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Aviation History
1948
1948 - 0820.PDF
6i6 FLIGHT JUNE 3RD, 1948 Size in Transport Fig. 4. decrease in the ratio of body surface areato wing surface area. The ratio of bare weight to all-up weight tended to decreasewith size, due to design experience, and Mr. Gouge had no doubt that designerswould continue to beat the " infamous square-cube law.' (This law states that withincrease in size, wing area goes up as the square of the linear dimensions,while weight goes up as the cube. That is, of course, assum-ing that geometric similarity is maintained.—Ep.) Mr. Gouge introduced as ameasure of engineering efficiency " pounds of aircraft per pas-senger." Curves representing this are given in Fig. 5. Theywere intended to show the ad- vantages to be gained with largemachines, especially, where long range was concerned, andapplied only to a specific family of aircraft, having similar per-formance and reciprocating en- gines. The same reasoningwould, however, apply to air- craft having turbo-props andturbo-jets. Having studied the transportproblem in general, and noted how in all cases vehicles haveincreased in size as the years went by, and as technical ad-vances permitted them to do so, Mr. Gouge reverted to some ofthe points made earlier, and illustrated them by considera-tion of two. specific cases. These cases were not intendedto apply to any particular route, but to indicate his per-sonal opinion as to how they should be developed. Taking first the provision ofair transport between two cities whose population might be counted inmillions, and the distance between which was approximately 250 miles, he assumedthat they were separated by some geo- graphical obstruction which precluded thepossibility of a modernized railway system ever competing in the matter of speed. Itshould, he thought, be possible, if thorough consideration was given to thewhole project,, eventually to carry almost the whole of the passenger traffic be-tween these two large cities. If that belief was correct, they should designnow to make it come true. Specialized Design With aircraft as we knew them to-day,the journey time would be in the neigh- bourhood of one hour, and therefore itmight be expected that the frequency should be of the same order. The sizeof aircraft would be determined by the volume of traffic. It was to be expectedthat traffic between these two cities would ultimately be of the order ofthousands a day rather than hundreds, and it was obvious, therefore, that thetask was worthy of a serious engineering undertaking. It would be seen that acomparatively large aircraft was neces- sary, and it should be specially designedfor the job and for nothing else. The comparatively short range avoided thenecessity for high-altitude flying, and if the cities were in the temperate zonethere was no reason why any part of the equipment should be considered fortropical flying. He thought the designer might even claim a relaxation on such thingsas maximum gust intensity. As the range was only 250 miles, thetankage should be designed specifically for this, and they should not equip the machinewith tanks for a greater range with a view to the possibility that there might be someother market. It was far easier to provide the right size of tank, holding the properamount, gauged correctly and installed easily. Also, such precision of design re-quirement would be a great assistance to the designer compared with the position inwhich these unfortunate gentlemen often found themselves to-day, namely, that ofdesigning an -aircraft for one particular route and having to consider all other routes inthe world at the same time. Another ad- vantage was that it would enable the air-craft constructor to turn out a new design in a very much shorter period of time thanwas possible under the present arrangement. QUEEN M»Rr Possible landing areas on the Solent compared with London airport as finally planned. He realized that it seemed uneconomicalto design a machine of which the number required was of the order of a dozen or sorather than a hundred, but insisted that they were not giving proper considerationto the magnitude of the job unless they set out to supply these two jet^es with air Fig. S. Pounds of aircraft weight per passenger for different ranges, plotted against all-up weights. transport worthy of the route. He felt thatthe extra cost involved was of little im- portance in comparison with the final under-taking. Turning to the second case, Mr. Gougestudied an aircraft route equivalent to that of the North Atlantic. This involves afligjit of some 3,500 miles and was thought to be the most difficult service in the -world.On the other hand, it had the greatest possibilities Without visualizing a great change in present-day aircraft, the speedof machines operating on the North Atlantic would be of the order of 350-400 m.p.h.This would give an average journey time of nine or ten hours, and so the frequencyrequired would be two or three aircraft per day for .each company operating. Dr. Edward Warner had estimated, in his1943 Wilbur Wright Memorial Lecture, 600 air passengers a day. Mr. Gouge made anestimate based on other considerations. He assumed that most people with an incomeof about ^2,000 a year would be potential travellers at least oncea year, and probably would always travel with one com-panion. In this country there were about 100,000 people withincomes of over ^2,000 a year, so it might be expected thatthere would be 200,000 British return journeys per year, andhe thought it should be their object to provide air transportfor these people, and they should envisage a density in thenear future of 600 persons per day. With a frequency of twoor three trips per day, they should, therefore, contemplatethe provision of aircraft to carry 200 to 300 passengers. ;••-••••• Large Aircraft In the interests of safety hethought the journeys should be made from point to point inorder to avoid the hazard of in- termediate landings and take-offs. From this it followed that, in view of the range and pay-load involved, they must be prepared to build in the futuremuch larger aircraft than they were building at present. From the fact that the sizeand cost of airports were be- coming prohibitive, it wasdoubtful if they could or should go much further in that direction. Thismeant that we were limited to land machines of the size of the Brabazon or a littlelarger. If that was so, then in years to come either the frequency must go upor the potential passengers could not be carried. As we should want to do all in ourpower to extend the service and cany all the passengers who became available,it was necessary and essential that the large flying boat should be developedirrespective of what anyone else was doing in the matter. This was the onlytype of aircraft which could develop in size without an extremely high ancillarycost (rei. Fig. 4). The areas in the Solent would accommodate a boat verymuch larger than those at present undi construction. They were not limitedexternal considerations and one could plan with some confidence flying boatsof such a size as would handle efficiently the vast traffic that will become avail-able across the North Atlantic. The route would be a highly specialized one,and so the same considerations applied as in his first example, but with muchgreater emphasis. The North Atlantic as an air routehad such enormous potentialities that 00 they should not in any way confuse the issue by attempting to design a machinelor any other purpose than this par- ticular route. This was a case where itwas absolutely essential to specialize. Many new problems arose in the designof these large machines, but they were being rapidly overcome, and he thoughtwe in Great Britain could claim to be in the forefront in giving the world this classof aircraft in the form of -the Brabazon and the S.R.45.In conformity with the usual custom, there was no discussion after the reading ofMr. Gouge's lecture, but he had given his audience much food for thought, and therewill be many informal discussions of some of the points which he raised.
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