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.

Design and development


At the beginning of 1942, as it faced the prospect of numerous Japanese air raids, the Australian War Cabinet found it impossible to obtain sufficient numbers of operational, up-to-date fighter aircraft, in any form. At CAC, a light-weight “emergency fighter”, which could be built quickly from scratch in Australia, was designed and a prototype built. As the CAC CA-13 Boomerang, it first flew in May 1942, and was rushed into full production.

It was acknowledged from the outset that the CA-13 was compromised by the only, low-powered engines then being manufactured in Australia. While Curtiss P-40 Kittyhawks were slowly becoming available to the RAAF, CAC became actively involved in three parallel solutions: upgrading the Boomerang when better engines became available (as the CA-14 and CA-19); local assembly, from components made elsewhere, of an already-proven fighter, and; development of an all-new replacement, with a full-sized airframe that was capable of mounting the largest class of aircraft engines then available (a project that later resulted in the CAC CA-15).

Local assembly of the P-51D (CA-17; Mk 20)

Plans to assemble a proven fighter locally began to bear fruit in December 1942, the War Cabinet began to make arrangements with North American Aviation (NAA) for CAC to assemble the P-51 Mustang. These arrangements were finalized in November 1943, with CAC scheduled to build 690 P-51Ds, from kits made in the United States by NAA. (As it awaited arrival of the kits, CAC privately continued work on the CA-15, as a possible back-up or even replacement for, the Mustang. However, the US-built radial engines intended for the CA-15 became unavailable, also hampering that project.)

Only 100 unassembled P-51s were ever delivered, and four reportedly had the “razorback” style canopy of the P-51B/C variant. In either late 1944 or early 1945, assembly of 80 of the P-51D kits commenced, under the designation CA-17 Mustang Mk 20 with Packard V-1710-3 Merlin engines, with the remainder being used for spare parts. The end of the war led to cancellation of the remainder of the kits ordered from NAA.

Local manufacturing of the CA-18 Mustang (Mk 21–23)

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.

  • The first 40 were 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.
  • A total of 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, as well as 250 two-seat variants, designated CA-21, were canceled in favor of further, US-built P-51D and P-51K variants.

Operational history

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.

CAC Mustang A68-1

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.


CA-17 Mustang Mk 20
Aircraft built from kits supplied by NAA with V-1710-3 engines. 80 built.
CA-18 Mustang Mk 21
Locally-built aircraft with V-1710-7 engines. 40 built.
CA-18 Mustang Mk 22
Reconnaissance variant with F24 cameras. 14 newly built aircraft and 14 converted from Mk 21s.
CA-18 Mustang Mk 23
Variant with British Merlin 66 or 70 engines. 66 built.
CA-21 Mustang Mk 24
Two-seat variant of the CA-18. 250 ordered but not built.
Dart Mustang
Civilian modification of a CA-18 Mustang with a Rolls-Royce Dart turboprop engine. 1 modified from a Mustang Mk 22 but never flown in this configuration.

Specifications (CA-18 Mustang Mk 21)

P-51D/CA-18 Mustang

General characteristics

  • Crew: 1
  • Length: 9.83 m (32 ft 3 in)
  • Wingspan: 11.28 m (27 ft 0 in)
  • Height: 3.71 m (12 ft 2 in)
  • Empty weight: 3,567 kg (7,863 lb)
  • Gross weight: 4,763 kg (10,500 lb)
  • Powerplant: 1 × Packard V-1650-7 Merlin liquid-cooled V12 engine, 1,110 kW (1,490 hp)
  • Propellers: 4-bladed


  • Maximum speed: 703 km/h (437 mph) [data from Aircraft of the Royal Australian Air Force, David Richardson & Peter Wood)
  • Range: 1,529 km (950 mi, 825 nmi); 2655km (1650 miles) with external tanks
  • Service ceiling: 12,771 m (41,900 ft)
  • Rate of climb: 17.65 m/s (3,475 ft/min)


  • Guns: 6 × 0.50 caliber (12.7mm) AN/M2 Browning machine guns
  • Hardpoints: 2 x 1,000 lb (450 kg) bombs or 10 x rockets