QT-1 Quiet Thruster Proposed single-seat powered glider based on the Schweizer SGS 2-32, not built.[5] QT-2 Two modified Schweizer X-26 two-seat sailplanes for evaluation, later modified with sensor packages as the QT-2PC.[5] QT-2PC PRIZE CREW Two QT-2s with combat sensor packages for evaluation in Vietnam theatre, one reduced to spares and the other returned to the United States Navy as the Schweizer X-26B.[5] Q-Star Modified Schweizer SGS 2-32 for engine/propeller development.[5] YO-3A Production aircraft for the United States Army, 11 built