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Aviation History
1959
1959 - 1401.PDF
682 A Westland Wessex of the Royal Navy, powered with a Napier Gazelle Westland Aircraft Ltd. Yeopil, Somerset. Westminster The Westminster hasbeen built in the first instance as a "crane- transporter" and is now undergoingweight-lifting trials. It is the largest twin- turbine mechanically driven single-rotorhelicopter in the Western world, and it is claimed that it is able to operate with fullpayload on one of its Napier Eland engines if need be. Discussing liftingtechnique Westland say: "The design of the crane-transporter versionprovides for the carriage of loads externally, although it is possible to dispose internally aswell where shape and size permits. The fuse- lage structure could be modified to introducerear-loading facilities should this be particularly desirable for certain roles. However, investiga-tions of the various methods of carrying loads have shown that for crane duties and for manytransportation duties over distances up to 100 miles freight and equipment is best carriedexternally. The increased flexibility of unres- tricted load sizes and shapes, and die rapidityof external loading and unloading, combined with the possibility of jettisoning the load in anemergency, are obvious advantages . . . More- over, by this method loads can be ferried intoand out of locations where it is not convenient or possible for the helicopter to land. A singleload anchorage point has therefore been built into the base of the fuselage structure forsecuring a sling mechanism, and a hoist is pro- vided to wind in the excess cable length afterthe load has been attached . . ." They add that with its disposable loadof some 14,000 1b the aircraft meets the requirement for a large military transportable to carry heavy field equipment, tactical and nuclear weapons and troopsover stages of 150 miles or more. Typical loads could be 51 troops, five missiles orfour jeeps. The structure is in four sections: cock-pit; main fuselage welded structure; tail pylon; and main rotor pylon supportstructure. The two Elands are mounted side by side ahead of the main gearbox ontop of the fuselage. A shaft from each engine drives an oil cooler fan beneatheach engine. To these fans are bolted the engine oil coolers which are mounted ona separate structure which also cradles the fuel header tank. A civil version is projected, capable ofcarrying 45 passengers or 7,650 lb of freight over stage lengths of 200 miles, at150 m.p.h. The data apply to the crane- transporter version with two Eland NE1.6s. • Rotor diam., 72ft; fuselage length, 71ft 4in;basic weight, 21,600 1b; normal gross weight, 36,000 lb; cruising speed, 115 m.p.h.; max.range, 180 nautical miles; rate of climb on two engines at 75 kt, l,900ft/min; hoveringceiling (10ft wheel clearance), 9,000ft. Wessex The makers regard the Wessexas the logical complement of the Whirl- wind, meeting the requirement of greaterlifting capacity and cabin volume. It was developed by the company from thepiston-engined Sikorsky S-58 and is claimed to be the first large turbine-powered helicopter in full production in any country. The type has been adoptedby the Royal Navy as its standard anti- submarine aircraft, and readily combinesthe roles of search and strike, carrying sonar equipment and weapons, and fullyautomatic devices that enable it to operate by day or night in all weather, either from FLIGHT, 15 May 1959 Helicopters of the World . . . carriers or shore bases. As a transport 16fully equipped troops can be lifted over short stages, i.e., between off-shore carrieranchorages and battle areas. A civil ver- sion could take 12 passengers in comfort. Light-alloy monocoque construction isused throughout. The main rotor head is four bladed and rotor movement is con-trolled by fully duplicated servos. Since the engine—a Napier Gazelle NGa.13—isof free-turbine type, the conventional clutch has been dispensed with and theengine drive is direct to the main gearbox. For civil work the standard seatingwould be arranged with the front three seats facing aft and a bank of six seatsin three pairs facing forwards. The remain- ing three seats would be side by side atthe rear of the cabin. • Rotor diam., 56ft 7in; fuselage length (tailfolded), 38ft 4in; equipped weight, 7,600 lb; gross weight, 12,600 lb; max. speed, 144 m.p.h.;economic cruising speed, 115 m.p.h.; vertical rate of climb at s.l., 600ft/min; hovering ceilingwith ground effect (1 hr power), 7,000ft. Whirlwind The Whirlwind continuesin production and is offered with the Alvis Leonides Major, Pratt and WhitneyR-1340 or Wright R-1300 piston engine. A recent version is the Mk 7 developedspecifically for anti-submarine duties with the Royal Navy and carrying a homingweapon or sonar gear as special equip- ment. The engine is mounted in the noseand is readily accessible by opening two clamshell doors. The all-metal main rotorblades can be folded to minimize storage space. Data below apply to a passengerversion with Leonides Major 755 engine. • Rotor diam., 53ft; fuselage length, 42ft;equipped weight, 5,375 lb; normal gross weight, 7,800 lb; max. cruising speed, 99 m.p.h. Widgeon The Widgeon is a general- purpose five-seat helicopter developed from the four-seater Dragonfly (S-51). The engine is the Alvis Leonides 521/2 and the aircraft is offered for the following [Continued on page 683] Above, a civil Westland Whirlwind (Alvis Leonides Major); below, a Widgeon (Alvis Leonides)
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