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Aviation History
1956
1956 - 0237.PDF
f: FLIGHT, 2 March 1956 235 NEW DC-8 DISCLOSURES Conway Version Offered: First Performance and Cost Data for Four Distinct Models THE fact that Douglas have definitely settled for theRolls-Royce Conway as an alternative powerplant forthe DC-8 was confirmed by the company on February 17th. Since the DC-8 was first revealed last June Douglas have released for publication only bare details of the two versions being offered—an over-water variant with J75s hav- ing a gross weight of 257,000 lb, and a domestic model with J57s (or J75s) of 211,000 lb. Details are now given of four basic types: two domestic versions, one with J57s, the other with J75s, and two over-water versions, with respectively J75s and Rolls-Royce Conways. Design gross weights of each class are 265,000 lb and 287,500 lb. These increases in weight are carried by a further 160 sq ft of wing area, obtained by increasing span with the addition of 2^ft at each root, inci- dentally providing more capacity for 20,000 lb extra fuel in each case. Fuselage length has been increased by 8ft 4in to allow for the accommodation of a further 19 (tourist) passen- gers. Dimensions and systems of all versions are identical, but the heavier overwater version has a stronger structure— wings, rear fuselage and tailplane all having heavier skin and stringers. The undercarriage of this version also is stronger, and has furthermore been redesigned for both models, the original "co-axial quad" being replaced by a tandem bogie whose rear wheels are designed to castor for improved ground manoeuvrability (see accompanying illustration). Of particular interest in the tabulated list of data for the four DC-8 models is the fact that installation of Conways results in a saving of some 4,860 lb in empty weight, as compared with the J75 version, and a difference in zero fuel weight of 3,800 1b. Cost per seat mile of this version is down by 0.07 cents compared with the J75 airliner, and range is increased by some 1\ per cent. This new three-view drawing of the DC-8 (dimensions of all versions are identical) shows the revised root trailing-edge planform: span has been lengthened by 5ft to restore wing area as weight has increased. A sketch is included of the new four-wheel main bogie with its swivelling rear axle, a complete redesign of the co-axial undercarriage. DOUGLAS DC-8 DATA (All range and performance data apply to the pay load and weights indicated) Engines Design gross weight, Ib Max. usable T.O. weight, Ib Design landing weight, Ib ...Manufacturer's weight empty, Ib Operating weight empty, Ib Design zero fuel weight, Ib ... Fuel capacity, Ib Fuel capacity, U.S. galCapacity cayload (space limited), Ib Number of passengersCargo, Ib Range, st. milesReserve fuel, Ib Cost per aircraft mile, $/st. mileCost per seat mile, cents/seat mileLevel flight speed (max cruise thrust)(a) 3O,OOOft at 220.000 Ib, m.p.h. T.A.S(b) 30,000ft at 200,000 Ib, m.p.h. T.A.S C.A. A. field length for T.O. at max T.O. weight, ft C.A.A. field length for landing at max. Idg. weight, ft ... Range with 6,500ft T.O. fieldlength, st. m J57 Domestic First- Class JT3C-4 (J57)265,000 250,000 189,000 114,489 119,726 161,200 114,400 17,600 34,280 12214,150 3,55016,500 1.54 1.26 561 568 9,440 6,680 1,830 J75 DomesticFirst- Class JT4A-3 (J75)265,000 265,000 189,000 118,265 123,532 165,000 114,400 17,600 34,280 122 14,150 4,030 16,680 1.72 1.41 586 — 8,640 6,630 2,650 J75* Overwater Mixed Class JT4A-3 075)287,500 287,500 190,500 120,737 128,862 167,550 140,500 21,615 35,930 132 14,150 4.47017,180 1.93 1.46 586 8.760 6.690 3.060 Tourist (144 passengers all versions) Capacity payload space limited, IbCargo, Ib Range, st. miles Cost per seat-mile, cents ... Range with 6,500ft T.O. fieldlength, st. miles ... 37,910 14,150 3,290 1.07 1,770 37,910 14.150 3,790 1.19 2,495 37,910 14,150 4,330 1.34 2,960 Conway Overwater Mixed Class Conway 287,500 287,500 190.500 115.877 123,726 163,750 140,500 21,615 35,930 13214,150 4.81016,800 1.835 1.39 582 I— 9,000 6,690 3,280 37,910 14,150 4,670 1.27 3,190 Applicable to all Models:— • Advanced rating Wing area 2,758 sq ft Wing span 139ft Bin Overall length 148ft 10in Overall height 42ft 4in Wing sweepback at 25 per cent chord 30 deg Landing gear type (swivel castor) ... ... ... ... ... dual tandem Turning radius (for wing-tip clearance) ... ... ... ... 91ft 1in Lower cargo compartments (two): Total volume (both compartments) 1,445 cu ft An order from Delta Air Lines announced on February17th for six DC-8s of the domestic version (engine unspeci- fied) brings to 110 the number of DC-8s now sold as follows:PanAm 25, United 30, National 6, K.L.M. 8, Eastern 18, J.A.L. 4, S.A.S. 7, Panagra 4, Swissair 2. The Boeing 707score to date is 80, as follows: PanAm 20, American 30, Braniff 5, Continental 4, Air France 10, Sabena 3, T.W.A. 8. STEEL FOR JAVELINS OWING to delays in obtaining steel in Britain and to theneed for maintaining a fast output of Javelin all-weather fighters, the Gloster Aircraft Co., Ltd., investigated the supplyposition in several European countries. As the outcome, an initial order to the value of £25,000 has been placed by the com-pany with the Societe Anonyme Usines Emile Henncot, of Court St. Etienne, Belgium, for about a hundred tons of high-grade steelto varied specifications. Belgium was chosen because of the speedy deliveries offered andalso because that country has been one of Gloster's best customers in post-war years (the Javelin is being considered as a likely nightfighter for the Belgian Air Force in replacement of the Meteor). Delivery of this Belgian steel will begin shortly and continue forsome twelve months. , The first Javelins are now being delivered to the R.A.K atter more than 2,000 hours of development flying and within the financial year for which they were ordered. CHEAPER TITANIUM RECENTLY, Imperial Chemical Industries announced a re-duction in the price of their raw titanium to about 21s (just under $3) per lb. In the United States—the largest producerand user of raw titanium—the current price is $3.45 (a little less than 25s).Some twelve companies have so far entered the field of raw- titanium production on a large scale, and there has been con-siderable competition to lower prices by means of improved extraction techniques. Two years ago the American price offirst-grade material was $5 per lb (nearly 36s). In August, 1953, I.C.I. announced plans to produce 1,500tons of titanium annually by a new sodium process. The plant came into operation less than two years later. Instead of thecoke-like "sponge" of the conventional Kroll process, titanium produced by the sodium technique is in the form of smallgranules which can be pelleted with alloying materials, thus facilitating the difficult process of melting.
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