Auxiliary Planes.—Minor plane surfaces, used in conjunction with the main planes for stabilizing purposes.
Biplane.—A flying-machine of the glider type with two surface planes.
Blade Twist.—The angle of twist or curvature on a propeller blade.
Cambered.—Curve or arch in plane, or wing from port to starboard.
Chassis.—The under framework of a flying machine; the framework of the lower plane.
Control.—System by which the rudders and stabilizing planes are manipulated.
Dihedral.—Having two sides and set at an angle, like dihedral planes, or dihedral propeller blades.
Dirigible.—Obedient to a rudder; something that may be steered or directed.
Helicopter.—Flying machine the lifting power of which is furnished by vertical propellers.
Lateral Curvature.—Parabolic form in a transverse direction.