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Aviation History
1918
1918 - 0659.PDF
JUNE J3, 1918. Notice to Correspondents in General. * FULL particulars regarding the conditions of service inthe Royal Air Service were given in " FLIGHT " of April nth.Application to join as a cadet should be made in letter form, stating full personal particulars, to the R.A.F. ReceptionDepot which is nearest to the registered address of the appli- cant. Applications for enlistment should be made personallyor by letter, stating full particulars, including age and trade to the R.A.F. Reception Depot which is nearest to theregistered address of the applicant. Boys are enlisted from time to time for long service only.They should be Class A and between the ages of 15 and 17 years. Applications should be made as above. No person is eligible for enlistment into the Royal AirForce unless he is a natural born British subject and the son of natural born British subjects. The Royal Air Force Reception Depots are :— 40, Upper Brook Street, Mayfair, London, W.i.8, Tyndall's Park Road, Bristol. 12, Newport Road. Cardiff. Carlton Chambers, Paradise Street, Birmingham.Midland Bank Warehouse, King Street, Nottingham. 117, Mount Pleasant, Liverpool. 6, Portland Crescent, Leeds. •-...10, Sydenham Terrace, North Road, Newcastle-on-Tyne. 9. Somerset Place, Sauchiehall Street, Glasgow. S. W. (West Bromwich).—It is quite possible, by putting the rudders over, for a twin-engined machine to fly with only one engine running. The machine will, of course, fly at a much reduced speed. We do not think this machine is now being used. H. C. P. (Coventry).—-We have published several illustra- tions of the machine you mention, and hope to publish others from time to time as opportunity occurs. We cannot promise to publish them in sets, however, as you appear to desire us to do. When flying " upside down " an aeroplane does not, as is frequently imagined, follow a horizontal flight path, but gradually loses altitude owing to the inefficiency of the wings when in the inverted position. The distance a machine can be flown in this position will vary very considerably according to the skill of the pilot, as the machine is, of course, unstable when upside down. Machines with a large dihedral are more difficult to fly this way than those with straight wings, other things being equal. There are no hard-and-fast rules for the use of wing flaps during a turn, some machines requiring to have the bank increased by means of the flaps, others having already a tendency to overbank and requiring to have the bank reduced by the flaps. Again some machines will automatically take up the correct bank for any turn without calling the wing flaps into play at all. C. H. S. (Hull).—From the rough sketch you send us we cannot identify the machine. We are not permitted to publish figures relating to the performance of war machines, and so cannot inform you which of the two is the faster machine. We have never heard of a large flying boat of the type you mention looping the loop, and very much doubt whether it would be able, to do so. At any rate it would be a risky proceeding. There is not, so far as we are aware, any difference. The two are synonymous. C. R. B. (Elham).—The problems you mention are toolengthy to be dealt with in this column. We would refer you to the book entitled " Aeroplane Design," by Captain Barnwell, R.A.F., a copy of which can be obtained frcm ouroffices. The price is 3s. post free. W. D. K. (Sanderstead).—We are not permitted to give1you the information asked for. This machine was probably a Maurice Farman " shorthorn." F. W. (Hanwell).—Sopwith "Dolphin." The former machines have occasionally been fitted with the engines fitted as standard in the latter. H. R. (Exeter).—We scarcely think that the " poor man'saeroplane " in days to come will be fitted with an engine of as low power as 9 h.p. Such a machine, although itcould possibly be made to fly after a fashion, would have to be very frail to keep the weight low, and there would belittle or no power in reserve for climbing. Also the speed would be so low, exactly what we cannot possibly say, but probablyabout 35 m.p.h., that the least bit of wind would prevent the owner from flying. It is dangerous to venture an opinionon the " popular " after-the-war machine, but we are inclined to think that it will be fitted with an engine of at least 25 h.p. P. F. D. (Muswell Hill).—For the explanation of the initial letters of certain German makes of aeroplanes see our reply to G. B. H. B. in our issue of May 23rd. Neither of the machines you saw were, as far as we are able to judge, from your brief description, captured German machines. Gr. W. S. (A.-A. Gun Station).—We regret that we do not recognise, from your description, the machine. De H. 4, S.E. 5a, Armstrong-Whitworth. In outward appearance the same as the B.E.2C, but has a curved fin and a different engine. B. F. Lt. (R. A.F.).—The movement of the centre of pressure on an aerofoil need not be different when the machine is on a steep dive from that occurring when the aferoplane is flying level. To realise this clearly it should be remembered that the angle of incidence is not an arbitrary angle between the horizontal and the chord line, but is the angle formed by the chord line and the direction of the relative air current. Now even suppose that a machine is in a vertical position, with its nose pointing straight downwards. In this position the flight path of the aeroplane will not be vertical, but will be a sloping line, the slope being determined by the ratio of the resistance of the machine at this particular speed and the lift of the aerofoils. By lift, as the term is usually employed, is meant the verticaliovce on the aerofoil, but when the machine is in a vertical position the lift will be in a horizontal direction, causing the machine to follow a path forming an angle with the vertical. The angle of incidence need not therefore have changed, nor the centre of pressure. If the flight path were vertical, the machine would have to be partly on its back, in such a position, in fact, that there would be a negative angle between the chord line of the aerofoils and the flight path, corresponding to the angle of no lift, which, in a cam- bared aerofoil, is a negative angle, since even at 0 degrees incidence the cambered aerofoil still gives a certain amount of lift. As the resistance of an aeroplane is proportional to the density of the air, it follows that if a machine, designed for a certain speed at 15,000 ft., is flown at the same speed near the ground (this is scarcely possible in practice) there will be an increased stress on the structure. Flying in clouds or in a mist does not in itself impose greater stress than flying in ordinary atmosphere, but, owing to the difficulty of ascer- taining whether or not his machine is on an even keel the pilot may easily subject his machine to greater stresses owing to too sudden variations in his flight path. How Lieutenant Fonck Fights. SOME of the methods followed by Lieutenant Fonck, the leading French ace, have been disclosed by him in an interview. He believes in group formation for fighting as the time had gone for flying as an individual sport, such as it was practised at the start by Pegoud, Garros, Gilbert, Navarre, and even Guynemer and Nungesser " TheGermans," he says, " when they inaugurated group flying, taught us and unfortunately made us pay dearly for the lesson, of the dangers attending an effete method. But I am by no means a partisan of flying in over-big groups like that of the ' Richt- hofen circus.' I generally fly with two comrades-—' a grcup a B of three'—and I am inclined to favour several groups of three sufficiently distant not to hinder each other's operations, but also sufficiently near to understand one another and give help at crucial moments. Too big a number may easily prove a peril, especially against a clever and daring enemy capable of practising the only tactics suited to the occasion, which is to throw himself into the middle of the group, para- lysing thus his adversaries, who can neither manoeuvre nor fire from fear of injuring each other, whilst he, on the contrary, retains every facility of action. The Boches have had a bitter experience of this, as it was frcm a patrol of seven that I brought down my last three machines."657
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