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Aviation History
1955
1955 - 1549.PDF
664 FLIGHT, 21 October 1955 Contestants for the Medium-haul Market Vanguard, Electra, Viscount or Metropolitan? The Choice Before the World's Carriers 1AST Monday's announcement (see pages 650-651) of theVickers-Armstrongs 900, or Vanguard as it has been•J named by B.E.A., calls for a review of the airliners com- peting for the favours of the world's medium-haul operators whose1,500-2,000 airliners carry at least half of air transport's annual ton-miles. Two—the Vickers Vanguard and the Lockheed Electra—are as yet untested, while the Vickers Viscount 700 and 800 and the Convair 440 Metropolitan may be regarded as service-tested, familiar designs. The Vickers V.900 Vanguard (four Rolls-Royce RB.109 Tyneturboprops and the Lockheed 188 Electra (four Allison 501-D10 turboprops) have one significant factor in common: they haveestablished a new conception of the medium-haul airliner. Both are big—in the 100,000 Ib class—with large-capacity fuselages for70 to 100 passengers, and both have range-bands extending to the 2,000 mile-plus mark. Five years ago they would have been classedas long-haulers. But it is not the product that changes the market, although this does sometimes happen; more often it is the marketwhich, developing naturally, calls for a change in the product. Vickers-Armstrongs and Lockheed would be the first to confirmthe influence that two of the world's most experienced medium- haul carriers, British European Airways and American Airlines,have had on the respective specifications of the Vanguard and the Electra. It has been convenient to regard medium-haul carriers asspecialists in 500-1,500 mile domestic or regional sectors—plus or minus a few hundred miles. The traffic has been carried largelyby some 350 forty-passenger Convair 240s and 340s, the similar- sized Viscount, with its great appeal, coming spectacularly intoprominence during the past two years. But the remarkable rate at which air traffic is growing—20 per cent each year—cannot bemet most economically simply by expanding fleets; for best effi- ciency the size of the vehicle has to increase accordingly. This,of course, is happening in the long-haul business, with the new contenders—the Douglas DC-8, the Boeing 707 Stratoliner, and(we presume) the new B.E.25-powered thin-wing, Bristol Britannia—all in the 150,000 to 250,000 Ib, 100- to 150-passengerclass. Medium-stage traffic is actually expanding at slightly more thanthe average 20 per cent rate for the whole industry, but it is experiencing also a shift in the distribution of that traffic; thetendency is towards higher densities on the shorter routes—i.e., 250 to 500 miles. This is the fundamental fact behind the medium-haulers' requirement for the bigger vehicle, which has resulted in the evolution of the yickers Vanguard and the Lockheed Electra. The remarkable thing about both aircraft, however, is the widescope of their range-capabilities. Their designers have recognized the significant tendency for medium-haul airlines to extend thefrontiers of their upper ranges into the territories of the long- haulers, who in turn are looking toward really long-distance, end-to-end overflying operations. Both Vanguard and Electra are being marketed with the promise of range-capabilities extendingto more than 2,000 miles. The Vickers Viscount (both 700 and 800) and the Convair440 Metropolitan have in common something that, in the con- sideration of operators who need to expand their fleets more orless immediately, give them an advantage over the Vanguard and the Electra: their operational and engineering qualities are proved,and they are available earlier. The Metropolitan, being an old 340 candy in a new wrapper, is available on a six months'delivery, a fact which has influenced S.A.S., Sabena and Swissajr in their surprising decisions to order; no doubt the fact that these European operators are already stocked with Convair 340 andPratt and Whitney R-2800 parts and equipment was a considera- tion also, as well as the fact that on very short domestic sectors—averaging, say, about 300 miles—the piston-driven airliner is undoubtedly slightly cheaper to operate than the turboprop. Newimpetus has been given to a production line slowed down by Viscount sales (although steadily moving