North American P-51 Mustang CA-18 Mustang Mk 21-23

In late 1946 CAC received a further contract to build 170 P-51Ds on its own account (later reduced to 120), this time manufactured almost entirely in Australia, designated CA-18 Mustang Mark 21, 22 or 23. The Mark 21 and 22 used the American Packard V-1650-3 or V-1650-7; the Mark 23, which followed the 21s, was powered by British Rolls-Royce Merlin 66 or Merlin 70 engines. The first 26 built were Mark 21s, followed by 66 Mark 23s; the first 14 Mark 21s were converted into fighter-reconnaissance aircraft with two F24 cameras in vertical and oblique positions behind the radiator fairing, and were redesignated Mark 22. A further 14 purpose-built Mark 22s followed, powered by either Packard V-1650-7 or Merlin 68 engines, completing the production run. All CA-17s and CA-18s, plus 84 P-51Ks shipped directly from the U.S., used Australian serials prefixed A68. After the USAF cancelled the P-51H, the RAAF followed suit, stopping 250 planned CAC CA-21 (Mark 24) two-seat trainers.