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Aviation History
1953
1953 - 1039.PDF
14 August 1953 w Left) Of Russian design and Jugoslav manufacture, this Type PP-01 has a distinctive square canopy designed to reduce oscillation. The author, who brought it back from Jugoslavia two years ago after competing in the World Parachute Championship, describes it as "strong, reliable and well made. Right) Knowledge Dispels Fear is the motto of the Parachute Training School. Live-testing, a major source of knowledge, is illustrated in the picture—one of an official series—by a U.S. Navy parachutist cutting away the rigging lines of a deliberately fouled parachute. There is no magic in a parachute, which is, after all, only a much-improved version of a large sheet with a piece of string at each corner. If by any long chance a parachute lingers in its pack when the ripcord is pulled in a spin, a sharp tweak with the hand should be enough to start things happening. It is not necessary to be a contortionist to reach the pack. Try to judge height by glancing towards the horizon rather than directly below. Looking down over the shoulder while in a back-down spin seems to produce an unpleasant fun-fair sensa tion and, as the ground appears as a blur, may serve no useful purpose. These few points, while intended purely for personal use, are offered here as suggestions for anyone who may have the oppor tunity to try them out in practice. They will help to pass the time, if nothing else. There seems to be no doubt of the need for some form of stabilizer, which would be in operation between the time of. leaving the aircraft and deployment of the parachute. From the packed-bulk point of view, its inclusion in emergency parachute equipment may present problems, but it will add only a small proportion to the already fairly considerable bulk of equipment used in premeditated drops. Presumably the high-altitude opening-shock characteristics of parachutes will apply in some degree to parachute-type stabilizers, and it remains to be seen whether, with a stabilizer large enough to do its work, the opening shock on deployment will be unacceptably high. Most parachutists seem to agree that there is a requirement for a really stable parachute. Various lift-web techniques are practised by professionals and sporting parachutists, to reduce the chances of oscillation on landing. Some of these techniques are good, some wishful, but none really foolproof. Announce to your friends that you have the situation buttoned up, and on your very next jump the ground will leap at you from a ridiculous angle. Your friends will laugh; but console yourself with the thought that your turn will come. Oscillation, while trouble enough on a comfortable grass field, can be embarrassing on tarmac and concrete. Any parachutist who has made a landing under these conditions would welcome a well-trained parachute that did not swing at the wrong moment. Professional parachutists voluntarily place themselves in situations in which they may be caught out by oscillation—but pity the poor pilot. , , Having failed to notice any difference between the feel ot a landing with a 32ft and a 28ft canopy, I might be the wrong person to ask this question. But (remembering that pilots are not used to the sort of rough-and-tumble business that occurs at the end ot a descent) would it not be a good thing to use modern lightweight materials to increase the diameter and lower the striking velocity of emergency parachutes? Although it is generally accepted that an emergency descent is supposed to save the victim s lite ana not necessarily his ankles, a slow rate of descent might enable him to be back at work more quickly than would a fast one Given an average piece of country on which to land, 1 tor one would prefer my rate of descent to be as low as possible, and this attitude comes perhaps of landing on runways, roads, fences, farmyards and in water-filled ditches. Any parachutist who has made a landing on a really windy day will have an idea of the drag produced by a parachute canopy and of the desirability of getting rid of it as soon as possible alter touchdown. There are two main ways of achieving this—release of the whole harness, or of one or both lift-webs. The old-time three-snap harness of pre-quick-release vintage is the neatest and most comfortable harness I have yet worn. In my opinion it is, when fitted with canopy releases, a thoroughly satisfactory piece of equipment. During a fast landing, and the accompanying roll, it is quite usual for one of the parachutist's legs to become entangled in the parachute rigging lines. Releasing the complete harness might easily result in the victim being towed by one leg, but release of one side of the canopy under these conditions brings the whole outfit to a sudden and very welcome stop. The really quickly releasable harness is, by virtue of its basic design, likely to be less comfortable than the three-snap type. If it is of a semi-quick-release variety—in which the leg straps are threaded Uirough another part of the harness before entering the quick-release box, it is possible under certain conditions for the leg straps to jam. This happened to me during a descent in a 30 m.p.h. wind, and resulted in a cross-country drag of about 700 yards before the canopy collapsed in water. When one is dragging in a face-down position, it is possible for dirt or objects or various kinds to lodge between the disc and body of a quick-release box, and so make its operation difficult or impos sible. I saw a demonstration of this when a canopy passed over a wire fence, and a strand of wire immobilized the box. Where the canopy has passed over an obstruction, against which the parachutist has then become wedged, a knife is a useful tool to have handy. Anyone who may find it necessary to jump on a windy day could usefully carry one, and this applies particularly in the case of descents into water. For the professional or sporting parachutist, the canopy-release system has an additional advantage. It allows the attachment of different canopies to one harness, thus making the carriage of several complete parachutes unnecessary when working away from repair facilities. The spare canopies, packed and complete with ripcords, can be attached to the basic harness as required. It may be that, in discussing a few of the factors affecting the professional, sporting and let-me-out-of-here-quick types of para chutists, I have given the impression that the parachute as we know it is not a great deal of use. A large number of satisfied users would agree with me mat this is not the case. There is, however (as in every other department of the aviation business) room for improvement. There is a wide gap between the operating height and speed of some modem aircraft, and the height and speed at which a conventional parachute can be expected to behave normally. Because of the basic simplicity and soundness of the original design, it seems unlikely that a really revolutionary parachute will appear in the future. The main problem seems, therefore, to be that of bridging the gap by some other means: of finding a way in which a freely falling human body can descend from high altitude to, say, 10,000ft, arriving at the lower end of the journey in good condition. If diis is in fact the problem, then the emergency parachute, in more or less its present form, it liable to remain with us for some time. Emergency escape from aircraft is going to cause a good crop of headaches in the future; and when the last pilot steps out of the last piloted aircraft at the end of its last flight, perhaps we will have arrived at the neatest solution. And, someone, please grab that last parachute for the Science Museum, before the wife of the last pilot gets her scissors into it.
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