The Briegleb BG-12 is a single-seat sailplane of wooden construction developed in the United States in the 1950s. It was marketed for homebuilding in plans or kit form, with over 350 sets of plans selling by 1978. The BG-12 is a conventional sailplane design, with a high cantilever wing and a conventional empennage. Later models featured a highly-revised fuselage, a swept-forward tail fin, and an all flying tailplane with balance tabs. The BG-12BD is a BG-12B with revised wing and ailerons.
The NSM BG-12 in a red orange and white color scheme, was donated to the museum in 1977 by Robert Kellner.