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Aviation History
1937
1937 - 0152.PDF
5& FLIGHT. JANUARY 21, 1937. The cause not lying in the field of radio, the cure will not be found there either—so long as two-way working has to be employed. "So far as control is concerned, there is at present no alternative to two-way communication; i.e., no direct method (e.g., anti-collision device) is in sight. The alternative is there fore to plan the air traffic organisation so that it is not com pelled to rely almost exclusively on radio for anti-collision pro tection (flight-paths, altitudes, spaced departures, etc.). "Navigation, on the other hand, can already in part be transferred to diiect action in the aircraft (homing, ultra-short wave beacons, etc.). Homing, in particular, can be used simul taneously by large numbers of aircraft, without the delays inseparable from two-way working. "Also, it can make use of existing radio services, broad casting, etc.. and so does not involve too many additional wave-channels. The transfer of navigation to the aircraft frees the ground stations for control functions," Mr. Duncan illustrated the above statement with figures showing how moderate air traffic congestion begets worse radio traffic congestion. Thus, a rise of 45 per cent, in the number of aircraft worked annually was accom panied by a 75 per cent, increase in radio traffic; "con trol " messages now outnumber all others by three to one. Some of these could probably be dispensed with, for Mr. Duncan has observed that messages from air to ground are seventeen times more numerous than those from ground to air. Clearly, we should now be approaching an impasse were not several European airline companies, by demon strating that very accurate bearings can be taken from machines in flight, already pointing the way out. In the matter of blind landing, it is a startling fact that the approach beacons in this country actually out number the aircraft that have so far been equipped to receive them. It has, in fact, taken a long time to make up for past indolence in regard to the screening of engines, and until quite recently there was no effective co-ordination between the manufacturers of aeroplanes, radio and ignition equipment respectively. Gradually this is being overcome. At the request of British Airways, the Marconi Company have evolved a promising screening harness for the Gipsy engine, and this is now undergoing its type tests at Stag A ROYAL AERONAUTICAL SOME films of outstanding interest, shown by courtesy of the Air Ministry, were the piece de resistance at the con versazione held at South Kensington Museum last week by the Royal Aeronautical Society. Some of the visitors to the conversazione—members and their guests to the number of about 400—had seen a portion of the films before, on the occa sion of the annual visit to the National Physical Laboratory at Teddington last summer. In the main, however, they had not been shown before and they had a very well-deserved re ception. First w^as shown a film taken at the Royal Aircraft Estab lishment showing a model in the vertical spinning tunnel, in slow motion and then at normal spinning speed. Next came a film showing the Parnall monoplane in the Royal Aircraft Establishment's full-size wind tunnel. This was followed by views in the R.A.E. water tank, in which a porpoising model caused particular amusement by jumping completely out of the water. The airflow film taken at a speed of 2,300 pictures per second was the part that had been shown at the N.P.L., but was none the less interesting on that account. In making a film of this kind the flow is made visual by discharging a series of sparks into the airstream. These travel downstream with the air and flow over the model which is being photo graphed, thus clearly indicating the airflow. The slow-motion film of seagulls was extraordinarily pretty, but most amazing, perhaps, was that which illustrated a pigeon being released from the hands of the man. The manner in which the pigeon's wings met above and below the body dur ing their violent beating was extraordinary, and few had realised that such big movements take place in bird flight. Extremely interesting was the slow-motion film of a hum ming-bird. This film was taken at the rate of 1,000 pictures per second, and one was easily able to follow the movements made by the bird's wings. This movement appeared similar to that made by the arms of a man floating on the surface e Lane. Integrally screened plugs are at last becoming e generally available, and ozone-proof high-tension cables complete the modern armoury against ignition inter- " ference. ' Our experience of ultra-short-waVe approach and marker beacons is so slight that it is premature to attempt to define ,. their limitations. Neither at Gatwick nor Croydon, nor even at Heston, can the present layout be said to con- e stitute an instrument landing system, for which an - extremely good runway and approach is necessary. A visual homing device would greatly assist in setting the s gyro when following a track beacon, and is being tried in America, where the extra wavelength required presents no I difficulty. _ s Auxiliary ground lighting is essential. There is scope for discussion on the best layout, but two lines of lights 1 are probably better than one, since the latter fails to give s any information at all regarding the orientation of the plane wherein it lies. The lights should extend for perhaps 1,000 yards beyond the boundary of the airport, and should be differentiated at certain points by colour variation. In America it has been reported that a system of 10-foot neon tubes, arranged at 100-foot intervals and extending 1 800 yards beyond the runway, was found to provide an 1 excellent approach system. It was to be supplemented by ? a double line of lights spaced 200 feet apart across the airport. 1 To say that visual assistance should be at hand towards the end of a blind approach is not to decry the work of : the radio engineer, who has successfully guided the pilot's hand in many hundreds of otherwise unassisted landings, i But unless and until the landing process is completely ; mechanised (as has been accomplished, for example, in the domestic elevator by the invention of automatic floor i levelling) it will obviously be prudent to relieve the pilot of the necessity for making mental transcriptions during the last moments of his descent. As his experience grows, he will probably require to make less use of the lights. But without their aid he will never discover the final limi- ; tations of the glide path. , SOCIETY CONVERSAZIONE of the water and just keeping himself afloat by a slow move ment to and fro of the arms, accompanied by a twisting of the hands to alter the angle of incidence. The commentator was Mr. R. P. Alston of the Royal Air craft Establishment at Farnborough. Mr. Alston's commen tary was just exactly the right sort, sufficiently non-technical to be of interest to the ladies present and to others not highly technically trained, and yet it was sufficiently technical to interest those with a deeper knowledge of the subject. The conversazione must be written down an unqualified suc cess and it is to be hoped that many similar functions will be held in years to come. The fact that there was no Wilbur Wright lecture to be read this year was probably rather wel comed than otherwise, as it is not everyone who wishes to combine a social function with a lecture which is sometimes of a highly technical character. Warmth with Safety AS everybody knows, the danger of fire (or, at any rate, its potentiality for destruction) is more serious in the case of aircraft and aircraft hangars than in most others. An exception might be quoted, namely, that of the petrol-earn ing barge, upon which even cooking and heating arrange^ ments were forbidden by Government regulations onti recently, when a safe method of neating was developed. Air Ministry and other experts last week attended a denion- strati on of that method, actually a new stove developed D> Aladdin Industries, Ltd., of Greenford, Middlesex. It I& guaranteed to be absolutely safe, and should therefore be very suitable for heating hangars and for keeping engines warm- la the test, for which there is an N.P.L. safety report, tn^ heater was placed in a petrol-impregnated atmosphere, w upset, and had petrol poured over it. In no case was a , harm done.
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