is supposed to take place from left to right, as in Fig. 57. Fig. 59 illustrates a modified form given in a further specification by the same inventor, 13,311 of 1891. These two figures show clearly the nature of the feature under discussion. In both specifications the theory given is inadequate.[1]
The advantages of the arched form of wing section were known to the late Herr Lilienthal at the time of his experiments in flight, 1890–94, and the discovery has been attributed to him by some writers.[2]
Fig. 58. It is possible that Lilienthal was unaware of Phillips' previous work, and that discovery by him was made independently.
Fig. 59. There is no evidence to show that Lilienthal possessed more than a practical acquaintance with the arched form.
- ↑ In his 1884 specification Mr. Phillips says:—
“... so arranged that a current of air striking the forward edge of the blade at an acute angle is deflected upwards by the forward part of the surface, and a vacuum (or partial vacuum) is formed on the after-surface, substantially as described.”
Further, in the patent of 1891 he writes:—
“The particles of air struck by the convex upper surface A at the point E” (compare Fig. 59) “are deflected upwards, as indicated by the dotted lines, thereby causing a partial vacuum over the greater portion of the upper surface.” - ↑ See article “Aeronautics,” “Encycl. Brit.,” O. Chanute.
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