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Aviation History
1963
1963 - 0244.PDF
Despite their obvious relationship, the Scout (left) and Wasp differ greatly in detail design and equipment. The machine on the left is the first Scout Mk 31 for the Royal Australian Navy; a Scout of the British Army is pictured at the foot of the page. On the right is seen the first production Wasp AS. I for the Royal Navy, which flew last October. Scout and Wasp tails are compared on page 233 WESTLAND HELICOPTERS... continuing programme of development to meet a wide range of military roles in all parts of the world. Comparison of the Wessex 2 with the similarly powered Sikorsky H-3 (S-61) family emphasizes the manner in which Westland have limited gross weight in order to achieve higher performance and improved handling in adverse con ditions, and further marks of Wessex may well appear. Napier Spraymat de-icing has been applied to Wessex rotor blades as put of an MoA research programme, but the present view of the British Services is that rotor de-icing is not worth while. Scout/Wasp In November 1957 Saunders-Roe Ltd began the design of a 5/6-seat utility helicopter powered by a 400 s.h.p. Black burn Turmo free-turbine engine. In 1958 the construction of two prototypes was started with the designation P.531-0. and the first flew on July 20, 1958. This machine, which was fully described in our issue of August 8 of that year, incorporated several features proven on the Skecter, and was successfully developed at a norma! gross weight of 3,8001b, the Turmo being derated to 325 s.h.p. to match the limitations of the transmission. Since 1959 the Royal Navy have conducted extensive evaluation trials with three P.531-0/N machines, differing from the two proto types in having skid undercarriages and such progressive refinements as tail-folding, main-rotor folding, anti-coning and droop stops, improved equipment and, at one time, a unique arrangement of four suction pads attached to the skids to hold the aircraft firmly on the deck of small ships in rough seas. These three aircraft were not fitted with an autopilot or powered controls, but were success fully operated from HMS Undaunted and HMS Ashanti while carrying a pair of 2701b torpedoes in a simulated AS strike mission. From these aircraft were developed a family of heavier and more powerful helicopters, for a variety of purposes. The prototype of this series was the civil P.531-2 Wasp Mk 1, powered by a 1,050 Close-up of a Scout AH. I, showing BS Nimbus powerplant, winch and a stretcher installed in place of three rear seats or equipment "Flight International" photograph s.h.p. Bristol Siddeley Nimbus engine, which flew on August 9, 1959. A variant named the Scout was soon adopted by the British Army for reconnaissance and liaison duties. The preproduction machine flew on August 4,1960. In the following month a substantial production order for the Westland Scout AH.l was announced, and the first off the line left the Fairey Aviation Division factory at Hayes on March 6, 1961. Flight testing is based at White Waliham. The Scout carries a pilot and four passengers, has bulged rear doors to accommodate a transverse stretcher, can carry slung loads of up to 1,5001b and is fitted with a 6001b Lucas air-driven hoist. The powerplant is the Nimbus 102, which, although having a 5min rating of 1,050 s.h.p., is derated in the Scout to a one-hour rating of 685 s.h.p., and 650 s.h.p. can be maintained up to 7,000ft at ISA ~r30cC. A skid undercarriage is fitted, with a single wheel on each skid for running take-offs and ground handling. For handling on rough surfaces the aircraft can be lifted by hydraulic hand- pumps incorporated in three separate twin-wheel units. No technical obstacle stands in the way of a full civil C of A for the Scout, but the design has been planned from the outset for army use, and the instrument layout and general equipment designed for a battlefield role. The Scout AH.l of the British Army can be fitted with Newmark four-axis stabilization and can carry wire-guided missiles such as the Nord SS. 11. It can operate from most types of ground with a slope of up to 1 : 8. It has been de signed as a high-performance machine with exceptional manoeuvr ability, and is proving extremely popular with all who have flown it. A pair of Scouts have recently been built for the Royal Australian Navy, who will employ them for general utility operations from a survey ship. Since May 3, 1960, Westland have also conducted extensive flying with a company-owned machine powered by a Bristol Siddeley Gnome engine, similarly derated to 685 h.p. The early trials with the Turmo-powered P.531-0/N showed that aircraft of this class can fulfil an AS W strike mission while operating from the decks of frigates. Accordingly, Westland received an MoA development contract for a helicopter adapted specifically for this role, and an order for a large number of Wasp AS.l machines was announced in September 1961. While retaining most of the struc ture and dynamic components of the Army Scout, the Wasp carries a great deal of special AS equipment, has a folding tail of entirely new design and a unique form of undercarriage designed and built by Lockheed Precision Products. Operation at maximum weight from restricted platforms on small ships in very rough seas has demanded careful stressing of thestructure. and especially of the undercarriage, to meet exceptional vertical and horizontal decelerations. Despite violent movements of the deck the Wasp must not slide or topple over, and the landing gear accordingly has four legs spaced as far apart as practical considerations will allow. The large tyres are inflated to a relatively low pressure, and clamping rings for deck shackles are provided immediately above each wheel. The oleo struts have exceptional travel, and all four wheels can castor freely or be locked in the fore-and-aft position. The castoring arrangement of the wheels is shown inset in plan view in the sketch on page 233. Trials with the Wasp have taken place on a special rolling platform, simulating a ship's deck, at Naval Air Department, RAE, Bedford (See page 246 of this issue.) Various methods of securing the Wasp to the deck are being investigated, and two types of stowage aboard HM frigates are envisaged. In one type of ship the helicopter lands on the hangar wfi .C^dnu ;?
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