HAL/Hawker Siddeley (Folland) Gnat Mk.1

During 1954 the Indian Government was expressing keen interest in light fighter developments in the U.K. and this was firmed after initial flights of the experimental Midge took place in the latter months of 1954. The project offered the advantages of simplified cost-effectiveness, a unit aircraft costing one-third and requiring one-fifth the production time of a comparable contemporary fighter. Folland Aircraft announced in October 1955 that negotiations with the Indian Government were at an advanced stage for the supply of a number of Gnats as well as a licence for the manufacture of the aircraft in India. The British Ministry of Supply had meanwhile ordered six Gnats for development purposes and an Indian test pilot, Wing Commander Suranjan Das, was attached to the Gnat Flight Development team at Chilbolten.

On September 15th 1956, the Indian Government concluded an agreement with Folland’s to produce the Gnat under licence at Bangalore, the agreement including a supply of 23 complete Gnat Mk.ls and 20 sets of components for assembly by HAL. The sixth Gnat of the original British M.O.S. order was diverted against the Indian contract and the aircraft, G-39-3, was to be used as a development aircraft. Sporting the I.A.F. serial IE 1059, this first Gnat was transported to India in an I.A.F. C-119G late in 1957 and the Indian public had their first glimpse of the sky-blue coloured Gnat on R-Day in January 1958. A Gnat Handling Flight was formed at the Aircraft and Armament Testing Unit at Kanpur to work out Standing Operating Procedures (S.O.Ps), establish syllabbi for training and evolve maintenance techniques. The Gnat at this stage was practically bought out as a prototype and had to be developed by the Indian Air Force into a fully proven service aircraft.

Teething troubles encountered were gradually ironed out but the major problem involved the all-moving flying (slab) tail plane. The system of longitudinal control with a Hobson unit was to remain the Gnat’s Achilles heel for years; improvements were dictated through the years of service life and these included a modification of the flying controls and hydraulic system and gun feed arrangements.

An Indian Gnat was “borrowed” by the Royal Air Force in 1958 to assess its usefulness as a tactical ground attack fighter but by mid-1959 the Gnat had been cleared for Squadron service with the Indian Air Force, primarily for the air defence role. No.23 Squadron, then flying Vampires at Poona, was selected as the first unit to equip with the light fighter and received a batch of six Gnats on 18th March 1960 at Ambala, the aircraft being from amongst the twenty-three Folland-built Gnats. Meanwhile some new factory buildings for the project at HAL, Bangalore were completed in 1959 and production of the airframe commenced from the imported components. The first HAL-assembled Gnat flew on 18th November 1959 while the first Gnat of an initial order for one hundred aircraft and built at HAL from raw materials flew over two years later, on 21st May 1962; the first Orpheus 701 turbojet for the Gnat had come off the assembly line on 21st November 1960.

The Gnat was an “exhilarating” aircraft to fly and at the time capable of outclimbing, outturning and out-accelerating contemporary transonic-class fighters in South Asia, although the light fighter demanded flying to greater accuracies and a high quantum of maintenance. More formations were re-equipped with the Gnat: No.2 Squadron supplanted its Toofanis with the Gnat at Ambala early in 1962 and was followed by No.9 Squadron. A fourth Gnat unit, No. 18 Squadron, was in the process of formation when tension on the borders broke into full-scale hostilities in September 1965.

The need for the IAF to go into action had been made imperative by the Pakistani armoured thrust across the international border and the ceasefire line in the Chhamb sector. Although the first strike by the I.A.F. staggered the Pak. thrust, the slower I.A.F. ground attack aircraft were engaged by enemy Sabres with losses suffered and the Gnats were cleared for offensive patrols. At 7.00 a.m. on 3rd September 1965 a formation of P.A.F. Sabres was reported over Indian army positions in Chhamb and a section of Gnats from No.23 Squadron were scrambled for interception. Inspite of the presence of F-104s, one Sabre was shot down by a Gnat, this marking the start of the air superiority which the IAF maintained through the war. All further Mystere IVA ground attack missions in Chhamb were given a Gnat escort; on the 4th September four Mysteres, covered by four Gnats, mounted a low level attack on Pak. army targets and were intercepted by four F-86Fs. The Gnats intervened and in the resulting dogfight two Sabres were shot down without loss to-the I.A.F.
The three Gnat Squadrons, with the fourth as a feeder unit, were mainstay in the air defence, fighter-escort role while also providing CAPs over most operational air bases. Gnats, in flights of four, provided escort to Hunters, Mysteres and, on occasion, Canberras, and frequently carried out fighter sweeps themselves into Pakistani territory but without challenge and only targets of opportunity were shot up. Air combat was thus restricted to interception of incoming raids as on 18th September when 4 Gnats of 23 Squadron engaged 6 Sabres in the Lahore-Kasur area, resulting in the destruction of two Sabres. On the 19th September, 4 Gnats of No. 9 Squadron, detailed to escort 4 Mystere IVAs on a close-support mission to Chawinda, where a great tank battle was being fought, were intercepted by 4 Sabres. The Gnats, going into a shallow left-hand climbing turn latched themselves behind the Sabres and the engagement, which started at 1,500 feet (460 m.) ended at tree-top height with two of the P.A.F.Sabres shot down, the low-level dogfight being witnessed by thousands of troops below. No F-104s (the Star-fighter being coded “Badmash” by the IAF) were involved in air combat with the Gnats but on at least two occasions, the diminutive fighter was in a commanding position when the F-104s engaged afterburner to escape to safety.

