EG-0108-01
The YO-3A aircraft was originally a Schweizer SGS-2-23 sailplane. During the late 1960s Lockheed modified over a dozen of these sailplanes to create ultra-quiet observation aircraft for use over South Vietnam during the conflict there. This particular YO-3A flew combat missions and was later sold to an airframe and powerplant mechanics school.
NASA’s Ames Research Center at Mountain View, CA, acquired the aircraft from the school in 1978. It restored the YO-3A to flight status and fitted it with wing- and tail-mounted microphones as an acoustic research aircraft. Ames operated it at Edwards Air Force Base for noise measurements of helicopters and tilt rotor aircraft. NASA also used the YO-3A for sonic boom measurements of a NASA SR-71 assigned to the Dryden Flight Research Center. NASA transferred the YO-3A to Dryden in December 1997, and as of April 2001 it was in flyable storage there.