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Aviation History
1960
1960 - 0860.PDF
868 FLIGHT, 24 June 1960 CUSHIONCRAFT VARIABLE-PITCH ^ PROPELLERS FORPROPULSION AND STEERING (4) CONTROL CABLES AND LINKAGE DECKING - BATTENS FOR PAYLOAD A new vehicle ; by Britten-Norman AT Bembridge Airport, Isle of Wight, Britten-Norman LtdA\ are now beginning trials of their new "Cushioncraft"— •*- •*- their name for an air-cushion vehicle built for Elders andFyffes. It will be used to study the potential of this type of vehicle for the carriage of bananas from plantations in the SouthernCameroons. Together with its associated company, Crop Culture (Aerial)Ltd, Britten-Norman have studied the potential for the Cushion- craft in many different countries. These investigations, they say,have revealed the possibility of a break-through in transportation techniques by the use of air cushion vehicles which could acceler-ate the pace of development in territories where roads are non- existent and costly to build and rivers are seasonally unnavigable. The Cushioncraft is circular in form and measures 18ft lOin indiameter. Empty weight is about a ton.< A driver and two pas- sengers are carried in a cab mounted on the deck, where there isalso space for some cargo. Designed operating height above water or ground is some 12-15in. The engine is a Coventry Climax giving up to 170 b.h.p. Thisdrives a large rotor, running round the circumference of the vehicle, and twin, rear-mounted propellers. The peripheral rotorsupplies air to a single jet nozzle around the bottom edge of the craft to maintain the air cushion. The peripheral rotor, it isclaimed, reduces losses by keeping the length of ducting to a minimum. The rotor is driven mechanically by a friction wheel at the rearof the craft and has 40 aerofoil blades fixed radially to an inner and an outer shroud ring, the whole assembly being maintained inplace by a series of rollers. The compressor is mounted in a short vertical duct which, below the rotor, curves inwards so that theair is directed towards the centre. The duct is lOin wide at the efflux and the resulting "thick" jet is claimed to help to stabilizethe craft when riding on the air cushion. The rotor is of laminated wood construction, covered by plastic sheeting. The blades andstator blades are of laminated wood with doped-fabric covering. As already mentioned, the engine also drives two propellers.These are, in fact, Hiller helicopter tail rotors. They are mounted above the deck at the rear to provide the Cushioncraft's horizontalpropulsion. Pitch may be varied collectively to provide ahead or astern propulsion, or differentially for steering. The driver has two separate controls: a combined hand throttleand clutch to engage the compressor and control ground clearance, and a steering wheel which can be pulled backwards and forwardsfrom the control panel, or can be turned. To move forwards the driver pushes the wheel in, and to reverse he pulls it back. Tomove left or right he turns it in the same manner as a car steering wheel. Two fuel tanks, each of 15gal capacity, give a 6hr endurance.Three twin-bogie wheels are fitted beneath the craft to enable it to be handled on the ground when the engine is pot running.These wheels can be jacked up and down to provide sufficient ground clearance for servicing. Concerning the optimum size for a commercial Cushioncraftthe makers state: "When we began seriously to consider develop- ing a Cushioncraft a study was made of the factors affecting theload and capacity desirable for a prototype machine that would Showing the Cushioncraft's inboard profile and pressure distribution ROTOR GLASS FIBRE LAMINATE HARDEY - SPICER DRIVE- SHAFTS LIGHT-ALLOY HOUSING 24 s.w. g. ALLOY WHEEL DRIVES ROTOR BY NYLON-COVERED TRACK (3) FRICTION -ADJUSTING TURNBUCKLE TWO MAINKEEL MEMBERS 48 SLOTTED STATORS SAME SECTION AS ROTOR BLADES
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