On May 20, 1927, Charles A. Lindbergh and the Spirit of St. Louis took off from New York bound for Paris for the first successful solo nonstop flight from the United States to Europe. The Ryan-built airplane incorporated some of the latest aeronautical developments: a radial air-cooled engine; monoplane configuration; earth-inductor compass; and a metal, ground-adjustable-pitch propeller. Even so, the heavily laden plane barely cleared the telephone wires at the end of Roosevelt Field by twenty feet. The Spirit's spectacular takeoff highlighted a critical limitation of its propeller. Built by the Standard Steel Propeller Company of Pittsburgh, the device's blades could be adjusted on the ground for efficiency for different operating conditions, primarily takeoff or cruise, but once the blades were set they could not be changed in flight. Searching for every bit of economy for the 3,610-mile flight, Lindbergh had two choices. He could have an easy takeoff with a possible fatal landing in the Atlantic short of Europe or attempt a risky one with a much more desirable landing on French soil. The metal ground-adjustable propeller was the best available technology using a promising new design that pointed the way toward more advanced propellers for high performance aircraft of the 1930s (Figure 10).

The development of the metal ground-adjustable propeller was a major technological milestone of the Aeronautical Revolution of the late 1920s and 1930s. It represented almost a decade of work to improve the overall performance of the airplane by propeller specialists working for the federal government and private industry. The two partners in this pioneering development were the propeller unit at McCook Field and the Standard Steel Propeller Company. Caldwell and his colleagues conducted research and issued specifications and contracts for the new propellers to increase overall aircraft performance. Their civilian partner, Standard Steel, developed new designs, attempted to make them practical, and produced them for profit. Tracing the development of the metal ground-adjustable propeller, known as the “Propeller That Took Lindbergh Across,” reveals important themes for the history of aviation: the key role a specific device played in an event that captivated the world, the importance of government–business partnerships in solving technical challenges, and how communities perceived new innovations, especially in terms of the fundamental choices they made to push technology forward.