Delivered to the US Army as 69-18010. Used in Vietnam from 1970 to 1972. Sold as N37778 then to NASA Ames Research Center, NAS Moffett Field, CA as N718NA in 1977 and used as a research aircraft. To NASA Dryden Flight Research Center as N818NA, Edwards, CA in 1997. Sold in 2015 and remained on the register.

Ex 69-18010. Operated in Vietnam from 1970 to 1972. To N818NA in 1977. NASA used the quiet aircraft to record noise emissions by helicopters in flight. Offered for sale in 2014. To Vietnam Helicopters Museum, Concord, California. Note the wooden propeller. Photo by: Tony Landis / NASA

The aircraft had reportedly been temporarily assigned to the US Customs Service at the time of the photo. Photo by Tim White.

At last report this YO-3A was in storage at the Vietnam Helicopter Museum in Concord, CA. Originally built for the US Army with s/n 69-18010.

On display at the Museum of Flight. This twin-seat Quiet Star was designed to operate as an observation aircraft to spot night-time activity. It was equipped with a night vision and infrared downward-facing periscope that was operated by the observer in the front seat. The Quiet Star was nearly silent, and this aircraft, one of only 11 built served in Vietnam from 1970-72.

Based on the Schweizer SGS 2-32 glider, the Lockheed QT-2 and YO-3 were designed for silent nocturnal observation missions. Eleven YO-3As were built. Although nine were deployed to Vietnam with some reported success in 1970, no further production followed.

Lockheed developed the "Quiet Star" ultra quiet observation aircraft for the US Army to track night troop and supply movements in Vietnam. 69-18005 was deployed there from 1970-72. Sold to the Special School District of St Louis County, Missouri in 1973, it was acquired by Harold and Vic Hanson of Seattle and rebuilt to flying status, registered N33YQ as a Lockheed-Hansen YO-3A with the FAA. The fairly unique aircraft was sold again in 1987, fully restored and donated to the Museum of Flight in 2014.