The CAC Boomerang, an indigenous fighter aircraft, was meticulously crafted and produced in Australia by the Commonwealth Aircraft Corporation during the period of 1942 to 1945.
Its production was swiftly authorised in response to the Empire of Japan’s involvement in the Second World War, as the Royal Australian Air Force (RAAF) urgently required fighter planes.
Remarkably, the Boomerang holds the distinction of being Australia’s inaugural combat aircraft, designed and built entirely within the country.
Various versions of the Boomerang were produced under different production contract numbers CA-12, CA-13, CA-14, and CA-19.
Each subsequent contract introduced modifications aimed at enhancing the aircraft’s performance.
The Boomerang faced limitations due to the engine variant available, resulting in lower power at higher altitudes and slower speeds compared to contemporary fighter aircraft.
It saw limited engagement in aerial combat, being primarily deployed to home-based squadrons during early wartime operations to free up other fighters for overseas use.
In later service, the Boomerang was commonly utilised for ground support missions, working alongside Allied army units, and also performing secondary roles such as aerial reconnaissance and air-sea rescue.
The Boomerang, a compact single-engine monoplane fighter aircraft, was specifically designed to prioritise exceptional manoeuvrability.
Its distinctive appearance was a result of combining the structure of the smaller Wirraway with a significantly larger 1,200 horsepower (890 kW) Pratt & Whitney R-1830 Twin Wasp radial engine.
This powerful engine drove a three-bladed Hamilton Standard Hydromatic propeller, which was licensed-built by de Havilland.
The engine was neatly enclosed by a close-fitting cowling, featuring two fixed air scoops on the upper and lower sides.
The upper scoop served as an intake for the carburettor, while the lower scoop provided cooling for the oil.
Fuel distribution was achieved through a combination of a self-sealing 70-imperial-gallon (320-litre) tank housed within the fuselage and a pair of 45 imperial gallon (200 L) tanks located in the centre section of the wing.
Despite the initial plan to utilise numerous Wirraway components, the final design of the Boomerang significantly deviated from its source.
The alterations included the adoption of shorter wings and a shorter fuselage, which was constructed with wood sheathing and an aluminium frame.
These modifications were implemented to enhance the aircraft’s strength and enable it to withstand the rigors of combat.
Additionally, an original centre section was incorporated into the design.
The Boomerang featured a low-mounted cantilever wing, which consisted of five sections: a central section, a pair of outer sections, and two detachable wing tips.
The outer sections boasted a swept-back leading edge and a straight trailing edge.
To ensure structural integrity, the wing employed a single spar and a stressed skin construction.
The ailerons were covered with fabric, while the aircraft also incorporated aluminum trim tabs and split trailing edge flaps.
In terms of landing gear, the main undercarriage was hydraulically retractable and stowed into wheel wells located forward of the main spar.
The Boomerang aircraft featured a novel single seat cockpit positioned directly above the wing’s center.
This cockpit was equipped with a sliding canopy, boasting a 1.5-inch (38 mm) bulletproof glass and armor protection.
In line with contemporary fighter planes, the Boomerang was armed with automatic cannons.
Since Australia had not previously manufactured such weapons, a pair of British-made Hispano-Suiza 20 mm cannons were utilised.
It is said that an Australian airman obtained an example of these cannons as a souvenir in the Middle East, which was then reverse engineered.
Additionally, the Boomerang was armed with four Browning .303 machine guns and had the capacity to carry up to four 20 lb smoke bombs.
All of these armaments were skilfully integrated within the wings of the aircraft.
Variants
CA-12 (Mark I)
The first single-seat fighter version, 105 built.
CA-13 (Mark II)
Improved version of the CA-12, 95 built.
CA-14
One aircraft fitted with a turbo-supercharged engine, did not enter production.
CA-14A
The CA-14 prototype was later modified to have a square tail and rudder.
CA-19
Tactical reconnaissance variant with a single vertical camera in the fuselage, 49 built.
Specifications
Crew
1
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.
Performance
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)
Armament
Guns
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.
Sources
Aircraft and Markings of the R.A.A.F. 1939-45-Geoffrey Pentland.
