Tag Archives: HAL

Lessons from the Gnat

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I was looking through net-space in search of interesting factoids from unusual ventures in aviation when I chanced upon this Web Page (http://www.airvectors.net/avgnat.html).

The page deals with the Folland Gnat. Since the Gnat and I have had a long lasting love affair, I went through this page carefully. Many little lines jumped out to catch my attention.

I am penning this little note to share the interesting tidbits with my readers even though this little note cannot really be called a ‘Tale’.

Point 1

The Gnat prototype was refitted with an uprated preproduction Orpheus engine to put on flight displays at the Farnborough air show that year. While the RAF had no requirement for such a machine, the government wanted to encourage Folland in their work, and so the British Ministry of Supply (MoS) ordered six prototypes of the full-development aircraft for evaluation.

The evaluation Gnats were powered by the production-spec Bristol Orpheus 701 turbojet with 20.1 kN (2,042 kgp / 4,502 lbf) thrust. Most of the test flights were conducted in the UK, though ground-attack trials were performed in Aden (now Yemen). The report from the RAF evaluation generally praised the Gnat’s performance, but there were criticisms of its flight-control systems, and there was no consensus that the Gnat was what the RAF needed. The Gnat fighter never served operationally in Britain, though the MoS did order two more Gnats on top of the original order for six.

This forward-looking interaction between the Government and the Industry is what we miss in India. By this singular decision to support Folland in their Gnat project, the British Government created an export market for military aviation that lasted for three decades.

Point 2

The Gnat went into IAF service in the spring of 1958, with the first Gnat assembled by HAL from a kit flying in Bangalore on 18 November 1959. HAL then went on to build 195 Gnats themselves up to early 1974. The first completely HAL-built Gnat flew on 21 May 1962. IAF pilots were delighted with the nimble Gnat, which they felt was more than a match for Pakistani F-86s and MiG-19s, and nicknamed it the “Saber Slayer”.

HAL took 13 years to produce 195 aircraft. Just over 15 aircraft per year. The Gnat was, by the way, a rather simple aircraft to manufacture (albeit it was a terrible toy to maintain!)

Point 3

The RAF had shown no real interest in the Gnat fighter, but Teddy Petter was persistent, proposing the tandem-seat “Fo-144” trainer version of the Gnat. The RAF liked the idea, and a contract for 14 preproduction “Gnat T.1” trainers was placed in 1958. The first performed its initial flight on 31 August 1959.

Just one year and five months to move from an order for 14 pre-production aircraft to the first flight of the first aircraft? How I wish this could happen in India!

Point 4

The Gnat T.1 had no gun armament, but retained the twin stores pylons. It was powered by a Bristol Orpheus 4-100 engine with 18.8 kN (1,920 kgp / 4,230 lbf) thrust. It featured a larger tail, plus a bigger wing with integral fuel tanks, 40% greater wing area, and conventional ailerons and flaps instead of flaperons.

The Gnat T1 was quite different from the Gnat F1. Different and larger wing, different and more numerous control surfaces, different (lower powered) engine, deletion of internal gun armament and related gunsight/radar ranging equipment. The metamorphosis was still achieved in real quick time.

Point 5

The RAF was pleased with the Gnat T.1 and ordered 91 more, for a total of 105. These were built between 1962 and 1965 by Hawker-Siddeley, which had bought out Folland since the government was strongly encouraging consolidation of Britain’s aviation industry.

91 aircraft were built over 4 years. A rate of production of 22 or 23 aircraft per year. Also noteworthy is the fact that 14 preproduction aircraft were used intensively for over three years before a larger production order was placed. Folland did not shy away from setting up an intensive production line even though the production order was only for 91 aircraft. A strong contrast to what we are seeing in the LCA project! Alas.

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