FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1948
1948 - 0344.PDF
290 FLIGHT MARCH IITH, 1948 Aircraft Design Procedure . . . (The Discussion) MR. S. SCOTT-HALL agreed with the lecturer that the speci-fication period was important. The problem always in hismind was how to ensure that the specification would lead to a tirst-dass aircraft, by whicli he meant a good flying machine andnot just an expanding suitcase which could take all the equipment that some specification-drafters would like to put into it. In the old days we had the " F.V.," bat private venture wasnow ruled out by cost, and he believed the answer nowadays was the design study. By means of this, the drafting of a few linesof specification and sending them to the designers enabled the latter to form their ideas of what the aircraft should be. Givenfreedom to mould the specification, the designer would produce the best kind of aircraft. With reference to committees, Mr. Scott-Hall said he sympathizedwith Professor Lickley, but modern aircraft w«re so much dependent upon radar, radio, armament, and navigational equipment, thatthere must be people sitting around a table who were able to say that, for instance, although the aircraft was a good flying machine,it was unsuitable for its purpose because it could not carry ail that equipment. He agreed with the need for specialists on adesigner's staff. There should be first-class hydraulic, electrical, radio and armoury experts, and they must have a status whichenabled their views to be heard. He pleaded with operators not to hurry the early stages. Days and weeks spent then could savemonths or years later in the life of the aircraft.' MR. W. E. \V. FETTER agreed with the lecturer that the bestdesigns were obtained by inspiration rather than by specification. Fortunately, we in this country were given our military specifica-tions in very wide terms, so that designers could think up a variety of solutions. He also agreed that weight control was important;we were now able to design more precisely. The lecturer was ri#ht in saying that the designer now was much more: he had to l>ea planner, a slave-driver and a co-ordinator. The accurate mock-up was a wonderful means of helping thevarious experts to work together and to understand each others' problems. The integration of effort, as in a game of chess, de-manded the bringing to bear as many pieces as possible in the right formation. All staff should have had experience in the shoj>sfor a time; all those who were to hold responsible positions should have moved around, and should have had experience in the air-worthiness, aerodynamics and design departments, as well as «nnt knowledge of the manufacturing side. Mr. Petter thought there were several ways of breaking downbarriers between departments. In his own organization (English Electric.) the stress office had been turned into the airworthinessdepartment and dealt with much more than stressing. An interested and competitive spirit was engendered which could lead to usefuland rapid development. We must aim at deploying the organization to a wider engineering background. Art, Science and Research MR. E. F. RELF admitted that although Pmlessor Lickley's state-ment about aircraft design being still an art and not a science seemed to be a reflection on the research people, he had to agree.We still knew very little about the real fundamental problems of flight. The position was now aggravated by our attempt to flyat sonic speeds, about which we knew practically nothing, nor were present methods of experimentation able to tell us more. Ourproblems were ten times more difficult than at the time of the Wrights, and we had to attack them with less equipment, relatively. Ms. WINGFIELD DIGBV did not agree that the watertight com-partments existed in all organizations. His own, for instance, (Westland) worked on the principle that the man in the stressoffice worked in conjunction with those in the drawing ofiice, and the man in charge of the weight uffice had free access to the variousdesigners. Regulations were becoming more and more complicated. As an example, he recently discussed with the chief test pilotthe number of flights needed to complete contractors' trials. To his horror they worked out at something !ike 250. MR. H. H. GARDNER recalled the simplicity of design in theearly days, when one chief designer went to the Air Ministry and had a chat with a few personal friends; he sketched out a designon the back of an envelope, and the prototype was flying within six months. In modern times the time spent by the design officehad increased ten times, and involved ten times as much personal effort. The subject of weight control was dear to him, but hepointed out that the effort put into control of structure weight was devoted to only some 30 per cent of the total. It was timesimilar weight control was exercised in connection with other items. On the subject of widening the basis of knowledge, he pointedout that specialization was necessary, and that the general tench- ing would have to be confined to the early years. ME. HOCKMEYF.R put in a plea for consideration of maintenance.It was no use, for instance, making the commutator of a starter motor easily removable if the starter could not be got off theengine or the engine out of the nacelle. The matter should be thought out all down the line. On civ-il aircraft it might !*• moreeconomical to reduce maintenance work by accepting an increase in component weight. For instance, one might justify doublingthe weight of a small component hidden away inside the aircraft if thereby one avoided serious penalties in the design of the aircraft. A. CDRE. T. G. PIKE pointed out that, although an aircraft mightbe a very good flying machine, the modern military types had to carry so much equipment that it was necessary that the designershould be Riven, right from the start, the very fullest details of the thing.'