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Aviation History
1962
1962 - 1206.PDF
In the first VA-3 the styling and execution of the interior furnishings was handled by L. A. Rumbold & Co Ltd. This artist's impression shows the aft-facing passenger accommodation VA-3... lift fans, each being carefully located to minimize the ingress of sea water or other material disturbed by the craft. The passenger cabin lies squarely in the centre, and to prevent the superstructure from being highly stressed by rough- Plan view of the VA-3 showing, in schematic form, the major elements of the control systems. In front of the driver are the con centric steering wheels, the inner being connected broken lines) to the port and starboard spoilers and the outer being coupled to the forefins and aft rudders, which are shown deflected as they would be in a turn to starboard. Connections are also shown from the outer wheel to side-force vanes in the front and rear transverse jets, although this system has not been coupled up. By the driver's left hand are the levers con trolling the pitch of the two propellers; by his right hand are the levers governing the power of the two lift engines. water operation it is divided into front and rear portions joined only by a flexible moulded strip around the centre of the cabin. As an accompanying artist's impres sion illustrates, the cabin is furnished with four rows of rearward-facing seats, each row having one Rumbold triple seat unit on each side of the central aisle. Space is provided for coats and for hand luggage, and the entire interior is insulated and sound proofed. Double-glazed windows and special door sealing guard against the entry of any spray, and heating and ventilation is provided. A final schedule of equipment for an operational VA-3 would depend upon customer requirements and the fruits of experience, but would include a v.h.f. radio, a full range of cockpit instru ments, fire detection and suppression systems, navigation lights, foghorn, lifejackets and emergency gear, and such normal seagoing equipment as an anchor, buoy, fenders and chains. Drawings for the construction of the first VA-3 were released from March last year, and the craft was complete a little over a year later. Initial trials over land began on the airfield at South Marston on April 10 of this year. Although the overland testing was of necessity confined to slow-speed hand ling, it immediately confirmed the great power of the propeller-pitch control. Operated in unison the two levers gave marked acceleration and deceleration, while differential movement proved capable of rotating the big machine almost within its own length. Since an air-cushion vehicle is quite free to move in any direction it is very sensitive to gradients, and it was soon found that it was necessary to apply slight yawing moments to counteract transverse slopes that could scarcely be discerned by eye. At the same time, the VA-3 showed that it could climb 1 in 10, and operate satisfactorily over quite irregular ground. Plenty of cut grass and hay went through the lift system without causing any trouble. FLIGHT International, 19 July 1962 Air-Cushion Vehicles SUPPLEMF- On May 13 the propulsion engines and outer ducts were taken off to reduce the overall dimensions of the craft for road transport. By May 17 the VA-j was hovering on the apron between the River Itchen, at Southampton, and the company's works there (which at one time built such dissimilar aircraft as the Southampton and the Spitfire). The waste area beside the old flying-boat slipway was filled in with gravel, and across this the remarkable new beast of 1962 slid smoothly on to its natural element. Although much had been learned at South Marston it was the overwater operation that really confirmed the opinion that the VA-3 was a complete success. A most encouraging discovery was the manner in which the craft always tended to bank correctly into a turn. On the other hand, like most of its tribe, the Vickers Hovercraft gives of its best only to a skilled practitioner who has a real "seat of the pants" sense of what his charge is doing. Such a skilled practitioner is Les Colquhoun, and he puts it like this: "If you were driving a fast car fiat out along an icy road you would probably lose control on the first bend. But if you were Stirling Moss you would sense what each end of the car was doing and be able to proceed in quite a respectable arc." It should not be inferred from this there is any similar analogy in the matter of safety; in a Hovercraft the worst consequence of failing to keep pointing in the direction of motion is unlikely to be anything more than temporary embarrassment. At speeds below 40kt the most power ful control is propeller pitch, and this is the basic means of manoeuvring at such speeds. Vickers have also had to demonstrate what happens when either propeller is placed in full reverse pitch at any forward speed: rate of yaw is high, but stability is quite satisfactory. At speeds above 40kt the basic turning control is the outer wheel, coupled to the aerodynamic servo tabs on the forefms. As a sketch shows, the two fins are turned together in the direction in which the craft is to turn. This imparts a lateral force which keeps the head of the craft moving round the horizon. At the same time the inertia of the vehicle tends to keep it moving in the original direction, and if there were no other control the stern would break away and skid outwards. The driver watches for this and counteracts it by the rudder pedals—left pedal for a right turn. The rudders impart a further inwards (centripetal) force towards the centre of the turn, their effect being continuously adjusted to keep the turn true and properly co-ordinated. Minimum radi u s 14
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