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Living Pictures

Living Pictures Aircraft Engineering THE MONTHLY SCIENTIFIC AND TECHNICAL ORGAN OF THE AERONAUTICAL ENGINEERING PROFESSION VOL XXIII No 266 the boundary layer with a shock wave formed and photographing it as a laboratory demonstration to model scale. HE scientist engaged on practical research and experiment We do not propose here to follow M R LAMPLOUGH in describing has to be something of an engineer and, indeed, of an inventor. the development of the further apparatus capable of being mounted An interesting example of the need for this kind of approach on the actual wing of an aeroplane in flight and recording photo­ to a problem is afforded by the account of the evolution of the graphically on cinema film the appearance and movement of ingenious method of obtaining actual film records of shock waves genuine shock waves as they formed and developed during the in action, so to speak, which appears in this issue. The whole matter manoeuvres of aeroplanes in high-speed flight approaching the speed arose, we believe, from the fact that pilots reported observing the of sound. Suffice it to say that the design of this is no less ingenious appearance at high speeds of lights, or bands of light, on the wings than that of the original piece of laboratory equipment. of their aeroplanes; which it seemed possible were due to the formation of shock waves rendered visible by the refraction of light. Elucidation Having developed the necessary appliances to produce the evid­ ence, the manner in which the technique of reading them was evolved Specialist Knowledge seems to us equally worthy of praise. At first glance, the photographs The steps taken to investigate the soundness, or otherwise, of this we reproduce appear to the uninitiate a hopelessly confused series deduction are another example of the extraordinary ramifications of of shadows, patches of light and scratches. Under the able tuition knowledge into which the modern science of aeronautics leads us. of M R LAMPLOUGH in his text, order, however, gradually begins to M R LAMPLOUGH, who was, we understand, responsible, with the appear out of seeming chaos and after a time one is able to grasp the help of others, for the development of the method which he himself meaning of the pictures, by eliminating the non-essential and describes for us, is a specialist in optics without any profound know­ fortuitous and concentrating on the true evidence, so that an ledge of aeronautics, though he was during the period in question illuminating picture of a shock wave in real life appears for our employed at the Royal Aircraft establishment. edification. At any rate, to him was entrusted the task of inquiring into the possibilities of making shock waves visible in the laboratory; which A Long-felt Want would not only test the soundness of what was at that time little We have had in recent times an increasing number of inquiries for more than an intelligent guess at the inner meaning of what the an up-to-date vocabulary giving the French equivalents of English pilots had noticed but, far more important, open up immense hopes aeronautical terms, but have always had to reply that no such aid of increasing our knowledge of the incidence of shock in com­ pressible flow by enabling us actually to see the waves forming existed. We have long had in mind the possibility of ourselves filling the gap and the publication of B.S. 185 produced by the BRITISH and in operation. STANDARDS INSTITUTION'S TECHNICAL COMMITTEE ACE/1—AERO­ NAUTICAL GLOSSARY, of which the Editor of AIRCRAFT ENGINEERING Approach is chairman, seemed to offer a suitable occasion by providing a recognized list of accepted English terms on which a vocabulary M R LAMPLOUGH, by virtue of his specialized training and know­ could be based. We placed the translation of these terms into their ledge, was in a position to approach this optical problem from first French equivalents in the capable hands of M. CHALMETTE who is a principles—which he proceeded to do, as he so clearly explains. trained engineer of considerable experience whose work at He started by constructing an ingenious model, the light-source for L'ARSENAL DE L'AERONAUTIQUE has given him a very wide know­ .vhich was provided by his own 'astrograph' lamp, which projected a ledge of the terms used in both languages. He has consulted a number shadow thrown by an artificial simulation of a shock wave provided of other French engineers and, as a double check, the vocabulary )y a bent piece of thin celluloid film suitably mounted for experiment has also becnexamined by M R LIONEL MOTE, whose name has long md test. A record was then obtained of the shadows thrown during been familiar to our readers for the translations into English of otation of the object through a wide arc. So far so good. The next articles originally written in various foreign languages that have tep, designed to prove the satisfactory character of the picture appeared in these pages. The American equivalents of the English obtained, appear s to us quite brilliant in its ingenuity. A tracing, in terms, where they are known to differ, have also been added to make white lines on black, of the required parts of the record so obtained the picture more complete. It is proposed ultimately to reissue the fas made and this was, as it were, 'played back' through the appara- Vocabulary in booklet form and therefore criticisms and suggestions JS and a fresh record made of the simulated shock wave, which for improvement will be welcomed as, though every effort has been atisfactorily produced an envelope giving the characteristic curve of made by all concerned to achieve perfection, this is beyond human he shadow thrown by the original object. capacity in such a matter. i Here, then, was a proved method of simulating the appearance of http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

Living Pictures

Aircraft Engineering and Aerospace Technology , Volume 23 (4): 1 – Apr 1, 1951

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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0002-2667
DOI
10.1108/eb032018
Publisher site
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Abstract

