Here is a option to make turn fin for sport40 or scale hydros, hard to get any one to make a good fin. Get a JAE 45 turn fin from ZIPP it is a good size with the curve on the bottom. Cut off top .5 inch for the scale and 1 inch for sport40 size. I would like to see ZIPP make up some fins to use on sport20, 40, and scale hydros. i have make up the L mount shown.