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Aviation History
1959
1959 - 1540.PDF
FLIGHT, 29 May 1959 Posed together for the first time at Wisley are B.E.A.'s turboprop relatives: a 63-seat Hi-D Viscount 701 and the up-to-139-seat Vanguard. The Corporation are currently concerned with the capacity that should be offered by the Viscount's jet successor—the D.H.121—in 1964 or 1965 AIR COMMERCE Subsonic Setback?I N a sudden flurry last week, a quartet of daily newspapers burstforth with articles in confirmation-of the loudest and most recent buzzing in the usually well-informed aeronauticalgrapevine—that the D.H.121 and the VC.10 were variously "in trouble," or "being redrawn," or that their "economic operationwas threatened," or that they would be "years late." Not surpris- ingly, the breakfast-table bombshell on the morning of May 20caused considerable alarm, not least among those who depend for their livelihood on the success of either project. Vickers-Armstrongs immediately issued the strongest denial,rebutting point by point allegations against the VC.10. It was not, they said, "in trouble," "delayed," "being redrawn," "underreview," "underpowered" or "years late," nor was its "economic operation threatened" on any route. Progress was to scheduleand the economics and technical performance were now better than ever because of engine development by Rolls-Royce. Theyadded that "no attempt was made to check the veracity of these unfounded allegations, so damaging to British industry and enter-prise, with the designers of the aircraft." Ominously, de Havilland said nothing, except to refer the matter to an equally non-committalB.E.A. There is, of course, nothing unusual about making quite radicalspecification changes in the early design stages of a new aeroplane, and the D.H.121 in particular is intended to meet as exactly aspossible B.E.A.'s forecast requirements for the mid-1960s. In July 1956 these were envisaged by the Corporation as a short-range jet with three engines, a gross weight of about 120,000 lb and accommodation for 80 tourist passengers or 100 in a high-density layout; and this was the specification to which the Rolls- Royce RB.141 engine was matched and on which more than 18months of active project and detail design have been based. That B.E.A. should now sing a different tune is hardly surpris-ing; foreshortening delivery time has provided a clearer idea of what will best be suited to European operations in 1965-70, andit now seems that the original estimates of size and weight were some 20 per cent optimistic. What is really needed, B.E.A. nowappear to argue, is an aeroplane with the same performance as the earlier 121, but weighing 100,000 lb or less and with a maximumof 80 seats. The design could then be stretched as extra capacity was required. There are also doubts as to the wisdom of the original D.H./B.E.A./Rolls-Royce decision to adopt a triple-engined layout, partly because of the intractable installation and removal problemsof the fuselage-mounted engine but also because the total thrust of three RB.141s would be excessive for the lighter airframe. Theoriginal 12,000 lb thrust from each engine has already been increased—in the characteristic fashion of Rolls-Royce develop-ment—to the embarrassment of Airco, who have been designing to a limited gross weight with no intention of stretching capacityand with little need to increase airfield performance. Nor can cruising speed be greatly increased without incurring economicPenalties as the Mach drag-rise begins to be felt. While B.E.A. are quite justified in keeping the design of theD-H.121 fluid until they are as certain as possible that their specification is commercially correct (the contract, for £30m for24 aircraft, was to have been signed three months ago) they can do so only at the risk of delayed delivery. What is much more dis- turbing is that, while it may not matter greatly to B.E.A. if theirshort-range jet services start in 1964 or 1965, it is of extreme concern to Airco and to the British industry, whose hopes ofexport sales may very well depend upon demonstrations and service experience with the D.H.121. It is not particularly comforting that much the same changeof viewpoint that is evident within B.E.A. has afflicted Boeing with the 727 and Douglas with the DC-9. The latter in particularis said to have undergone—albeit at an earlier stage—a similar reduction in size. At one time the gross weight was to have been125,000 lb, but Douglas now seem to favour about 94,000 lb, eventually increasing to 105,000 lb. Boeing's market analysissuggested a slightly smaller aeroplane, intended to carry rather fewer passengers over shorter stages; the take-off weight wouldprobably be 75,000 1b increasing to 94,000 lb. Neither manu- facturer has yet chosen a powerplant, but the most likely selectionis said to be a 7,000 Ib-thrust turbofan (four per airframe) that would be common to both aircraft. The DC-9 and Boeing 727might then be adjusted in size to become more nearly the same weight. The total thrust envisaged for the D.H.121's American counter-parts is thus about 28,000-30,000 lb, and this order of power may well be that now required for the British short-range jet. Thereare possibilities that by 1964 two RB.141s would be adequate for Airco's needs and would still have the development potential toallow an eventual 20 or 30 per cent airframe stretch (see "The Twin-Jet Airliner," Flight, March 6). But it is hard to discreditthe logic of the argument for three engines by any event of the past three years—with the sole exception, perhaps, of the easyacceptance of the Caravelle. There may be more resistance to two engines outside Europe and South America—as Boeing andDouglas seem to believe—but airline fashions tend eventually to receive universal acceptance. Whatever de Havilland now decide(and a change of engine to say, Bristol-Siddeley fan-Orpheus has been suggested) the project has almost certainly been put back byperhaps nine months, perhaps a year; or, in other terms, to be level with—or even a little behind—the DC-9 and Boeing 727 atthis stage. This is the penalty of designing under what Mr. W. E. Nixon, de Havilland chairman, described in his recent annualreport as "terms more onerous than anything D.H. had previously undertaken," which tie Airco so closely to the particular needs ofB.E.A. In contrast, the American short-range jets are each a com- promise between what several U.S. airlines say they want andwhat Boeing and Douglas—from experience and a comparison of viewpoints—think they will want. And both aircraft are stillfirmly expected to be available in 1962 or 1963, probably the earliest time at which they could be sold. The pitfall into which the industry has again stumbled is thatof having designed exclusively for one customer an aeroplane that has potentially a much wider scope. (To point to the Viscount assuccessful endorsement of this policy is to overlook two factors— the lack of direct competition at the time and the influence ofT.C.A. in preparing the Viscount for the American market.) But now there are signs that the new specification will soon befrozen. Then the onus will be on de Havilland, as prime con- tractor, to exercise single-minded drive in producing the D.H.121in the minimum possible time. A. T. P.
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