All parts can be printed without supports. The cross member on the spring component uses a cascaded bridging method to achieve this. There will be a small disk in the center of it only a layer or two thick that should be very easy to remove afterwards.

To use:

Wind up spring and place the pull cap on, this is held in place with its ratcheting teeth. Pull this piece to send the propeller flying.

Some light sanding may need to be done on the shaft of the propeller if your part didn't come out smooth