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Aviation History
1951
1951 - 0637.PDF
FLIGHT, 6 April 1951 \ 395 ON FLYING-BOATS A Short Hytht (four Bristol Pegasus engines) of Aquila Airways, Ltd., now tht sole British operators of large commercial flying-boats. REFLECTIONS OF AN OLD HAND ... By J. LANKESTER PARKER, O.B.E., F.R.Ae.S. e flying:an Informal dissertation by Mr. J. Lankester Parker, O.B.E., F.R~A.e-S., who will always be remembered as chief test pilot and(now) a* a director of Snort Brothers. Though quite unpreten- tious, the article presents some major issues with exceptionalclarity. It appears in the Journal of the Guild of Air Pilots and Air Navigators, to the editor of which we are Indebted for per-mission to reproduce it here. In the original article Mr. Lan- kester Parker begins by saying that his first reaction on beingasked to write it was to refuse on the ground that flying-boats were now, perhaps, to be classified with dirigible airships—asold-fashioned devices that elderly gentlemen loved to talk about in the comfort of the club lounge. But, as will be seen below, hesoon warms up to his subject. IT is, I am told, a sign of old age when one's main concern andinterest is centred around things and events of the past. But itwould seem that, despite my years, I am not yet fully qualified in this sphere, for it was only after I had made up my mind that flying-boats have a future, perhaps a very important one, and that there are lessons to be learned from those already in being—useful both to flying-boat and runway-using aircraft designers—that I agreed to write this article. In the beginning there were special difficulties facing the would-be seaplane flyer, and it was not for some years after air- craft flew successfully that anyone managed to take off from water. The great resistance of water to high-speed motion seemed to be a problem impossible of solution. But man is a stubborn animal and does not readily give up, particularly, I think, if he does not suffer from a pseudo-education which has taught him to think he knows what is and what is not possible—and so he continued to experi- ment. These researches led to the development of the planing bottom. Which means that, by suitably shaping its under part, a hull which is entirely supported by its water displacement (or buoyancy) when at rest becomes subject to dynamic forces when moved. These forces get larger and larger as speed increases until finally the hull can be said to be entirely so supported. It is as though an airship, which can remain airborne at no air speed, could entirely dispense with its gas as it got under way. Both sub- marines and airships are, of course, subject to substantial dynamic forces or they would not be fitted with elevators. But not to the same degree as flying-boat hulls. I claim indulgence for the length of the above explanation, for there is some misconception in the matter. The idea that the hydro- plane runs along the surface at speed is not really sound. In truth, the existence of the surface is a complication rendering it more difficult to achieve as high an efficiency as when the wing (aerofoil or hydrofoil, if your prefer) is entirely surrounded by the fluid, as with an aircraft in flight. During the course of these early experiments I well remember one, which was, to the few of us privileged to watch, a very amusing episode. A rather eccentric gentleman, an inventor of some note in other spheres, thought the planing-bottom idea unsound and so fitted a craft with two large hollow wheels of suitable buoyancy. The underlying principle, it seemed, was that, as speed increased, the wheels would rotate until they would be running over the sur- fece of the water on the same principle that a car can travel at high speed over sand so loose that it would become bogged in it if speed were reduced. It turned out that this ingenious water-craft had a maximum speed of not more than walking pace, for the drag must have been terrific, and the wheels turned slowly and sedately in the wrong direction! A huge bow-wave built up in the front of each wheel as though the devil in the water had formed himself into a chock to prevent forward progression and mock at man, the fool. It was cruel of us to laugh, for there was much to be learnt from that experiment. History alone can tell whether flying-boats will ever again be used—except, of course, in a small way for special and unusual duties—but it is fitting, I think, at this stage to pause awhile to look back at the past and ponder the way development might have taken place had it been a straight battle of man versus Nature and not one complicated with international tension and war. When the Short "C" class flying-boats first went into service with Imperial Airways in 1936, and did a magnificent job of work on both the Australian and South African routes, there were few, if any, aerodromes in the world from which a landplane of this size and performance could be operated. Even if there had been, the point of my argument remains, for the "C" class could have been used if, by some stroke of genius, they had been produced ten years earlier. Of what use would, say, a Constellation, magnificent aircraft that it certainly is, have been in those days ? Indeed, of what use would it be to-day except for the aerodromes created to satisfy the needs of war and to serve national prestige? I very much doubt if economically the aeroplane would be in the running against the contemporary flying-boat for civil use if both had to bear their full operating costs reflected in the fares. Whilst it is true that one has to deal with a world as it is, and not much is normally to be gained by spending time in reflecting how it might have been and in what way other conditions might have affected the development of aircraft, such reflections are worth while from the point of view of how the immediate future may be concerned. It is not necessarily correct to assume that the impact of military requirements will play so important a part in the future as they have done in the first half-century of aeronautical progress. There is much difference of opinion as to what constitutes the ideal size for the long-range civil aircraft. Much weight attaches to the view that frequency of service and cruising speed are the goals at which to aim, and that we have already reached, some think exceeded, the ideal size. I remember very well the same arguments being put up, largely by the operators, about the good old Dakota, at the time it was in its prime. Personally, I have not the slightest doubt that aircraft larger than any at present in ser- vice will be in regular use by the airlines of the world in the not- far-distant future. The stressing problems inherent in the large spans in disturbed air will be taken in their stride. After all, the Tiger Moth is of almost infinite size to a household fly, and the fly stressman must wonder indeed how the clever human copes with the hundred-and-one up currents and down currents that so great a structure must be subject to at one and the same time ! In the event of my forecast on size proving right the important question will arise : will the military requirements of the world provide large enough aerodromes, suitably sited and in sufficient numbers really to satisfy civil needs and standards of safety ? The answer to this question is anybody's guess. My own is that crew- carrying military aeroplanes, other than as a sort of glorified army service corps, may well be non-existent. To get back to my seaplane story. I said earlier that the problem of overcoming the resistance to high-speed motion through water had to be solved before seaplanes could fly at all. Even then they
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