The next radical design change came in the late 1940's when aircraft engineer Howard Head introduced a ski made of laminated metal and wood to replace the skis of solid wood construction. Finally, in the 1950's plastic running surfaces were introduced to give the modern ski its maneuverability. The concept of having a curved sides on skis to assist with turns was actually developed by Nordheim back in the 1800's. Most modern designers use this same approach today with varying degrees of radius. Have the students design their own skis and construct them out of cardboard to test how the amount of side curvature effects the turning radius of the ski.
Nothing is for free.
In this case, the fact is it is mostly gain. Some loss of straight downhill speed because of turbulent air flow. Have each cut to be about 3 inches wide and set up each between 2 cement blocks. Pile on bricks until it cracks and see which one can support more weight. Technically, blimps are not much more than simple gas bags with fins, using the natural buoyancy of Helium gas to stay aloft.