In 2008, the Rocket Racing League announced that Armadillo Aerospace engines would be used in a second generation of X-Racer aircraft [REF].
, the Rocket Racing League was utilizing a highly modified Velocity XL FG airframe and an Armadillo Aerospace 2,500 pound thrust liquid oxygen (LOX) and ethanol rocket engine in both the Mark-II X-Racer and Mark-III X-Racer demonstration vehicles [REF].