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Aviation History
1955
1955 - 0788.PDF
786 FLIGHT, 10 June 1955 CIVIL AVIATION... smoothness and comfort even surpassing that of earlier versions,and will carry its capacity payload of nearly 60 first-class passengers on practically all of the established inter-continentalstages, including the few which exceed 2,500 miles. To fulfil this world-wide function economically appears to us more worth-while than the ability to fly with full load non-stop from London to New York against prevailing westerly winds of both fair andadverse seasons, but even on this route the new Comet, with one halt westbound, will probably afford the fastest and favouritemeans of travel. "The principal carriers have been quick to see the significanceof the capabilities of the Comet 4 and they appreciate the wealth of experience which is being built into it, and to which there isno short cut. No airliner design has been so thoroughly scrutinised and tested, and it is important to recall that the Comethas behind it 30,000 hours of airline operation which, apart from the one problem now resolved, was highly satisfactory." Further information on the Comet 4 comes from a "preliminarystatement" issued by de Havillands on May 26th; its contents are summarized in the following notes: — Structure. Advantage has been taken of recent advances in theknowledge of metal fatigue and during the past months a great deal of repeated-load testing has been undertaken on full-scale components.In particular the stress level in the fuselage seam joints and cut-outs has been kept low so that local damage will not affect the safety of thestructure: the integrity of the new structure will be beyond question. Power Units. The Avon RA.29s of the Comet 4 will each deliver10,500 lb s.t. for take-off, compared with 10,000 lb for the Comet 3's Avon RA.26s. Cruising specific fuel consumption will be about 9 percent lower. Reverse thrust is under active development for the Comet 4, but present figures do not allow for it. Weight and Loadings. Maximum take-off weight of the Comet 4 willbe 152,090 lb, compared with 150,000 lb for the Comet 3. Usable fuel capacity is increased by an unspecified amount to a total of 8,750 Imp.gal. Capacity payload of the Comet 4 will be 16,850 lb (58 passengers plus luggage, mail and freight). Equipped tare weight is quoted as68,000 lb and maximum landing weight is 113,000 lb. It is hoped that the introduction of titanium will bring reduced structure weight, andthat early production aircraft will benefit in this way. Take-off performance, say de Havilland, will very rarely be a limitingfactor. In general, the Comet 4 will take-off 3,500 lb heavier than the Comet 3 for a given runway length. An example of Comet 4 take-offperformance is as follows: 7,140ft (2,380 yd) to 50ft, with failure of one engine at critical point; sea level altitude and temperature of30 deg C (86 deg F). Speed. Optimum cruising speed of the Comet 4 will correspond toa Mach number of .74, which is equivalent to 489 m.p.h. in standard atmosphere, rising to 506 m.p.h. in I.S.A. plus 15 deg C conditions. Payload-range Performance. Stage-lengths with capacity payload of16,850 lb will be 2,870 miles; this example of typical performance assumes a continuous headwind of 50 m.p.h. and the necessary fuelreserves, including allowances for a 30-minute stand-off at 1,000ft followed by a 200-mile diversion from sea level. The maker's studiesshow that the Comet 4 will carry its capacity payload with 85 per cent regularity or better over the great majority of the important trunkroutes. Examples of forecast Comet 4 journey times from London to fivemajor cities are: to Tokyo (9,386 miles) with four intermediate stops, 22 hr 3 min; to Sydney (11,164 miles) with four stops, 27 hr 37 min;to Johannesburg via Cairo and Nairobi (6,220 miles), 15 hr 23 min; to New York (3,502 miles) with one stop, 9 hr 30 min. Estimated flighttime from San Francisco to New York (2,612 miles non-stop) is 5 hr 18 min. I.A.T.A. FORESEE NEW NAVAIDS \)SjriTHIN five to ten years it may be possible to equip airliners~ * with automatic airborne navigational aids which will be com- pletely independent of ground stations. This intriguing possibilitywas among the topics discussed by delegates to the eighth Technical Conference of the International Air Transport Associa-tion at San Juan, Puerto Rico. A post-conference summary by I.A.T.A. included the following reference to the subject: — "One such aid which was examined—within certain security limita-tions—was the 'inertial navigation' system. This system employs the physical properties of near-perfect gyroscopes to provide a continuousindication within the aircraft of true horizontal and vertical. In con- junction with these references, accelorometers are then used to determinethe instantaneous velocity of the aircraft and the distance and direction it has travelled. Finally computers can be added which will permitpresentation of the navigational information in any required pictorial or symbolic form. "The maximum accuracy possible with inertial navigational deviceswas not disclosed but the hope was expressed that errors would not exceed one or two miles in position per hour flown. Since such errorswould