Aileron Input Roll Maneuver

Aileron input roll maneuver data are used for estimation of roll damping and aileron effectiveness. Starting from a trimmed horizontal level flight, a doublet or 3-2-1-1 input command is applied to the aileron stick. The time width of the input signal is chosen appropriately to excite the aircraft rolling motion dominantly. Roll damping and frequency are also determined. The roll mode time constant could be 0.1-2.5 s. An airplane normally has neutral static stability in roll. The maneuver generates

bank-to-bank motion, which can be used to estimate roll derivatives. The maneuver is initiated with a (short duration) pulse input to aileron in one direction (for about 30° roll) and after a few seconds, the aircraft is brought back to horizontal level position with an input to the aileron in the reverse direction. The process is then repeated in the other direction. At the end of this maneuver, the heading angle should be approximately same as at the beginning. Pure roll-related derivatives Lp, Ld can be estimated from these data.