on the strength of U.S.military orders), but it would be unrealistic to regard the Metro- politan as a serious world challenger to the Viscount, if only onthe judgment of today's turboprop-conscious passengers. One wonders at the effect of a turboprop Convair 340 on the market,and there is a very strong case to be made out for the Eland- powered version—now being engineered by Napiers—which ifdeveloped in time will be a most formidable contestant. The Viscount has, more than any other design, set the pace ofmedium-haul airliner development, and has formulated a new taste in public standards of air travel. Its appeal to world opera-tors—22 of whom have already chosen it—was further extended by the announcement last Monday (coinciding with first news ofthe Vanguard) that the 700 and 800 models are to have improved performance. The two models, which were designed to operatein partnership (the 800, or "Major," is a short-range, high-payload version of the 700), differ only in fuselage-size, the cabin of the800 being 9ft 3in longer than that of the 700 to accommodate the additional payload. Both models are to benefit markedly in pay-load-range performance and speed by the fitting of the latest Rolls-Royce Darts, type RDa.7, of 2,100 s.h.p. down-rated to1,700 s.h.p. for take-off—an increase in cruising power of over 300 s.h.p. over the RDa.6 on which figures were previously based.And on Monday came news of a yet further improved 400 m.p.h. Viscount, to take the developed Dart RDa.8 of some 2,500 s.h.p. We have made no mention of other airliners that may influencethe market to a greater or a lesser degree. The massive re-equip- ment programmes in which the long-haulers are indulging arebound to release quantities of second-hand 749 Constellations and DC-6s, whose capacities and flexibility of range will match wellthe developing requirements of the medium-haulers, especially those with domestic routes not immediately threatened by turbo-prop competition. One takes for granted the decisive superiority of the turboprop, while overlooking the need of many operatorsto get more ton-mile capacity quickly, regardless of whether the customers prefer turboprop travel or not. There is only one jet contender, the S.E. Caravelle (two Rolls-Royce Avon RA.26s), the de Havilland Comet 4 being essentially a long-hauler. The Caravelle, while less versatile operationallythan its rivals, is certain to draw the traffic on selected 1,000-mile- plus routes where its speed will show to best advantage. To sum up, the bulk of the traffic over the world's mediumStages, say 250 to 1,750 miles, will be competed for over the next decade by four basic types of aircraft and their developments: theVickers V.900 Vanguard, the Lockheed Model 188 Electra, the new Vickers Viscount 700 and 800, and the Convair 440 Metro-politan. The first two are advanced designs, for delivery three to five years hence; the latter two are in production now. Inconsidering the chances of each for big world sales, the choice between the Vanguard and the Electra seems likely to dependon the prospects of the Rolls-Royce Tyne and the Allison 501-D10 (T56), with the odds heavily in favour of the Tyne.The Viscount-Metropolitan tussle is essentially one between a product that is decisively superior operationally, and another thatcan be bought earlier. It seems certain that the judgment of history will give the verdict to the turboprops. J. M. R. SIX MEDIUM-RANGE TYPES: COMPARATIVE DATA (ROUND FIGURES) Aircraft Vickers V.900 Vanguard (4 Rolls-Royce RB.109 Tyne) (4 Allison 501-D10) ; Vickers Viscount 800 .. ... „, (4 Rolls-Royce Dart RDa.7) . Convair 440 Metropolitan (2 Pratt and Whitney R-2800 CB17) S.N.C.A.S.E. 210 Caravelle (2 Rolls-Royce RA.26) Seats 93-105 64-90 40-59 44-70 44-52 70-91 Gross weight (Ib) 110,000 (approx.) 98,500 62,000 65,000 49,100 90,000 Take-off e.s.h.p. 4x4,400 (approx.) 4 x 3,750 4x1,800 2 x 2,500 2 x 10,0001b (st. thrust) Total fuel (Ib) Not 5enounced 26,670 15,6001 11,300 33,500 Max.payload (Ib) 21,000 18.000J 12.800 14.200 12,700 20.900 Max. payload range (with reserves) (st. m.) 2,000 plus 1,850 950 860 1,200 1,300 Cruising speed (m.p.h.) 425 415 365 360 275 450 Approx. price <£) 750,000 550,000 (less engines) 350,000 300,000 440,000 Numbers sold to date 20 75 239 46
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