F121 Engine
Williams International F121 turbofan of 70 lbs. thrust powers the AGM-136A Tacit Rainbow. Tacit Rainbow developed a jet-powered "mini" drone for finding and destroying enemy ground based radars. The Tacit Rainbow unmanned aerial vehicle (UAV) was conceived in the early 1980s using experience gained with anti-radar missiles in Vietnam. The first Tacit Rainbow air-launch occurred on July 30, 1984. More than 30 test launches were made, from both bombers and fighters. The program was cancelled for budget reasons in 1991, prior to the planned start of production in 1992.
