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Aviation History
1947
1947 - 1634.PDF
344 PLIGHT SEPTEMBER I8TH, Correspondence .... suited to club training. It will also, presumably, enableVolunteer Reserve pilots to keep refreshed at a much higher standard of applied flying than would be possible on Tigers. Mr. McKay's concluding remarks concerning the advisabilityof starting off pupils on the easiest aircraft possible raises one of those arguments which appear to be useless to argue,for the simple reason that: the supporters of the two sides are each more bigoted than the most hardened supporters of pro-fessional sport teams. I would merely say that a lot depends on what you mean by the easiest possible type, and that thereis a school of thought which would like to see the Service ab initio trainer a quite, different type in order to weed out theleast apt pupils at the earliest possible stage. After a lifetime in aviation, I still wonder at the conserva-tism of pilots and call to mind those who forecast the collapse of Service training when Smith Barry made the "dangerous"Avro 504 its ab inilto trainer. Finally, I would say that tlu Prentice version of the T.23/43Specification is a pleasant and simple aircraft to handle. Its "complications" are its instruments, taps, etc., the use ofwhich are probably best taught by a pupil's first instructor in whom he has the perfect faith never to be met with again. The Airport, Luton. "STILL A.I." Time Saved in Giving InstructionI HAVE read with much interest the recent letters signed"One-time A.2 " and "Donald A. S. McKay," discussing the pros and cons of the side-by-side, three-seat elementarytrainer controversy. I am greatly interested in this, since I spent long, gruellinghours during the war on all aspects of flying instruction. I am wondering if both of the recent writers have borne inmind one very important point in favour of both side-by-side seating and the inclusion of the third seat, namely, the prece-dent created by the Director of Flying Training in considering the welfare of the flying instructor as well as the overallbenefit to training that either or both these seating arrange- ments have. During the peak periods of wartime training—and it mustbe remembered that the T23/43 specification was initiated at that period—the flying instructor "often found himself thepossessor of four to six students per six weeks' course. During this time each student was supposed to complete a period of50 hours' flying, and the aim in each case was to ensure that the student spent half that time under dual instruction. Due to the, circumstances peculiar to the time, it couldhappen that all students had- to be shown the same exercise iri one day, involving endless repetition, in such wordy exejcisesas low flying, where the flying instructor found himself ex- plaining several times in a day the optical illusions broughtabout by the effects of drift on an aircraft flying close to the • ground. This individual form of flying instruction was theinevitable result of the two-seat tandem arrangement in vogue in Training Command at that time. This endless instruc-tional repetition had a marked effect on the instructor and Sept. Sept. Sept Sept. Sept. Sept. Sept. Sept. Sept. Oct. Oct. Nov. Nov. Nov. Dec. FORTHCOMING EVENTS 9th to 12th.—S.B.A.C. Exhibition and Display. 13th to 15th.—Cannes Aero Club " Ailes d'Aiur " Film Festival air rally. Cannes-Mandelieu airfield. 14th.—Royal Aeronautical Society : Garden party. Radlett airfield. !7th to 19th.—Federation Aeronautique Internationale : Annual General Conference, Geneva. 19th.—Institute of Navigation : Inaugural Address by Sir Harold Spencer Jones, M.A., Sc.D., F.R.S. " Navigational Work of Nautical Almanac Office," D. H. Sadler, M.A. " Wind Statistics and their Application to Airline Operation," Capt. E. Brook Williams. 20th to 22nd.—Butlin'i air rally at Pwllheli Holiday Camp. Land at Broom Hall airfield. 23rd.—R.Ae.S. (Graduate and Student). Discussion " The Design of Wings " : Introduced by F. Tyson, A.F.R.Ae.S. 25th.—Air league of the British Empire : Annual General Meeting, I, Pall Mall East, S.W.I. 27th.—Society of Licensed Aircraft Engineers : " Liquid Springs." R. H. Bound, F.R.Ae.S., M.I.M.E., A.M.A.E. 19th to Nov. 24th.—Royal Aero Club of Belgium : Air rally to the Belgian Congo. Brussels to Le Kivu. 21st.—R.Ae.S. (Graduate and Student). "Interplanetary Flight and Rocket Propulsion." A. V. Cleaver, A.F.R.Ae.S. 1st.—Society of Licensed Aircraft Engineers : " Aircraft Pneu- matics." H. R. Haerle. 4th.—K.Ae.S. (Graduate and Student). " Maintenance Difficulties in the Field." M. J. Kemper. M.B.E. A.R.Ae.S. d ) Aircraft Photography." th Fiel. M M.B. 19th,—R.Ae.S. (Graduate and Student). John Yoxall. 12th.