[1] He was fascinated with flight from a very young age and began building balloons and gliders in his backyard as a teenager.

[2][3] In the video, Terry Sweeney describes the inspiration for his biplane, and Weatherby documents the efforts to get the glider off the ground.

[4] To improve pitch stability of these early Rogallo designs Sweeney added a strut under the sail of each wingtip, which were then attached to the top of the kingpost with a cable.

In 1977, he developed a twintube kingpost mount for attaching an engine to a Rogallo-type flex-wing glider; this proved to be quite a dangerous design in turbulent conditions.

His beginner lessons in the "Clay Pit", an open field by a slope near his house in Dunbarton, New Hampshire, were well known throughout the East Coast by hang gliding aficionados.