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Folland Gnat

The Folland Gnat is a British compact swept-wing subsonic fighter aircraft that was developed and produced by Folland Aircraft.

Envisioned as an affordable light fighter in contrast to the rising cost and size of typical combat aircraft, it was procured as a trainer aircraft for the Royal Air Force (RAF) as well as by export customers, who used the Gnat in both combat and training capacities.

Designed by W. E. W. Petter, the Gnat has its origins in the preceding private venture Folland Midge.

The issuing of Operational Requirement OR.303 by the British Air Ministry served to motivate the type’s development; the Gnat was later submitted to meet this requirement.

Its design allowed for its construction and maintenance tasks to be carried out without specialised tools, making it suitable for use in countries that had not yet become highly industrialised.

The Gnat has been viewed as a major motivating factor towards the issuing of the NATO NBMR-1 requirement, which sought to make available a common strike/attack light fighter with which to equip the air forces of the various NATO members.

Although never used as a fighter by the Royal Air Force (RAF), the Gnat T.1 jet trainer variant was adopted and operated for some time.

In the United Kingdom, the Gnat became well known due to its prominent use as the display aircraft of the RAF’s Red Arrows aerobatic team.

The Gnat F.1 was exported to Finland, Yugoslavia and India.

The Indian Air Force became the largest operator and eventually manufactured the aircraft under licence.

Impressed by its performance during combat, India proceeded to develop the improved HAL Ajeet, a modified variant of the Gnat.

In British service, the Gnat was replaced by the Hawker Siddeley Hawk.

The Folland Gnat was a purpose-built light fighter aircraft, suitable as both a trainer and a combat aircraft in ground-attack and day-fighter roles. 

The cockpit offered many features expected in standard fighter aircraft: full pressurisation, climate control, and an ejection seat.

According to Folland, the Gnat offered advantages over conventional fighter aircraft in terms of cost, man-hours, handling, serviceability, and portability. 

Its tricycle landing gear let it operate from austere grass airstrips, thanks to the aircraft’s low weight.

The Gnat design used a conventional metal stressed-skin structure, with extensive flush-riveting.

To reduce workload and cost, intensive fabrication methods such as machining, forging, and casting were minimised.

The airframe could be constructed using simple jigs without any specialised skills or tooling.

The wing (for example) could be produced at a quarter of the cost, with less than one-fifth the labour, required for the wings of other contemporary fighter aircraft.

Similarly, the layout and construction techniques used allow the airframe to be rapidly disassembled into its major subsections, without the use of cranes or ladders; the Gnat was vastly easier to service than most other 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 gals (210 US gal; 800 l) in seven fuselage tanks


25 imp gals (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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