University of Virginia Library

The Matter of Lateral Balance.

"All successful aeroplanes thus far have maintained lateral balance by the principle of changing the angle of incidence of the wings.

"Other ways of maintaining the lateral balance, suggested by observation of the flight of birds are—extending the wing tips and spilling the air through the pinions; or, what is the same thing, varying the area of the wings at their extremities.

"Extending the wing tips seems to be a simple and effective solution of the problem. The tips may be made

to swing outward upon a vertical axis placed at the front edge of the main planes; or they may be hinged to the ends of the main plane so as to be elevated or depressed through suitable connections by the aviator; or they may be supported from a horizontal axis parallel with the ends of the main planes so that they may swing outward, the aviator controlling both tips through one lever so that as one tip is extended the other is retracted.

"The elastic wing pinions of a bird bend easily before the wind, permitting the gusts to glance off, but presenting always an even and efficient curvature to the steady currents of the air."