Figure-1 from <span><a rel="nofollow" class="external text" href="https://patents.google.com/patent/USRe19412">U.S. Patent Re19,412</a></span>, "Aircraft and Control Thereof," dated January 1, 1935, E.F. Zaparka, inventor. This patent describes, and this image shows, a movable "microflap" similar to the fixed <a href="https://en.wikipedia.org/wiki/Gurney_flap" class="extiw" title="en:Gurney flap">Gurney flap</a> independently discovered and first used by <a href="https://en.wikipedia.org/wiki/Dan_Gurney" class="extiw" title="en:Dan Gurney">Dan Gurney</a> in 1971.
E.F. Zaparka
1935-01-01
<span><a rel="nofollow" class="external text" href="https://patents.google.com/patent/USRe19412">U.S. Patent Re19,412</a></span>