How to construct an artificial Wave Wing on the Insect type.—The following appear to me to be essential features in the construction of an artificial wing:—
The wing should be of a generally triangular shape.
It should taper from the root towards the tip, and from the anterior margin in the direction of the posterior margin.
It should be convex above and concave below, and slightly twisted upon itself.
It should be flexible and elastic throughout, and should twist and untwist during its vibration, to produce figure-of-8 curves along its margins and throughout its substance.
Such a wing is represented at fig. 122, p. 239.
If the wing is in more than one piece, joints and springs require to be added to the body of the pinion.
In making a wing in one piece on the model of the insect wing, such as that shown at fig. 122 (p. 239), I employ one or more tapering elastic reeds, which arch from above downwards (a b) for the anterior margin. To this I add tapering elastic reeds, which radiate towards the tip of the wing, and which also arch from above downwards (g, h, i). These latter are so arranged that they confer a certain amount of spirality upon the wing; the anterior (a b) and posterior (c d) margins being arranged in different planes, so that they appear to cross each other. I then add the covering of the wing, which may consist of india-rubber, silk, tracing cloth, linen, or any similar substance.
If the wing is large, I employ steel tubes, bent to the proper shape. In some cases I secure additional strength by adding to the oblique ribs or stays (g h i of fig. 122) a series of very oblique stays, and another series of cross stays, as shown at m and a, n, o, p, q of fig. 123, p. 241.
This form of wing is made to oscillate upon two centres viz. the root and anterior margin, to bring out the peculiar eccentric action of the pinion.