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Aviation History
1923
1923 - 0714.PDF
-NOVEMBER 22, 192S LIGHT 'PLANE AND GLIDER NOTES ALTHOUGH the official rules governing the light 'plane competitions to be held next year have not yet been issued, it is understood that on one point at any rate a definite decision has been reached. This relates to the engine capacity, which has, we believe, been limited to 1,100 c.c. Some time ago we published in these columns the arguments for and against a larger engine capacity, and we arrived at the conclusion that 1,100 c.c. would be sufficient for the purpose of the com- petitions, even if it should be found desirable afterwards to increase the size of engine slightly so as to enable it to develop sufficient power when not in perfect tune, under conditions such as might be expected to be met with in the case of the private owner who is not an expert mechanic. THERE are, however, a number of other points that still remain to be settled, and as designers are naturally anxious to be getting on with their drawings, but can only plan out their designs in very general terms, we would urge the necessity of the Air Ministry making an announcement without further delay. A complete statement of all the rules and regulations is not yet required, but sufficient of the nature of the com- petitions, and especially such items as tank capacity, single or dual control, minimum landing speeds, or other stipulations which will affect the design, should be intimated at once, so as to give the designers as much time as possible in which to plan and carry out their work. This year's competitions were announced rather too late, and in all fairness to competitors; the main outline of the 1924 tests should be announced witbout a moment's delay. * * * • FRANCE i? losing no time in introducing her light 'planes abroad. Last week Lieut. Thoret left Paris for Prague with a Dewoitine " avionette " and two Dewoitine gliders in order to demonstrate these, before the Czecho-Slovaks. Originally it was intended that Adjutant Descamps was to head the mission, but as he has resigned from the Service Technique in order to become chief pilot to Buscaylet-de-Monge, Lieat. Thoret was chosen in,his place. N * •• '•., . - * * * IN America the Farman representative, Mr. Wallace Kellett, has already got one of the Farman " Moustiquee," with Anzani engine, and it is reported that he will endeavour to obtain some specimens of the latest Farman light 'planes with a view to placing them on the market in America. * * # BOTH these French firms are thus showing commendable enterprise in introducing French light 'planes abroad. How many of our constructors, we wonder, have sent, or are con- templating sending, samples of their light 'planes abroad, or even to the Dominions ? Yet our machines are admitted by the French aviation press to be superior to the French. AMATEUR CONSTRUCTION OF LIGHT AEROPLANES : l ' Scheme Not Generally Favoured by Aircraft Firms -•• • :'< ~ ' - • ONE of the results of the recent competitions at Lympne for light aeroplanes has been a very widespread interest in this latest type of aircraft, and one direction in which, among many others, this interest has manifested itself has been, as far as FLIGHT is concerned, that we have received, during the last few weeks, a very great number of enquiries from young men who are anxious "to become owners and pilots of machines of this type. In most instances our correspondents have expressed a desire to save money by building the machines themselves, and at first sight such an undertaking might appear relatively simple. When one begins to go into detail', however, it is found that the suggestion is not without its difficulties. To begin with, any aeroplane, and the light 'plane is no exception to the rule, requires to be carefully designed, both as regards its aerodynamic characteristics and its structural details. This presupposes a very considerable degree of designing skill, and not only theoretical knowledge but long practical experience. It is realised at once that the average amateur cannot be assumed to possess these to the required degree. Then there is, moreover, the question of airworthi- ness certificates. If individual machines are to be " stressed " by Air Ministry experts—and a machine designed and built by an amateur would require this to a very much greater extent than does a machine designed and built by an experi- enced aircraft firm—the cost of obtaining such a certificate would naturally be rather high, and would add so much to the cost of building that any financial gain due to amateur construction might be practically nullified. Considering all these difficulties, one is forced to the conclusion that the amateur-designed and built light aeroplane is, in the majority of cases, out of the question. There might, of course, be isolated instances in which a man with aircraft experience and training might be in a position to design a perfectly sound machine, but such cases would certainly be relatively few. The question then arises whether some other and simplified system could be adopted which would combine the lower cost oi amateur construction with the skilled design of experienced aircraft engineers. The first solution to suggest itself is, naturally, whether it might be possible to follow the method employed—to a very great extent in America, and to a smaller degree in this country—in the building of small boats, known as the " knock-down " system. By this system the prospec- tive amateur constructor is supplied, by firms making a speciality of " knock-down " boats, with all the necessary frames, timbers, planking, decking, keel, keelson, and even bolts and nuts, screws, rigging, paint and varnish, necessary for the building of the boat, all machined to size and ready to be erected, the " construction " carried out by the amateur boatbuilder being confined to putting the parts together—in other words, to " erecting " the boat. Now it will at once be seen that there is a very considerable difference between the amateur construction of a boat and that of an aeroplaae. In the former case there is no great necessity for weight reduction. Consequently all the parts can be made amply strong for the work they have to do. In an aeroplane, a*kd not least in a light 'plane, every ounce of weight counts, and it is not possible to make such wide allowances in the size and strength of components as in the case of a boat. In other words, in an aeroplane one cannot afford such high factors of safety as may be relied upon to make up for any small deficiencies in construction and erecting. Let us examine briefly how the " knock-down " system might be expected to work when applied to amateur con- struction of light aeroplanes. It is often stated that the greatest single item of the cost of building an aeroplane is fhat of erecting. Now in the " knock-down " system thitt', is precisely the function which it is intended the amateur should perform. Presumably, therefore, such a system might be expected to result in a not inconsiderable saving in the first cost of a machine, provided the amateur was willing to make up for this saving by his own personal efforts in constructing the machine. A further development, which appears to promise added interest and wider scope, is the formation of light 'plane clubs and associations, whose members would take a hand in the construction and would thus accumulate some considerable practical experience in aircraft work—a fact that might not be unimportant in developing that " air sense " which several of our leading personalities in air matters maintain is essential to the future development of aviation in the British Empire. , As we see the matter, the original design would be got put by an aircraft firm, who would build one oi more machine? and thoroughly test them out before placing them on the market. These machines would then be for sale complete in the ordinary way, but when they had become standardised a number of component parts would be manufactured and kept in stock. A set of clear instructions for assembling and erecting would then be prepared, illustrated by sketches and photographs to show the various stages, and a complete schedule got out, with numbered sketches of every part, and diagrams indicating their location and attachment in the machine. A customer would then receive these instructions, schedule, etc., with all the parts machined to size and cut to. length, and his share of the work would consist in putting the • parts together according to instructions. If machines were built of parts inspected and passed by the A.I.D., there should, presumably, be no difficulty in arranging with the Air Ministry for the certificate to be issued, provided an undertaking was given by the purchaser of the machine that no part in the structure had been replaced by one not passed by the A.I:D. In planning the original design the manufacturer would, of course, keep in mind that the machine was intended to" be 714
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