Semi-Truck Aerodynamics

A project to test the viability of boat-tails as a way to reduce drag on semi-trucks. Mark Chodas helped build a 1/27th scale model for initial tests at the MIT Wright Brothers wind tunnel. The tests showed a 40-50% reduction in total drag using the equivalent of a 3 meter tail. This translates to a 25% reduction in fuel consumption, or $35 billion per year in the U.S. if every semi-truck was outfitted with a usable boat-tail. Further tests tests were scrapped after it was discovered that there is a legal length limitation for drag-reducing airfoils of 5 feet. As of Summer 2010, Nathan Moshman at the Naval Postgraduate School was running optimizing simulations to flesh out the idea.