How Does the Area of the Controllable Slope Affect the Tumblewing's Ground Speed?

This project requires students to be able to fly a tumblewing walkalong glider by controllable slope soaring over a fixed straight distance at a constant altitude.

Make a tumblewing from a light weight paper such as tissue paper or phone book paper. Make controllable slopes of varying area from a sheet of cardboard. Stores which sell new bicycles usually dispose of the cardboard boxes which can be cut into large and small area sheets. Example sizes might be 20cmX40cm and 40cmX80cm. Find a room with little or no drafts and measure a straight, fixed distance over which to fly. Measure the time it takes to fly the measured distance using the different sized controllable slopes. An airplane's speed relative to the earth is called its ground speed. How might the size of the controllable slope affect the headwind experienced by the tumblewing?