 measur dimension deriv wing-aileron-tab system measur dimension deriv wing-aileron-tab system measur direct two-dimension damp stiff deriv incompress flow correct aris apparatu discuss refer attempt measur direct tab deriv effect frequenc paramet amplitud oscil reynold number aileron angl posit transit wing variat frequenc paramet vortex-sheet theori variat amplitud produc chang deriv lowest reynold number chang deriv variat aileron angl condit natur transit higher reynold number stiff deriv increas forward movement transit reduc stiff deriv smaller aileron angl lowest reynold number increas trend observ damp deriv comparison vortex-sheet theori measur valu stiff damp deriv 0 6 theoret valu measur direct tab deriv cross aileron-tab deriv cent aileron 4 cent approx tab addit measur direct aileron deriv comparison earlier number static deriv wing control influenc frequenc paramet reynold number posit transit tab angl seal control hing gap test ailcron set minu 8 deg tab 12 deg condit hing moment aileron reason agreement valu equival profil theori direct damp deriv direct tab stiff deriv direct aileron stiff deriv departur theoret natur transit comparison valu flat-plate theori approxim factor suffix denot theoret valu 