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An EverPresent Peril

An EverPresent Peril Aircraft Engineering THE MONTHLY SCIENTIFIC AND TECHNICAL ORGAN OF THE AERONAUTICAL ENGINEERING PROFESSION VOL XXII No 261 NOVEMBER 1950 Another Amenity This brings us to various other aspects of the safety in operation E feel that the article in this issue on the risk of in­ of commercial aircraft. How often, for instance, does one read of an advertent stall with civil aircraft is particularly important, airliner flying around in the vicinity of its airport of departure for Wnot only by reason of the resume that is given of warning several hours in order to burn a sufficient quantity of fuel to make devices that have been from time to time proposed, but also for the it light enough to be able to re-land when this has become desirable implications which make the need for dealing with the subject in owing to some fault such as the failure of an engine or an under­ these days pregnant with significance. carriage obstinately refusing to retract—what time the whole para­ phernalia of fire tenders and ambulances on the ground is alerted. Experientia Non Docet Apart from anything else, it is a most disturbing, and indeed alarm­ One's first reaction so far as aeroplanes engaged on air transport ing, experience for the passengers who see themselves returning services are concerned—with which, sad to relate, we in England are again and again over the same piece of scenery with the disquieting almost exclusively concerned since to all intents and purposes private knowledge of the reason for this and the thought that when they do eventually get down they may be involved in a crash of varying flying has ceased to exist—is undoubtedly that the pilots employed on this type of flying are as a rule so experienced that they are seriousness. What we are leading up to here is whether it is really unlikely to allow themselves to get into a position where irrecoverable out of the question to provide commercial aircraft with fuel jettison­ stall is to be seriously considered as a possibility. In his article, ing equipment to be used in such an emergency. We are, of course, however, M R CLARK quotes a figure from American experience that aware that the argument against such an installation is the danger of fire from a static discharge, but experience with service aircraft surely shows that this is not in fact the case and goes on to mention a small, but none the less significant, number of stalls with com­ shows that this must be very small; while the development of flight- mercial aircraft of which he has knowledge. In fact most of us know refuelling equipment would indicate that apparently wholly satis­ of other instances, in some of which an accident was avoided but in factory preventative measures can be taken. others the issue was less happy, apart from still others in which there is some reason to suspect that this phenomenon was the final Future Benefits event in an accident, though definite evidence of the occurrence is Looking to the future, the supersession of piston by gas-turbine not available. Indeed, it can without exaggeration be stated that the engines will immeasurably reduce the dangers of fire in a crash. conditions in which an aeroplane approaching its terminal airport is The heavy fuels used may of course ignite on coming into contact 'stood off' in conditions of low cloud and bad visibility when it is with the high temperatures of metal parts, but they will not do so put on to a circling course are at least conducive to stalling. In such with the explosive violence of petrol and will therefore give the circumstances the pilot is likely to be so occupied with a number of occupants importantly more time in which to make their escape. matters that there is obvious possibility of his allowing his aeroplane In this connexion, we hope that the tendency in some circles towards to approach its stalling point without noticing the fact. the use of petrol as the fuel for gas-turbine engines will, for this reason if for no other, be firmly nipped in the bud. A Possible Solution There is one other point which we feel should be mentioned in this connexion. We are not all sure that the incorporation of integral It seems, therefore, that the case for a special audible or visual fuel tanks, in which a portion of the main wing structure itself forms stall warning is amply made out. Incidentally, it appears to us that the fuel container, is, from this aspect, a desirable feature. It has quite apart from the use of a warning device in conjunction with the of course many desirable features from the design point of view, existing instruments, such as the turn-and-bank and airspeed in­ but we should like to enter this small 'caveat'. dicators, here is an argument in favour of the lift coefficient indicator advocated by MR E. N. BRAILSFORD in the article by him which French Courtesy appeared on pp. 194-196 of our July issue this year. Surely, by comparison with the airspeed indicator, which it was proposed that We should like to thank AEROSUDEST for having on two occasions the new instrument should supersede, it would give to the pilot in­ invited our Technical Editor to visit them for the purpose of studying formation having a direct relation with the breakdown of flow that most interesting aeroplane the Armagnae, on one of which he leading to a stall which would be exactly what he would, in the was able to observe for himself the behaviour of the machine during circumstances envisaged, require. At any rate, we are strongly of the stability tests in the air which he found to be notably good, parti­ opinion that MR CLARK has done good service in directing fresh cularly in respect to its responses to the controls. We are indeed attention to this danger and reminding us that it is by no means a glad that the lamentable loss of the prototype, from what can only phenomenon that can be ignored, since it is at least doubtful be described as a stupid cause, has not stopped the development. whether it is in fact practicable to make even the modern airliner The unusual method of static test described in this issue, as a result unstallable. of the return visit, is most interesting. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aircraft Engineering and Aerospace Technology Emerald Publishing

