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Aviation History
1953
1953 - 0093.PDF
23 January 1953 91 From A. Cdre. GRIFFITH POWELL, C.B.E., R.A.F. (Ret.) T AM glad of the opportunity of stating the Silver A City interest in helicopters, firstly because of the special advantages that a suitable type would bring to our short cross-Channel services and secondly because some of our requirements are MF I. materially different from those of the conven- P^ JH tional passenger-carrier. Jm Briefly, it seems to us that a helicopter opera- Jm H tion offers the simplest possible satisfaction of our jj formula of flying cars where they cannot be driven. Many of our problems would disappear if we could operate literally between sea-level platforms on each side of the Channel; and these, so far as our principal route is concerned, might be only 22 miles apart. To get a better balance between ground loading and air time, we favour a helicopter prime-mover and pannier arrangement, the upper half to be capable of a lift of five tons plus—that is to say, two main vehicles plus a selection of cars, cycles, and small freight. Each pannier would be 56ft 6in long, with a forward 15-seat passenger compartment and a rear freight hold about 37ft by 7|ft. We visualize the prime mover attaching itself to each pre loaded pannier, departing on a 10-minute airlift, depositing its pannier at its destination, and reconnecting with another pre loaded pannier. Such operations could go on day and night in practically all weathers except fog and gales. We could thus offer Managing Director, Silver City Airways, Ltd. a practically continuous service which might be used in normal hours by tourists and at night for freight and perishables. In presenting our ideas to British manufacturers, we have not expressed any fixed views on methods of proportion; it is interest ing to mention, however, that the noise objection—already being advanced against gas-turbine developments using tip thrust— may not be a disability to a completely over-sea operation pro vided, of course, that there is a reasonable noise-level within the cabin itself. From this point of view, therefore, and having regard to present military research on "air cranes," a basic mili tary design with civil trimmings might well fill our bill. Technically, there is little doubt that our modest lift require ments could be met in five to seven years. Certainly the type of cross-Channel operation envisaged by us would constitute an admirable proving-ground for the developments for subsequent military purposes of such an "air crane." Notwithstanding the admirable development work of B.E.A., we are still a long way from public acceptance of the hehcopter as a means of transport. If this very necessary public interest is to be aroused and kept in step with our technical development more use must be made of military and civil opportunities, although at this stage the latter are somewhat restricted. For this reason I believe that this special number of Flight will provide a valuable boost for a side of civil aviation development which is far from over-emphasized. From *LORD BOYD-ORR, D.S.O., M.C, LL.D., F.R.S. Chairman of Pest Control, Ltd. THE world population is increasing at the rate of over 50,000 per day. This, coupled with the fact that the increase in food production is by no means keeping pace, indicates the dangerous state of the world's food store—a state which is daily becoming more acute. Every available acre must be cultivated; that is obvious enough, but it is also essential to increase the amount of food gathered from each acre. Steps are already being taken to cultivate more land and to improve standards of cultivation the world over; but this will not be sufficient—new irrigation schemes and improved methods of cultivation take time to become produc tive and at best can only lag behind the demand for more food. One of the ways in which the demands of the ever-increasing population of the world can be met to some extent is in the extermination of the pests and diseases which are at present destroying such a large percentage of the food which is now being grown. Modern science has shown that the chemical means of controlling crop pests can be successful, and that it is now a matter of finding the swiftest, surest, and most economical ways of applying them. That is where the hehcopter adds to its already *Lord Boyd-Orr was unable to give a personal message, but this statement vias made with his approval. formidable number of humanitarian roles in that it enables more to be done more quickly in defence of our food supplies. For many years, agricultural scientists had foreseen the advan tages of the hehcopter as a crop-spraying machine, but it was not until 1945 that the opportunity occurred to put these ideas to the test. During the first few flights it was increasingly obvious that the spraying machine of the future had arrived. The first tests showed the slipstream of the helicopter to be an excellent medium for carrying the spray droplets to the foliage of the plants, the speed of the stream causing the droplets to rebound and thus ensure full cover to both sides of the leaves. Here was a highly manoeuvrable, slow-flying aircraft that could treat large areas economically, accurately, and quickly, and which would not damage the crop in the process. There was still a tremendous amount of research and develop ment to be done, and many lessons to be learned in both the aeronautical and agricultural aspects of the helicopter, but a start was made in 1948 on the first contract work of agricultural spray ing. Since that time many hundreds of thousands of acres have been treated by helicopter in this and in many other countries and hundreds of thousands of tons of irreplaceable foodstuff which would otherwise have been destroyed have been saved. From IGOR I. SIKORSKY Engineering Manager of Sikorsky Aircraft Division of United Aircraft Corporation A NUMBER of facts justify the statement that the middle of the twentieth century may be regarded as the period when the helicopter reached its maturity. Among other proofs we may point out the five years of uninterrupted airmail operation by Los Angeles Airways. Out standing evidence can be found in the brilliant transatlantic flight of our two H-19 helicopters of the Air Rescue Service. By far the most important is the excellent service these craft rendered in Korea. The start that has been made already by this newcomer in air travel justifies, I believe, an attempt to foresee its future develop ment. The ideas expressed are strictly my present personal ones. There seems to be no limit to the size and lifting capacity of the hehcopter. Indeed, giant machines, in all probability, will not be designed as enlarged copies of a modern, small hehcopter. They would have to be different. In particular, in very large helicopters it would be more practical to apply the power directly to the tips of the blades by the use of jets, small auxiliary propellers, or other devices. However, the main line of helicopter development will probably follow the present formula, with the power of one or several engines applied to the rotor shaft by way of transmission. This formula may be successful for aircraft carrying up to 60 or even 100 passengers. The question of configuration, the number of lifting rotors, etc., still remains a controversial one concerning which competent designers have expressed very different opinions. I believe that the single-rotor helicopter, in other word's, an air craft in which most or all of the lift is supplied by a single rotor, will remain the most efficient and most successful type. Probably the ordinary or pure helicopter will never travel very fast. A speed of between 150 and 175 m.p.h. may prove to be the maximum practical operating speed. Much greater speeds could be obtained by a so-called convertible helicopter which means an airef aft which takes off as a helicopter and, once in the air, trans forms itself, in one way or another, into a partial or complete airplane. A multitude of designs has been prepared and some actual attempts to construct an aircraft of this type are under way, but only the future will indicate whether the advantages gained will compensate for the complications, cost and weight involved. In spite of its limited speed, I believe that the pure helicopter will remain the most important type in its class, while the convertiplane will be used only in exceptional cases. It would be difficult to over-estimate the valuable services which the helicopter of the future will render. It will probably replace the airplane for short-range travel, say up to 150 miles or so, in which case the helicopter could carry passengers and cargo directly from the heart of one city into the center of another. Helicopters would also prove valuable in the transportation of passengers between huge air terminals and the hearts of industrial or residential sections of cities. The helicopter requires neither roads to travel nor airports for taking off or landing. In this respect it is unique and superior to any other vehicle.
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