AERONAUTICS: Most Valuable Improvement

The "most valuable single contribution to airplane efficiency since the War" was the epithet that Chairman Joseph Sweetman Ames of the National Advisory Committee for Aeronautics last week placed upon a new form of cowl for radial air-cooled motors. The cowl, shaped like a huge bowl, fits over the cylinders back of the propeller and over the entire motor. It cuts down air resistance; it lets a plane that can go 118 m. p. h. go 137 m. p. h.; it saves in such case about three gallons of gasoline for every hour of flight, and it costs only $25 if put on the plane at the factory as standard equipment.