- the machine had to carry. At what Professor Licklryhad described as a bargaining match, which was known in the Ministry by the more sedate term •" Advisory Design Conference,"the purpose was to advise the designer on the more detailed points of the requirements. The reason was that the specification, if Hwas a good one, would have been in broad terms, and the designer must be told at some stage just what was required. MR. SYDNEY CAMM said it was not, perhaps, surprising if thepaper seemed very familiar, as he and Mr. Lickley had worked together for 11 years. He agreed with most of what was said, andemphasized the importance of enthusiasm if the result was to be good. A design was never in practice started ab initio. There wasalways a preceding design, and there was a tendency to deal with problems of the immediate present, leaving the Project Office toplough through all the various schemes and pictures. On the subject of drawings, Mr. Camm said that if a prototypewas wanted quickly, the drawings could be fairly sketchy, but if it was going into immediate production they would take loi\/One must guard against the desire to put drawings into the r' drawing office before the overall design was satisfactory. A m^which worried him was that of foreseeing the increasing loads i!2& might be imposed later. They would affect wins loading, strengthand e.g. movement. Mr. Camm stressed the importance of spending enough time on a project in the early stages. The average timefor drawing-out a small fighter was two years. Tooling Expense MR. G. R. EDWARDS referred to the matter of complexity raisedin the discussion, and said this had got completely out of hand, resulting in delays so that by the time a type appeared in pro-duction the purpose for which it was originally intended had almost been lost. Loss of time incurred great expense, and he was im-pressed by the fact that the American industry appeared to be charging into bankruptcy even more rapidly than were we in thi?country. On examination it was found that the cost of tooling and the production of even a conventional type fitted with pistonengines could reach svich astronomical figures that the manufac- turer would have to make 300 aircraft before he got his moneyback. The world market was such that there was no hope of selling 300 of one type He thought it was time we took stock01 the situation and decided that perhaps for some types it might be cheaper to save a large, amount in development costs and addinga little more to the running cost ol the machines. All the complexity led to the question of employing specialistson the staff; there was no escape from that. He agreed with Mr. Scott-Hall that the specialists should cover a wider field. Thelayout of an aircraft might well be governed by a major piece of navigational equipment. The practical solution was to have a tribeof experts in branches which had not been considered necessary hitherto. They must hammer out the job at the beginning, andthey must be given time to hammer it out before the design was thrown to all the multitudinous group leaders in the drawingoffice who wanted to have a go at it. He thought that band of specialists would have to get on to a design twelve months beforeit was spread far and wide, and they must be given their head and encouraged to say what they wanted. Mr. Edwards agreed with Mr. Camm that in producing a proto-type, the experimental shop was important and that it and the drawing office must work side by side, fired with the same ideaswhether drawings were being produced for production at the start or for getting out the prototype quickly. MR. j. A C. MANSON was disappointed with the low prioritythe lecturer had given to considerations of production. It had, he said, become good practice in the aircraft industry for theproduction people to be consulted in the very early stages. MK. X. E. ROWF. agreed that one should concentrate, in militaryaircraft, on making one which would carry its equipment,jjjfcj, one should always make sure it would be a good flying macfPiF;The lecturer had given no background to some of the essential things. Take, for instance, applied research. Who should do it,the firm ? Or rely on national resources, and to what extent should they carry out ad hoc research in connection with design?His own view was that the organization should be complete to the extent of having aerodynamicists, mathematicians, etc, so thatthe designei coold integrate into his project his own ideas of the things he had been told by the basic research men He wouldlike to hear the lecturer's ideas as to the right balance of the design team, and asked how much one should concentrate on thevarious sides of the.team. If there was too much concentration on one, another would suffer. He did not like the idea of areally first-class artist having to be a slave-driver. That function should be in the hands of someone else. The designer's mindshould be 011 the broader issues. MR. WEBB emphasized the importance of inspiration and en-thusiasm and asked Professor Lickley how he thought such enthusiasm could be re-created in the industry. Since the war,individual enthusiasm had been largely swamped by the system which was developed solely to meet "war needs. He thought ita shameful reflection on existing methods that many app'rentices lost all their initial enthusiasm by the, third year or so. The train-ing methods concentrated on developing the mind whilst providing no stimulus for the imagination. The resultant product was toooften a square peg in a round hole. He pleaded for the abolition of part-tiiiH courses and that instead of them there should becentralized full-time courses at intervals during works training. After training, good technical personnel should be encouraged^ tokeep in close contact with aircraft. It shonld never be possible for anyone to boast of having designer] an aircraft without evenseeing it'
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
