Download and share free model airplane and boat plans. featuring thousands of radio control, control line and free flight freely downloadable plans, 3views and. A few months ago brian contacted me, asking a few questions regarding the capacity of my coroplast boat designs. i tend to be over cautious when specifying maximum. Airframe parts list: 2 4’x8′ sheets of 4mm thick coroplast in whatever color you choose i wanted cub yellow 1 4’x8′ sheet of 2mm thick coroplast used for top of wing.