Aircraft Engineering THE MONTHLY SCIENTIFIC AND TECHNICAL ORGAN OF THE AERONAUTICAL ENGINEERING PROFESSION VOL XXIII No 266 the boundary layer with a shock wave formed and photographing it as a laboratory demonstration to model scale. HE scientist engaged on practical research and experiment We do not propose here to follow M R LAMPLOUGH in describing has to be something of an engineer and, indeed, of an inventor. the development of the further apparatus capable of being mounted An interesting example of the need for this kind of approach on the actual wing of an aeroplane in flight and recording photo­ to a problem is afforded by the account of the evolution of the graphically on cinema film the appearance and movement of ingenious method of obtaining actual film records of shock waves genuine shock waves as they formed and developed during the in action, so to speak, which appears in this issue. The whole matter manoeuvres of aeroplanes in high-speed flight approaching the speed arose, we believe, from the fact that pilots reported observing the of sound. Suffice it to say that the design of this is no less ingenious appearance at high speeds of lights, or bands of light, on the wings than that of the original piece of laboratory equipment. of their aeroplanes; which it seemed possible were due to the formation of shock waves rendered visible by the refraction of light. Elucidation Having developed the necessary appliances to produce the evid­ ence, the manner in which the technique of reading them was evolved Specialist Knowledge seems to us equally worthy of praise. At first glance, the photographs The steps taken to investigate the soundness, or otherwise, of this we reproduce appear to the uninitiate a hopelessly confused series deduction are another example of the extraordinary ramifications of of shadows, patches of light and scratches. Under the able tuition knowledge into which the modern science of aeronautics leads us. of M R LAMPLOUGH in his text, order, however, gradually begins to M R LAMPLOUGH, who was, we understand, responsible, with the appear out of seeming chaos and after a time one is able to grasp the help of others, for the development of the method which he himself meaning of the pictures, by eliminating the non-essential and describes for us, is a specialist in optics without any profound know­ fortuitous and concentrating on the true evidence, so that an ledge of aeronautics, though he was during the period in question illuminating picture of a shock wave in real life appears for our employed at the Royal Aircraft establishment. edification. At any rate, to him was entrusted the task of inquiring into the possibilities of making shock waves visible in the laboratory; which A Long-felt Want would not only test the soundness of what was at that time little We have had in recent times an increasing number of inquiries for more than an intelligent guess at the inner meaning of what the an up-to-date vocabulary giving the French equivalents of English pilots had noticed but, far more important, open up immense hopes aeronautical terms, but have always had to reply that no such aid of increasing our knowledge of the incidence of shock in com­ pressible flow by enabling us actually to see the waves forming existed. We have long had in mind the possibility of ourselves filling the gap and the publication of B.S. 185 produced by the BRITISH and in operation. STANDARDS INSTITUTION'S TECHNICAL COMMITTEE ACE/1—AERO­ NAUTICAL GLOSSARY, of which the Editor of AIRCRAFT ENGINEERING Approach is chairman, seemed to offer a suitable occasion by providing a recognized list of accepted English terms on which a vocabulary M R LAMPLOUGH, by virtue of his specialized training and know­ could be based. We placed the translation of these terms into their ledge, was in a position to approach this optical problem from first French equivalents in the capable hands of M. CHALMETTE who is a principles—which he proceeded to do, as he so clearly explains. trained engineer of considerable experience whose work at He started by constructing an ingenious model, the light-source for L'ARSENAL DE L'AERONAUTIQUE has given him a very wide know­ .vhich was provided by his own 'astrograph' lamp, which projected a ledge of the terms used in both languages. He has consulted a number shadow thrown by an artificial simulation of a shock wave provided of other French engineers and, as a double check, the vocabulary )y a bent piece of thin celluloid film suitably mounted for experiment has also becnexamined by M R LIONEL MOTE, whose name has long md test. A record was then obtained of the shadows thrown during been familiar to our readers for the translations into English of otation of the object through a wide arc. So far so good. The next articles originally written in various foreign languages that have tep, designed to prove the satisfactory character of the picture appeared in these pages. The American equivalents of the English obtained, appear s to us quite brilliant in its ingenuity. A tracing, in terms, where they are known to differ, have also been added to make white lines on black, of the required parts of the record so obtained the picture more complete. It is proposed ultimately to reissue the fas made and this was, as it were, 'played back' through the appara- Vocabulary in booklet form and therefore criticisms and suggestions JS and a fresh record made of the simulated shock wave, which for improvement will be welcomed as, though every effort has been atisfactorily produced an envelope giving the characteristic curve of made by all concerned to achieve perfection, this is beyond human he shadow thrown by the original object. capacity in such a matter. i Here, then, was a proved method of simulating the appearance of

Journal

Aircraft Engineering and Aerospace TechnologyEmerald Publishing

Published: Apr 1, 1951

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