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Aviation History
1963
1963 - 0241.PDF
FLIGHT International, 14 February 1963 229 pr ving trials with which were successfully completed last summer. Se eral battlefield exercises have been carried out with Army units, and a company sales tour took one HAR.10 all the way to the Lebanon, where nine troops were flown 50 miles, landed on a 10.500ft peak and taken off again. Wessex In March 1954 Sikorsky Aircraft flew the prototype of the S-58 which, although having a configuration similar to the S-55, was considerably larger and more powerful. Westland obtained a licence to manufacture the S-58, but chose to produce a substantially modified machine with the American piston engine replaced by a Napier Gazelle free-turbine engine. The Gazelle was developed specifically for such an application, and although no more powerful than the Wright R-1820 used in the S-58 is consider ably lighter and more attractive to military operators in its use of standard turbine fuels. Manoeuvres on Salisbury Plain in which the Royal Marine Commando as sault-transport version of the Wessex I was em ployed for the first time. Although normally equipped to carry 15 troops and their equip ment, or 4,0001b stores, these aircraft can readily be converted to an ASW search and strike role Westland imported an S-58, installed a Gazelle engine and had it in the air by May 17, 1957. On June 20 the following year a Westland-built prototype started its flight trials, and production of the Wessex HAS. 1 for the Royal Navy was put in hand. Much of the cost of development was borne by Westland, but the Ministry of Supply made a contribution since from the outset the Wessex was envisaged as the standard ASW helicopter of the Royal Navy, This it has now become, Service trials having started in April 1960, and front-line service with an operational squadron dating from July 4, 1961. Although the Wessex was fully described in our issue of Novem ber 29, 1957, it has developed so much since that time that we are reproducing here a new cutaway drawing showing the HAS.l in its present configuration. The powerplant is a Gazelle NGa.13 Mk 161, with a one-hour rating of 1,450 s.h.p. It is installed at an angle of 35° to the horizontal, in line with the drive-shaft to the rotor system, and there are two exhaust stacks on each side of the aircraft. The complete tail unit and all-metal main rotor blades fold to facilitate stowage in carriers and other ships. The helicopter ASW mission is an arduous one, and it demands a great deal of special equipment. Much of this equipment is restricted, but in I960 it was announced that the Wessex HAS.l is fitted with the Ryan APN-97A Doppler radar, used in conjunction with a Lear autopilot manufactured in Britain by Louis Newmark as the Mk 19. A full all-weather control system and comprehensive navigational aids are fitted, and a "dunking" asdic and strike weapons are carried for detecting and destroying submerged submarines. Moreover, every HAS.l is delivered with 15 troop seats, which are stored by HM Dockyards ready for immediate installation should a sudden change in role be required. In fact, the brief conflict in Kuwait in 1961 underlined the need for an assault helicopter bigger than the Whirlwind, and urgent measures were taken to arrange for the delivery of a batch of Wessex Mk Is specifically for this purpose. The assault version of the Wessex 1 is operated by the Royal Navy on behalf of the Royal Marine Commandos, and differs from the HAS.l in having no automatic flight-control system, asdic or ASW weapons, but instead having 15 troop seats and provision for a slung load of Deliveries of the Wessex HC.2 to Roycl Air Force Transport Command will take place this year. Powerplant is a Bristol Siddeley Coupled Gnome 4,0001b and for carrying and firing various combinations of Nord SS.ll missiles, 2in rockets and guns. These aircraft have been painted a "desert sand" colour, the ASW machines being "midnight blue." In June 1961 the Royal Australian Navy ordered 27 Wessex Mk 31 helicopters for use as standard ASW machines. These aircraft are based upon the HAS. 1 but incorporate special equipment to meet Australian requirements; they have the 1,540 s.h.p. Gazelle NGa.13 series 2 Mk 162 engine. The Mk 31 represents an inter mediate stage between the original Mk 1 and the new HAS.3 which is discussed presently, and the RAN may decide to incorporate Mk 3 equipment at some future date. Deliveries to Australia have been in progress since the summer of last year. During 1960 de Havilland Engines and Westland worked together on the evolution of a new version of the Wessex powered by a Coupled Gnome engine. This powerplant comprises two Gnome power sections linked to a common output gearbox and trans mission. The Bristol Siddeley Coupled Gnome H.1200 has power sections each rated at 1,350 h.p.; the Wessex transmission is limited to 1,550 h.p. so that 1,150 h.p. remains in hand. This is reflected in a substantial improvement in performance at altitude and in high ambient temperatures, and the Coupled Gnome also confers a degree of single-engine security. In August 1961 Westland received their first order for the Wessex with this new powerplant, a substantial contract being placed for the Wessex HC.2 for RAF Transport Command. The first of these aircraft flew on January 18 last year, and the Mk 2 is scheduled to enter service with 38 Group before the end of 1963. Finished in standard green/grey camouflage, they will be employed purely in transport and such subsidiary roles as casualty evacuation. No automatic flight-control system is fitted, but provision is made for carrying 16 troops, an internal or slung load of 4,0001b, a 6001b hydraulic winch (also fittted to the Wessex 1) and possibly various combinations of weapons. Westland have received an MoA "instruction to proceed" on the next Wessex mark, the HAS.3. This will be the next standard ASW helicopter of the Navy, and it differs from the Mk 1 principally in having the Gazelle NGa.18 Mk 165 engine, derated to the tranmission limit of 1.550 h.p. from a one-hour rating of 1,750 h.p. This increased power enables the Wessex 3 to carry a heavier oper ational load and still maintain the requisite time on station. No details of this equipment may be divulged beyond stating that it will include the very latest flight-control, asdic and strike systems. At present there is no Wessex 4, for even numbers are reserved for the RAF. The next mark is therefore the Wessex 5, which is a Royal Navy transport based on the Wessex HC.2. Assault with Royal Marine Commandos demands maximum hot-and high performance, in contrast to ASW operations which call for sustained power at low speeds at sea level. The Mk 5 will be operated like the present assault-transport version of the Mk 1 from RN assault ships. Commando carriers and shore bases: the anti-submarine Wessex 1 and 3 operate principally from Fleet carriers and guided- missile destroyers. This concludes the versions of the Wessex for which contracts are held, but this helicopter is envisaged as being suitable for a Continued on page 232, after double-page drawing of the Wessex Mk 1
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