Test
We set up a ruler 65mm away from the hovercraft with
and without a skirt with the motor on and off, then we attached
three rubber bands to it, and we pulled the end of the rubber bands
with a pencil until the hovercraft moved. Then however far the
pencil was upon the ruler, that was how much force we used, the
farther the rubber band stretched, the more force was used to pull
the hovercraft.