FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1948
1948 - 2098.PDF
694 FLIGHT DECEMBER 9TH, 1948 Helicopter Problems Discussion of Five Papers at R.Ae.s. and H.A. All-day Meeting SUMMARIES of four of the five papers read at the jointmeeting of the Royal Aeronautical Society and theHelicopter Association of Great Britain on November 20 were published in Flight of November 25th, and last week we dealt with Mr. Shapiro's paper on the Cierva Air Horse. The papers were discussed at one session in the morning, one in the afternoon and one in the evening. The discussion of VV/C. Brie's and Capt. Liptrot's paperswas opened by MR. W. TYE, who said that in spite of feeling an innocent abroad, he must not be deterred from makinga quixotic tilt at all the windmills he saw around. His engin- eering instinct rebelled against the many different configura-tions, but he did not propose to suggest what a helicopter should look like. Mr. Tye pleaded for efficiency and safety to be developedhand in hand in spite of the fact that the two would pull in opposite directions. The only satisfactory way would beto get much operational experience as quickly as possible. As examples of things we wanted to know he quoted the loadsapplied by pilots in manoeuvres; means to determine fatigue conditions for blade design; the velocity of descent in normaland emergency landings; the use of engine power in typical flights; the effect of ice on rotor blades; and the degree ofstability necessary for safety. Having served on A. R. B.'s Helicopter Committee he knew how difficult it was to preparea design code in the absence of this sort of information. MR. O. L. L. FITZWILLIAMS, acting on the principle thatcontradiction was good for discussion, accused the authors of the first two papers of grumbling too much about the short-comings of the helicopter. All the main complaints had been of a minor nature, and the main hold-up in helicopter develop-ment was lack of funds and of experienced aircraft engineers. The mechanism was reliable, and as for maintenance, theinspection schedule called for was out of all proportion to the trouble actually found. Some major parts of one heli-copter were not dismantled for inspection over a period of 600 hours. Lack of stability was not serious in view of the use to whichthe helicopter was being put. It would be provided by the time it was needed. What was necessary was money, andthat had to come from the customers. MR. L. S. WIGDORTCHIK said there was no militaryincentive to helicopter development, and therefore they had to produce helicopters which could be made a commercialsuccess by an efficient operator. Contemporary helicopters cost too much and did not carry enough far enough in agiven time. He thought there was no need to follow fixed- wing practice for undercarriages, structure, etc. He believedthat great advance in commercial characteristics could be obtained with the very^large helicopter in the 1,500-2,000 h.p.class. History showed that vehicles became really economic only when man evolved his society around their potential. City Landing Sites AIR COMMODORE H. PRIMROSE thought the lecturershad failed to deal with two of the problems stated by Mr. Masefield in his Empire Lecture: efficient ground organiz-ation, and an air-faring outlook by the public. It was no use developing the helicopter if, by the time it was a satisfactorymachine, there were no developments of city centre landing sites. Without them, the advantages of the helicopter couldnot be reached. As for the air-faring outlook, he recalled the good work done by Alan Cobham. He thought we shoulddevelop alighting gear which would save a lot of weight and drag, and, by spreading the load, reduce the bearing-strengthrequirements of landing sites. If of air pressure type, it might enable the helicopter to operate from water. With the heli-copter, much time could be saved by a quick turn-round. MR. S. SCOTT-HALL was glad to hear Mr. Fitzwilliam:promise that stability would be forthcoming when it was wanted, but at present the helicopter impressed him as beineas unstable as a billiard ball balanced on a pin. He hoped two subjects in particular would be dealt with in the discussion: stability and blind-flying ability. MR. A. McCLEMENS criticized present maintenancemethods. We pulled the machines to pieces for inspection ai ' certain periods and put them together again, often doing moreharm thati good, and the result was that for every hour a helicopter spent in the air. it spent z\ hours on the ground being tinkered with. That figure bore no relation to theactual reliability of the machine, and was due to lack of know- ledge of the mechanism, so we must find out the hard way. Thedesigner must give the operator maximum possible utilization potential for the minimum engineering effort. We shouldabandon the present system of discovering defects by looking for them, and the manufacturer ought to find out what thelives of his components were, so that the operator could leave them alone until their lives were over, and then changethem. Close attention should be paid to interchangeability and accessibility, and to provision of special tools for ser-vicing. MR. H. FENNESEY stressed the navigational differencesbetween fixed-wing aircraft and the helicopter. The helicopter had to land in a small space, probably approached by adevious route. Navigational aids must be of minimum weight and entirely automatic. He welcomed the realization of thisamong helicopter people, and said his firm was working with B.E.A. on an entirely automatic solution based on radioinformation which was automatically compared with the track it was desired to follow. The result was fed to the pilotelectronically, in terms of his position to left or right of track, distance from track (in miles or yards), and distance todestination. The B.E.A. Helicopter Development Unit had flown with that system, and a practical solution of theproblem was within easy reach. Replacement Costs In the afternoon, after Dr. Bennett, Mr. Hafner and Mr.Shapiro had read their papers, MR. A. DAVENPORT opened the discussion. He pointed out that probably the helicoptercould render the sort of service that could be run at loss, or without profit, provided the whole organization of which itformed a part was run at a profit. Improvement in horse- power per passenger (at present about 75) might be attainedby better design and construction of rotor blades. He did not agree with Capt. Liptrot that real replacements were exces-sive. In the S.51 there was a major inspection at 400 hours, and the replacement cost was less than ;£ioo. That wasremarkable in a machine which had been used for demonstra- tions and that sort of thing. Better fuel consumption waswanted, and he thought designers might pay more attention to streamlining. But the helicopter had already proved itspracticability over many thousands of flying hours, with excellent reliability and easy maintenance. MR. NORMAN HILL, as a would-be operator of Britishhelicopters, asked designers to give operators a helicopter which could be operated at a profit. There was as yet noBritish helicopter which had a full C. of A. Insurance; underwriters quoted harsh rates. At State airfields landingfees were heavily against the type, although the wear and tear it caused was negligible. He advised manufacturers toseal their machines as soon as they were practical propositions, and they should then go to operators for the proper opera-tional testing necessary. To insurance people he would say: do not burden this promising aircraft with heavy rates withoutregard to the safety features clearly seen when the helicopter is in the hands of airline operators with an appropriatetechnical and financial background. To the legislators he would say: frame your regulations with wisdom and visionso as not to hamper this new vehicle in its development. MR. G. A. FORD, speaking as a pilot, said he would liketo see some form of manual control which would give a cushioning effect in a vertical landing, and which would alsoincrease pitch to compensate for loss of engine power with altitude. Attention should be paid to instrument panel layout,and blind-flying instruments should be in front of the pilot and close together, even at the sacrifice of a little of theforward view. MR. ROBERTS thought the authors of the papers had saida lot about the causes of helicopter problems but little about solutions. Many of the solutions suggested were not reallysolutions at all. Stability could only be achieved through really hard work by a team. We had many experts but noteams on the scale required. In America it was different, and he thought we should be behind America for a long time.Stability in hovering flight was difficult to achieve, and h felt it was begging the question to say it was not wanted. MONSIEUR P. RENOUX, a French visitor to the meetingreferred to the SNCASE helicopter with twin tail rotors, and .1 26
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
