Lockheed’s Missile and Space Division designed the YO-3A as a nearly silent observation aircraft. The United States Army used the plane to spot nighttime enemy activity and direct artillery fire during the war in Vietnam. A downward-facing periscope equipped with night vision and infrared (heat sensing) capabilities allowed the aircraft’s forward observer to spot activity on the jungle floor, even in nearly complete darkness.

The YO-3A and it's prototype, the QT-2 represented the first use of aerial stealth technology in combat. Unlike the stealth aircraft we know today, the QT-2 and YO-3A were not designed to hide from radar, but to hide from human detection. The plane’s muffler-equipped engine drove a special slow propeller that eliminated the buzzing sound typical of propeller aircraft. This let the YO-3A operate almost unheard by people on the ground. Lockheed project manager, Stanley Hall described the aircraft’s noise as “the gentle rushing sound of the ocean surf”.

The Museum’s aircraft, 69-18005, was the sixth of just 11 aircraft constructed. It served in Vietnam from 1970–1972 before it was sold to an aviation school. The Museum acquired the aircraft in 2010 from Mr. Bruce Elliot of La Connor, WA.

The YO-3A exhibit tells the story of this highly unique aircraft and looks at the sources of airplane noise and ongoing efforts to quiet them down.