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Folland Gnat

Folland/Hawker Siddeley Gnat

During 1965 I had heard the Red Arrows would make an appearance at Usworth Airfield near the A19 on the outskirts of Sunderland.

Arriving early at the site, which is now known as the Nissan Car Plant, i had wondered if I'd come to the right place and hadn't arrived at the birth of a car boot fair due to the lack of flying activity and lots of cars around. Then a garbled message over the 'tannoy' announced the Reds would be arriving soon and with a swift ear and eye check wondered how soon as there was no sight and sound yet. Then bang they arrived from nowhere and scarlet fever hit Usworth like the Jimmy Hendrix music experience had come to town. It was brilliant, ice cream were dropped everywhere, dogs were jumping up and down and barking like mad and some people were ducking behind cars. Soon the small sedate airfield of Usworth resembled a scene from 'Apocalypse Now' with red white and blue smoke everywhere smelling a bit 'iffy' and the little jets thundering around rooftop height creating havoc with Joe public who didn't know which way to look to catch a sighting. Their departure brought a deafening silence but also created a great interest within me to find out about the small red jets I'd seen flying that day which I soon learnt were Folland/Hawker Siddeley Gnat TMK1 variety.

Gnat (XS111) - photo by John Bilcliffe
Gnat T.1 (XS111)
photo by John Bilcliffe

The two seat trainer followed a pattern set in those days where the single seater was made first and a twin stick followed to learn on, only in the TMK1s case it was favoured from scouring some plans rejected on proposed ideas put forward on variants around the single seat FMK1.

A guide insight into the TMK1s genesis goes back to 1951 at Hamble near Southampton where the Folland Aircraft Company was based. Follands Managing Director and Chief Designer then was WEW Teddy Petter and he wanted to design a small, light and less complicated fighter around one of the new small jet engines built at the time. A power plant was chosen, the Bristol BE22 Saturn turbojet 3,800 lb-st and the first design was coded F.O.141, but this concept was short lived as the Saturn encountered serious problems. Interest in the concept was still held and under a private venture F.O.139 Midge prototype was built around the less powerful ASVS, (Armstrong Siddeley Viper) 1,640 lb-st, the same unit chosen to power the jet provost.

First flight was made from Boscombe Down in Wiltshire on the 11th August, 1954, with 'B' condition registration G-39-1. 'B' condition registrations were issued to manufacturers to enable company aircraft to over-fly countries in foreign skys, the 'G' denoted British nationality and 39 was the number of the company which is Folland and '1' shows first prototype.

This aircraft was lost in a fatal crash a year later at Chilbolton on 26th September, 1955. Next to arrive was design F.O.140 considered the first true Gnat type powered by the BOR 1 engine of 3,285 lb-st, first flown from Chilbolton with company chief test pilot Sqn. Leader E. A. Tennant at the controls with condition registration G-39-2.

This flight paved the way for a few Gnat F.1s to be made and evaluated now powered by the more potent BOR2.701 engine of 4,520lb-st. Records show the Gnat narrowly missed the boat in favour of the bigger, heavier, more costlier Hunter Fighter.

While all this had been taking place a decision in 1956 had already been taken by the Air Ministry and MOS, (Ministry of Supply) to award a design study contract to specification T.185D to build a trainer. This contract seemed to stem from ideas and a new wing that was designed and built for a navalised version of the Gnat F.1. This wing which was simply thinned down by reducing the T/Chord ratio from 8% to 7% which gave it a bigger area avoiding a weight penalty in the process and giving it the ability to perform at lower speeds.

Gnat (XR538/G-RORI) at Kemble in 2004 - photo by webmaster
Gnat T.1 (XR538/G-RORI) at Kemble in 2004
photo by webmaster

Gnat T.1 (XR991 (originally XS102
)/G-MOUR) at Kemble in 2005  - photo by webmaster
Gnat T.1 (XR991 (originally XS102 )/G-MOUR) at Kemble in 2005
photo by webmaster

Folland Gnats at RAF Waddington in 2014 - photo by John Bilcliffe
Folland Gnats at RAF Waddington in 2014 - photo by John Bilcliffe

Also some strict design criteria had to be adhered to in order for the Gnat to succeed and W.E.W. Petter, still head of design, would implement and construct these requirements. These included such items as new flight and navigation instrument presentation to conform to OR.946, put simply this concentrates an essential flight information on two display units occupying the centre of the panel, provision for engine anti-icing, a centralised failure warning system and installation of liquid oxygen facilities and last but not least was to stretch the fuselage to fit the second seat. The crew ejector seats were newly developed using the company's own lightweight seats with work beginning as early as 1953 following the SAAB seat layout as the original basis but discarding this later for independent versions know as MK4 GT1 front and MK4GT2 rear fitted with 80ft/sec telescopic guns to give clearance of the fin down to 0 feet runway level at 90 knots.

