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Aviation History
1961
1961 - 0635.PDF
;/:£,:, '• ••-;--&—•? May 1961 645 CORRESPONDENCE The Editor of "Flight" is not necessarily in agreement with the views expressed bv correspondents in these columns. The names and addresses of the writers, not for publication in detail, must in all cases accompany letters. onstant-frequency Systems IT vwuld appear to me that the necessity for a complete constant-frequency a.c. electrical supply now currently being recom-mended and used on modern aircraft has been, to put it mildly, ovcr_e;nphasized. There is no doubt in my view that the cost and•weigh'- along with the complication of a constant-speed drive, with all its associated necessary protective control circuits, outweigh any• possible advantages with such a system. 1 feel that there is a lot to be said for a basic aircraft electrical generating system of "wild" frequency 208V a.c. which, over the normal flight operating speeds of jet engines, would not provide sufficient variation in frequency to preclude the use of a.c. induction motor? for most services, such as control hydraulic motors, actua- tors, etc. The fairly considerable d.c. requirement still necessary on modern aircraft could then be catered for either by rectified a.c. to 112V d.c. or 28V d.c. or by the use of a brushless d.c. generator. The constant-frequency supplies—which, in fact, I understand only amount to about 10 per cent of the total electrical requiremems of the aircraft—could be catered for either by rotating invertors or, if there is an objection to this due to brush troubles, transistorized invertors. Apparently therefore we have to put up with a complete full-scale constant-frequency supply in order to keep the alternators all parallelled together. 1 am aware that there might have to be automatic load-switching devices to cater for failures of individual alternators, but only for direct a.c. supplies. A constant-frequency system is an electrician's paradise, but is it the most all-round efficient system for an aircraft ? Anyhow, 400 c/s is the wrong frequency to have chosen as a higher frequency system; nearer 1,000 c/s would have been lighter. I think it would be useful if some of our aircraft electrical engineers would be honest enough to set down the actual cost and weight of a constant-frequency system on an aircraft compared to the system 1 have outlined. Derby H. E. WEST Airliner Fleet Names WITH reference to the letter in Flight of April 20 concerningairliner fleet names, the following may be of interest, especially to your correspondent Peter W. Moss. Last year I wrote to BOAC suggesting that their forthcoming Vickers VC10 airliners be named individually after holders of the Victoria Cross. Despite the then chairman's reply to the effect that it was no longer corporation policy to name individual aircraft, I still feel that the introduction of these new airliners will present a most apt and unique opportunity of further perpetuating names of which this country can justly be proud. I would welcome comment on this idea. Feltham, Middx ARTHUR W. SMITH Senegalese Air Force Aircraft1 HAVE pleasure in sending you photographs [one of which is reproduced below—EdJ of the aircraft recently delivered from the French Air Force to the new Senegalese Air Force. Its main base is Dakar (Yoff) Airport, on the other side of the civil airport, along the parallel runway. Senegalese crews are being trained by the French for servicing the aircraft, but training will not be com- pleted for a year. Equipment comprises six aircraft (two C-47s and four MH.1521M Broussards) and two helicopters (Bell 47G-2s). Dakar, Senegal ROGER CARATINI Airline Costing READING Mr K. G Wilkinson's fascinating letter [April 27]on his methods of arriving at aircraft operating costs, 1 was at once struck by the similarity between them and the methods of the organization of which 1 have the honour to be president, the International Confederation of Aeronautical Financial Geniuses, better known as ICAFG. Our methods of costing are recognized by airline accountants the world over, and differ from Mr Wilkin- son's only in that, whereas he uses design seat-capacity (all cases adjusted to 100 seats at 34in pitch), we use fuel-tank capacity (US gal) multiplied by the nosewheel tyre-pressure (kg/cm3). Also, where he used design stage (adjusted to 1,000 statute miles), we use compressor stages (turbine engines), or supercharger stages multiplied by boost pressure (in Hg) (piston engines). In both cases, of course, results are corrected to ISA conditions. As regards the other interwoven sources of variation, we have a curve of s.f.e. against captain's coffee temperature, which we find most useful for unravelling such complexities. (Copies are available to non-mem- bers on cash payment of a fee of five guineas.) The Confederation has recently conducted a survey similar to that carried out by Mr Wilkinson, using these methods, and the results are so nearly coincident with his that he is to be sincerely congratulated on obtaining such results without access to the ICAFG formulae. With regard to the letter published together with Mr Wilkinson's, Mr Rew appears to be rather ill-informed as to the multifarious variables used in airline costing. ""Profits in real money" indeed; that, with all respect to Mr Rew, is typical of the technician's unrealistic attitude towards airline finance. Nr Princeton, Devon A. FIDDLER. Short-range Forecast I DESIRE to put in an appeal for the use of astrology in thedetermination of flying deliberations, such as the drawing-up of schedules, prospects for individual flights, air fetes, sports days, times for test flights or prototypes, etc, day and hour for a first solo flight, also for assessing the pros and cons of aircrews, test pilots and pupils by candid, expert examination of their individual birth data. 1 would first like to point out, immediately, two wretched days in the very near future not fit to see any aircraft in the air. They are: Satwday, May 13, and Sunday, May 14, next. I hope that one day there will be daily and nightly astrological forecasts for flying. For years I have noticed that aircraft mishaps predominate on days which, according to astrological judgment, were not fit for joy-rides, let alone payloads. After the morning of February 15 last both the Sun and Moon were in opposition to Uranus (as seen from the Earth), signifying undue danger to flight operations, because at that time, according to astrological interpre- tation and my own experience, the human element would be at fault. On that morning an airliner crashed at Brussels with the loss of 73 lives. No aeroplane would normally have been on the wing at that hour had Administration been astrologically conscious. Astrology is based on electro-magnetic radiations emanating from each of the moving bodies of the solar system and from the constellations of the zodiac. This electrostatic condition of the atmosphere can be detected in radio interference, and is as inherent and intrinsic as the force which moves the tides, and that which causes the compass needle to point northward. London NW1 WM. P. ROST One of the Senegalese Air Force MH.IS2IM Broussards referred to by M. Caratini, and details of its markings YELLOW
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