Inducted in 2020
Developed the Variable Pitch and Hydromatic Propellers
1889–1974
Frank Walker Caldwell was a leading American propeller engineer and designer. As the United States government’s chief propeller engineer, he pioneered propeller engineering and propeller testing facilities and techniques. Mr. Caldwell’s many contributions to aviation in propeller technology highlighted by his winning with Hamilton Standard the 1933 Collier Trophy for design of the controllable-pitch propeller. His design innovations led to the Hydromatic constant-speed propeller used by virtually every frontline US aircraft in WWII, and his pioneering whirl test procedures were indispensable to the development of all modern high-performance propellers during the 20th Century.