Two Schweizer 2-32s, 67-15345 and 67-15346, from the U.S. Naval Test Pilot School X-26 Program, were modified to QT-2 configuration (QT for Quiet Thruster) by the Lockheed Missiles & Space Company and civil registered as N2471W and N2472W. In 1967 the aircraft were modified by adding a
Continental O-200 engine, V-Belt RPM reduction system, four-bladed Fahlin fixed pitch wooden propeller, and associated airframe upgrades. After demonstrating quiet flight, the aircraft were again modified to military QT-2PC configuration, known only as Tail Numbers "1" and "2", with
avionics and
camouflage for night operation. They were successfully evaluated in
Southeast Asia under the Prize Crew OpEval program for covert (
"stealthy") tactical airborne observation in the spring of 1968 (during
Têt). The two QT-2PCs were returned to the Test Pilot School in 1969 and re-designated X-26Bs. The #1 QT-2PC was re-designated "67-15345" and the #2 aircraft was used for spare parts. The original X-26 glider version was then designated X-26A. Lockheed continued the covert airborne surveillance program with one Q-Star (House Test Aircraft) and eleven pre-production
YO-3As. ==Surviving aircraft==