NASA constructed the Ames-Dryden (AD-1) as a flight test program between 1979 and 1982. Alongside the Hyper III, NASA tested the Ames-Dryden at their Flight Research Center in California.
The AD-1’s wing, known as the Scissor Wing, pivoted 60 degrees for greater high-speed functioning. The design of one wing forward and the one back provided less drag when flying. The designers limited the aircraft to a max speed of around 170 mph for safety reasons.
NASA evaluated the AD-1 in investigation of the oblique wing concept. The flying of this subsonic jet-powered aircraft proved the validity of the oblique wing design. The AD-1 conducted 79 flights for research purposes. The aircraft was not without its weaknesses.
The AD-1 experienced poor handling under certain conditions and angles. A common belief is that the aircraft’s fibreglass structure stiffened the wing contributing to its handling woes. Like many of the aircraft on this list, the AD-1 exhibits itself at a museum.