Tubular Aileron Spars

To build stiff ailerons and flaps and to minimize the chance of them warping, incorporate thin-wall aluminum-tube spars into them, and apply the balsa covering with the grain running chordwise. To stiffen the trailing edge, sandwich a narrow strip of the 1/64th-inch plywood or carbon fiber between its two sides. Note the plastic shim washer and the plastic bearing in which the tube can turn for aileron hinging. Adapted from 400 Great R/C Modeling Tips...