to have four 0.79 in (20 mm) British Hispano cannons and had provisions made to carry two bombs or 8 rockets under the wing.
The first prototype (SM809) was completed in July 1947 but was damaged beyond repair during road transfer to Boscombe Down, Wiltshire, England, UK, for first flight in August 1947. Building of the second prototype (TX145) was accelerated and the aircraft made its first flight from Boscombe Down on March 9, 1948 piloted by Bill Waterton.
Performance was quite good with a top speed over 600 mph (965 kmh) and a satisfactory rate of climb, but handling qualities fell short of requirements. To improve the handling qualities the third prototype (TX148) was fitted with a revised tail assembly similar to the Meteor F.Mk.8, moving the tail plane from the fuselage up mid-fin position and this proved very effective.
The aircraft performance was quite satisfactory but had no further development potential, so the project was abandoned with the fourth prototype nearly completed. TX145 and TX148 were used at Farnborough, Hampshire, England, UK, for some years testing braking-parachutes and flight control systems.
Single-seat day fighter
One 5,000 lb (2,268 kg) st Rolls-Royce Nene II turbojet
36 ft 0 in (10.97 m)
38 ft 0 in (11.58 m)
11 ft 8 in (3.56 m)
254 sq.ft (23.60 sq.m)
8,260 lb (3,747 kg)
11,470 lb (5,203 kg)
620 mph (998 km/h) at sea level
to 40,000 ft (12,192 m) 12.5 min
48,000 ft (14,630 m)
1 hr at 30,000 ft (9,144 m)