![]() The idea was to consider the possibility of an airplane that would fly at the speed of birds, permitting launching and landing like a hang glider, yet with the performance and control that would permit extended soaring flights on good days. In 1985, I recruited a group of outstanding graduate students at Stanford, many of whom were hang glider or sailplane pilots, to investigate what was possible at the boundary between these two aircraft types. Furthermore, the simple, yet subtle, techniques for hang glider control using pilot weight-shift seemed to limit further performance improvements and led to less than ideal handling qualities under some flight conditions. Flying was often restricted to a very small corridor on a ridge, and more often than not, consisted of an unimpressively short glide to the bottom of the hill. Hang gliders were inexpensive and could be flown from many local sites, but their performance was such that long distance flights were uncommon. But while hang gliding avoided many of the problematic aspects of sailplane flying, it introduced new difficulties. This, of course, was one of the reasons that the sport of hang gliding became popular. That one was often restricted to flights near this airport also made the reality of soaring somewhat less inspiring than the vision. ![]() Especially for a group of graduate students in the San Francisco Bay Area, the cost of sailplane flying, along with the long drive to an airport that supported such activities, meant that achieving the goal of bird-like flight was only somewhat more realizable than it was 100 years ago. Although the performance of sailplanes has increased dramatically over many decades so that lift-to-drag ratios of 60:1 have been achieved and 1000 km flights are possible, certain aspects of high performance sailplanes seem counter to the vision espoused by Lilienthal and others. This was the motivation for, and is the appeal of, modern soaring aircraft such as paragliders, hang gliders, and sailplanes. Introduction and Background Pioneers of heavier-than-air flight were inspired with the idea of being able to fly like birds – not for the purpose of efficient, high-speed transportation, but for the shear freedom that such a capability would permit. This paper describes the design, development, and flying of this unique aircraft. Although it is a fullycantilevered rigid wing with aerodynamic controls and flaps, it is light enough to launch by running from a hillside and is easily transported on the top of a car. It takes off and lands like a hang glider, yet maintains exceptional performance at high speeds, achieving a lift-to-drag ratio of about 25:1. The SWIFT is a high performance foot-launched glider, designed to combine some of the convenience of hang gliders with the soaring performance of sailplanes. Abstract: This paper describes the development of what might be considered the first successful ultralight sailplane.
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