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Aviation History
1944
1944 - 1392.PDF
22 FLIGHT JULY 6TH, 1944 CORRESPONDENCE The Editor does not hold himself responsible for the views expressed by correspondents. The names and addresses of the writers. not necessarily for publication, must in all cases accompany letters. DISCLAIMER Identity of a Correspondent IN the Correspondence column of your issue of June 15th refer ence is made to "Mr. Blackburn." We should like to point out that this reference is to the \V. D. Blackburn who wrote the letter published in your issue of May 18th, and not to Mr. Robert Blackburn or anyone asso ciated with this company. N. BILES, Publicity Manager, Blackburn Aircraft, Ltd. ratio, so that the lower speed of the gases obtainable by means of a thrust augmentor makes this ratio attainable without lowering the kinetic energy of the gases, since their mass has been increased by the additional air obtained through the use of the thrust augmentor. The increase in efficiency causes an increase in thrust. A. R. BILLIGHEIMER. POWER OUTPUT Racing Engine Performance FOR some time now I have been troubled by a question the answer to which must be simple, since none of your more knowledgeable readers have raised it. It seems generally accepted that the Napier Sabre engine, of 2,220 h.p., is the most powerful of our aircraft engines, but in Flight of June 1st there" is a photograph of the Rolls-Royce " R " of 2,300 h.p.; it also has the enviable quality of having a specific weight of 0.71 lb./h.p. There is, too, a photograph of the Fiat double engine, which has a horse-power of 2,800 ! Why are these engines no longer being employed ? The answer would be welcome. Would one of your readers oblige? "MUSHARAPH." JET PROPULSION FOR AIRCRAFT Thrust Augmentor Theory I HAVE followed with great interest the articles and letters published on jet and rocket propulsion. At last I feel that I have to put in a word on the question of thrust augmentors. Mr. E. Burke, M.Sc, states that the additional thrust from the use of a thrust augmentor is caused by the pressure of the atmosphere. This is probably partly so, but I cannot imagine this additional thrust increasing the thrust of a jet by as much as 40 per cent. The problem as I see it in its widest aspects is centred round efficiency. The mass of the gases in a jet are increased by means of a thrust augmentor, but the energy remains the same so that, as a consequence, the final velocity of the mass of gas leaving the nozzle is less than it would be without the use of a thrust augmentor. Now it is a well-known fact that the efficiency of a rocket is at its maximum when the forward velocity of the rocket is in a certain ratio to the velocity of the exhaust gases. Rockets do not usually attain a sufficient speed to obtain this EXHAUST-DRIVEN TURBINES Could They Operate Flaps, etc. I READ with great interest the article on exhaust-driven turbo-superchargers which appeared in Flight of February 24th, and was impressed with the possibility of using exhaust gases to operate such controls as flaps, undercarriage, airscrew pitch, and gun firing mechanism. Is this practicable? Perhaps other readers would like to give their opinions. I am particularly interested as this would eliminate hydraulics, and I imagine it would be quite as reliable and much lighter. The possibility of engine failure would, of course, necessitate * emergency devices, such as manual operation and gravity, as used on present-day machines. I doubt whether exhaust gases could operate the above-mei " tioned controls in addition to the turbo-supercharger, but i. my suggestion is practicable, it could, with obvious advan tages, be used in advanced trainers, where turbo-supercharging is unnecessary. F. C. ROBERTS. THE FUTURE OF CIVIL AVIATION • Solution Lies in Co-operation MR. GRINSTED'S letter in your columns on June 8th is another salutary reminder that there are grave dangers ahead if we allow ourselves to be drawn into an international race for air supremacy. There is no moral justification for such expenditure in a war-stricken world, and it may well lead to bitterness, which will again menace the peace of the world. The solution to this problem is surely to co-operate in every possible way to establish internationally operated airlines on asd*' regional and world-wide basis. Such an effort can be directed towards unifying the human race and might well become a great safeguard against any nation again using air power to menace the security of the world. We should consider the creation of an International Civil Aviation Board controlling European and other regional organi sations. Money spent on such aeronautical research, develop ment and airline subsidy will be wisely spent and can with every justification be spent liberally to the benefit of all, in cluding the aircraft industry. GROUP CAPTAIN R. FULLJAMES, M.C., B.A., A.F.R.Ae.S. BOOK REVIEWS ** The Model Aeroplane Manual," by Lawrence H. Sparey and Charles A. Rippon. Percival Marshall and Co., js. 6d. THIS is the third editipn of a book which has deservedly come to be regarded as the standard work in its field. It has been extensively revised, new information added, and designs for new, up-to-date models incorporated, with detailed instruction for their construction. We do not recall any other book which treats the subject of model aircraft construction so comprehensively and seriously. Moreover, it is phrased with a simplicity that is admirable for its literary style alone. Both the experienced and the newcomer to this fascinating sport will find that this book will show a good dividend in results obtained. Pointing out in his preface that the pleasure of building and experimenting with flying models is keenest when supplemented by sound technical information, Mr. A. P. Thurston, F.R.Ae.S., says: '' Many of our leading aeroplane designers and manufac turers have graduated from the ranks of aeromodellists and still retain a keen interest in the welfare of the sport." Canada's War in the Air. By Leslie Roberts. Alvah M. Beatty. Montreal. T HIS very weighty and imposing volume tells the really remarkable story of how the aircraft industry in Canada, starting from almost nothing, grew until the Dominion became the greatest producer of aircraft in the world, in proportion to her population. The book is extensively illustrated, and the photographs, which are mainly of the interiors of factories, are large and well produced, but are so crowded together on the expansive pages of the volume that it is not easy to take them in. One' can see the forest, but can hardly distinguish the trees. In short, the appearance of this book is worthy of the great story which it has to tell, but we think that the said story could have been better told in a less ambitious setting. .* * • : u I New Edition. \ Gas Turbines and Jet Propulsion for Aircraft j By G. GEOFFREY SMITH, M.B.E. • A THIRD and enlarged edition of this "FLIGHT" book with illusn-ated de- : : A scriptions and comments upon the varying forms of steam and gas : • turbine-compressor units, is now available. Fifteen chapters and many new \ : drawings are included. In this latest edition the original chapters have been : : retained with modifications and additions. The joint official announcement ': : of the R.A.F. and U.S.A.A.F. has made it possible to extend due credit to the j : inventive genius and pioneer work of British technicians who developed gas : ; turbine units to a practical stage for aircraft. There is a foreword by j : Sir Geoffrey de Havilland. \ Copies are obtainable through a Bookseller, Price 6/-, or 6/4 by post \ : cfrect from : Flight Publishing Co. Ltd., Dorset House, Stamford Street, London, S.E.I : t
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