Tag Archives: Welkin

The Midge & Its Contribution to Gnat’s Design

By Anandeep Pannu

Specifications

Type: Single Seat lightweight fighter prototype
Powerplant: 1 Amstrong Siddeley Viper ASV.5 Mk 101 turbojet engine rated at 1640 lb st
Performance: Max speed 600 mph at SL; service ceiling 38,000 ft
Weight: Max take off 4500 lb
Dimensions: Wingspan 20 ft 8 in, length 28 ft 9 inches, height 9 ft 3 in, wing area 125 ft (11.61 m2)

History

The Folland Midge was a private venture prototype from the fertile mind of W.E.W Petter. Petter had designed a number of aircraft for his family’s firm, Westland Aircraft, where he was Chief designer.  His family owned Petter engines, and Westland Aircraft was an offshoot of that. Westland made the Wapiti and Lysander aircraft with which the IAF was intimately familiar. The Lysander was Petter’s design and he went on to design the Whirlwind, Welkin and Wyvern for Westland. These aircraft were all revolutionary in their design, but were plagued by engine and other problems that limited their widespread use.

Westland decided after the war to concentrate on building helicopters, due to their license building tie-up with Sikorsky. Petter left the firm to join English Electric after disagreement with Westland management. Though Petter was soft spoken, he was very strong willed and this pattern of forming new teams when he didn’t agree with management was to continue. At English Electric he started a team from scratch in a car garage and designed the English Electric Canberra (see here ), another aircraft the IAF is intimately familiar with. Petter left English Electric after designing the P1.A, the prototype for the English Electric Lightning Mach 2 fighter. He had become disenchanted with the increasing weight and complexity of the fighter aircraft and the emphasis the Air Staff was placing on supporting these complex designs.

The Russians had copied a Boeing B-29 Superfortress bolt for bolt after a USAAF B-29 had landed in Siberia after damage from a Japan raid. The strategic bomber was called the Tupolev Tu-4 (NATO code name “Bull”) and was mass produced in large numbers by the Soviets. Petter believed that the fighters being developed (Hunter, Javelin and Lightning) could not be produced in large enough quantities to counter hordes of Tu-4s coming across the English channel. He believed a lightweight fighter produced in large quantities was needed to counter that threat.

Petter said,”I was looking for a product for a fairly small firm with not unlimited resources, with a factory that was good at mass producing small components, and I was also looking for something which would not automatically be killed by competition for existing types or by much larger firms.” The firm that he chose was Folland Aircraft which he joined in 1950 to become its Managing Director, Technical Director and Chief Designer. Here he proposed a fighter that would destroy Tu-4s by day, in the height band of 25000 to 35000 ft. It would have an engine that was a gas turbine based on a missile engine. The Air Staff Target (AST OR/303) was issued in July 1951. Petter at first responded with a design with max AUW of 5000 ft and the capability to climb to 35000 ft in 2.5 minutes. This was based on the Bristol BE 17 Saturn engine being available or alternatively two Rolls Royce RB 93 engines being available. Unfortunately for Petter, the engines he was relying on did not get built. In the ensuing delay, the lightweight fighter concept was no longer based on the Tu-4 threat assessment, since newer higher performance Soviet bombers had appeared. Petter did not give up however, he decided to approach Armstrong Siddeley and use their Viper engine as a basis for a precursor prototype of the Gnat fighter (which had already been named). He called this prototype the Midge – and he built this a private venture prototype, spending the company’s own money. He had the knowledge that the Bristol Orpheus was being built, but wanted to continue the momentum by using a lower powered prototype for airframe, aerodynamic and power system proving trials.

The Midge first flew on 11 August 1954 at Boscombe Down, the aircraft being trucked from the factory at Hamble to the bigger airfield at Boscombe rather than Folland’s development airfield at Chilbolton. The pilot was Sqn Ldr A.E. “Ted” Tennant, who had done his test pilots course along with FlT Lts Roshan Suri and Suranjan Das. The aircraft was doing a fast taxy when it lifted off the ground and Tennant took it into the air. He flew the aircraft twice that day even executing what an experienced observer called “the finest slow roll I have ever seen” on his second flight.

The Midge was entirely representative of the Gnat except for the lower power (only a third of what was expected from the Orpheus). Petter’s gamble succeeded, at least in gaining foreign orders for the Gnat. The Midge was evaluated by a number of pilots from a number of different Air Forces a few years before the Gnat itself was available. This included the Indian Air Force, which in mid-1954 had an evaluation team in Chilbolton that had come there to take a look at the Supermarine Swift. In November 1954, Air Commodore PC Lal became the first foreign pilot to fly the Midge followed later by Gp Capt Moolgavkar and Squadron Leaders Suri and Suranjan Das. Indian pilots continued to fly the Midge, Air Cdre Lal suffering an accident in it on 20 Sept 1955. According to the accident report “a faulty approach was made and a touch down made too far down the runaway, and the aircraft overshot into rough ground”. The pilot was unhurt but the Midge had to have some repairs done on it. Other Air Forces that evaluated the Midge included the RAF and the Swiss Air Force.

The Midge had some modifications made to it during flight testing that were incorporated into the Gnat. These included moving the ailerons inboard and combining them in a flap aileron combination. The one complaint that most people had was that the nose high attitude during landing reduced visibility during that phase of flight. This was corrected in the Gnat by the flaperons and the exaggerated tail down stance that the Gnat had compared to the Midge.

Unfortunately the Midge was destroyed in a fatal crash only six days after Air Cdre Lal’s accident. On Sept 26, Swiss pilot Max Mathez was flying and crashed near Chilbolton. The accident report concluded that full nose down trim may have been applied inadvertently, since the trim button was in the place where the “push to talk” button was on the Vampire that Mathez usually flew.

The Midge had flown 109 hrs and had been flown by 20 different pilots. It played a role in ensuring the Gnat’s future and was a great start to the Gnat story.

References

The Complete Encyclopedia of World Aircraft, Paul Eden & Soph Moeng (Eds), Barnes & Nobles Books, 2002, New York.
W.E.W Petter, http://en.wikipedia.org/wiki/W._E._W._Petter
Spotlight on the Industry, Flight International, 1 Feb 1957, http://www.flightglobal.com/pdfarchive/view/1957/1957%20-%200127.html
Folland Midge, Flight International, 20 August 1954,
Folland Gnat: Sabre-Slayer and Red Arrow, Victor Bingham, J&KH Publishing, East Sussex, England, 2000.
Folland’s Midge & Gnat, Aeroplane Monthly, September 2008.

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