The Commonwealth Aircraft Corporation (CAC) 'Boomerang' was a World War II fighter aircraft designed and manufactured in Australia between 1942 and 1945. The Boomerang is significant as the first combat aircraft designed and built in Australia. When Japan entered World War II in December 1941 Australia's situation was precarious as there was not a single modern fighter aircraft in the country. Britain was unable to meet its own needs and the U.S. was only just starting to produce fighter aircraft in quantity. Designed as an interim fighter and then produced within 3 months, based on the Wirraway trainer, it provided Australia with some fighter protection till more modern aircraft from Great Britain and the USA could be supplied.
Development
On 17th October, 1936 a syndicate was registered in Victoria as the Commonwealth Aircraft Corporation Pty., Ltd. (C.A.C.). Whilst plans were being prepared for the building of aircraft and engine factories and an engine test-house at Fisherman's Bend, Victoria, machine tools and equipment were purchased in the United Kingdom and the United States. The Commonwealth Wirraway, a version of the North American NA-33 two-seat advanced trainer was selected for production, the first aircraft built by C.A.C. being Wirraway A20-1, which flew on 27th March, 1939. Built in response to Australia's urgent need for fighter aircraft in WWII, the Boomerang utilised the design principles and construction techniques of the Wirraway advanced trainer, already in production at CAC. Such was the speed of its development that no actual prototype was produced. Named the 'Boomerang' (CA-12), 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 Australian-built Beaufort bomber. To speed production, many Wirraway aircraft components were incorporated into the design, and production proceeded so well that the first aircraft progressed from drawing board to first flight in only 14 weeks. The Boomerang was a small fighter, designed with an emphasis on manoeuvrability. It had an overall length of just 7.7 metres (25.5 ft) and an 11 m (36 ft) wingspan. Although the original intention had been to use as many Wirraway components as possible, the final design was quite different, with shorter wings, a shorter, wood-sheathed, aluminium-framed fuselage, increased strength for combat stresses and a new center section.
Back to Top
Production
When war broke out in the Pacific, the CAC examined the possibility of designing and building fighters. The main challenge was the fact that fighter aircraft had never been built in Australia. Only two military aircraft were in production at the time with the Bristol Beaufort twin-engined bomber and the CAC Wirraway, a single-engine armed trainer/ground attack aircraft, based on the North American NA-16. While the Beaufort was not a suitable basis for a single-engine fighter, its 1,200 horsepower (890 kW) Pratt & Whitney R-1830 Twin Wasp engines were made under license at the CAC plant in Lidcombe, Sydney and also powered the Grumman F4F fighters used by the United States Navy. Consequently, the Twin Wasp was a logical choice for a stop-gap fighter design. Fred David was the head of design, and it was Alan Bolton that drew up the early design sketches under Fred's orders. It then became a project headed under Bill Aire. Fred David had worked in Germany with Heinkel and then in Japan with Mitsubishi and Aichi in so he had an intimate knowledge of new aircraft technology, though he was mistrusted by many as an enemy alien. On 21 December 1941, detailed design began, and just over 22 weeks later on 29 May 1942 the first aircraft had test flown. Like the latest fighters at the time, planning for the Boomerang included automatic cannons. As no such weapons were manufactured locally, a British-made Hispano-Suiza 20 mm which an Australian airman had collected as a souvenir in the Middle East was reverse engineered.
Back to Top
While the CA-12 was effective at low level, its performance fell away rapidly above altitudes of 15,000 ft (4,600 m), and its maximum speed of 265 knots (490 km/h) was not sufficient to make it an effective counter to Japanese fighters like the A6M and the Imperial Japanese Army Air Service(IJAAS) Nakajima Ki-43. Similarly, the best European fighters were reaching almost 350 knots (650 km/h), and even relatively sluggish fighters like the F4F Wildcat and the P-40 (which would become the main fighter used by the Royal Australian Air Force(RAAF) during the war) were much faster than the Boomerang. Production of the initial series continued until June of the same year, and the Boomerang Mk I was followed by 95 aircraft belonging to the Mk II series, which were slightly modified and designated CA-13. The final series included 49 CA-19 Boomerang Mk IIs, with further improvements, and the last of these was delivered in February 1945.
Back to Top
In Service
On the 10th October 1942, No. 2 Operational Training Unit at Mildura, Victoria, received its first CA-12 and immediately began training Boomerang pilots. Most of these pilots had no previous operational experience and although they had received their training on Wirraway aircraft many ran into troubles when first being acquainted with the Boomerang. But overall, the Boomerang was considered a successful aircraft, except for engine overheating which necessitated flying the aircraft with gills partly open with a resultant reduction in speed. In early 1943, many in Australia, including the Commonwealth Government, feared that the Japanese would attempt an invasion. No. 84 Squadron(RAAF), at Richmond, New South Wales, received its first aircraft on 2nd March, 1943 and was declared operational on 4th April. Within ten days the squadron was ordered to proceed to Horn Island where it was to provide patrols of Boomerang aircraft over Merauke, New Guinea. Standing air patrols continued uneventfully during the summer and in October 1943 No. 84 Squadron was re-equipped with Kittyhawks. No. 85 Squadron, (RAAF), was the second unit to receive Boomerangs and was declared operational at Guildford, Western Australia, on 9th May 1943, until it was disbanded in January, 1945. This squadron provided air defence to submarine bases in Western Australia.
Back to Top
New Guinea
When higher performance American and British aircraft became available to equip RAAF fighter squadrons, the Boomerangs were assigned to Nos. 4 and 5 Army Cooperation Squadrons(RAAF), operating in Papua New Guinea and the Solomon Islands, as its higher speed and heavier armament gave the Boomerang a better chance to survive than the Wirraway. No. 4 Army Cooperation Squadron received its first Boomerangs on 15th June 1943 and took them into action during the assault on Nassau Bay, near Salamaua in New Guinea, on 1st July. The Boomerang found its niche in these roles, particularly army cooperation and ground attack. The excellent low level performance of the Boomerang combined with a tough structure was ideal for this alternate role. In the tactical role, as well as strafing where the aircraft were also used for artillery spotting and close support, and 'FAC' type work marking targets. It is in this later role that the type became well known to some New Zealand pilots. The 'Smokey Joes' used up to four 9kg (20lb) smoke bombs carried under the centre section to mark targets for (R.N.Z.A.F.) F4U Corsair fighter-bombers. The aircraft could also carry up to a 227kg (500lb) bomb on the centreline.
Back to Top
Final Operations
The Boomerang had the range to go wherever it was needed when it was based close to ground operations; had heavy armament; was agile and easy to fly, meaning that pilots could get close to ground targets, avoid ground fire and rough terrain; and featured extensive armour plating along with a wood and aluminium airframe that could withstand significant battle damage. While RAAF records show that the Boomerang was never recorded as having destroyed any enemy aircraft, the type proved to be more useful in its capacity as a light ground attack aircraft used by Army co-operation squadrons, often replacing the lightly armed Wirraway in this role. On 14 August 1945, the wartime role of the Boomerang came to an end when the suspension of all offensive operations against land targets, except for direct support of Allied ground forces in contact with the enemy, was issued.
Back to Top
Swordfish
Gladiator
Hurricane
Typhoon
Tempest
Spitfire
Mosquito
Beaufighter
Blenheim
Wellington
Halifax
Lancaster
Stirling
Sunderland
Boomerang
CA-12 'Boomerang'
