Khalid MBT (Jordan) In 1974 Iran ordered an upgraded version of the Chieftain MBT. The order was cancelled after the 1979 revolution and none were delivered. However, Jordan ordered 274 of the new tanks, with delivery starting in 1981. The Khalid, or "sword" is a late model Chieftain with an improved power-plant and fire control system. The tank became the basis for the Challenger I.