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Aviation History
1955
1955 - 0975.PDF
Viscount H74O2, poting tor the camera shortly before the ferry flight to Washington, makes a fine picture in its Capital colours THE DOLLAR-EARNING VISCOUNT Development of a British Turboprop Airliner for Service in North America AS these words are written Capital Airlines are completing£\ plans for the opening of passenger services between L •* Washington and Chicago with the Vickers-ArmstrongsViscount turboprop airliner. When these plans become reality the Viscount will be the first turbine-powered aeroplane to carry fare-paying passengers on a United States domestic route, and the first British airliner of any type to be approved for revenue airlineservice in the United States. Flight's salute on this Capital-Vickers occasion takes the formof the new cutaway drawing reproduced overleaf, which was designed to emphasize features particular to the North AmericanViscount. The aircraft illustrated is, in most respects, representa- tive of (so far) 92 Viscounts, of which 60 have been ordered byCapital Airlines, 26 by Trans-Canada Air Lines, five by private corporations in the United States, and the remaining one by theCanadian Department of Transport. These 92 aircraft are sufficiently similar between themselves—and dissimilar enoughto all Viscounts ordered for service elsewhere—to be considered as a separate branch of the Viscount family: hence our use ofthe term North American Viscount. The evolution of this version vividly expresses the theme ofmanufacturer-operator liaison, which has dominated the develop- ment of the Viscount as a world-wide airliner. Superficially,there appear to be few differences between any aircraft in the V.700 series; in fact, each Viscount customer has influenced thedesign and construction of his particular aircraft, although to a varying extent It might thus be said that there is no such aircraftas a standard Viscount. The 229 aircraft ordered to date may, however, be regarded asoffsprings of three parent versions, with the V.630 and V.7C0 prototypes as grandparents. These parent versions (with thenumber of "descendants" shown in parentheses) are the V.701 for B.EJV. (104); the long-bodied V.802 for B.E.A. (33); and theV.724 for T.C.A. (92). As a measure of the depth of development work involved inmeeting "customer requirements," it may be noted that the total design man-hours spent on the original V.700 were matched bythose devoted to the V.701—and, moreover, that design of the V.724 to T.C.A.'s specification was a drawing-office project ofcomparable magnitude. The work of producing a North American Viscount began inearnest when Mr. George Edwards returned from a flying sales visit to Montreal in 1952 with T.CA.'s initial contract for 15aircraft. The order was subject to a re-working of the design to the engineering and operational requirements of the Canadianairline, and the resulting discussions between Vickers and T.C.A. led to a list of some 250 changes in the 700-series Viscount asthen in production. Many of these modifications were required to "winterize" theViscount, which had previously been ordered only for temperate or tropical areas. With the prospect of cold-weather operations inmind, the V.700 prototype had been sent to Northern Canada early in 1953 for two months of trials, which gave useful—andencouraging—results. This journey, incidentally, made the Viscount the first—and, as yet, the only—turboprop aircraft tocomplete a two-way Atlantic crossing. Other modifications re- sulted from T.C.A.'s desire to use North American equipmentwherever fleet standardization could be maintained, and ease of servicing improved, without loss of efficiency. A third factor influencing the ultimate form of the NorthAmerican Viscount was that T.CA.'s engineers, with their impressive background of operational experience, regarded somefeatures of the existing version as capable of improvement—and did not hesitate to say so. T.C.A.'s criticisms, offered construc-tively and received in the same spirit by Vickers, undoubtedly helped to "improve the breed"; and some of the Canadian-inspired modifications will be standard on future Viscounts. When, early in June 1954, Capital Airlines signed a contractfor three Viscounts (with an option, soon taken up, on 37 more), the first of T.CA.'s V.724s was approaching completion; it wasdelivered, incidentally, in December of that year—25 months after the signing of the T.C.A. order. The existence of a NorthAmerican version was of immeasurable value to Vickers in the negotiations leading up to the Capital contract—as shown bythe United States airline's original proposal to buy the V.724 in virtually unaltered form. In the event, a number of new "customer requirements"emerged during the discussions between Capital and Vickers engineers which followed the signing of the American order.But—as the following pages will show—the differences between the Canadian and U.S. versions of the Viscount are not ofa radical kind; they have not involved large s=ale re-designing, with consequent prejudice to delivery times. A few words might be said at this point about U.S. certificationof the Viscount, a subject which at one time received more than its share of pessimistic and ill-informed comment. It will beappreciated that an airliner carrying fare-paying passengers must be approved as fit to perform this work by the airworthinessauthority of the country of registration. Canadian airworthiness requirements are based on those of Great Britain so, in mostrespects, the Viscount automatically qualified for a Canadian C. of A., and this endorsement is sufficient to permit the operationof T.C.A. Viscounts from United States airports. A Capital Airlines Viscount operating from the same airports, however,requires the approval of America's airworthiness authority, the Civil Aeronautics Administration. The question of an American type certificate for the Viscountwas approached jointly by the C.A.A. (which sent a team to England to study die design, construction and operation of theaircraft) and its British counterpart, the Air Registration Board. The outcome of these negotiations was a letter, dated July 20th,1954, from Mr. F. B. Lee, administrator of the C.A.A., to Mr. R. E. Hardingham, chief executive of the A.R.B., listing 26 itemswhich would require modification in order to make the Viscount
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