I have a 2d physics engine, with three boxes: "body", "left wing" and "right wing". The wing boxes are connected to the body using a hinge joint. The physics world has no gravity.
I'm attempting to rotate the wings around their hinge connection, as if the joint is motorized but I'm not exactly sure how to achieve that. If I exert force with a downward vector on the center of the wings, the body itself flies down. This is undesirable. With an actual hinge motor, only the wings will rotate about the hinge, affecting the body only when they hit it.
Which forces should be added to the wings, and at which origin points?