Comparison of the Lateral Controllability With Flap and Plug Ailerons on a Sweptback-Wing Model

摘要

An investigation has been conducted to compare the dynamic lateral control characteristics provided by step plug ailerons with those provided by conventional flap ailerons on a sweptback-wing model. The model used had a 38c sweptback wing with an aspect ratio of 3 and a taper ratio of O.5. The static stability and control characteristics of the flight test model were determined from force tests and the lag characteristics of the ailerons were determined from roll-free stand tests. Flight tests of the model were made through a range of lift coefficient from 0.6 through the stall by using the data obtained from the force tests to establish the flight test conditions. At each lift coefficient in the flight test range the flap ailerons were adjusted to produce the same static rolling moment as was obtained by maximum projection of the plug ailerons. The controllability of the model was more satisfactory with plug ailerons alone than with flap ailerons alone except at lift coefficients below about 0.7. At the lower lift coefficients the time lag from full control deflection to maximum rolling acceleration caused by the plug ailerons was more objectionable than the slight adverse yawing caused by the flap ailerons; whereas, at the higher lift coefficients, the loss of rolling effectiveness caused by the large adverse yawing moments of the flap ailerons was more objectionable than the lag of the plug ailerons. At the stall, the model could be controlled satisfactorily with the plug ailerons alone or with the flap ailerons and rudder but could not be controlled satisfactorily with the flap ailerons alone.