Folland Gnat

The Folland Gnat is a British compact swept-wing subsonic fighter aircraft. 


Fo.140 Gnat

Private-venture prototype fighter, one built.

Fo.141 Gnat

Gnat F.1

Single seat lightweight fighter exported to Finland, India and Yugoslavia, 50 built by Folland at Hamble.

This was also built in India under licence as the HAL Gnat.

Gnat FR.1

One aircraft for Finland was built with three nose-mounted 70mm Vinten cameras and designated FR.1, it was joined by a Ministry of Supply aircraft purchased by Folland and modified to the same standard.

Both aircraft were delivered to Finland on 12 October 1960.

Fo.142 Gnat / Gnat F.2

This was to be an improved F.1 using a wing with a 6% thickness-to-chord ratio and powered by a Bristol Orpheus with simplified reheat (BOr.12SR), developing 8000 lbF (35.6 kN) thrust.

A prototype wing was built but not mated to a fuselage or engine.

It was anticipated that this would be capable of Mach 1.5 and have a “marked increase in rate of climb” development was ended because Bristol declined to back development of the reheat.

Fo.143 Gnat / Gnat F.4

Proposed improved F.2 with air intercept radar and ability to carry guided weapons, not built.

Fo.144 Gnat Trainer / Gnat T.1

Two-seat advanced trainer aircraft for the Royal Air Force, 105 built by Hawker Siddeley.

Gnat F.5

Proposed development from January 1960, with larger wing (and flap) area.

It was to be powered by two Rolls-Royce RB153 engines with reheat.

The design also considered operation from aircraft carriers.


This was a two-seat design with variable geometry wings based on a combination of the Gnat Mk5 and the Gnat Trainer.

It was to be powered by two Rolls-Royce RB153 engines with reheat and thrust-reversers.

It was to be produced as either an advanced trainer with weapons capability or as a fighter.

This, and later studies were led by Maurice Brennan.

HAL Ajeet

Indian development of the Gnat F.1

HAL Ajeet Trainer

Two-seat tandem trainer version for the Indian Air Force.

This version was derived from the HAL Ajeet and differed considerably from the Gnat T.1 used by the RAF.





29 ft 9 in (9.07 m)


22 ft 2 in (6.76 m)


8 ft 10 in (2.69 m)

Wing area

136.6 sq ft (12.69 m2)


RAE 102 modified

Empty weight

4,800 lb (2,177 kg)

Gross weight

6,575 lb (2,982 kg) interceptor

8,765 lb (3,976 kg) tactical, with external tanks and armament

Max take-off weight

9,040 lb (4,100 kg)

Fuel capacity

175 imp gal (210 US gal; 800 l) in seven fuselage tanks


25 imp gal (30 US gal; 110 l) in two optional rear fuselage tanks


Two optional 66 imp gal (79 US gal; 300 l) jettisonable underwing slipper tanks,

Maximum fuel 332 imp gal (399 US gal; 1,510 l)


1 × Bristol Siddeley BOr.2 Orpheus 701-01 turbojet engine, 4,705 lbf (20.93 kN) thrust


Maximum speed

604 kn (695 mph, 1,119 km/h) at 20,000 ft (6,096 m)

Maximum speed

Mach 0.98


434.5 nmi (500.0 mi, 804.7 km)


1 hour 10 minutes (normal)

2 hours 15 minutes (Max fuel)

Service ceiling

50,000 ft (15,000 m) +

Rate of climb

20,000 ft/min (100 m/s)

Time to altitude

45,000 ft (13,716 m) 5 minutes

Take-off distance to 50 ft (15 m)

2,190 ft (668 m) (interceptor)

Take-off distance to 50 ft (15 m)

3,780 ft (1,152 m) (tactical)

Landing distance from 50 ft (15 m)

2,200 ft (671 m)



2x 30mm ADEN cannon with 115 rpg


12x 3 in (76 mm) rockets


2x 500 lb (227 kg) bombs


VHF radio

Nav aids

Gyro gun sight

Ranging radar.



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