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Aviation History
1922
1922 - 0026.PDF
It is found that K is substantially constant, varying from 164 to 176 ; a single exception of 158 corresponds to a series of tests on a biplane arrangement, the wings of which were equipped with flaps and represent abnormal conditions. It therefore appears that the angle of downwash can be represented to a good approximation by 170 170 (x + 1)-o^ • ty + i)-o-2*L, ' ¥x • Fy • Lt F* and Fy being the values of the functions of x and y which are given in Fig. 5. The validity of this formula is obviously confined to that range of angle of attack or lift coefficient in which the air flow about the aerofoil is not abnormally turbulent. Application of the Doimwask Formula.—The chief use of a downwash formula is the calculation of the aerodynamic JANUARY 13, 1922 angle of attack of the horizontal tail surfaces. For this purpose a reference point is taken on the leading edge of the horizontal tail surfaces and the values of e obtained from the formula. The aerodynamic angle of attack of the tail surfaces will then be at = a — & — 6 where a is the angle of attack of the wing and 0 is the acute angle between the chord lines of .the wings and horizontal tail surfaces, considered positive (in the equation) if the tail is set at a less apparent angle than the wings. The data from tests seem to indicate that in case of a biplane the maximum angle of downwash occurs in the horizontal plane midway between the two wings. The effect is so slight, however, that the above method may be used, referring the co-ordinates of the reference point to the nearest wing (preferably to the no lift line), with the assurance that the results so obtained will be as precise as it is practicable to calculate them with the data now available. E H H M LONDON TERMINAL AERODROME Monday Evening, January 9, 1922 THE weather has played some curious pranks with the London-Paris aeroplane service during the week. There has been little flying to schedule, and the machines which have completed their journeys have done so with difficulty. On Tuesday, for instance, when there was a strong northerly wind, a Handley Page " 0-400 " was five hours on the journey from Park to Croydon, and, though her tanks had been filled with 240 gals, of fuel before she left Paris, there was only sufficient for about ten minutes' flying left by the time Croydon was reached. On Wednesday, when the wind was again blowing strongly from the north, a Messageries Aerienne five-seater Spad flew from Poix to Croydon, but had to descend at Lympne for • petrol before finishing the journey to Croydon. There was an amusing scene on the aerodrome on Monday,,. and one which illustrates the risks of premature publicity, so far as aviation is concerned. A consignment of live pigs was to be dispatched by a special " Goliath " to Paris, and, the fact having been well " advertised " in the daily papers beforehand, the result was that a number of Press photo graphers, including at least one moving-picture expert, swarmed round the aeroplane, firing off plates and films at top speed. The weather, however, was far from good, and though one of the Instone Air Line " D.H.i8's," with Mr. Powell in charge, got away, other firms decided against flying, and the pigs' departure was, therefore, postponed. The Engines of the "Air Express " I AM able to give details, which should, I think, prove interest ing, as to the running of the 450 h.p. Napier " Lion " motors on the continental air service. One of these engines, which was running in Aircraft Transport and Travel days, in an " Airco " 16, has now put in 407 hours flying. Another " Lion " went for 160 hours without overhaul, and was only dismantled then, owing to regulations and as a matter of policy. The engine at present in the " D.H.18 G-EARO " has been running for over 130 hours since its last overhaul, and seems good for another 130 hours. Actual fuel measurements, taken over long periods of commercial work, show that the consumption of petrol with the " Lion " is 24 gals, an hour, while the amount of oil used is about 7 pints an hour. Mr. Butler, who is the private owner of a Bristol " tourer," was down at the aerodrome on Sunday, and gave a few friends joy-rides in his machine. He afterwards flew over to Stag Lane aerodrome, and left the Bristol there. It is under stood that he intends to purchase a " D.H.9." He is shortly H H Aerial Advertising OUR Editorial remarks on this subject in last week's issue called forth a visit from the inventor of this new form of smoke signs. While he does not yet wish to have details of his invention published, he placed at our disposal sufficient material to enable us to form the opinion that, not only are the prospects of a general application of the invention far less annoying than appeared at first sight, but that actually, apart from any question of aerial advertising, the invention has its numerous scientific uses, some of which are undoubtedly of very great value indeed. Without going into details, it may be intimated that the invention will probably enable experiments to be made on full scale machines on problems connected with such complicated subjects as the accurate determination of downwash and of the air velocity at various points in the neighbourhood of the fuselage, wings and tail leaving for Newfoundland, and will take the "9 " with him, but details as to what he intends to do with the machine there are, at the moment, lacjfing. The Surrey Flying Services have now almost completed the Avro for the Marconi Co. It has been altered to take a Renault engine, and has been allotted the registration number " G-EBAJ "—which, incidentally, is worthy of note, showing as it does that civil aircraft now registered have, apparently, run through the combinations of the last two letters, and have started on the last three. Another Avro is being built-up for a private owner, and Mr. Grant is having quite a busy time. Captain Muir is at present in Liverpool, where he is testing a Parnall " Puffin " for the Disposal Co. Demonstrations of this machine are to be given in the presence of representatives of various foreign Governments, and are to include all the " stunts " a deck-amphibian is capable of. Mr. Leysmith was at the aerodrome during the week, collecting a few odds-and-ends he required for the search lights and other lighting equipment at Lympne. Judging by the time he has been away from Croydon, the lighting arrangements at Lympne must be on a very comprehensive scale. The lighthouse at Croydon has not, as yet, been moved to Titsey Hill. Apparently the erection of the tower there to accommodate it is occupying rather more time than was anticipated at first. Telephoning to Machines in Flight AN " extension " from the wireless cabin has now been carried to the control-tower, and the wireless operators can, when required, " plug " the control-tower through to any aeroplane in flight. This arrangement has been adopted in connection with the " sectionalising " of the aerodrome for an improved method of direction-finding when an aero plane is near the 'drome, but is unable to see it in mist or fog. Each pilot will have a map, showing the sections of the aero drome, and the man in the control-tower will be able to tell him which section he is over, without any such short-time lag as may be reckoned with in the normal direction-finding method. A small army of painters have invaded the aerodrome, and are busy on the Instone offices. The new Instone goods- office is approaching completion. It is interesting to note that the recent reductions in freight rates, announced by Instones', have been followed by other firms, who have brought their charges into line. H H of an aeroplane. Even the smoke signs themselves, we are given to understand, so far from being a blot on nature, are most fascinating things to watch, although the advertisement side is merely an incidental. We are awaiting a demonstra tion at an early date. A Fairey Weight-Lifter. HITHERTO it has been the fashion, at any rate where sea planes are concerned, to employ twin-engined machines when great loads had to be carried. This precedent now appears to have been destroyed by a Fairey single-engined seaplane, which lias carried a useful load of 3,100 lbs. The machine is a tractor seaplane, with Rolls-Royce " Eagle " engine, and as the total weight lifted was 7,250 lbs., the power loading was about 20 lbs. /h.p. Incidentally this performance probably constitutes a record for weight lifted by a single-engined machine of this power. 26
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