10. Length of Struts, Positions of Fittings, Warp in Planes.—The above instructions are given for machines that are true, that is, machines having no bends, warps, or bows in the spars and leading or trailing edges.
(a) Similar struts should be of the same length.
(b) Similar fittings occupying similar positions should be spaced the same. If difficulties are encountered in getting the measurements to tally, check up the lengths of the struts and the positions of the fittings.
(c) If the planes of a machine are warped, the machine should be so aligned that the warp is equally divided between both planes.
11. Alignment of Ailerons.—Before aligning ailerons, place the shoulder yoke or wheel controlling the ailerons in the center of its path of movement.
(a) Trailing-edge Ailerons.—Trailing-edge ailerons should be set ¾ inch lower than the trailing edge of the plane to which they are attached.
(b) Interplane Ailerons.—Interplane ailerons should be set so that they are both in the same plane, when in neutral position.
In machines having interplane ailerons, nose heaviness and tail heaviness may be corrected by setting the trailing edges of the ailerons up or down.
The proper amount to raise or lower the trailing edges can be determined only by experimenting with each particular type of machine.
(c) The control wires should be just tight enough to eliminate any lost motion.