Page:Aerial Flight - Volume 1 - Aerodynamics - Frederick Lanchester - 1906.djvu/367

Rh on the plane: this, however, proved abortive. Mr. Dines attributes the failure of this portion of his investigation to the existence of eddy currents subsequently discovered to have been set up by the frame of the machine.

Experiments with roughened surfaces and with the planes thoroughly wetted showed a diminished reaction, in both cases equal to about a 20 per cent, drop for the angle of maximum moment when compared with the same plane polished and dry.

Experiments are also recorded, made with the object of determining, in a rough and ready manner, the direction of the stream lines in the immediate vicinity of the surfaces of an inclined plane. A number of pins were driven into the face and back of the plane, and short lengths of coloured silk attached to act as weather-cocks from point to point, and show the local direction of the air currents. The results were drawn from observation; sample diagrams for a square plane at 45 degrees