|CA-18 Mustang Mk 21 in 2005|
|Manufacturer||Commonwealth Aircraft Corporation|
|First flight||29 April 1945|
|Introduction||4 June 1945|
|Retired||1959 (Citizen Air Force)|
|Primary user||Royal Australian Air Force|
|Developed from||North American P-51 Mustang|
The CAC Mustang is an Australian variant of the North American P-51 Mustang. It was built under license by Commonwealth Aircraft Corporation in the final stages of World War II, and though it was too late to see combat, it did participate in the Occupation of Japan after VJ-Day.
In December 1942, the Australian War Cabinet made arrangements for the local production of the P-51D Mustang. These arrangements were finalized in November 1943, with Commonwealth Aircraft Corporation to build 690 aircraft through kits supplied by North American Aviation (NAA). Only the first 100 unassembled aircraft were delivered, and four reportedly had the "razorback" style canopy of the P-51B/C variant. 80 of the kits were assembled under the designation CA-17 Mustang Mk 20 with Packard V-1710-3 Merlin engines, the remainder being used for spare parts. The end of the war led to most of the orders being canceled.
In late 1946, CAC received a contract to build 170 (later reduced to 120) Mustangs locally from scratch. These aircraft carried the new designation CA-18, with the first 40 being designated Mustang Mk 21 and powered by Packard V-1710-7 Merlins. 66 Mustang Mk 23s followed with British-built Rolls-Royce Merlin 66 or 70 engines. 14 Mustang Mk 22 reconnaissance aircraft were built with F24 cameras, and a further 14 were converted from Mk 21s. Additional orders for the CA-18 and 250 two-seat variants to be produced as the CA-21 were canceled in favor of US-supplied P-51D/Ks.
The first production CA-17 Mustang Mk 20, serial number A68-01 (not to be confused with the US-built prototype A68-1001), made its first flight on 29 April 1945 from Fishermans Bend, Victoria. The aircraft was handed over to the RAAF on 4 June 1945 and was tested by the No. 1 Aircraft Performance Unit. Trials ended in October 1946, and the aircraft was placed in storage until 1953. Only 17 CA-17s were delivered to the RAAF by VJ-Day.
The first operational units to receive the CAC Mustang were No. 84 and No. 86 Squadron. Additional squadrons equipped with Mustangs (both American and locally-built) were No. 3, No. 4, No. 76, No. 77, and No. 82 Squadron as well as No. 21, No. 22, No. 23, No. 24, and No. 25 Squadron of the Citizen Air Force. The RAAF replaced its last Mustangs with de Havilland Vampires in 1959, while the last Mustang-equipped Citizen Air Force squadron, No. 24, retained its Mustangs until the CAF was disbanded in 1960.
Main article: List of surviving North American P-51 Mustangs
A full-scale replica of a CA-18 Mustang Mk 23 is located at the Queensland Air Museum at the Caloundra Airport. Construction of the replica began in May 2005 and was placed on static display on 27 December 2008. It carries the fictitious serial number A68-201, continuing the original sequence which ended with A68-200.
Main article: Accidents and incidents involving the North American P-51 Mustang
Data from 
Aircraft of comparable role, configuration, and era