Externally, Fire Shadow Overseer looks almost identical to Boeing Insitu ScanEagle, and the only difference between the two UAVs is in winglets: the winglets of Fire Shadow Overseer point downward, as opposed to that of ScanEagle, whose winglets point upward.
XT-01X is a MAV that somewhat resembles a miniature Boeing Insitu ScanEagle without winglets, but with swept wings at sweeping backward at greater angle.
At the 1991 World Gliding Championships in Uvalde, Texas, the trophy for the highest speed went to a winglet equipped 15-meter class limited wingspan glider, exceeding the highest speed in the unlimited span Open Class, an exceptional result.
After modifications (addition of auxiliary winglet over engines to improve air flow and lift), it was sold to Francis Francis as G-ABJP, who onsold it in September to Gibraltar Airways for the Gibraltar-Tangier route.
At least three different winglet designs have been produced for the ASW-20, including a NASA winglet fitted to the Centrair gliders (FP), a design by Peter Masak, and a second generation winglet designed by Prof. Mark D. Maughmer of Penn State University (USA).