German Stick Control With Double Grips. A. Latch on the Side of the Stick Acts on a Sector So That the Lever Can Be Held at Any Point. It Is Released by the Pressure of the Knees.
Wing Stability. Under wing sections, the subject of the center of pressure movement has already been dealt with. The variation of the center of pressure with the angle of incidence tends to destroy longitudinal stability since the center of pressure does not at all times pass through the center of gravity. On some wings, the camber is such that the variation in the position of the center of pressure is very little, and hence these are known as stable wings. A reflex curve in the trailing edge of a wing reduces the center of pressure movement, and swept back wings are also used as an aid in securing longitudinal stability. Introducing stagger and decalage into a biplane pair can be made to produce almost perfect static longitudinal stability. It should be noted that stability obtained by wing and camber arrangements is static only, and requires damping surfaces to obtain dynamic stability.
Form of Control Used on the Nieuport Monoplane.
Manual Controls. In flight, the aviator has three control surfaces to operate, the ailerons, elevator, and rudder. In the usual form of machine the ailerons and elevator are operated by a single lever or control column, while the rudder is connected with a foot bar. In the smaller machines "Stick Control" is generally used, the ailerons and elevator being moved through a simple lever or "Joy Stick" which is pivoted at its lower end to the floor. The Deperdussin or "Dep" control is standard with the larger machines and consists of an inverted "U" form yoke on which is mounted the wheel for operating the ailerons.
Stick Control. With the stick pivoted at the bottom, a forward movement of the lever causes the machine to descend while a backward movement or pull toward the pilot causes the aeroplane to head up or ascend. The stick is connected with the elevators with crossed wires, so that the flaps move in an opposite direction to the "Stick." Moving the stick from side to side operates the ailerons.
Standard Stick Control and Movements Used in the U.S.A.
Deperdussin Control. A "U" shaped yoke, either of bent wood or steel tube, is pivoted the bearers at the sides of the fuselage. Wires are attached to the bottom of the yoke so that its back and forth movement is communicated to the elevator flaps. On the top, and in the center of the yoke, is pivoted a hand wheel of the automobile steering type. This is provided with a pulley and is connected with the aileron flaps in such a way that turning the wheel toward the high wing tip causes it to descend. Pushing the yoke forward and away from the aviator causes the machine to descend, while a reverse movement raises the nose. The "Dep" control is reliable and powerful but is bulky and heavy, and requires a wide body in order to allow room for the pilot.
