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Aviation History
1962
1962 - 0628.PDF
626 Letters The Editor of" Flight International" is not necessarily in agreement with the views expressed by correspondents in these columns. Names and addresses of writers, not for publication in detail, must in all cases accompany letters. Defining Man-powered Flight SIR,—With the evolution of man-powered flight new ques tions are coming up and satisfying answers have to be found. Several readers of my last letter to the Editor ("Firsts in man-powered Flight," February 15) asked me for more details about defining performance. Since generally accepted definitions do not yet exist, the following points may serve as a proposal:— (1) The definition of man-powered flight which I used in my letter (and which was first laid down by the Man-powered Flight Group of the Canadian Aeronautical Institute) could be adopted. (2) For all types of take-off the influence of kinetic and potential energy used during take-off would be deducted to find the man-powered element. (3) According to the type of take-off, three separate cate gories of man-powered flight should be recognized and the performances in each should be regarded separately: (a) Flight after unassisted take-off. (b) Flight after take-off assisted by externally stored pilot- power. To retain conditions as similar as possible to those of the unassisted take-off, the take-off height attained by externally stored pilot-power should be limited to 10ft. It can be expected that, after unassisted take-off, flight distances up to 100yd can be achieved with kinetic energy only, which corresponds to a theoretical take-off height of about 8ft. In both categories the level element of the man-powered flight is inextricably mixed up with the sinking glide element arising from kinetic or potential energy used for take-off. However, the sinking glide element is kept at the unavoidable minimum and its influence on the total flight becomes remark able only in very short flights. Therefore, only flights over a distance of more than three times the distance attributed to the influence of kinetic or potential energy should be recog nized as man-powered flight in these categories. (c) Man-powered flights after take-off with other power (teams and rubber bungee, car-tow, winch). Since here the power used for take-off is outside the limits of categories (a) and (b) only that part of the flight which is above the height at which an unaccelerated flight condition is attained should be recognized as man-powered flight. The part of the flight below this level will be a glide stretched by man-power. The flight should be limited to a maximum height up to which no vertical air movements could be expected (about 30ft). At greater heights than this the flight should be called "soaring assisted by man-powered flight." Which category will be preferred for competitions is a separate matter which will change with time and experience. Richmond Hill, Ontario HELMUT HAESSLER Boffin Genealogy Sm,—The enquiry of Mr Ronald W. Clark in Flight Inter national of March 29 could perhaps be partially answered if he saw a note which appeared after the sub-titles at the beginning of the British film School for Secrets. The date of this was 1946-47. Also about this time appeared several books by ex- members of the Bawdsey Manor research team who had worked almost from the start on radiolocation and opera tional research. This group existed from 1935 to the start of the war in 1939 and they constituted a body separate and in many ways different from other Government research workers at Farnborough, Felixstowe, Martlesham Heath, etc. FLIGHT International, 19 April 1962 Their contact with professional Service people who were requested to assist in strange work whose purpose could not be divulged created an atmosphere which could be said to exist to this day. Thus it would not be unreasonable to assume that the word "boffin" first appeared about 1937-38 in the context that we are familiar with. After the radio/radiolocation people had been dubbed with the word it must have spread generally to other workers. Therefore it would be unlikely to refer to pre-rearmament era Government research workers connected with military aviation. It must not be forgotten that in mid-1940 the civilian research staff of the Air Ministry were absorbed into the Ministry of Aircraft Production. A "barrier of the spirit" might have been formed at that date. If the reminiscent literature of that period (i.e., 1935-40) were referred to, a more exact dating could perhaps be found. The best people to enquire from would be Service officers of that period who had been detached for flying and testing work. Rather like the real-life character on whom Jack Train based his "Col Chinstrap" in ITMA, if you talked to a Government research worker at Farnborough or elsewhere he would never admit to being a boffin but would know of several individuals and of them say "now he was a real boffin." Before memories dim too far the boffin should receive a detailed study all his own and maybe a memorial—abstract in character as was so often the appearance of his efforts —be erected to his memory on some windswept moor or bleak tidal estuary, typical of his trial grounds. Portsmouth, Hants B. c. KERVELL Taxi Fare or Bus Fares? SIR,—It seems that the airlines are strangling the tremendous potential growth of air transport, and hence the aircraft industry, by their reluctance to enter on a programme of really significant fare reduction. Under the present system of internationally agreed fare levels each airline has to place the emphasis on speed and the latest fashion in design when re-equipping, to compete with its rivals for the slowly increasing market, and economy must take second place. (See "BEA's share of London - Paris traffic" chart, Flight, December 21, 1961.) This policy has up to now protected the scheduled airlines from destructive methods of cut-throat competition and hurried along development in the speed and reliability of civil aircraft; but it has led to an unbalanced air transport system which still charges taxi fares when the aim should be bus fares of 2d per mile or less. Seen against the present background of high fares the economics of the supersonic airliner do not look too bad, but they are ridiculous com pared with what could be done if the same effort was applied to designing purely for economy. An indication of the public demand for lower fares is that on the North Atlantic last year the group charter traffic rose by more than 50 per cent over the previous year, compared with the overall increase of 13 percent. With present types of aircraft some independent airlines can make a profit at 2d per passenger mile ("Twopenny Trooping," Flight International, February 8), whereas the average European tourist rate is over 7d and the North Atlantic IATA propeller economy fare is 5.3d per mile, and still the airlines lose! For 1960-61, when BEA made a small profit, their passenger revenue from 4m passengers was about £40m, or £10 per passenger. Hence if "twopenny trooping" is achieved with a 100 per cent load factor, and we assume in this case that indirect costs are negligible, then the direct operating cost for BEA with approximately 65 per cent load factor is just over 3d per passenger mile, so that out of the £10 more than half is taken up by the indirect operating costs. Thus it costs BEA more than £5 to process each passenger before he is flown anywhere. Indirect costs for the Atlantic trip are more difficult to assess, since revenue does not meet the total costs; but as load factors are more of the order of 50 per cent, direct
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