Grumman G-83 / XF10F Jaguar
Greater success attended the development of variable-geometry wings, which allow the use of a minimum-sweep position for take-off and landing, an intermediate-sweep position for fuel-economical cruise, and a maximum-sweep position for high dash performance. The navy’s first essay in this field was the Grumman XF10F Jaguar, which was conceived in 1948 as a possible successor to the F9F Panther. The aerodynamic features of a variable-geometry type had already been explored in a number of aircraft, most notably the Westland Pterodactyl IV developed in the UK during the early 1930s, the Messerschmitt P.1011 designed in Germany during World War II, and the experimental Bell X-5 sponsored by NACA and the LTSAF with the ultimate purpose of validating a fighter-type wing with sweep variable between 20 deg and 60 deg. The X-5 had not flown when Grumman set to work on the Jaguar, but a considerable quantity of engineering data was available and this proved valuable to the Grumman engineers, who were faced with a host of problems.
Originally the XF10F had been planned as a development of the Panther with clipped delta flying surfaces. Designed as a transonic single-seat shipboard fighter with an internal armament of four 20-mm cannon and provision for an external bomb load of up to 4,000 lb (1814 kg). The sweep angle of the wings could be varied hydraulically between 13.5 and 42.5 deg, and high-lift devices consisted of full-span slats and an 80 per cent Fowler flap. The concept was then refined to the point at which a tilting variable-incidence wing was in adopted for reduction of the take-off and landing speeds. The navy then added additional responsibilities to the basic fighter-role, and these so increased the structure weight that the company came up with the notion of providing a variable-geometry wing. Further refinement was added after this when it was decided to allow the wing to be swept at any angle between the minimum- and maximum-sweep angles. The provision of such wings increased the type’s weight by 2200 lb (998 kg) but reduced landing speed from 132.5 mph (213 km/h) to 109 mph (175 km/h). The Jaguar was also provided with an advanced control system that included a delta surface forward of the fin to act as a servo for the all-moving tailplane and so improve control response at transonic speed.
The tailplane was operated by a novel arrangement where the pilot controlled a small delta-wing airfoil at the tip of the tail bullet. This in turn moved the main elevator Unfortunately, a lag in the response between stick and surface usually resulted in a Pilot Induced Oscillation (PIO) and the Jaguar was virtually uncontrollable much of the time.
The engineering of so complex an aeroplane took considerably longer than expected, and it was May 1953 before the XF10F prototype flew, three years behind schedule. The Jaguar was intended to be powered by a Westinghouse XJ40-WE-8 turbojet rated at 7,400 lb (3 357 kg) military thrust and 10,900 lb (4 944 kg) with full reheat, but when flight trials were initiated on 19 May 1952, a J40-WE-6 rated at 6,800 lb (3 084 kg) was fitted. The novel servo-control system for the tailplane proved far too slow in operation, and was replaced by a conventional powered tailplane, but it soon became clear that considerable revision of the basic design would have to be undertaken before production aircraft could be considered. Numerous problems arose during the test programme and as some of these could not be resolved, trials terminated with the 32nd flight on 25 April 1953. Orders had been placed for 112 production F10F-1s, but 100 of these were cancelled on 1 April 1953 and the remaining 12 on the following 12 June.
Empty weight, 20,426 lb (9 265kg).
Max loaded weight, 35,450 lb (16080 kg).
Span (min sweep), 50 ft 7 in (15,42 m), (max sweep), 36 ft 8 in (11, 17 m).
Length, 54 ft 5 in (16,59 m).
Height, 16 ft 3 in (4,95 m).
Wing area (min sweep), 467 sq ft (43,38sq.m), (max sweep), 450 sq ft (41,81sq.m).
Max. speed: 1143 km/h / 710 mph
Range: 2687 km / 1670 miles