When you stretch a rubber band, it tries to return to its original shape. You can easily harness this power to keep one of your model aeroplanes uplifted. It's simple to attach one of these to a model aeroplane. These are typically used on balsa wood planes because balsa is a light and strong wood. You can alter the instructions for attaching one of these engines from a balsa plane to your aeroplane but once you understand how the piece attaches it's simple to alter.
Attach the propeller to the nose of the aircraft so that the hook attached to the back of the propeller points toward the back of the aeroplane. On balsa wood planes, these often come attached to a bracket which fits over the nose of the aircraft.
Nail, screw or glue the small tack or hook to the tail end of the aeroplane. The hook should face toward the tail of the aeroplane, or the nail should tilt away from the nose of the aircraft.
Loop the elastic band around the hook or nail at the end of the aeroplane. Pull the band around to the front and hook it onto the propeller's hook.
Twist the propeller of the aeroplane around. As you twist it, the elastic band will also spin and coil up. When you release the propeller, the elastic band will uncoil and spin the prop.
Gently toss the aeroplane to launch it.