Navigating the Air; A Scientific Statement of the Progress of Aeronautical Science Up to the Present Time

Navigating the Air; A Scientific Statement of the Progress of Aeronautical Science Up to the Present Time

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 edition. Excerpt: ...more closely the astronomical and kindred societies of the world, for the better and speedier verification of alleged discoveries; the collection, classification and dissemination of data, etc. When aerial navigation is an accomplished fact, it will be possible to take observations of the heavens through an atmosphere unobscured by clouds; a point, at all times, of the highest importance, but especially so at critical moments during rare conjunctions and eclipse. VIII THE VERTICAL SCREW OR HELICOPTERE By Prof. Wm. H. Pickering Harvard University FLYING machines may be divided into three classes: a--those with flapping wings, whose origin is prehistoric, b--the aeroplanes, invented in the last century, and c--those dependent on the action of one or more vertical screw propellers. This last form, it is said, was invented by Leonardo da Vinci, who made some successful paper models about the year 1500. The writer first became interested in this form of flying machine a little over thirty years ago, when he constructed some models with feathers, cork, and whalebone, that flew successfully to the ceiling. In 1880 he made measures of the speed, lift, and power consumed by various small fans; and in 1881 a 4O-inch fan, driven by power, was tried. With this it was shown that the air currents set in toward the fan, not only from the front and sides, but also from the rear, gradually increasing in intensity until we reached the surface of a cone, having the center of the fan for its apex, the shaft of the fan for its axis, and an angle at the apex with the axis of 45 degrees. At the surface of this cone, the direction of the air currents suddenly reversed in direction, and rapidly increased in strength, attaining a maximum shortly before the axis was...show more

Product details

  • Paperback | 70 pages
  • 189 x 246 x 4mm | 141g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 123666471X
  • 9781236664716