The big change was in the aircraft itself. In 1968, the U-2C, which had an 80-foot wingspan, was revised into the U-2R, which was significantly larger than the original U-2 design, with a 104-foot wingspan. In 1981, a structurally identical "Tactical Reconnaissance" version of the U-2R design, designated the TR-1, went into production, and 33 were built between then and 1989. In 1992, all TR-1s and U-2s were redesignated U-2Rs. In 1994, the U-2Rs were re-engined with General Electric F-118-101 engines and redesignated the U-2S.