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Aviation History
1923
1923 - 0715.PDF
NOVEMBER 22, 1923 assembled and erected by amateurs, and would design hisdetails and scheme out his forms of construction accordingly. Metal fittings and wire bracing requiring trueing-up would, wetake it, be eliminated as far as possible. Needless to say, all parts would be made on jigs so as to ensure accuracy andinterchangeability. This is the scheme in broad outline, and on the face of itthere would, appear to be no reason to suspect that it would not work satisfactorily in practice. As, however, we naturallycannot lay claim to the great practical experience possessed by " The Trade," we have communicated an outline of thescheme to a numbei of British aircraft firms for their " con- sideration and necessary action," as they say at the AirMinistry. We have had very interesting and concise replies from most of these firms, and the consensus of opinion seemsto be that, although in theory the " knock-down " system has every appearance of being feasible and of offering a methodof reducing the first cost of light 'planes, in practice the problem is less simple, and several objections exist. It is impossiblefor us to reproduce all the letters which we have received on the subject, but as in several instances the opinions expressedand the objections raised by various correspondents are almost identical, the general opinion of all may be fairlycorrectly indicated by quoting a few. Here is a letter raising some of the more typical objectionsto the scheme :— " While we absolutely agree with the view that manyenthusiasts have sufficient money to buy the parts, but cannot afford to pay the cost of a complete machine, we are afraidthat the objections to the scheme are insuperable. So much would depend on the skill and workshop equipment of theamateur concerned, that we feel we could not possibly take the responsibility for machines which had been assembled by anamateur. We think that you will agree that in the event of machines collapsing in the air—even though they had beenassembled by the owner—a large amount of discredit would reflect upon the designers and manufacturers of the parts, andas the accident might easily be due to faulty assembly or to the substitution of unsuitable parts or details for some thatmay have been mislaid or damaged by the amateur con- structor, we feel that the risk is one which we could notafford to run. " In our opinion the only ways in which light aeroplanescan be made popular and available for the average owner- pilot are : (1) that the Government order sufficient quantitiesof these machines for training pilots to enable the cost to be reduced to a figure within the reach of the average amateur,and (2) the formation of amateur flying clubs." Another letter on this subject raises the point of engineinstallation : " Regarding the question of erection, this depends to a great extent on the type of construction of themachine, as to what proportion the erection bears to the total work on the machine. For instance, a fuselage of ply-woodconstruction is hardly what one would call an amateur's job. On the other hand, if the fuselage were of the braced type,the manufacturing cost of the parts is probably greater. Then again, the question of engine installation is not so simplea matter unless the parts could be turned out in quantities and all completely interchangeable, so that the installationbecomes purely and simply a matter of putting the parts together and requiring no technical knowledge other than theability to follow the erection drawing. Before going too deeply into this point it seems to us it would be wise to obtainthe attitude of the authorities concerning machines erected by amateurs. The question of airworthiness certificates issomewhat of an obstacle in the light 'plane question, and a clear idea of the procedure regarding these should be laid downso that prospective owners may realise what regulations are to be conformed with." The airworthiness certificate problem is one which we haverepeatedly urged the Air Ministry to pronounce upon at the earliest possible moment, and, needless to say, the problemwould not tend to be made easier by the adoption of amateur erection of machines, even if made from "passed" com-ponents. Until, however, the authorities know whether or not constructors would be willing to undertake the marketingof parts for amateur assembly it is hardly likely that an official statement would be forthcoming. One letter received agrees with the opinion that a large chassis, etc. In other words, we agree that a great deal of amachine's expense is due to the cost of assembling and erecting, but until machines are made in large quantities thisassembling cannot be done by amateurs." Slightly different points, "but tending nevertheless to thesame general conclusions as those reached by other corre- spondents, are raised in the following letter : " Probably (inthe not distant future) the course suggested could be followed, but at present we think it would be wise to let aircraft designersget on the soundest possible lines in the construction of light aeroplanes before they are more generally put into civil ormilitary purposes. Either one of two things could happen : (1) All parts would be jig drilled so that all the amateur hasto do is to put in the bolts, as with a Meccano set. In such case we might as well assemble ourselves, as then the assembly /work would not be the most expensive part of the work. (2) Details would have to be drilled and fitted on the job.This is where the danger comes in. An amateur would make a horrible mess of it, and we should have breakages in the airin every direction. Also there could be no adequate inspection of such work. Even if the erection were soundly carried out,the finish in most cases would probably be very bad and not such as we would care to subscribe our name to." Finally, the following letter confirms nearly all the viewspreviously expressed ; " We feel that the time has not yet come for this method of aircraft construction, as the lightaeroplane is really a large marhine in miniature, calling not only for carefully selected parts, but extreme accuracy andskill in erection, the erection as important as the selection of material. The assembly of aeroplane parts and the finalerection call for certain special training and skill, which the average amateur does not possess, and in the event of anaccident occurring to a machine due to defective assembly, a certain amount of criticism would be made regarding the £•materials supplied." From the foregoing contributions, which are representativeof most of those received on the subject, it is evident that the aircraft industry is not generally in favour of amateur con- ,struction, even when such is reduced to the assembly of inspected and " passed " components. In case anyone shouldsuspect " The Trade " of being influenced in this view by considerations of profits, we would point out that nothingcould be farther from the actual facts. The aircraft industry is composed of as fine a set of sportsmen as one could ever wishto meet, and we claim without fear of contradiction that in ". no other industry does one find so many sincere enthusiasts,nor so much pioneer work being done, as in the aircraft trade. If the views of practically all the firms consulted coincide on thesubject of amateur construction, it is because the industry is genuinely convinced that the scheme would be too risky. Inany case, any suspicion that the negative attitude taken is connected with financial considerations is countered by theobvious fact that a manufacturer laying himself out to seU machined and finished components for construction of light ''planes would necessarily charge for these at such a rate as to , remunerate himself for their manufacture, and would makehis profits in this way, instead of on the sale of complete erected machines. Certain of the objections raised by our correspondentswould appear to be capable of being met, and there is still a possibility of a firm coming along with a suitable design andwilling to manufacture the parts in accordance with the scheme outlined. Others, however, are incontrovertible—orseem to be at the present moment—and as the penalty exacted in case of structural failure due to some small defect is greaterin an aeroplane than in, perhaps, any other means of loco- motion, it is absolutely essential that every safeguard shouldbe taken to ensure the structural strength and soundness of machines. Perhaps the greatest objection—and one which none of ourcorrespondents appear to have raised—is that of too early standardisation. At the present moment we have only juststarted with light aeroplanes, and really nobody knows what a light 'plane should be like. We have produced a number ofvery successful types, but he would be a bold man indeed who would dare to prophesy that the light 'plane of the next four orfive years will be like those at present in existence, or even contemplated, and too early standardisation means, to acertain extent, stagnation in development, which is the last proportion of the cost of a machine is due to the cost of thing one wants at the present moment, assembling and erecting, but states that it would be expensive WV h^re- Hpalt with fhic «,ihi/Vt *><- VP- to supply parts in small quantities. Thus the letter :— " When aeroplanes are built in small quantities, it is by no means economical to manufacture spars, ribs, struts, longerons, etc accurately to jig so that they may be assembled without skilled fitting. Therefore we think it would only be possible to design unfabriced components such as wings, fuselage, We have deal this subjec at very considerable length,as it is one of some importance, and we would ask the many prospective owner-pilot-constructors who have written us onthe matter to read carefully the opinions of the aviation industry, as exemplified in the letters quoted above, and toregard these as containing the considered views of the majority, at any rate for the present. 715
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