LR-8 Jet Engine that surpassed the speed of sound

XLR-8 Rocket Engine

The XLR-8 rocket engine which was used to power the Navy D-558 Skyrocket to a speed of Mach 2.5, the first to do so. A variation of this engine, the XLR-11, was used to power the Bell X-1 and Chuck Yeager through the sound barrier for the first time in 1947 and was also used in the early flights of the X-15.