The flying-machine from an engineering standpoint
Frederick William Lanchester
Paperback
(RareBooksClub.com, Sept. 13, 2013)
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1917 edition. Excerpt: ...machines has been studied experimentally at the National Physical Laboratory, at the Aerodynamic Laboratory at Gottingen, and by M. F. Eiffel, in Paris. A few results relating to strut sections are given in Fig. 31a. The graph a a is a plotting from National Physical Laboratory data,2 relating to the section A, representing one of the best forms tested, graphs b and c relating to sections B and C as determined by M. Eiffel.1 In Fig. 31a ordinates represent resistance coefficient both in absolute units and in terms of normal plane (the normal plane unit being that of maximum section). In Fig. 316 are shown two strut-sections designed at the Royal Aircraft Factory. These were reported upon by the N.P.L. as giving less resistance for given strength than a number of others submitted. Approximately, strength for strength, 1 Report of the Advisory Committee for Aeronautics, 1912-1913, No. 83. J Report of the Advisory Committee for Aeronautics, 1912-1913, p. 111. 1 "Resistance of the Air and Aviation," p. 184. 20 30 VELOCITY Fig. 31a. these gave one-fourth the resistance of struts of circular section.2 The resistance of wires and ropes has been investigated both by the National Physical Laboratory and by Professor Prandtl of Gottingen. The position may be summarized here by saying that the resistance of a rope or stranded cable, at right angles to the direction of motion, is virtually equal to that of its area projected on a normal plane. The resistance of smooth wires is about 20 per cent. less. Both these results only hold good above a certain minimum value of LV, which may be taken at about 1-5; thus at 100 feet per second, the rule may be taken as applying to cables or wires down to about inch ( = 0-015 foot) diameter.1! Report of...