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Aviation History
1913
1913 - 0316.PDF
l/GGHTJ MARCH 15, 1913- form of energy, should give 25 lbs. thrust, which is absolutely impossible. G. E. BI.UNDELL. [It would be more to the point to compare Da than D. Thus, when D« 7 ft., l>" =» 49 sq. ft., for 30-h.p. this represents an expenditure of 1 -6 j-h.p. per sq. ft. Alternatively when D — 7 ins. D*«0'3 sq. ft., which for 2j-h.p. represents 8-3 h.p. per sq. ft. Clearly the energy wasted in the smaller propeller is immensely greater than in the larger propeller and the thrust proportionately will be much less,—ED.J »'«u riqa "to n<»* Streamline Bodies. 11737) I have been reading the discussion that is going on in your paper of late on "stream-lining." To tell the truth it is a difficult matter to prove, because the favour of the argument tends in both directions. I shall here try to point out the favours in both. First of all we know thai a point is gradually going nearer to nothing than a hemispherical thing, consequently offering less resistance, and again the pointed section divides the fluid more gradually than the hemispherical section, because the hemispherical section displaces the air more abruptly, thus causing more pressure on section, and, i.e., more head tesistance. It is very difficult to make a point, and, therefore, it would be best to round the point off a little as in Fig. 1. I do not at all agree with Mr. M. L. Robinson, who states that a section, as in Fig. 2, is the most perfect stream-line. Mr. Heller is incorrect when he states that battleships have pointed bows, because tin bow goes as in Fig. 3, not to a point. This is a fact which if Mr. Heller wants to investigate into the matter he will find it a •correct statement. Again, he states that a pin is pointed ; it may sound funny to some if I say that a pin is not pointed. If you magnified a pin to the site of an aeroplane fuselage it would apjwar thus, as in Fig. 4, so it seems that Mr. Heller is incorrect in most of his arguments. 1 "lkestone. A. M. O'NEILL. [1738] With reference to Mr. Ferguson's letter (1684), he appears to have taken for granted that the direction of the wind is always horizontal to the path of flight. This, oI course, is not the case, as the direction of the wind is greatly influenced by the contour of the ground over which it is passing. I entirely agree, therefore, with Mr. Robinson's state ment (1671) that th- figure "B" has less resistance than figure •"A," and for the following reason :— Referring to page 91 in that excellent little book, " Principles of Flight," it is there stated that " The trend of the relative wind in flight is always changing and, unless a sharp cutting edge properly <livides the stream, it would seem likely to give rise to surfaces of discontinuity, which are sources of inefficiency. A rounded or hemispherical head, on the other hand, would be equally effective in any forward direction, and the air stream would make its own division at the point best suited to the condition of the moment." This, 1 think, needs no further explanation. With reference to Wetm. Robinson and Keller's letter (1685), their remarks re battle ships are answered by Mr. Macdonald's letter (1680) in his final iciuarks re submarines, i.e., the decks would 1« always awash. Uopini; to hear more correspondents' views on this matter. F'inchley. F. D. LEGO. Stability. L'739] I' seems to be commonly assumed that " inherent stability" is an alternative to "automatic stability," but if stability is to be maintained either by manual or automatic adjustment of surfaces, it is of importance that no great angular velocity shall be acquired before the controls can be put in operation. Any rigid design which keeps small the movement of the line of resultant pressure away from the centre of mass on any change of wind direction is therefore of the greatest value, whatever system of control be used, provided that the design is suitable for construc tion ; and in this limited sense "inherent stability" is a necessary preliminary to the operation of any system of control, automatic or manual, without great force and great rapidity of action. Bath. H. D. CAREY. Aviation in Japan. WITH a view to encouraging aviation, the Japanese Govern ment has issued a decree granting pensions to amateur and professional aviators injured while flying, and grants will be made to the families of aviators killed while flying. Bonuses also will be given for each meritorious flight accomplished. ® ® ® ® IMPORTS AND EXPORTS. and parts AEROPLANES, airships, balloon separately before 1910):— Imports. 1912. 1913. £ £ 619 12,027 3,110 17,361 1912-13. thereof (not shown January .. F'ebruary Exports. 1912. 1913. £ £ 2,412 4,005 36 3.447 Re-Exportation. 1912. 1913. £ £ — 1,510 — 690 3,729 29,453 2,448 7,452 — 2,200 ® ® ® ® NEW COMPANIES REGISTERED. British Wright Co., Ltd., 33, Chancery Lane, W.C — Capital £(>,ooo in £l shares. Constructors of aeroplanes and other aircraft, ike. Acquiring certain patents in the names of Orville and Wilbur Wright. First directors, O. Wright, G. Brewer, A. Ogilvie, G. N. Ogilvie, and T. P. Searighl. Dover Aviation Co., Ltd., Whitfield Aerodrome, Dover.— Capital ,£2,000 in £1 shares. Acquiring the business carried on at the Whitfield Aerodrome, Dover, as R. Chalmers. First directors, R. A. Chalmers and A. Bonsor. Mann and Grimmer, Ltd.—Capital £5,000 in £1 shares (2,000 pref.). Aeronautical engineers and aeroplane manufacturers, &c. Acquiring the business carried on at 20, Arlington Road, Surbiton, as Mann and Grimmer. First directors, R. F. Mann, R. P. Grimmer, and D. S. Ball. ® ® ® ® PUBLICATIONS RECEIVED. Les Aviettes. By G. Houard. Paris : Revue du Cerf-Volant, I, Boulevard Henri IV. Price I fr. Tit Bosch News. January, 1913. No. I, Vol. 4. New York : The Bosch Magneto Co., 223-225, West 56th Street. Catalogues. Handley Pa^e Aeroplanes. Handley Page, Ltd., 72, Victoria Street, S.W. Astronomical, Scientific, and Mathematical Works. John Grant, 31, George IV Bridge, Edinburgh. The London Aerodrome : Programmes Season, 1912. London: The Grahame-White Aviation, Co., Ltd., 166, Piccadilly, W. The Automobile Engineer Year-Rook for 1913. London : The Automobile Engineer Publishing Co., Ltd., 20, Tudor Street, E.C. Price 1.?. net. ® ® ® ® Index and Title Page for Vol. IV. THE index and title page for Vol. IV, January to December, 1912, has now been published and any reader can obtain a copy by sending 2d. to the publishers, 44, St. Martin's Lane, W.C. After March 22nd a charge o(6d., post free, will be made. ® ® ® ® Aeronautical Patents Published. Applied lor In 1019. Published March 13M, 19x3. 4,378. G. K. H. AUSTW. Aeroplanes. 18,219. L. P. MCKHONB. Aerocraft. FLIGHT. 44, ST. MARTIN'S LANE, LONDON, W.C. Telegraphic address: Truditur, London. Telephone: i828Gerrard. su BSCRIPTTONPRATES. FLIGHT will be forwarded, post free, at the following rates:— UNITED KINGDOM. ABROAD. 3 Months, Post Free ... 6 ,, ,, s. d. 3 9 7 6 IS o 3 Months, Post Free ... b » » 12 ., s. d. 5 0 10 0 20 0 Cheques and Post Office Orders should be made payable to the Proprietors of FLIGHT, 44, St. Martin's Lane, W.C., and crossed London County and Westminster Bank, otherwise no responsibility will be accepted. Should any difficulty be experienced in procuring FLIGHT from local newsvendors, intending readers can obtain each issue direct from the Publishing Office, by forwarding remittance as above. 322
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