be independent of the distance flown, aids of this type would be increasingly attractive as aircraft speeds advance. The conferencestrongly underlined the point that there are many sound operational reasons why inertial and other self-contained aids will not eliminatethe continuing need for ground-referenced radio navigational aids." Discussing air traffic control the delegates agreed that futureturbine-powered aircraft would reduce flexibility in the choice of cruising altitudes and that consequently it would become necessaryto make extensive use of aircraft separation in the horizontal plane. There would, in turn, be a requirement for navaids permittingprocedures to be based on finer lateral and longitudinal limits of separation. The conference also pointed to the need for revision, in thelight of present-day traffic densities and speeds, of criteria deter- mining whether flights should proceed under visual or instrumentflight rules. It was concluded that V.F.R. flights should be per- mitted only under the following conditions: pilot's forward visi-bility of at least five miles; minimum lateral distance from cloud, 2j miles; minimum distance above cloud, 2,000ft; and verticaldistance below cloud of at least 1,000ft. The conference also reaffirmed the I.A.T.A. view that, ultimately, all air traffic shouldbe subjected to positive control, irrespective of weather conditions. It was agreed that, in the interim, revision of V.F.R./I.F.R.criteria on the lines indicated would increase the percentage of aircraft under control in marginal weather. AIRLINE PILOT TRAINING ALL-THROUGH flight and ground training, ab initio to the** Commercial Pilot's Licence and Instrument Rating standard, is now being provided by the London School of Air Navigation inconjunction with Airways Aero Associations, Ltd. The new courses, recently approved by the M.T.C.A., have been put for-ward by Mr. Ian McNicol, director of the L.S.A.N., both as an immediate facility and as a future line of entry into the professionshould the need for a regular civil-aircrew training scheme become officially recognized. The ground subjects for C.P.L. and Instrument Rating willbe taught by the London School at its headquarters at 33, Ovington Square, London, S.W.3. Flying instruction, at Croydon, wifi bethe responsibility of Airways Aero Associations which, in addition to running the Airways Aero Club for personnel of the twoCorporations, has performed outside contract work for some time. During 1954, total flying hours amounted to over 5,600, includingalmost 3,000 hr devoted to commercial-pilot training for B.E.A. radio officers and B.O.A.C. navigators, and 450 hr on A.T.C.scholarship flying. As a long-term policy, a three-year apprenticeship scheme forcivil pilots has been suggested by Mr. McNicol, under which the initial cost of training would be borne by the operators. Selectedcandidates, of P.P.L. standard, would undergo one year with the operator's maintenance department and other technical sections,a second year being trained to C.P.L. standard by an outside training organization, and a third year of advanced type and routeexperience as junior pilot or navigator with the operator. Inden- tured for the next five years, the pilot would repay over this periodpart of his training expenses. No comment on this proposal has yet been made by either of the Airways Corporations, who wouldpresumably be the main British operators concerned in such a scheme. ........ BREVITIES •pORMAL United States certification of the Viscount will be-*- marked by a handing-over ceremony in London on June 13th. At the ceremony, Mr. Fred B. Lee, administrator of the C.A.A.,will present type certificates for the Viscount, its Dart turboprops and its Rotol airscrews to representatives of, respectively, Vickers-Armstrongs, Rolls-Royce and Rotol. * * * Tokyo Airport's new £lm terminal building was officiallyopened on May 18th. A Qantas Super Constellation, operating a scheduled service to Sydney on May 20th, was the first inter-national aircraft to use the new terminal. * * * Seaboard and Western Airlines announce the opening of a salesoffice and cargo depot in Boston. The airline, which has just completed eight years of non-scheduled transatlantic freight ser-vices, now operates four Super Constellations and six DC-4s. On June 2nd Britannia G-ANBA flew from Filton to Belfast,where the aircraft was inspected by Government officials and by representatives of Short Bros, and Harland, Ltd., who are settingup a second line for production of the type. Aboard the aircraft was Bristol's chairman, Sir Reginald Verdon Smith, who conveyeda goodwill message from the Lord Mayor of Bristol to the Lord Mayor of Belfast. * * * The inauguration of B.E.A.'s helicopter service between theSouth Bank and London Airport, due to have taken place this month, has been postponed pending further development of thesilencer fitted to the float-equipped S-55s which will operate the service. During trials, the silencers over-heated to the extent thatholes were burnt in them after a comparatively short period of use; another result of the trials is that B.E.A. are negotiating with theLondon County Council for a larger site at the South Bank.
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