The canopy was blown from a single piece of Perspex with an additional internal windscreen fitted a top of the rear instrument panel to cover and protect rear seat occupant when the main canopy is jettisoned. TACAN and ILS and the air data computer were fitted aft of the canopy by enlarging the spine fairing. TACAN is tactical aircraft navigation system and ILS is instrument land system. All this work was to try and produce a trainer to take over from the Vampire T.11 which made its first flight in December, 1951. It seems crazy to think the Jet Provost lasted nearly 40 years and here was the Vampire T.11 being ready for replacement in the same decade it flew. Reasons for change were cost effectiveness in training programme cost. Cost also affected the engine unit and de-rated Orpheus BOR.4.JK100 4,230 lb-st was fitted powering the FO.144 prototype aircraft for the first flight from Chilbolton on the 31st August, 1959, again with Sqn. Leader A. A. Tennant at the controls bearing the registration XM691.

Gnat (XM693 (originally XP504 
)/G-TIMM) - photo by John Bilcliffe
Gnat T.1 (XM693 (originally XP504 )/G-TIMM)
photo by John Bilcliffe
               Gnat (XR538/G-RORI) at Waddington in 2001 - photo by John Bilcliffe
Gnat T.1 (XR538/G-RORI) at Waddington(2001)
photo by John Bilcliffe

XM691 was just one from fourteen aircraft that had been built following finalisation of the design to spec T.185. For further production to continue Folland aircraft had to join forces with Hawker Siddeley as the government favoured larger organisations to undertake large scale manufacture. This took place around the early sixties and now serving as the Hamble division of Hawker Siddeley orders were awarded for 30, 20 and 41 being built between February, 1960 to March 1962. First to fly with the new long nose was XM696 in August 1960, marking how fairly quickly things were going at the time.

XM709 last of the pre-production batch of 14 first flew in January, 1962. First T1 Gnat from main production order XP500 to make first flight in June 1962, with Gnat XP501 going down first on the RAF's inventory joining the (CFS) Central Flying School at Little Rissington on 5th November, 1962, with 4 (FTS) flying training school RAF Valley in Wales receiving XP-502 two days later. Serials for production ran as follows :- XM691-698 (8) XM704-709 (6) XP500-516 (17) XP530-542 (13) XR534-545(12) XR 567-574 (8) XR 948-955 (8) XR976-987 (12) XR991-999 (9) XS100-111 (12).

The honour of first student to solo the type went to Pilot Officer K. B. Latton from New Zealand training at 4 F.T.S. RAF Valley in April, 1963. Course length at 4 F.T.S. consisted of about 70 hours on the type with average time of dual to solo at around six hours with a student having 160 hours total flying time logged.

Although all seems fair and well with the Gnat, it had quite a few drawbacks, these included from a flying point of view, poor vision from the rear cockpit, and unsolved pitch controls problems which made it a poor weapons training platform, and the trend to produce a less complex aircraft had the reverse affect of being overly complex with maintenance crews once in service, not only due to its small cramped working space.

Last course to graduate on the type was on 24th November, 1978, at 4 FTS with the Red Arrows surrendering their Gnats at the end of the 1979 display season to swap with the Hawk. Other users of the Gnat were the Royal Aircraft Establishment and the Yellow Jacks fore runners to the Red Arrows.

Gnat T.1 (XP502) at Kemble in 2003 - photo by webmaster
Gnat T.1 (XP502) at Kemble in 2003
photo by webmaster
               Gnat T.1 (XS104/G-FRCE) at Church Fenton in early jpg
Gnat T.1 (XS104/G-FRCE) at Church Fenton
in early 1990s
photo by John Bilcliffe

There are many private aircraft operators who have invested in the Gnat for advanced jet training and the show biz circuit. One such as this comes from the Kennet Aviation stable who have now moved from Cranfield to North Weald and have four listed on their books on last check on their website.

Typical from these four is XM693 which was registered with the RAF as XP504 and also carries civil registration G.TIMM after its owner Tim Manna, brought it back to flying condition after spending some time at 1 SOTT Halton (School of Technical Training). The aircraft is painted in the training scheme colours worn in 1961 and is often seen on the airshow circuit and usually takes part in the classic jet meet in June at Kemble.

Thanks to the few operators that fly these classic aircraft, enthusiasts such as myself and those that are to come, can witness in the air show season an aircraft that represented a once larger aircraft industry all now but gone.

I came to find the 'Iffy' smell was coloured dye mixed with diesel oil pumped out with pressure into the jet efflux.

                              Article and photos by John Bilcliffe