Abstract: A closure for an opening in an aircraft hanger includes a curtain having its top marginal edge connected to the header of the opening and its bottom marginal edge connected to and taken up on and paid out from an elongate tube. The marginal side edges of the curtain overlap the side walls which define the opening. A vertical track is supported adjacent the side marginal edges of the curtain and rollingly support respective tube guides moving therealong in a vertical direction. The tube guides are connected to the tube at one end by a rotational journal therewith and at the other end by a fixed shaft of a fluid motor which has the motor proper, or a gear reducing mechanism therefor, mounted within and connected to the interior wall of the tube. The fluid motor is reversible so as to rotate the tube to take up and pay out the curtain, the tube and tube guide following the curtain up and down along the vertical track.