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Aviation History
1922
1922 - 0028.PDF
at the front of the cabin, somewhat below the roof ; the velocity of air entering here can readily be governed by the insertion of right angle bends in the trunks leading to the inlets : each such right angle bend reducing the total flow by 50 per cent." " It must be remembered that it is essential that the in coming air should be free from impurities, due to exhaust gases, petrol fumes, stale oil, and so on. Special arrange ments for the aspiration of the air from the engine compart ment—which should in any case be bulkheaded off from the passenger cabin—may be of value in preventing leaks of impure air into the cabin. " Heating is closely bound up with ventilation, and at the temperature likely to be met with in ordinary flying, it is essential that arrangements should be made for warming the cabin. It is possible to arrange for a supply of air heated by the exhaust pipes, but it should be remembered that air that has been in contact with metal heated to some 2000 C, is definitely unsuitable for breathing. If a muff on the exhaust is used, it should therefore be stepped up, the in-coming air for the cabin being taken from the outer step." " Some of you, however, may remember the footwarmers which Cody fitted to his machine, heated from a bye-pass off the engine cooling system. While there are objections to the introduction of such complications in a matter so important as the running of the engine, no serious difficulty should be experienced in fitting a hot water or steam heating system which draws its heat from the exhaust. Such a system, once developed experimentally, should prove very satisfactory and require little or no attention, while its weight ought not to be excessive." " A suitable arrangement for ventilation and heating might be as follows :—At the forward end of the cabin fresh air enters at a rate of 3 ft. per sec, through an inlet about 12 ins. by 12 ins. in size, slightly below the roof. Aspirators, arranged below the seat level at the back of the cabin, suck out the vitiated air. An exhaust heated tubular boiler supplies steam or hot water to a radiator fitted two or three inches in front of the fresh air inlet, and the same heating system includes footwarmers in the cabin floor. Such an arrangement should imply fresh air, warmth and comfort for the passengers. I am indebted to Colonel Heald for much of the information upon which the foregoing is based." " The form of construction of the cabin directly affects its warmth, and from this point of view the fabric-covered cabin is very bad. With this material radiation to the outer air is so rapid that adequate warming in cold weather is almost out of the question." Seats.—" However, I must return to the subject of pas sengers' comfort, and I wish to say a word or two about seating accommodation. It always seems to me that chair designers work entirely by tradition, and that if any scientific study of the subject has been made, no attention has been given to the conclusions reached. If the tyres on the wheels of a motor-car are too small, the vehicle is uncomfortable to ride in, and the tyres wear out rapidly. Similarly, if the weight of one's body is carried by a small portion of it, that part quickly gets fatigued and the whole body feels uncom fortable. Only too often seats are designed so that an un necessarily small portion of one's anatomy bears the majority of the weight. Why should not designers study the problem carefully in conjunction with anatomists and produce a light chair properly designed to suit the human form and to keep the loading per sq. in. of flesh at a low figure." Number of Engines.—" There is room for much diversity of opinion in regard to single engine versus twin engine, or multi-engine machines. WTiile traffic is smaE the lower first cost and running cost of a single engine machine has an important bearing on the matter. If a twin engine machine will carry nearly double the load of a single engine machine, it immediately becomes a serious competitor economically if the available traffic is sufficient to fill it. Here arises the problem of how large can a fuselage be built practically for a single engine machine. In military aircraft great weight can be carried in a small compass, as the load is in a very condensed form. But in commercial types there will be a continual demand for more cubic space per passenger. Will fuselages be necessarily so large that high-powered engines will be economically unsound? In the De H.i8, eight passengers are carried at 56 h.p. each; in the De H.32, eight at 45 h.p. each." " Let us assume that we are considering the use in a single engine passenger aircraft of a 1,000 h.p. engine. For that power we must accommodate at least 22 passengers, and we should endeavour to allow at least 40 cubic ft. of space per head. Is such a fuselage practicable for a single-engined machine ? What is the limiting size ? How is propeller efficiency likely to be affected ? These questions, which also JANUARY 12, 1922 concern the practicable size of twin-engine aircraft, are matters on which I feel sure that engine designers would like the considered views of aircraft designers, otherwise they may be devoting their attention to engines of a size likely to be xinsuitable for commercial work." " The twin-engined machine has some advantages over the single-engined, particularly if it will fly on one engine. Greater reliability is thereby secured, and to the psychological desire of many passengers for a rnachine with more than one engine is added the greater favour with which insurance companies may regard it." Salvage.—" From the insurance point of view, emergency exits for passengers should be provided, and the question of salvage is of some importance. Attention to details which facilitate quick repairs in the event of trouble, and easy transport of spare parts, may assist a constructor in obtaining the favour of those august underwriters whose opinions are reflected with much emphasis in the balance sheet of the transport firm." The Discussion THE discussion which folllwed the reading of the paper was opened by Sir Samuel Instone, Director of the well-known Instone Air Line, who stated that he was not a technical man, and had never claimed to be one, representing the commercial side solely. He stated that he would like to emphasise how essential it is that the Government should help financially. Commerce, he said, has been bled white by taxation, and it was no good expecting financiers in the City to find the means for commercial air development. In the old days, there was plenty of money in the City, and financiers were able to find the money for the development of the Mercantile Marine. As things are at present, this could not be repeated on behalf of Civil Aviation, and the Govern ment simply must assist. The percentage set aside for sub sidies was totally inadequate—£200,000, out of a total vote of £16,000,000. And even that small percentage, he stated, appeared to be grudged. To him it seemed that the spirit at the Air Ministry was not how best to spend that £200,000, but " How much can we save out of the £200,000 ? " Sir Samuel expressed satisfaction at hearing the lecturer say that there was an advantage in two-engined machines, as his firm had always found that the public were more confident in a twin-engined than in a single-engined machine. As regards the question of giving free return tickets to de signers, as suggested by the lecturer, his firm had always done so on demand, and would always be pleased to do so whenever possible. Mr. F. Handley Page said that, in his opinion, commercial aircraft would become more and more specialised as time went on, and he thought that the development would be towards the smallest possible head resistance, so as to waste no single horse-power that could be saved. Once in the air, one would throttle down, and thus spare the engine as much as possible. The question of the passengers' comfort was a very important one, and especially that of ventilation. With reference to the suggestion of giving free tickets to designers, Mr. Handley Page caused much amusement by saying, jokingly, that perhaps his machines had not so many seats to spare as those of Sir Samuel, but that nevertheless he would promise to do what he could. He was pleased to hear twin-engined machines spoken so well of, the more so as a distinguished member of the Royal Aero Club had, that very afternoon, slated him for saddling commercial aviation with some of the most damnable creations in the way of out-of-date twin-engined machines. He was glad to hear other people confirm the faith of the public in twin-engined 'buses. Major C. C. Turner disagreed with the lecturer in considering Great Britain too small for air lines, mentioning several distances which exceeded that of the London-Paris services. He thought that the public faith in twin-engined machines was largely caused by lack of information, and did not think that a well-designed single-engined machine was any less safe than a twin-engined one. Major Kennedy was somewhat disappointed with the small attention given in the paper to specialised aircraft. From the title of the paper, he had expected to hear something about special types for mails, parcels, etc., as well as about passenger machines. He also would like to emphasise the necessity for strong Government support. In his reply, Commander Beatty said he agreed that he had said nothing about specialised machines for mails and parcels, chiefly (amid merriment), he said, because he regarded the present machines as mail and parcels machines, and not really fit for passenger carrying. Finally, Sir Samuel Instone stated that it might interest those present to hear that his firm had ordered three machines specially designed for carrying goods and parcels. 28
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