When Japan entered World War II in December 1941, the RAAF did not possess a single fighter aircraft for home defence and, consequently, a decision was hurriedly made to produce a local fighter as a stop-gap measure to meet the threatened Japanese onslaught.
Fortunately, the Commonwealth Aircraft Corporation already had plans in hand for an interceptor aircraft, and this promising design was ordered into production on 2 February 1942.
Thus, Australia’s first single-seat fighter came from an organization headed by Lawrence Wackett, who was also responsible for the country’s first indigenous fighter, the two-seat Wackett Warrigal Mk II of 1930.
Named the Boomerang, the new fighter was designed as an interceptor with a high rate of climb and good manoeuvrability.
To obtain the best performance, the aircraft was fitted with the most powerful engine in Australia – the 1,200 hp Twin Wasp – which was in production for the DAP Bristol Beaufort.
Incorporating many Wirraway components accelerated airframe construction, and production proceeded so well that the first aircraft progressed from drawing board to test flight in less than four months.
Test pilot Ken Frewin flew A46-1 on 29 May 1942, and subsequent tests revealed that the Boomerang had a lively performance, good handling qualities, and was an effective gun-platform for its cannons and machine-guns.
As production progressed, many improvements and modifications were incorporated, and the various standard versions were grouped under three CAC designations: CA-12, CA-13 and CA-19.
In addition, a high performance prototype, the CA-14 was built with a turbo-supercharger.
This same aircraft was later streamlined and fitted with a square-cut tail assembly and became the CA-14A.
Altogether, 250 Boomerangs were built and the various versions included 105 CA-12s, (A46-1/105), 95 CA-13s (A46-106/200), 49 CA-19s (A46-201/249), whilst the sole CA-14/CA-14A was numbered in the prototype range as A46-1001.
The RAAF accepted the first Boomerang, A46-1, on 15 July 1942, and the last aircraft, A46-249, was delivered on 1 February 1945.
Initial pilot conversion was carried out with No 2 Operational Training Unit at Mildura, and these pilots formed the first operational units, Nos 83, 84 and 85 Squadrons.
The first enemy contact was made on 16 May 1943, when Boomerangs from No 84 Squadron intercepted and drove off three Betty bombers.
For many months, the Boomerangs successfully carried out many similar sorties until replaced by Kittyhawks and Spitfires.
Relegated to the army co-operation role with Nos 4 and 5 Squadron, the Boomerangs soon established a strong reputation for effective strikes throughout New Guinea, the Solomon Islands, and Borneo; particularly so in co-ordinated operations with RNZAF Corsairs.
The operational effectiveness of the Boomerang was due largely to the extensive evaluation program carried out by No 1 Aircraft Performance Unit under Squadron Leader J.H. Harper.
In particular, test flying on the supercharged CA-14A, A46-1001, developed this version into an effective high altitude interceptor.
Also, it is interesting to record that a Boomerang at No 1 Aircraft Performance Unit was modified to take two seats, the second position was placed inside the fuselage behind the pilot and was used by an observer to record instrument and performance data.
Length: 25 ft 6 in (7.77 m)
Wingspan: 36 ft 0 in (10.97 m)
Height: 9 ft 7 in (2.92 m)
Wing area: 225 sq ft (20.9 m2)
Empty weight: 5,373 lb (2,437 kg)
Gross weight: 7,699 lb (3,492 kg)
Powerplant: 1 × Pratt & Whitney R-1830 Twin Wasp 14-cylinder air-cooled radial piston engine, 1,200 hp (890 kW)
Propellers: 3-bladed constant-speed propeller.
Maximum speed: 305 mph (491 km/h, 265 kn) at 15,500 ft (4,724 m)
Range: 930 mi (1,500 km, 810 nmi)
Service ceiling: 29,000 ft (8,800 m)
Rate of climb: 2,940 ft/min (14.9 m/s)
Wing loading: 34.2 lb/sq ft (167 kg/m2)
2× 20 mm (0.787 in) Hispano or CAC cannons
4× 0.303 in (7.7 mm) Browning machine guns
Bombs: provision for a bomb, when the large ventral drop tank was not carried.
Aircraft and Markings of the R.A.A.F. 1939-45 vol 1-Geoffrey Pentland
Aircraft and Markings of the R.A.A.F. 1939-45 vol 2-Geoffrey Pentland
RAAF Museum, Point Cook, Victoria, Australia
Wirraway and Boomerang Markings- Geoffrey Pentland