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Aviation History
1953
1953 - 1446.PDF
6oo FLIGHT CIVIL AVIATION OVER, THE WEATHER: The first prototype Britannia is the subject of this aerial portrait. It will soon be joined by the second, G-ALRX, which —on completion of all its fight tests—is intended to pass into revenue service with B.O.A.C. Extern ally almost identical with the machine illustrated, the second Britannia will probably begin C. of A. trials before the end of the year. C.P.A. IN THE NEWS TT was reported last week that Canadian Pacific Airlines had * decided to exercise an option on three Comet 2s—presumably for the important Pacific route discussed on pages 580-1 of this issue. A similar order has already been placed by British Common wealth Pacific Airlines, who operate between Sydney and Vancouver. C.P.A. had intended to be the first operator of jet airliners in the Pacific, but after the loss of one Comet 1A on a delivery flight the remaining aircraft was sold to B.O.A.C. Meanwhile, the DC-6B has been introduced on C.P.A.'s net work and one of these aircraft—the Empress of Honolulu—made a notable flight on October 14th. Flown by Capt. T. A. Tweed, the DC-6B made the first non-stop commercial flight between Japan and Canada, flying from Misawa to Vancouver in 14 hr 42 min. It carried a crew of nine and 43 passengers, plus 3,000 lb of mail and cargo. COAST-TO-COAST COMPETITION "P| ELI VERY of new equipment has made it possible for both -*-' T.W.A. and American Airlines to operate, for the first time, non-stop flights between Los Angeles and New York. Keen competition between the two carriers has been intensified by the fact that T.W.A. are using Super Constellations, whereas A.A. have slightly newer and faster DC-7s. T.W.A. were first off the mark, operating their first service on October 19th. Scheduled flying time for the Super Connie is eight hours. Although American Airlines will not introduce regular daily services until November 29th, an impressive "crew training" flight on the Los Angeles-New York route was made by one of the com pany's DC-7s on the same day. Flown by Capt. W. N. Braznell, and carrying A.A., Douglas and C.A.A. representatives, the air craft completed the 2,470 miles in 6 hr 52 min—an average speed of some 360 m.p.h. "without benefit of major tailwinds." Its cruising altitude was 21,000ft. In regular service, the airline states, the DC-7 will fly the route non-stop in 7 hr 15 min eastbound and 7 hr 50 min westbound. FATIGUE IN TRANSPORT AIRCRAFT THE importance of the structural-fatigue problem is widely •*- recognized in present-day design of transport aircraft. In a paper published in the October issue of the Journal of the Royal Aeronautical Society, P. B. Walker, M.A., Ph.D. (whose previous papers on fatigue topics have also appeared in the Journal), presents an attempt to estimate the safe life of a transport aircraft, under reasonably good operating conditions, from the standpoint of wing fatigue. Dr. Walker—who is head of Structures Department, R.A.E.— bases his calculations on four main assumptions: (1) that gusts are the main fatigue hazard; (2) that practically all the fatigue damage caused by gusts is produced by gusts within a fairly narrow velocity range, say from 5 to 15ft/sec; (3) that the fatigue effect of the complex fluctuations of loading occurring in actual flight can be represented by the effect of a single loading cycle applied repeatedly to destruction; and (4) that the gust conditions foreseen for the life assessment are known. After discussing the basis and limitations of these assumptions, POTENTIAL CUSTOMERS for the Viscount are Scandinavian Airlines System, who will eventually have to replace over 30 DC-4s and DC-3s. The Viscount production line at Weybridge was inspected recently by senior executives of S.A.S.; seen here (left to right) are: G. Fredricksson, superintendent of airframe engineering; R. C. Handasyde, Vickers- Armstrongs sales manager; C. Carlstein, vice-president engineering and maintenance; A. Karlsson; and L, Fullberg, inspection manager. Dr. Walker describes the simple fatigue test which is required on critical components before the fatigue formula can be applied. The loading cycle for this test corresponds to a sequence of up-and-down gusts of 8ft/sec equivalent velocity. From the number of cycles to destruction obtained from the test, and the derived safe minimum or "nominal endurance" (taken to be two-thirds of the logarithmic mean of the endurance values), the final formula for the "standard life" (L flying hours) is found to be L = 2.5 — where N is the nominal test endurance and V the equivalent operating speed in knots. The operating conditions assumed in this empirical formula are those normally obtaining on European airlines. For general use, it is emphasized, the estimate has to be used with discretion, and corrections have to be introduced for conditions differing widely from those envisaged. The operating height above the ground is the most critical of these variable conditions. The formula as given is intended to apply to aircraft normally operating above 8,000ft; for those flying below this height a shorter life is to be expected due to the greater turbulence of the lower regions. Stage-length is also a factor to be considered, for whatever the aircraft's height or distance flown, it has only once per journey to ascend and descend through the gusty lower levels of the atmosphere. The geographical region is another factor influencing fatigue life, as gust frequencies and intensities vary in different parts of the world—although not as much as was previously believed. Fatigue life can also be influenced by the operating techniques used; for example, care in avoiding, or slowing down for, gusty regions can considerably improve fatigue characteristics. It is possible, Dr. Walker concludes, to obtain closer estimates by adjustment of the formulae to meet certain special conditions. The treatment described, however, is essentially a general one. "SAUCER" ON THE PARIS ROUTE? ONE of the most intriguing "flying-saucer" stories yet published is that told by Capt. P. Fletcher and First Officer R. L. Lemon, pilots of a B.E.A. Elizabethan which operated a morning service from London to Paris on October 9th. From the flight deck of the airliner, they watched for some 30 min a highly polished machine which appeared to be flying on the same course as the Elizabethan but at a greater height (about 20,000ft). Capt. Fletcher reported that visibility was excellent on the day in
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