The S-38 was the first commercial success for the fledging Sikorsky Corporation. A metal ground-adjustable propeller was flown earlier by Lindbergh on the Spirit of St. Louis, and was the best ...

McCauley, manufactured by his company, and was the first solid steel propeller used by the U.S. Army Air Corps. It has an adjustable pitch, and a concave-convex shape to improve rigidity. The design ...