36" Mr. Smoothie.The 1938 National Air Race in Cleveland, Ohio was the site of the Thompson Trophy Race 300 lap/300 mile race. New aircraft entry the 1938 PearsonWilliams PW1 “Mr. Smoothie” was designed around the Curtiss D12 Conqueror engine by Rodney Nimmo capable of 375 mph and built by Bud Pearson and Lee Williams.