An EverPresent Peril

Aircraft Engineering and Aerospace Technology , Volume 22 (11): 1 – Nov 1, 1950

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Publisher
Emerald Publishing
Copyright
Copyright © Emerald Group Publishing Limited
ISSN
0002-2667
DOI
10.1108/eb031962
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Abstract

Aircraft Engineering THE MONTHLY SCIENTIFIC AND TECHNICAL ORGAN OF THE AERONAUTICAL ENGINEERING PROFESSION VOL XXII No 261 NOVEMBER 1950 Another Amenity This brings us to various other aspects of the safety in operation E feel that the article in this issue on the risk of in­ of commercial aircraft. How often, for instance, does one read of an advertent stall with civil aircraft is particularly important, airliner flying around in the vicinity of its airport of departure for Wnot only by reason of the resume that is given of warning several hours in order to burn a sufficient quantity of fuel to make devices that have been from time to time proposed, but also for the it light enough to be able to re-land when this has become desirable implications which make the need for dealing with the subject in owing to some fault such as the failure of an engine or an under­ these days pregnant with significance. carriage obstinately refusing to retract—what time the whole para­ phernalia of fire tenders and ambulances on the ground is alerted. Experientia Non Docet Apart from anything else, it is a most disturbing, and indeed alarm­ One's first reaction so far as aeroplanes engaged on air transport ing, experience for the passengers who see themselves returning services are concerned—with which, sad to relate, we in England are again and again over the same piece of scenery with the disquieting almost exclusively concerned since to all intents and purposes private knowledge of the reason for this and the thought that when they do eventually get down they may be involved in a crash of varying flying has ceased to exist—is undoubtedly that the pilots employed on this type of flying are as a rule so experienced that they are seriousness. What we are leading up to here is whether it is really unlikely to allow themselves to get into a position where irrecoverable out of the question to provide commercial aircraft with fuel jettison­ stall is to be seriously considered as a possibility. In his article, ing equipment to be used in such an emergency. We are, of course, however, M R CLARK quotes a figure from American experience that aware that the argument against such an installation is the danger of fire from a static discharge, but experience with service aircraft surely shows that this is not in fact the case and goes on to mention a small, but none the less significant, number of stalls with com­ shows that this must be very small; while the development of flight- mercial aircraft of which he has knowledge. In fact most of us know refuelling equipment would indicate that apparently wholly satis­ of other instances, in some of which an accident was avoided but in factory preventative measures can be taken. others the issue was less happy, apart from still others in which there is some reason to suspect that this phenomenon was the final Future Benefits event in an accident, though definite evidence of the occurrence is Looking to the future, the supersession of piston by gas-turbine not available. Indeed, it can without exaggeration be stated that the engines will immeasurably reduce the dangers of fire in a crash. conditions in which an aeroplane approaching its terminal airport is The heavy fuels used may of course ignite on coming into contact 'stood off' in conditions of low cloud and bad visibility when it is with the high temperatures of metal parts, but they will not do so put on to a circling course are at least conducive to stalling. In such with the explosive violence of petrol and will therefore give the circumstances the pilot is likely to be so occupied with a number of occupants importantly more time in which to make their escape. matters that there is obvious possibility of his allowing his aeroplane In this connexion, we hope that the tendency in some circles towards to approach its stalling point without noticing the fact. the use of petrol as the fuel for gas-turbine engines will, for this reason if for no other, be firmly nipped in the bud. A Possible Solution There is one other point which we feel should be mentioned in this connexion. We are not all sure that the incorporation of integral It seems, therefore, that the case for a special audible or visual fuel tanks, in which a portion of the main wing structure itself forms stall warning is amply made out. Incidentally, it appears to us that the fuel container, is, from this aspect, a desirable feature. It has quite apart from the use of a warning device in conjunction with the of course many desirable features from the design point of view, existing instruments, such as the turn-and-bank and airspeed in­ but we should like to enter this small 'caveat'. dicators, here is an argument in favour of the lift coefficient indicator advocated by MR E. N. BRAILSFORD in the article by him which French Courtesy appeared on pp. 194-196 of our July issue this year. Surely, by comparison with the airspeed indicator, which it was proposed that We should like to thank AEROSUDEST for having on two occasions the new instrument should supersede, it would give to the pilot in­ invited our Technical Editor to visit them for the purpose of studying formation having a direct relation with the breakdown of flow that most interesting aeroplane the Armagnae, on one of which he leading to a stall which would be exactly what he would, in the was able to observe for himself the behaviour of the machine during circumstances envisaged, require. At any rate, we are strongly of the stability tests in the air which he found to be notably good, parti­ opinion that MR CLARK has done good service in directing fresh cularly in respect to its responses to the controls. We are indeed attention to this danger and reminding us that it is by no means a glad that the lamentable loss of the prototype, from what can only phenomenon that can be ignored, since it is at least doubtful be described as a stupid cause, has not stopped the development. whether it is in fact practicable to make even the modern airliner The unusual method of static test described in this issue, as a result unstallable. of the return visit, is most interesting.

Journal

Aircraft Engineering and Aerospace TechnologyEmerald Publishing

Published: Nov 1, 1950

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