Stearman XOSS
... that the Stearman XOSS observation biplane was equipped with full-span flaps on its upper wing, allowing its pilot better control at low speeds?
... that the <b id="mwB7w"><a href="./Stearman_XOSS" id="mwB70" rel="mw:WikiLink" title="Stearman XOSS">Stearman XOSS</a></b> observation <a href="./Biplane" id="mwB74" rel="mw:WikiLink" title="Biplane">biplane</a> was equipped with full-span <a class="mw-redirect" href="./Flap_(aircraft)" id="mwB78" rel="mw:WikiLink" title="Flap (aircraft)">flaps</a> on its upper wing, allowing its pilot better control at low speeds?