FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1963
1963 - 2343.PDF
Air-Cushion Vehicles FLIGHT International supplement, 26 December 196? LETTERS TO THE EDITOR., by Mr Trillo are on the basis that the airliner flies as often and as far as possible, while a specialized liner such as France operates a weekly schedule across the Atlantic, sailing on fixed days. To do better than this is not the object of the company and the ship is held up in effect to permit a weekly sailing. Furthermore, it is not reasonable to consider a liner with accommodation of a super-luxury standard. If she or her type were fitted out to good, normal, passenger-ship standards rather than super-luxury standards, she would be quite capable, without any alteration in weight or size, of carrying nearly twice the number of passengers. It must be borne in mind that each Queen car ried over 15,000 troops during the war on each voyage. All I attempted to point out in my letter was that one cannot compare extreme unlikes. If one takes the restricted super-luxury sailings of France, multiplying the number of days when she is actually at sea, i.e., say 240, by her average speed and by her passenger capacity, one arrives at 3.14 X 108 passenger miles per annum. The com parable figure for a mixed-class Boeing on a 4,000hr per annum utilization is 2.28 X 108 passenger miles p.a. and on 3,000hr p.a. utilization, which is more reasonable, 1.71 x 108 passenger miles p.a. (I ignore the fact that, at the moment, average aircraft load factors on the Atlantic are below 50 per cent.) However, if one really wants to com pare the earnings capacity of a ship such as France on the same basis of passenger amenity related to voyage time as in, say, a mixed-class jet airliner, she would not operate a weekly sailing but would operate with a minimum turn-round, would carry her passengers in comfort but not in super-luxury, and on this basis could turn in over 6 X 108 passenger miles p.a. For example, even though Canberra is a luxury liner, she carries 10 per cent more passengers than France at very nearly the same speed on something like half the capital cost and on a gross tonnage only two-thirds that of France. Mr Trillo's article was an excellent one and most interesting. The comparison with ships of the France type, however, is misleading and I feel, as a naval architect, pointless. Regarding cargo carriers, the long- range air freighter, like the airliner, carries the maximum weight that it is possible to get into a relatively standard aircraft and a large increase in dimen sional size is not possible. Air freight is attractive in some cases because of the door-to-door speed possible; but it is an inescapable fact that, unless speed is economically attractive in itself the cost per ton-mile of sea transport is a minute fraction of that of air transport. The cost of bringing wheat from Australia to Britain by sea is so low that it hardly affects the final price of a loaf. If, how ever, it were brought by air the cost of the loaf would increase several hundred per cent. Finally, Mr Trillo asks a direct question, namely, why are not more passengers carried on a liner like France•? The answer is very simple: She caters deliberately for a luxury market because it pays to do so. If designed to compete for the coach and economy traffic across the Atlantic, at present dominated by aircraft, she would be designed differently internally and would probably carry anything from 4,000 to 6,000 passengers, in reasonable comfort but not in luxury. Basingstoke, Hants E. C. B. CORLETT, MA, PhD [Mr Trillo comments: I think that this letter from Dr Corlett throws some light on the reasons for our previous points of disagreement, which appear to stem mainly from the inclusion of the France in my article. The reason that I had mentioned liners at all was simply to show that on a basis of design work capacity, they are, as far as first cost is concerned, at a distinctly higher level compared with, say, aircraft and day-service ferry boats. It was perhaps unfortunate that I did not have data to present on a greater number of ships to give a more general picture of this difference. At the present time, interest is strong est in comparisons of ACVs with hydro foil boats, ferry boats, aircraft and heli copters, as well as fixed facilities such as bridges, causeways and tunnels. Ultimat ely though, it is conceivable that large ocean-going hovercraft may be developed, in which case, the relative merits of these craft and of liners would doubtless be argued. The speed of such hovercraft would mean that less accommodation volume per passenger will be required than on a liner, and this factor combined with the fundamental improvement in hovercraft efficiency as size increases, would suggest that on a basis of similar design work capacity, the first cost of ocean-going ACVs will not reach the level of that of conventional liners. The effect of journey time on the standard of passenger accommodation appears to be an underlying factor in this price difference.] UNION DYNAMICS LTD. 95 Gresham St., London E.C.2 DESIGNERS and MANUFACTURERS of AIR CUSHION VEHICLES International Boat Show Earls Court, l-l Ith January STAND UH4 92 Gas Turbines and Jet Propulsion By G. GEOFFREY SMTTH, M.B.E. Revised by F. C. SHEFFIELD In addition to the fundamental principle of jet propulsion and its historical background, extended treatment is given to combustion and metallurgical problems. Some chapters deal with pulsejets, rocket propulsion and gas turbines for road transport. 6th Edition (1955) 419 pp. 35s net (BY POST 36s 9d) Obtainable from leading booksellers, published by ILIFFE Books Ltd Dorset House Stamford St London SEI PS. S%U~%' IS rS^OKvoair-v.
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
