Hargrave, 1893, Flying Machine Motors and Cellular Kites
Lawrence Hargrave presented a paper called "Flying Machine Motors and Cellular Kites" to the Royal Society of New South Wales on 7 June 1893.
A similar paper was read, seemingly in absentia, at the Aeronautical Navigation Conference at 1893 World's Fair (August 1–4), with an introduction by Albert Francis Zahm. Zahm suggests that readers unfamiliar with Zahm's work consult past issues of the Journal and Proceedings of the Royal Society of New South Wales as well as Chanute's recent pieces in the American Engineer and Railroad Journal.
The last paragraph of Hargrave's original article seems to be omitted in the conference Proceedings.
In the article, Hargrave discusses his experiments with steam boilers
Regarding the whirling arms connected with experimenters Samuel Pierpont Langley and Hiram Stevens Maxim, Hargrave mentions:
The expense of constructing and erecting a large whirling machine similar to Prof. Langley's or to Mr. H.S. Maxim's being too great, and knowledge of the fact that planes or other things moving at the end of an arm through still air are not under the same conditions as bodies flying in disturbed air, determined the selection of kites as the best means to the desired end.
Hargrave suggests the value of parallel aeroplanes and describes his kites as resembling "two pieces of honeycomb put on the ends of a stick, the stick being parallel to the axes of the cells".
He says that the idea of "two planes separated by an interval in the direction of motion" was "patented by Danjard in 1871, made and exhibited by D. S. Brown in 1874", and in the attached footnote cites Chanute's Progress in Flying Machines (then being published serially by the American Engineer and Railroad Journal):
In "The American Engineer and Railroad Journal", Vol. LXVII, No. 3, Mr. O. Chanute states, that Mr. H. F. Phillips patented in 1890 an aerial vehicle with superposed surfaces in two or more series, the surfaces might be fifteen feet long, six inches wide, and two inches apart; no mention being made of vertical surface which the writer finds essential to stability. Prof. Langley shows that the distance apart of the superposed surfaces cannot, with advantage, be less than eighty-three per cent of the width of the plane.
Engine
Kites
Comparison of E. and F. Same weight and area, but E. has curved surfaces (convex sides up) and F. has flat ones. "Roughly, E. pulls twice as hard on the string as F. does. So that a flying machine with curved surfaces would be better than one with a flat body plane, if the form could be made with the same weight of material."
Yet: "When the kites E. and F. are discharged from the crossbow in calm air, they both have the same trajectory. It is difficult to imagine a more convincing or simpler proof that the laws governing the motion of a body through still air are distinct from those that determine its action when moving through wind. Evidently a machine with curved surfaces flying against the wind would come to grief if the wind fell calm, unless provision had been made for either increasing the surface or the driving power.
Links
- Proceedings of the Conference on Aerial Navigation: Held in Chicago August 1, 2, 3, and 4, 1893, American Engineer and Railroad Journal, 1894. Hargrave's paper begins on p. 287.
- Journal and proceedings of the Royal Society of New South Wales, Vol. XXVII, 1893. Hargrave's article beings on p. 75. The plates are all at the end; for Hargrave's start at p. 545 of the pdf.
