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Aviation History
1955
1955 - 0264.PDF
264 FLIGHT THE BRITISH HELICOPTER INDUSTRY . . . engineers that the lines of the design and the presentation of thebrochure are more important than the technical merit. The job of the project office is to produce a project which "looks fight,"after which it is up to the directors, chief designer, and politically adept administrators to sell the idea to the Ministry and damntheir competitors with what faint praise they can manage to slip in. Once the contract has been obtained the design can be re-hashed and put into a more practical form. It is interesting to note in passing that the art of selling one's firm to the Ministryaffects the way of life of the whole aircraft industry, and is responsible for such widely differing phenomena as full pageadvertisements in Flight and lectures read before learned societies. The inherent weakness in this situation is that contracts do notalways go to finance technically sound projects. Mr. John Brown's lecture to the Helicopter Association lastautumn was an interesting independent testimony of the poor theoretical performance of pressure jets, and it was given with theauthority of the National Gas Turbine Establishment. If Mr. Brown had had access to drawings of the mechanism necessaryto duct gas through a rotor head and out along the blades it is probable that he would have come down even more strongly infavour of shaft drive. It is always found that project weight estimates are low (there is a pair of floats in this country whose actual weight is 800per cent of the project estimate) and since data exist only for shaft-drive installations we are very prone to conclude thathypothetical alternatives are lighter. Before pressure-jet systems can fly, problems of control andvibration will have to be solved which, to say the least, are arduous. And in France S.N.C.A.S.O.—who lead the worldin pressure-jet design, having assumed the mantle (or part of it) of Doblehoff in 1945—have come to the conclusion that tip-burning is not practical with a pressure jet. Is it not to pile our eggs dangerously high in one basket, when the requirementfor an ultra-light helicopter enables another contract to be placed, again to award it to a pressure-jet design? A third malady which impairs the efficiency of the helicopterindustry is the lack of any basic research at the Royal Aircraft Establishment or elsewhere. There is not even a standard methodof estimating performance reliability, and any deviation from a strictly conventional design means that the company involvedhas no external guidance whatsoever. If some of more recent large orders for helicopters had been 10 per cent smaller and thedifference devoted to financing a five-year programme of basic research the future would have been a little more secure for allhelicopter designers. Despite its imperfections, the writer wishes to remain in thehelicopter industry. After the wigging that Galileo received it is perhaps for the best if he signs this article A. HERETIC. THE HELICOPTER AS A LIFEBOAT TPHE Royal National Lifeboat Institution operates 150 lifeboats•* around the shores of Britain. Due to the limited speed of the lifeboat, these could certainly be replaced by about one-third thatnumber of suitable helicopters and, what is more important, the lifeboat can only carry out rescue operations at sea, whereasthe helicopter can be equally effective over floods, marshes or mountains. The same chain of helicopters could improve their utilizationby providing service, crew transport, etc., to all the lightships, lighthouses and buoys around our coasts; a duty which is at presentcarried out by fairly large ships—large, because their slow speed demands a round trip to a large number of stations at a time. Itcould also take over coastguard duties. The most severe criticisms which can be levelled at the present-day helicopter are, undoubtedly, the facts that it is expensive to buy and very expensive to maintain, and has too short a life. Forthe purpose at present being examined, the first case is not terribly important—after all, a lifeboat is very expensive compared withany other boat of similar size—but simple, inexpensive main- tenance, great robustness and long life are essentials. These qualities can be built into a flying machine—even if itis a fatigue-producer like a helicopter—by allowing the empty to gross weight ratio to rise. Such a policy would, no doubt, horrify the purist who worksout how much it costs in pence per ton-mile to rescue a drowning mariner; but, of course, in this case, payload efficiency is quiteirrelevant when compared with the ability to do the job all the year round in any weather with the minimum of maintenanceand the maximum of safety. The Sikorsky S-55 is probably the best helicopter to use as anexample of current modern practice; this machine has a tare to gross weight ratio of 58£ per cent and will lift a total of twelvepeople on 600 h.p. for a gross weight of 3i tons. IN sending us the accompanying notes, Mr. F. H. Robertson—whowas recently appointed chief project designer to Short Bros, and Harland, Ltd.—remarks that our leading article of February 4th sug-gested two uses for the helicopter which, in his view, this type of aircraft could fulfil better than any other. In a Belfast R.Ae.S. lectureearlier this year he drew the conclusion that the helicopter's future lies in those fields in which its capabilities are unique. In his view,operating cost leaves it "without a hope" of competing with fixed- wing aircraft in other directions. Assuming that we could get the desired standard of robustnessfor a tare to gross weight ratio of 70 per cent and that we want to lift twenty-four people, our R.N.L.I. helicopter would weighalmost nine tons and would require 1,650 h.p. It would probably be sensible to over-power it and fit twin de-rated engines to givereliability and safety. A helicopter like this could be produced for about £75,000 to£100,000 if a quantity of about 200 were built, and I cannot see that there would ever be much point in replacing it by something"more efficient." The supply of spares, provision of after-sales service and steady replacement of aircraft would provide con-tinuous employment for a medium-sized firm for a more or less indefinite period. Passing on to police duties, the vital needs are again robustness,reliability and simplicity of maintenance. The carrying capacity does not need to be greater than the average big car—say, four tofive people and sundry tools, baggage or equipment; a total of about half-a-ton. Taking the S-55 again as a measuring stickand increasing the tare weight to 70 per cent, the a.u.w. should be a little under three tons and the power required just under550 h.p. It should be capable of production at a price between £25,00#and £33,000 if quantities of 200 are contemplated. HIGH IN THE ARMY'S ESTIMATION LIKE the estimates for the other two Services, dealt with else-' where in this issue, the Army Estimates—issued* last week— were accompanied by an explanatory statement by the responsibleMinister. In this statement, the Secretary of State for War made severalbrief but complimentary allusions to aircraft. The work of heli- copters in Malaya he characterized as "invaluable," saying thatthe knowledge that a wounded man could be speedily evacuated to hospital had a great effect on the morale of the security forcesengaged on operations in the deep jungle. In Kenya during the past year, most effective support had been given to the groundtroops by the Royal Air Force. Techniques for locating terrorist hides by means of air photography had been improved andmethods had been developed whereby accurate bombing could be carried out in all weather conditions.The value of air trooping was appreciated in these words: — "Air trooping has been steadily increasing its share of the totalload during the pasr few years and has now reached some 49 per cent of the total Army trooping to and from theatres other *Cmd. 939S, Her Majesty's Stationery Office; price 9d. than the British Army of the Rhine. In October last year a newcontract for the operation of an air trooping service to Singapore was placed, and the service is now carrying about 1,000 passengersa month in each direction. Hermes aircraft are used for this ser- vice and also to East Africa and Cyprus. We want to encouragethe use of more modern aircraft on other routes and some Viscounts will, we hope, shortly be introduced. In addition weplan to bring Britannias into service when they are available, ID about three years time. "Air trooping by reducing the time spent by troops en routegives a manpower saving of about one-seventh on the Far East route, so that out of 10,000 men moved in a year we are gaining1,400 or 1,500 in effective manpower in the field. To a smaller extent the same applies to the Middle East, Mediterranean, Eastand West Africa, to each of which all trooping, except unit moves, is done by air. Furthermore, air passages to the Far East andMiddle East are costing us less per head than sea passages." In a review of "The Army and the Future," the Ministerobserves that, though helicopter experiments are starting, progress will be slow, as quantity production of a heavy load vertical-lifraircraft, helicopter or otherwise, is still some way off.
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