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Aviation History
1945
1945 - 2073.PDF
428 FLIGHT OCTOBER IOXH, 1945 (CONTI senger-miles by 1950, a sevenfold increase in ten years, and equivalent in total to that of the 1940 Pullman traffic. The corresponding figures for rail and bus had shown even greater increases in the same period, but various war- time factors, such as the restriction on use of private pas- senger cars, had affected the totals and the comparison. The extrapolation of the pre-war curves was-, therefore, not a sure enough basis on which to assess post-war probabili- ties and makes it difficult to judge whether or not the beginning of air transport expansion started in this country and the U.S.A. in 1933-1935, as some signs would seem to indicate. Contrasts had been made of an aircraft cost of 3od. per Ion-mile, and shipping cargo costs of less than i/3oth of a penny per ton-mile, so that passage by air AID T P A would cost you 900 times as much A I K I K A as passage in a tramp steamer. Clearly the carrying trade catered for was quite different, and in fact it had been stated that air trans- port would cut much more into message traffic than into surface carrying trade, as so many more people would travel "to settle matters by interview rather than by cable or letter. Much more likely was the result that with this added means of international and imperial communication new traffic would be created and the sum total would increase. Fares would naturally vary accordingly to the length of the non-stop stage flown, but passenger fares between 3^ and 4 cents per mile seemed feasible in the future, com- pared with rather more than 5 cents per mile at the present time, provided that something like a two-thirds load factor could be achieved. We had already reached a stage where air passenger costs were getting very close to first-class railway fares. Sir Frederick showed a table which suggested clearly that, in many cases, the air fare between cities in the U.S. was actually lower than that for first-class railway travel. Speed in itself brought many advantages, not the least that the effect of headwinds, so potent a factor against the regularity of services just after the last war, was greatly minimised. Air transport was that much less dependent on weather. Moreover, comfort and safety had both materially improved; British Overseas Airways Corporation was able to quote passenger insurance rates exactly the same as those charged for travel by sea. Speed, in other words, had increased enormously without a corresponding increase in operational costs. Disproportionate Costs A break-up of operational costs emphasised the relative magnitude of fuel and oil charges and of the cost of main- tenance. Figures had been quoted giving 18 per cent, for fuel and oil cost, 12 per cent, for maintenance, and only 3 per cent, for depreciation. These indicated the relative unimportance of first cost of airline equipment and sug- gested that expensive improvements in design might be well worth while if they secured greater economy in use of fuel and oil, or simpler and quicker maintenance. Obviously, up to the present the United States had had a great advantage in cheapness of fuel. Before the war, .Imperial Airways fuel costs averaged approximately three •times as much per imperial gallon as those of the American domestic air-lines—2s. 3d. per gallon against iod. Jet propulsion units burnt cheap fuel, but it was by no means impossible that costs of kerosene might jump if the demand went up. American figures showed that in 1941 air transport was responsible for one death in approximately every 45,000,000 passenger-miles. In the same year, the U.S. authorities recorded one death for every 36,000,000 passen- ger-miles travelled in private automobiles. The word '' speed'' embraced more than the speed of the vehicle. It includes speed from the time when the intending passenger makes his decision to travel. This involved brief intervals between services in comparison with c ompeting forms of transport. Airline operators were attaching great value to frequency of service, which • favoured the use of aircraft of the smallest size compatible M with distance to be flown. Generally, it was better to have smaller craft departing frequently than larger craft depart- ing at much longer intervals. Obviously, the statement could not be pushed too far. There was an optimum size of airliner for a given volume of traffic for every length of haul. For example, an airliner designed for journeys in still air of 4,500 miles—a non-stop crossing between London and New York plus an adequate margin of range to over- come adverse weather—must, with present-day . power plants, be large if it is to transport a reasonable pay-load as well as enough fuel. On the other hand, quite a small aircraft might be adequate for high- frequency services over distances of ^1 Q Q .~ p y about 200 miles. IN o r \J K I Frequency must be appropriate N.I I I C n \ *° *ne *ramc available. Aircraft do IN U t D ) not run efficiently with 100 percent. loads, which involved a system of priorities and did not give a cushion of marginal capacity to accommodate the passenger who made up his mind to travel at the last moment, but they should if possible not go far below 70 per cent, of capacity. Most operating schedules nowadays were worked out on the assumption of an average use of some 60 to 65 -\ per cent, of total capacity. Maximum Utilisation The adoption of relatively small aircraft did not mean that the loads transported over the airlines would be neg- ligible. The aeroplane attained a very high degree of. utilisation, amounting nowadays in actual operation to as much as fourteen hours out of every twenty-four. The experience of the American domestic air lines was again illuminating. In 1940, 338 aircraft flew 1,000,000,000 pas- senger-miles. During the next few months the airlines lost half of their fleets to the Services, yet in 1942, with only 165 airliners, passenger-miles accomplished rose to 1,389,000,000, and in 1943 to 1,632,000,000. For the sevenfold air passenger increase forecast for 1950—compared with 1940—the Curtiss-Wright Business Research Department calculated that an aggregate of not more than 570 aircraft would be required with an average capacity of twice the present-day standard. How fast would the post-war airliner fly? Economic speeds deserving consideration in commercial air transport were still far below Service aircraft level A safe generalisation was that the 150-180 m.p.h. which •was a reasonable economic speed before the war could be increased in more modern aircraft to 200-225 m.p.h., due to improved aerodynamical form and the use of high engi?.S"* 1 boost to improve take-off with heavy loads at the high wing loadings. Research into laminar flow and improved aero- foils should greatly decrease "drag" and it was possible to envisage 300 m.p.h. as a cruising speed attainable in the next few years without more expenditure of power. Jet propulsion promised a long step forward, but there was yet much to learn in ways and means of reducing the weight of fuel consumed by the jet or gas turbine. By way of present example, Sir Frederick gave the figures for the Hermes. Yet another aspect of distance was gained if the world was redrawn on the basis of freight-rates, whereby countries between which freight rates were low were shown rela- tively close together and those between which freight rates were high were shown far apart- When completed, such a map revealed the astonishing advantage of seaborn^ freight over any other form of transport, and explained why sea communication and a favourable position on the world s sea highways had earned Great Britain her predominance. Air transport was obviously more international in its scope than any other form of transport. Hence, air trans- port could only be fairly surveyed from the global angle of approach. It must infallibly abolish the geographical separation of sea and mountain which had led to varying civilisations, and would tend to make the entire world one unit.
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