The JB-4, developed under project MX-607, was a basically a GB-4 guided glide bomb fitted with a Ford PJ31 pulsejet engine (the same type as used in the JB-2/LTV-N-2) to extend the standoff range to 120 km (75 miles). <br />Like the GB-4, it was equipped with an AN/AXT-2 TV transmitter, sending its TV camera image to an operator in the launching aircraft, who could send radio commands to change the course of the missile. <br />The JB-4 is reported as a surface-to-surface missile in some official records, so it seems that is was also intended for ground launch. <br />The missile was tested in 1945, but the program was cancelled at the end of World War II.
