FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1956
1956 - 0868.PDF
10 COMMERCIAL AIRCRAFT . . . and Boeing. These "big six" will establish new standards of economy, and while the turboprop Britannia is at present un- equalled among them in operational flexibility, the pure-jet types are less handicapped in this respect than was until recently believed. Though excelling in speed, range and capacity, the inter- continental versions of the Boeing 707 and DC-8, by reason of their protracted take-off and landing runs and their great weight even at destination, will—unlike the Comet—demand improvements at many airfields intended to receive them. In layout these giants are of the same pattern, having four podded turbojets underslung from a moderately swept wing, and both are remarkable for a high ratio of gross to tare weight. Some interesting variations in detail treatment are discernible, par- ticularly in the matter of control systems. "Straight" or by-pass (Rolls-Royce Conway) turbojets are optional. The moderate-sweep podded formula promises to implant itself not in the long-range class only, but in the medium category, this being exemplified by the Convair Golden Arrow and Douglas DC-9; but here a sharp and refreshing contrast is presented by France's Caravelle which, though it certainly has podded powerplants, carries them in an eminently sensible location at the rear of the fuselage. Russia's Tu-104—like the Caravelle, a redoubtable competitor in its field—is a rations i development of an established bomber type, and commenuj> itself by low initial cost and (it is supposed) early availability. The extent to which such pure-jet machines will rival the turboprop Vickers Vanguard, late-model Viscounts and Lock- heed's Electra is not yet clear, but extensive business has already been transacted by Vickers and Lockheed. Turboprop conversions of the various Convair models (and possibly of ' FLIGHT, 6 July 1956 Douglas DC-6s and other large aircraft also) may attract valu- able orders for Britain's Napier Eland turboprop. Holding high promise as a mixed-traffic machine or freighter'is Lockheed's C-130, planned for military employ- ment but eminently suitable for (and firmly intended for) civil conversion. And who is to say that the mammoth 255,000-lb Douglas C-133, now flying in prototype form, and laid out along the same lines as the C-130, may not eventually be seen in civil colours? In the so-called feederliner class Holland's Fokker Friend- ship is regarded with favour by American and other operators and will find increasing acceptance by virtue of its Rolls-Royce Dart turboprops, these being already widely standardized in the Viscount. Darts are specified also for the Aviation Traders Accountant; but in the piston-engined Handley Page Herald both Friendship and Accountant find a doughty challenger— and one having four, instead of two, engines. Piston engines remain in the running not only in the Herald and in the still-unique Scottish Aviation Twin Pioneer but in the initial versions of the Frye Safari (representing a class of inexpensive, short-haul, short-field, mixed-traffic aircraft) and the Blackburn and General Aircraft Universal. Turboprop conversions, however, are feasible in both instances. We conclude this note with an expression of regret—that in the pages apportioned to new projects not a solitary example of the large, short-take-off or vertical-take-off aircraft appears, though machines of this class have been brought I-anitely nearer practical possibility by the immense power and light weight of the latest turboprops and by new forms (aad adaptations of old forms) of high-lift device. That such aircraft will come about is not to be doubted; and that they ; iay yet take tr.e place of the large transport helicopter is a spreading belief. E X P L A NjA TORY O T E S The aim of any journal in publishing such a mass of informa-tion and statistics as is to be found on the following pages must be standardization of treatment. Unfortunately this is never quitepracticable—certainly not in the present state of affairs. For example, direct operating costs, although by no means the onlycriterion determining whether an aeroplane will make money or become a liability, are of sufficient importance for us to haveincluded appropriate curves wherever possible. Yet they are based on so many different methods and are worked out on such varyingparameters (such as dollars per 2,000-lb statute mile or pence per available seat nautical mile) as to render comparison an oneroustask. For the record, the following theme has been adhered to, as far as practicable: — 1. All gallonages are Imperial (Imp. gal =1.2 U.S. gal), exceptfor the figure appearing on the DC-7C payload/range curve on page 52. 2. All performance figures, unless otherwise stated, are basedon International Standard Atmosphere conditions at Sea Level (for field performance) at maximum take-off weight (for take-off)and maximum landing weight (for landing); climb figures are for maximum weight in the clean condition and cruise figures are fora clean aircraft with gills closed, ice-protection systems inoperative and no unusual excrescences. 3. Payload/range curves are based on information supplied bythe manufacturer, and the different procedures adopted by different companies make direct comparison inadvisable without carefullystudying the quantities plotted. In general the capacity payload in pounds is plotted against stage length (sometimes termed sectordistance), the latter being in either statute or nautical miles (n.m. = 1.15 st. miles); in certain cases, however, the x-axis repre-sents range, which may be more than 50 per cent greater than the maximum stage-length which can be flown. Wherever possiblethe assumptions and allowances made are quoted; manoeuvre fuel is normally that expended in taxying and in other positioningwithout making good any distance towards the destination. 4. Costs are also subject to variation and wherever possible themethod used and the assumptions made are quoted. Where no method is stated it is generally safe to assume that the 1955 A.T.A.method has been employed for American machines and the latest S.B.A.C. method (a rather more rigorous treatment) on Britishaircraft. 5. In most cases the large cut-away drawing shows a typicalversion of each aircraft. Although most of these drawings do, in fact, depict aucraft exactly as they will be bought by one particularoperator the customer has not been named, except in certain cases where a note is added to the caption. Each of these drawingshas been prepared specially for this issue, with the exception of four which are revisions of drawings published in 1955. As faras we ourselves are concerned, none of the material is conjectural. 6. Seating plans have in most cases been chosen to depict aconfiguration different from that shown in the large drawing. 7. Three-view general-arrangement drawings are not to a com-mon scale. 8. In many of the o.escripikns station numbers are used toidentify locations. These:.. - variably distances in inches from a reference datum; for example, .station 620 in the Boeing 707 is620 inches from the nose. 9. The following further notes are provided by way of amplifi-cation, certain additional information having become available since the rest of this issue closed for press: — a. The fuel tankage of the Comet 4 has been revised and the totalcapacity is now 8,950 gallons (not 8,766) of usable fuel. There is only one large integral tank in the extension wing and this is betweenthe spars. b. (Page 71) The text headed "Britannia developments" reflects thethinking of Bristol Aircraft at this time. In spite of a report to the effect that the company are actively considering a pure-jet version of theBritannia, with a new wing and four Bristol Olympus engines, there is no intention of departing from the turboprop until the way can be seento making a really big advance in performance, perhaps into the supersonic field. c. (Page 16) The item numbered 78 in the key to the DC-8 drawingshould read "0.064in" and "0.063in." d. (Page 52) The DC-7C payload/range curve gives a tankage inU.S. gallons (7,824). The cost curves are in dollars per mile and cents per 200-lb-mile (not cents per lb-mile). e. It is reiterated that Handley Page have effected certain detailchanges to the Herald (page 59), particularly in the electrical system, as noted m the text. It will shortly be possible to describe these changes.f. It will also shortly be possible to report upon Lockheed's revised calculations concerning the Electra (page 39) at the increased weightof 113,000 1b. Detail changes are still being made to this aircraft and they are sufficient to render the April 1956 figures inapplicable. n !i/ uc ce Friendship performance data went to press,Fokker have announced a ten per cent improvement in take-off per- formance. Field length is reduced from 3,800ft to 3,400ft. This is at aweight of 33,000 1b; at the gross weight of 34,520 1b, field length is reduced from 4,200ft to 3,850ft AN INDEX WILL BE FOUND ON PACE 72
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
