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Aviation History
1954
1954 - 0338.PDF
162 FLIGHT PROSPECT FOR 1955: Two Britannias are now flying and the type is expected to enter revenue service with B.O.A.C. next year. An estimate of the outstanding range-pay- load performance ex pected of this turboprop airliner is quoted below. An interesting feature of this new aerial study is the effect produced by paint ed bands near the tips of the D.H. hollow-steel air screws (diameter 16ft). CIVIL AVIATION BRITANNIA ROUTE ANALYSIS AN impressive picture of the commercial capabilities of the '^developed Bristol Britannia 300 with 4,150 e.h.p. Proteus turboprops is painted in the latest edition of The "Bristol" Quarterly. The journal publishes an analysis of the Britannia's estimated performance on a 9,928-mile international route— between London and Tokyo. This is flown in five stages, with stops at Cairo, Karachi, Bangkok and Manila. Although long by normal standards, these sectors are described as modest when measured against the maximum range ability of the Britannia. Carrying a capacity payload of 104 passengers, baggage and freight, the aircraft would complete the outward journey in just under 28 hours' flying time. With refuelling stops of 45 minutes each, the elapsed time between London and Tokyo would be only 31 hr; and the return journey, because of stronger headwinds, would be 38 hr 45 min. No estimates are made of operating costs but the manufacturer's journal claims that "no aircraft yet exist ing could do this job more cheaply than the Britannia." Wind values assumed in the analysis are taken from Meteorological Report No. 7, and are those found on 85 per cent of days in the least favourable quarter of the year. Thus, a head wind of 82 m.p.h. is assumed on the Bangkok-Karachi stage; even so, it is stated that the Britannia would fly this 2,300-mile stage with a full complement of 104 passengers. An extract from the analysis is quoted below, showing the figures for a typical stage of the return journey:— Stage: Tokyo-Manila (1,860 st miles): Cruise procedure, 285 m.p.h. I.A.S.; mean wind, —44 m.p.h.; take-off weight, 154,353 lb; landing weight, 120,483 lb; stage fuel, 32,400 lb; reserve fuel, 10,930 lb; pay- load, 26,680 lb (104 passengers with baggage plus 2,680 lb freight); block time, 5 hr 53 min; block speed, 315 m.p.h. Three cruise procedures were used in the analysis: (i) maxi mum speed at 285 m.p.h. IAS, (ii) intermediate speed at 260 m.p.h. IAS, and (iii) long-range procedure at 345 m.p.h. TAS. In each case the speed chosen was that involving no payload limitations. In practice, operators would use a more flexible method of cruise control whereby the aircraft would always be flown at, or close to, the optimum speed. Fuel allowances and reserves were as follows: starting and taxying, 530 lb; take-off, 355 lb; de-icing, 1,115 lb (approx. 3 hr); engine and airframe depreciation, etc., 5 per cent of stage fuel. Reserves: 373 miles at long range cruise procedure against 58 m.p.h. headwind—two hours' stand-off using two engines with two idling. Time allowance: 0.25 hr for taxying, etc. AEROFILMS' NEW VENTURE AT a reception held last week Aerofilms, Ltd., announced the introduction of aerial colour photography on a commercial scale. Examples on display included a number of 5in by 5in Ektachrome transparencies and some coloured enlargements made from them by the Carbro process. The transparencies were wonderfully bright and critically sharp in outline. With a high- power magnifying glass separate blooms could be distinguished in an aerial view of a large nursery. Of aeronautical interest was one of the assembled aircraft on the runway at Farnborough during last year's S.B.A.C. Display. As would be expected, the enlargements lose a little of this wonderful crispness of outline. The Carbro process requires the superimposition of three or four prints made in the primary colours of the spectrum and this causes the very tiniest details to disappear. They compare, however, very favourably with a normal enlargement of the same size. Announced at the same time is the compilation of a classified index to the more than 100,000 air photographs taken by Aerofilms, Ltd., since Mr. F. L. Wills, now the managing director, first started the concern in 1919. This is the work of the librarian, Miss T. Hamilton-Jones, M.B.E. The examples used as illus trations make it a most striking volume in its own right far removed from any "index" in the ordinary sense of the word. Aerofilms, Ltd., is one of the Hunting Group of companies, which has aerial survey concerns in Africa, Canada, New Zealand and Australia. COMET 2 PERFORMANCE ON the basis of preliminary flight tests with the Avon-powered Series 2 Comet, the de Havilland Aircraft Co. has published a statement in which the performance of this developed version of the world's first jetliner is related to the requirements of every day commercial operation. It is immediately apparent that from the viewpoint of range—and in many other respects—the Series 2 represents an enormous improvement on its predecessor. It is capable of handling stage-lengths of up to 2,400 miles with a full complement of 44 passengers, and is thus capable of regular operation on most of the world's main international routes. Two recent flights by the first production Comet 2 for B.O.A.C. left little doubt that the original brochure figures were conserva tive. On January 22nd, flying non-stop from Hatfield to Khartoum for tropical tests at an average speed of 481.1 m.p.h., it completed the 3,080-mile journey with 1,200 gallons of fuel left in the tanks. Six days later the same aircraft flew non-stop from Khartoum to Johannesburg, a distance of 2,913 miles, at 460 m.p.h.; on this occasion the amount of fuel remaining was suffi cient for a 400-mile diversion from sea level plus 30 minutes' stand-off. Both flights were made with an equivalent payload of 10,500 lb, corresponding to 44 passengers with baggage. After taking into account the severe fuel-reserves policies enforced by commercial operators (B.O.A.C., for example, allo cate about one-third of the Comet l's fuel capacity for diversion, stand-off and emergency, and their sector fuel estimate includes a 5 per cent allowance for performance variation and navigational error), it remains evident that stages of well over 2,000 miles are well within the Comet 2's capacity. The decision to adapt the original Comet to take advantage of the axial-flow Rolls-Royce Avon turbojet, with its higher thrust and lower fuel consumption, was taken in July 1950. Flight test ing has been in progress since February 1952 wkh a Drototype obtained by equipping the sixth Comet 1 airframe with Avons. The production Series 2 embodies several innovations, including a slightly longer fuselage, greater fuel capacity and, not least, a new wing section which greatly improves slow-flying characteris tics. Combined with the extra thrust of the Avons, it has given
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