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Aircraft Engineering THE MONTHLY SCIENTIFIC AND TECHNICAL ORGAN OF THE AERONAUTICAL ENGINEERING PROFESSION matters which are omitted from the summary that we publish we feel that it would be useful and helpful to give a brief resume of them HORTLY after the holding in America in May this year of the here. second Anglo-American Conference arranged jointly by the Royal Aeronautical Society and the Institute of the Aero The Author's Conclusions nautical Sciences—the first having taken place in London in Sep The fact is emphasized that the airframe must be designed from tember 1947—we received a very brief summary of the paper on the start with the knowledge that it is to employ turbines. For 'Turbine-engined Transport Aircraft' presented by MR G. R. instance, high drag flaps are needed to replace the high idling drag EDWARDS of VICKERS-ARMSTRONGS LTD. We at once realized its of a piston engine which, on a turbine, with or without propellers, outstanding interest and importance and sought MR EDWARDS' tends to become a small thrust. Problems of propeller control have permission to publish it in full in AIRCRAFT ENGINEERING. He readily been successfully overcome and the handling of engine/propeller granted this but unfortunately the Institute preferred—as was, of controls by the pilot is no worse than with a piston engine. course, its right—to withhold the full text till it could appear in the full report of the Conference, which it is hoped to publish early next There is no doubt that the use of kerosene, with its relatively high year at the price of 15 dollars. The Institute, however, had no objec flash point and low rate of flame propagation, reduces the danger of fire after forced landings. tion to our publishing an extended summary of it. As we learnt that the paper had not been circulated before the meeting, at which an The almost complete absence of vibration increases the standard abbreviated version only was read, and therefore there had been no of comfort for passengers and all the evidence so far available points opportunity of studying it even by those present at the Conference, to a striking increase in airframe serviceability owing to the absence we felt that we should be doing useful service if we made available of power-plant vibration. This may well be the biggest contribution as full a version of it as possible at an early date. Feeling that the towards increased earning power that the turbine engine will abbreviated version read at the meeting—which was very kindly bring. It has been proved that no measurable vibration is fed made available to us—gave a less true picture of the value of the full back into the airframe by the addition of a propeller to the turbine- paper, which we had by then had an opportunity of studying, than engine. we desired, we persuaded M R EDWARDS to have another, and still The great reduction in noise level also brings greater comfort— fuller, version prepared specially for us and it is this which appears with the reservation, in the case of pure jets, that passengers must in this issue. be housed forward of the jet orifice, as experience shows that the jet 'rumble' aft of the je t pipe is quite intolerable. From the reactions of seasoned travellers who have flown in the Appreciative Thanks turbine-engined aircraft now available, in the author's belief the We cannot express too warmly our thanks to MR EDWARDS and combined effect of the reduction in vibration and noise will be his staff at Weybridge for the immense amount of trouble they have that once having had the taste of the comfort of a turbine-engined aircraft the air travelling public will turn its back on what it now gone to in making available to our readers this extended summary, accepts as first-class air travel. which runs to about one-third of the length of th e full paper and has actually some advantages over the original in that certain of the The importance of maintaining height with a pure jet places great curves have been amended to include details of further knowledge and emphasis on the need for developing a high standard of pressure experience gained since the paper was first compiled. When it is cabin engineering. realized that this is the fourth variant of the paper that has been First cost of a civil aeroplane fitted with centrifugal turbine written—the full paper, the abbreviated version read at the Con engines will not be appreciably different from those of a comparable ference and the brief summary circulated in June being the others— aircraft fitted with piston engines. So far as direct operating costs are the debt which we owe to M R EDWARDS can be appreciated. concerned, on short and medium ranges up to 1,000 miles the As chief designer of the Weybridge Works of MESSRS VICKERS- propeller-turbine aeroplane is at least as economical as a comparable piston-engined type. Over the longer ranges of about 2,000 miles ARMSTRONGS M R EDWARDS has had—with the Nene-engined Viking there is little to choose between the operating economics of the pure and the Dart-engined Viscount—experience of the performance in flight of a pure jet and a propeller-turbine transport aeroplane, in jet, propeller turbine and compound piston-engined aircraft. All comparison with the piston-engined Viking, which is unrivalled in the these are more economical than their piston-engined equivalents. world. At the present time the chief designer of no other firm is in a The pure jet aircraft, however, still suffers from the lack of flexi bility which must impose considerable limitations on its practical position to draw comparisons between the three types and it is this operation. This defect is not so important on the propeller-turbine unique knowledge which makes his paper so important at the present time. He is able to write from practical experience and give which is so much less dependent on high forward speeds and the high data gained from actual practice on a subject which has been hitherto altitude necessary to obtain them. one of pure conjecture evolved from theory. A great case can be made out for the propeller-turbined aircraft At the end of the complete paper the author draws certain con on the basis of direct operating cost, safety and improved mainten clusions of a general nature on the problems of design and operation ance but the improvement in passenger comfort is the- most im that he has been considering. Although some of these deal with portant factor.
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Nov 1, 1949
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