The operational success claimed by the Gnat was remarkable and, to foreign observers, one of the major surprises of aerial combat in the 23-day conflict. The diminutive fighter earned the appelation “Sabre Slayer” for it had achieved much distinction, proving capable of outfighting both the F-86F Sabre and the F-104A Starfighter by which it was opposed and was particularly effective in air combat at low altitudes where its out-standing manoeuvrability enabled it to evade Sidewinder AAMs launched against it. Because of its small size, Pak. pilots found the Gnat difficult to see let alone engage with the Gnat also confirming the traditional values of acceleration, turning performance and superior vertical manoeuvres. Backing this was a very high serviceability rate while the Orpheus 701 engine proved itself tough and reliable. Production of the first batch order at HAL was scheduled for completion by early 1966 but phase-out was stopped, production fully reinstated for the establishment of additional Gnat Squadrons. Total Gnats on order were thus 23 imported, 120 as first batch, a further 43 ordered late in 1965 further augmented by another batch of 50 Gnats, taking the total in IAF inventory to nearly 240. In the years 1966-68, a further four Gnat units (Nos.15,21,22 and 24 Squadrons) were formed with the Gnats becoming the point-defence day fighter complement to the MiG-21s for the air defence of India.

Six years after guns were first fired in anger, the Gnats were again to meet their adversaries in air combat. By November 1971, Pakistani forces in East Bengal were under constant guerilla attack and, in reaction, were shelling border areas with West Bengal and the Eastern Air Command was alerted for any eventuality. Gnats of No.22 Squadron were scrambled on November 22nd to fly a protective sortie over Indian troops in the Boyra area, 60 miles (100 km.) north of Calcutta. Four P.A.F. Sabre Mk.6s were intercepted at low level and in the ensuing dogfight, two Sabres were shot down, a third being severely damaged.

With the outbreak of full-scale hostilities, the Gnat formations were entirely committed to providing air defence of VP/VAs and tactical areas, including dawn to dusk CAPs over all major airbases on the Western front, from Uttarlai to Srinagar. The P.A.F. still respected the Gnat’s capabilities and instructions were apparently issued to avoid air combat with Gnats. The “Sabre Slayers” nevertheless, chalked up a tally in air kills, including a Mirage III badly damaged by a Gnat of No. 23 Squadron while over Pathankot. The highest award for gallantry went, posthumously, to a Gnat pilot Flying Officer N.S. Sekhon of No. 18 Squadron. Taking off while the Srinagar airfield was under attack by six Sabres on 14th December 1971, Sekhon scored hits on two Sabres before being overwhelmed. In the East, Gnat squadrons switched their role from air defence to short range interdiction and close air support tasks after the P.A.F. had ceased to be a viable force. Operating from Dum Dum, Bagdogra and Agartala, Gnats rocketed and strafed retreating Pak. army columns and concentrated on riverine traffic south of Dacca.
The Gnat has earned a special place of pride in an Indian’s heart. Almost revered as akin to a “devta” by the humble villager, postage stamps have been issued in its honour and the Gnat gets special attention at all airshows and static displays. The Indian Air Force, and HAL, look on it as an indigenous fighter for they were the first to unreservedly accept the light fighter concept and two shooting wars have vindicated that trust. The series of difficulties, some serious, that initially dogged the Gnat have been painstakingly resolved and HAL have been working on the design and development of the Mark 2 variant. The performance of the Orpheus 701 is being uprated by 150 lb.s.t. (68 kg.). the low range is to have a boost with the Gnat Mk. 2 incorporating integral fuel tanks in its 8% wings thus eliminating, the present need for fuel drop tanks, these hard points being freed for carriage of additional ordnance; the Mark 2 will primarily be a close support aircraft carrying a reasonable weapons load and well able to fend for itself if attacked by enemy interceptors at low level. Avionics are to be updated and a major re-design of the system for longitudinal control is in progress but all changes will take place within the concept of the light fighter. The Gnat Mk.2 (now christened the Ajeet) will carry the tradition well into the seventies and may be offered for export to friendly countries.

Notes :
The concept of a light fighter was most significant in the years following World War II and was a brave attempt to check the trend over forty years increasing the size, weight, cost and complexity of the standard fighter. A leading protagonist of the concept was W.E.W. Petter who joined Folland Aircraft Ltd., a small firm with not unlimited resources, to design and develop a light fighter when the Tu-4 threat was most serious in 1951. Lack of official support threatened the project but development continued as a private venture in spite of U.S. funds being allocated then to others in the NATO light-weight fighter contest. The Gnat development continued as having a valuable export potential with India, Finland and Switzerland specifically in mind. The diminutive Gnat was proposed as an interceptor with the objective that as it should cost only half as much as a Hunter and on the basis of cost-effectiveness, it could be proved to have “more airpower per kilo buck”.

Evolution of the design which eventually went into production as the Gnat covered a number of studies based on availability of the Saturn engine. In 1953, with resumption in development by Bristol’s of the engine that was to become the Orpheus, the Folland light fighter design was revised and the prototype, powered by the earlier Viper, was known as the Fo-139 Midge which made its first flight on August 11th, 1954. The Fo-141 Gnat first flew on July 18th 1955, a novel feature being the use of ailerons as flaps, a linkage in the control system causing the ailerons to “droop” 20° when the under carriage was lowered. The fifth M.O.S. Gnat (XK 767) was used to develop the flying tail in which tailplane and elevators operated as a single unit. Besides the Indian requirement, Follands received orders from Finland and Yugoslavia for twelve and two Gnats respectively, all Gnat Mk.I s being powered by the Bristol Siddeley Orpheus 701 turbojet rated at 4,700 lb. s.t. (2,135 kg.) The Fo-144 Gnat T.1 tandem-seating advanced trainer was evolved from the Gnat fighter and the first of 105 trainers entered service with the R.A.F. in February 1962.