A counter-rotating fluid-propelling apparatus uses an oblong drive mechanism being oriented substantially orthogonal to the axes of rotation of a pair of counter-rotating impellers and which temporarily and simultaneously engages the edges of the impellers while they are in substantial contact. Each impellers can include a number of substantially rectangular planar panels, hingedly connected to one another along common edges to vertices. Each impeller has an axis of rotation that passes lengthwise through the middle of the impeller such that the axis is parallel to and equidistant from the panel edges. The impellers counter-rotate and remain in constant contact with respect to one another. During each revolution of the impellers, each of the panels of one impeller contacts its counterpart on the other impeller so that planar panels meet flat surface to flat surface and vertex to vertex. The impellers collapse so that constant contact is maintained. A paddled drive belt successively engages drive pins extending from the vertices and pushes them in order to drive the impellers.