much greater plane surface (double that of a monoplane
of the same size) and consequently much greater weight-
carrying capacity.

Differences in Biplanes.

While all biplanes are of the same general construction
so far as the main planes are concerned, each aviator
has his own ideas as to the "rigging."

Wright, for instance, places a double horizontal rudder
in front, with a vertical rudder in the rear. There
are no partitions between the main planes, and the
bicycle wheels used on other forms are replaced by skids.

Voisin, on the contrary, divides the main planes with
vertical partitions to increase stability in turning; uses
a single-plane horizontal rudder in front, and a big box-
tail with vertical rudder at the rear; also the bicycle
wheels.

Curtiss attaches horizontal stabilizing surfaces to the
upper plane; has a double horizontal rudder in front,
with a vertical rudder and horizontal stabilizing surfaces
in rear. Also the bicycle wheel alighting gear.



CHAPTER V.