—R.Ae.S. (Graduate and Student). "Aircraft Design 'rom th' Airline Point of View," Christopher Dykes A F.R.Ae.S. also on the quality of instruction, and there have beta instances where operational pilots have preferred a second iour of operations to a sojourn at a Flying Training School The Director of Flying Training was quick to appreciati- thebad effects of boredom and repetition. All flying instructors were aware of the desirable features of side-by-side trainingas practised, for instance, in the Oxford aircraft, and so it became one of the prominent features of the T23/43 specifica-tion. Thoughts were then turned to the inclusion of a third seat to enable a further student to benefit by holding-a watch-ing brief. Low flying, navigation, etc., could be demonstrated most ably to more than one student at a time so that whenthe second student's turn came to perform, much time had already been saved by listening-in to the demonstration givento the first student. Investigation of this aspect of the specification proved thatthe quantity of the individual dual instruction could be re- duced, which meant that each student in turn was at thecontrols for a longer period under the eye of his instructor. At the same time, by reducing the amount of flying instion required to complete the syllabus, the instructor able to introduce added variety with beneficial results to allconcerned. J PRE-WAR A.2. THE AEROTEC SPORTSMAN Attainment of Stated Performance Questioned HPHE announcement in your journal of September 4th of a-*• new ultra-light aircraft project by the Aerotec Research Group will be of interest to private owners and flying clubsalike. However, a number of the figures given in the report appearto raise doubtful points, and any clarification from the staff of Aerotec would, I think, prove helpful to your readers. The landing speed mentioned is low, even for this class ofaircraft, and as the Reynolds number must inevitably be in the region of 2 x io° it appears that this can only be attainedby the adoption of a very low wing-loading and consequent large wing area. With reasonable aspect ratio, a CLma:r withoutflaps of 1.35 might be assumed, although this would probably entail a better surface finish than that obtainable by theamateur kit builder, and the corresponding wing-loading is 3.11 lb/sq ft. With serni-span split flaps the CLmaa: might btraised to 1.80, giving a"fcdng-loading of 4.14 lb/sq ft. Now the all-up weight of this-single-seater will presumably lie betweeTi600 lb and 800 lb, giving a minimum wing area of 145 sq ft'for 600 lb. A.U.W. and split flaps, an unlikely combination ir)view of the extremely light structure weight of "this supposi- tion: 600 lb — 170 lb (pilot) — 120 lb (engine) — 70 ft(fuel and oil) =" 240 lb (inc. radio, etc.)'. The greatest prob- able wing area, that deriving from 800 Ib A.U.W. and no flaps,is 257 sq ft, but this is also unlikely because of the dispropor- tion of size to weight (cf. the Tipsy Junior, with 60 h.p. engineweighing 170 lb, ' A.U.W. 660 1b, wing area 113 sq ft and stalling speed 40 m/hr). Whatever the compromise chosen, we are left to supposea relatively large wing area, with correspondingly high induced drag figures. The tricycle undercarriage will also add to theparasite drag of the aircraft even if well trousered, and to attain a cruising speed of 100 m/hr an engine of approximately60 h.p. would appear to be needed, even allowing very favour- able drag figures. Apart from the difficulty of procuring aBritish engine of suitable weight and pow.er, this would give a. fuel consumption higher than that suggested. The figure or18s for 300 miles will just cover the cost of eight gallons of petrol and oil; and gives a minimum performance of 37! m/gallon, which could only be attained by a 40 h.p. engine 0.5 lb/b.h.p./hr at the speeds quoted. The cost of operating thus seems to be confined solelv to'petrol and oil, and no account has been taken of maintenance and inspection, C. of A., hangarage, insurance, landing fees or,more impertant still, first cost. The implication of the use of, flaps, plus a tricycle and therefore braked undercarriage,indicates a fairly high first cost, even for a back-garden con- structor. The two-way radio also implies the provision atleast of electrical services, and the total weight of batteries, aerial, cable, etc., to be carried seems steep for the typf of.aircraft under consideration. The question of weight control, which appears to be the governing factor with this enterprisingproject, is also important when it is realized that a high-per- formance aircraft for "sporting" flying will doubtless be de-signed to A.R.B. Aerobatic Category, necessitating higher load factors than are used, say, for the current four-seater charteraircraft. There is every indication that the Aerotec Research Groupmust have something up their sleeves, and fulk-r details of the'r design would be greatly appreciated. R. CHEAT! R.
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