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Aviation History
1909
1909 - 0124.PDF
FEBRUARY 27, 1909. PROPELLERS AND MOTORS. To the Editor of FLIGHT. SIR,—Re Mr. Hollands' letter in FLIGHT, February 20th. In the first place, I beg to say that I was ignorant of the existence •of a Hollands' propeller until FLIGHT came into existence, and I ihave never had the pleasure of reading the testimonials mentioned. It appears to me that Mr. Hollands is "word-twisting" and .avoiding the main issue by trying to impress your readers that the meaning of my letter is entirely opposite to that expressed. If Mr. Hollands is certain that he has a propeller of great efficiency, then he must have an aeroplane or aeroplanes on which he has been flying "on the quiet," to have been in a position to obtain the data for the designing of such a propeller, as it is impos- sible, in my humble opinion, to have obtained the data without actual experience with large aeroplanes in free flight. I am sure your readers will be delighted to hear of such flights, if only for the satisfaction of knowing that another Englishman has " come to the top." I, for one, have not yet heard of any aeroplane at present flying fitted with a " Hollands," and should be glad to hear that a machine is fitted with one. It would appear that "Frenchmen" are not the only " conservative " people in the world ; there appear to be many such. F.ither Mr. Hollands is perversely dense or my writing is unintelligible, and I will slightly alter my query in FLIGHT of February 13th. What is the difference in the mechanical efficiency of a "Hollands " and a "Voisin" both on an aeroplane ? To obtain this data correctly, it is necessary to fit an aeroplane •with one propeller, obtain a flight with recording instruments in use, and then test it fitted with the other propeller in the same way. How is it that the " king of flyers " has " knocked creation" with a mechanically-crude wooden propeller made by himself? I think this alone proves the point in my letters, viz., that it is absolutely •necessary to have experience in flight before one knows the par- ticular propeller for a particular machine, and the slightest alteration in a machine requires an alteration in the propeller to again reach the point of highest efficiency, although the machine is still the same size, assuming that the efficiency was a maximum in the first case. I am afraid I shall never agree with Mr. Hollands until he leaves ironical generalities and levity, and gives some exact data, in which case I shall be pleased to "climb down" and say, "Well done, Englishman!" from a patriotic point of view, and with the same feeling as I view the performances of Mr. Moore-Brabazon on his •" Voisin." Yours very truly, MONTFORD KAY. THE TREVOR SCHOOL. To the Editor of FLIGHT. SIR,—We are pleased to inform you that on Monday next we actually commence tuition in aeroplanes. Our " flying department " will be inaugurated on March 1st. In view of the rather contradictory reports that have been pub- lished concerning our schools, may we be permitted to point out that we are not at present proposing to teach the theory of construc- tion. We are limiting ourselves to training the practical flyer, and not the builder. The aeroplane which we have ordered is an all-British machine, which we expect will be ready in about ten or twelve weeks. We have not yet decided upon the flying ground, but full particulars as to this we shall be in 0 position to publish later. In the meantime, you will be glad to hear lhat we have secured the services of Mr. T. W. K. Clarke, B.A., A.M.I.C.E., who will be the general instructor in the flying department. Yours faithfully, TREVOR, LTD. TREVOR WRIGHT, Managing Director. THE AERO EXHIBITION. To the Editor of FLIGHT. SIR,—I should be glad to communicate with some reader and prospective exhibitor who would be willing to include my propeller in his display, and, preferably, with suitable power available for running it. I can give him choice of three sizes, viz., 8 ft. 3 in., 6 ft. 7 in., and 5 ft. 6 in. diameters. Yours faithfully, York, Feb. 15th. SIDNEY H. HOLLANDS. [We would suggest that Mr. Hollands should communicate with the Secretary of the Aero Club, or the S.M.M.T., as every encouiagement is to be given for the display of legitimate exhibits. —ED.] A MODEL ENGINE DESIGN. To the Editor of FLIGHT. SIR,—I enclose a rough sketch of an engine which I think might be of use to amateurs in search of an engine for model aeroplanes. It is easy to construct and compact, and gives high speed to the shaft and propeller. It can be driven by compressed air. The clutches, A3, which are coupled together by rods, A4, are driven by means of the piston in cylinder, A, up and down the threaded shaft, C. On the shaft are two units, B, which engage with the clutches, A:i, thereby causing the shaft, C, to revolve. As this detail sketch shows, the clutches are only single-acting and therefore only one nut is engaged in each direction of travel. When a convenient place is reached on the shaft, the engine is reversed through operation of the tappet-rods, A2, controlling the slide-valve. - *s 3 1 1 \_ ^\ \\ \ .1i / m-/ \ fji k 1L | f\3 1 3 Pi -- At each dead-centre, that nut, B, which was driving, becomes detached from its clutch-face, but is, of course, still retained by the clutch-cage, although now free to revolve with the shaft. The other nut then takes up the work of driving the shaft and is sub- sequently disengaged in a similar manner. The shaft, C, being cut at the one end with a right-hand thread and the other with a left- handed thread, thus continues to rotate in a uniform direction and great speed of revolution and comparative slow motion in the working parts may, in this way, be obtained. I invented this engine many years ago as a turbine, with the object of gaining the maximum advantage from the expansion of steam. I protected it with a provisional patent, but never completed it, so that I shall be very glad if it proves useful to any of your readers, as it is simple to construct, and with a thread of 60° gauged as in the Archimedian drill, causes little friction. I am a member of the Aero Club and am much interested in everything relating to flight. Yours faithfully, E. B. POTTER. A "TIP" TO AEROPLANISTS. To the Editor of FLIGHT. SIR,—Having been enabled to show aviators that they need not go abroad for propellers, but can get them much better and quicker at home, while encouraging the British industry, I have another hint to offer, which I hope may prove timely and acceptable. In view of the increasing demand for suitable trial grounds, I would draw the attention of those who are on flight intent, or " who fain would fly to other climes," to an admirably adapted tract of land adjacent to this grand old city of York, where I am at present located. This excellent tract of country is the York racecourse, a treeless and otherwise unobstructed level area of about a mile and a half by threequarters. It is certainly the most suitable ground I have seen in England, and I gather that its use would be free of all charge. York is within four hours' rail of London. * Referring to Mr. Jack Humphry's letter of last week, I thank him for his favourable mention of my propeller. This is due to the fact that Mr. Humphry has not only " heard of the ' Hollands' propelkr," but has seen it. Yours faithfully, York, Feb. 6th. SIDNEY H. HOLLANDS. * P.S.—I would gladly obtain full information locally for any who are interested. Aeronautical Patents Published. Applied tor in 7908. Published March 4/h, 1909. 28,026. R. ESNAULT-PELTERIE. Aeroplanes. 126
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