Investigation Of Lateral Control Near The Stall

Flight tests were made with a typical light airplane to investigate possibilities for obtaining reliable control at low flight speeds. It was found that satisfactory lateral control occurred consistently, even under conditions simulating extremely gusty air, at angles of attack approximately 2 degrees below that for the maximum lift coefficient (or the stall of the wing as a whole). This 2 degree margine was substantially the same both with full power and with the engine throttled and throughout the range of center-of-gravity locations tested. Supplementary tests were then made on the control at high angles of attack under actual gusty air conditions, on the possibility of entering spins, and on the amount of elevator control required for normal three-point landings. It was found that with the original plain untwisted wing obtaining the constant 2 degree margin below the stall required widely different elevator deflections for the range of power and center-of-gravity locations tested. Also, none of these settings ws high enough to produce a three-point landing.

These results are intended to provide quantitative flight-test information which may be useful to designers in attempting to provide for adequate low-speed control and which may be correlated with analytical analyses as presented in the third and finai report in this series (Technical Note 3677).