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Aviation History
1963
1963 - 0477.PDF
IGHT International, 4 April 1963 © lliffe Transport Publications Ltd 1963 Although the illustration on the right is quite unofficial, it indicates the principle of operation which the H.I26 has been built to prove. The Bristol Siddeley Orpheus inside the forward fuselage discharges into a 90° cascade which turns the major part of the efflux up through a vertical drum. From the top of this three pipes lead into each wing to serve the trailing-edge fishtails and the roll-control jet at the tip. An additional pipe leads to the pitch/yaw jet in the tail. These are the first control jets to use hot engine gas instead of bleed ': air. Additional ducts lead aft from the cascade box to propulsive nozzles in the centre-fuselage sides. The aircraft is painted yellow -fin has three main and two subsidiary spars, and an anti-spin parachute is mounted in its tip. The rudder has a trim and anti- balance tab, and is hung on two hinges. Each main undercarriage unit consists of a single wheel located Iby two diagonal struts hinged to the bottom of the fuselage. The nosewheel unit has twin wheels attached to a vertical shock absor ber, braced to the fuselage by drag struts. Fuel is carried in flexible jcells in the fuselage, the forward tank being behind the cockpit and rthe two rear tanks, one above the other, aft of the rear-spar frame. :The forward tank and the lower rear tank each have a booster pump, iand a fuel recuperator ensures a fuel supply under negative-g con ditions. Hydraulic power for the operation of the tailplane, ailerons, flaps and wheel brakes, is provided by two independent hydraulic Jumps and systems. Normally both systems supply the power, but Jeither can provide full power for all controls and brakes. An emer gency accumulator provides power for the operation of all controls or a limited period, and a separate accumulator provides power or the brakes. Direct current electrical supply is provided by a IkW engine-driven generator and a main and stand-by battery. ^n a.c. supply is provided by three inverters, two in use and one tand-by. Radio equipment consists of a main and a stand-by /HF; the stand-by can also be operated from the emergency bat- ery. The test instrumentation is very extensive and most of the ear fuselage is occupied by automatic recorders, their associated nstruments and equipment. One of the main reasons for the choice of Hunting to produce he ER.189D research aircraft was the experience of the Luton oinpany in hot-gas ducting systems. This experience was gained during lengthy research into helicopters with tip-driven rotors (Flight, December 23, 1955), and the former Percival hot-gas rotor test pit was converted by Hunting to serve as the main full- scale rig to prove the H.126 fishtail/flap design. Manufacture of the H.126 was essentially complete last summer, and the machine was rolled out in August. Stanley Oliver familiarized himself with it and conducted limited taxying trials at Luton, and the aircraft was then dismantled and taken by road to Bedford. All through the very severe winter the RAE deliberately left the runway covered in ice and snow in order to carry out extensive slush tests. The H.126 finally got out to the runway on March 19, and put in some fast taxying—with the wheels several feet off the ground on occasions—before proceedings were halted by an anti-spin chute which streamed but failed to jettison. About 10° of flap was used, and all systems appeared to function normally. On the afternoon of March 26 Mr Oliver found everything, including the weather, to his liking. With flaps at 0° he took the H.126 off at about 80kt after a run of some 600yd. Afterwards he said, "Taking this plane off is an entirely new sensation; it just floats off the ground, and then you go up like a lift."' He cruised around in a characteristic slightly nose-down attitude for some 18min, accompanied by a two-seat Meteor chase plane, and at one point put down some flap. Upon his return he climbed down from the lofty cockpit and announced that it had been "a perfect, no-snags flight."' Hunting will do about six months of preliminary flying with the H.126, and will then hand it over to its owners (the MoA) for extensive RAE research programmes. When these programmes are complete Hunting will carry out investigations at very low speeds. : he photographs below depict two aspects of the widespread test programme on the H.126 carried out by Hunting Aircraft at Luton: left, fuel flow tests progress with the almost complete aircraft in a nose-down attitude; right, a hot-flow rig in the former rotor test pit. In the latter test smoke is injected to the hot gas and discharged through a single inverted fishtail and flap section
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