Since this is just for demonstration purposes, you might be able to take a dowel, say 5/8" dia., and wrap some i/8" diameter vinyl insulated wire around it and glue it in place with super glue. It's not the same a true flight, but it might demonstrate the idea. You would have to pay attention to the size of the "corn" you transfer with it. Too big and it'll jam. If some slips backwards, it's OK. It's just a demo. Piece of acme threaded rod might work too.