The 'X' prop is a 'Jarray' propeller. My spelling may be in error. In lieu of a static prop cut a properly sized disc from clear plastic. 'Pinch' it with 200 grit sand paper then give it a turn or two so that it gets arcuate scratches. Cut a hole in the center to fit the prop spinner on the model. Voilà! Or... rather... Hier! It will look like a spinning prop!