Landmark in the Air

This paper reviews contributions of John Montgomery toward controlled glider flight. It was recognized that a glider descending in still air is converting potential energy into motive power equal to the product of its weight and rate of sink. John Montgomery concluded that more basic research was needed. During the next few years, he designed an ingenious test apparatus in which water with suspended particles would flow around surfaces that represented various wing shapes. He also took photographs of the flow patterns. He was able to combine measurements, observations, and analysis. Montgomery had devised a technique to control pitch with a linkage to a pivoting tail section. The California Institute of Technology and other universities established advanced programs to support the increasingly challenging needs of the aircraft industry.