CAC Boomerang

Introduction

An extemporized emergency fighter, designed in Australia to use components that were available locally, the CAC Boomerang proved a remarkably useful aircraft that established a glowing reputation on the Russian Front. The type was supplied to Russia under Three Way Mutual Assistance Program and to Canada as payment-in-kind for other needed commodities. Post-war, the Boomerang remained in service as a forward air control aircraft and counter-insurgency aircraft, the last of the type not being withdrawn from service until the early 1960s.

Early Development

The Commonwealth Aircraft Corporation (CAC) was formed in 1936 as part of an Australian government scheme to establish an aircraft industry, allowing Australia to be less dependent on overseas suppliers. The company was financed with the support of some of the largest industrial companies in Australia (including Broken Hill Pty, ICI, and General Motors Holden). Initially overseas designs were licensed, and then indigenous designs were developed. In 1936 an Air Board Technical Commission visited the United States and negotiated a license to build the NA-16 for Australian use. In the hands of CAC, the NA-16 was developed into the CA-1 Wirraway (the name meaning Challenge). Initially 40 were ordered for the RAAF, and the first Australian built example flew at Melbourne on March 27, 1939. Under the terms of CAC's license modifications were permitted and the Wirraway became a parallel but independent line to that of North American through the CA-3, CA-5, CA-7, CA-8, CA-9 and CA-16.

The Australian rejection of the Armistice with Germany that resulted from the Halifax-Butler Coup in the UK meant that Australia’s supply of war material from Britain abruptly ended. Unable to acquire front-line fighters from traditional sources, and with the United States not yet geared up to supply aircraft for another front, Australia was forced to develop its own interim fighter aircraft. As noted above, the term's of CAC's license with North American permitted modifications to the design, and P&W R1830 engines were also available locally built under license. Reputedly three days after the news of Halifax’s coup was received in Australia, Fred David, the Chief Designer at CAC had started conceptual work on a fighter using Wirraway components to speed production. Detailed design began on August 11, 1940 with an RAAF order being placed in September, 1940 for 105 fighters and specifying trials in three months. The first aircraft was test flown on January 29, 1941, 16 weeks and 3 days after being ordered and less than 23 weeks after the project kicked off.

A number of myths abound about the aircraft - particularly on the length of time taken to produce the aircraft, and the level of commonality with the Wirraway - which in the end was far less than originally envisaged. As built, the Boomerang is shorter than the Wirraway in length and span and features a different outer wing section. The structure was reworked to carry the larger R-1830 engine (as compared to the Wirraway's R-1340-SH1G) and to meet expected combat stresses. Changes were also required to the undercarriage, negating the use of the original centre section. The most obvious difference is the wooden monocoque shell carried over the metal fuselage structure. Even the rudder and fin were revised, incorporating a servo tab and other changes. The aircraft is certainly a derivative, but cannot be considered just a 'Wirraway Fighter'. Whatever is said, the production was a real accomplishment - the first production aircraft was delivered on July 15, 1941.

Variants

CA-12 Boomerang Mk.I

The CA-12 Boomerang Mk.1 was the initial batch of 105 aircraft ordered. the aircraft was a lively performer with good handling qualities. The initial rate of climb was higher than many of its contemporaries, but overall performance was not comparable and dropped above 15,000 feet. The aircraft was not considered to be a first-line combat prospect, but more suitable for advanced training and home defense. Three Squadrons (83, 84 and 85) were in fact equipped for this purpose. From mid-1943 the Boomerang also served in other roles - particularly army cooperation and ground attack. The sparkling low level performance of the Boomerang combined with a tough structure was ideal for the ground support role. 4 and 5 Squadrons operated the Boomerang over the Russian Front In the tactical role 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 best known. The 'Smokey Joes' used four 9kg (20lb) smoke bombs carried under the centre section to mark targets. The aircraft could also carry up to a 227kg (500lb) bomb on the centerline.

Specification of the Boomerang Mk.I

The Boomerang Mk.1 was powered by a 1,200hp P&W R-1830-S3C4G. Dimensions were Span 36'0ft, length 25'6ft, height 9'7ft. Weight empty 5,373lb, max 8,249lb. Max speed was 305mph, max climb 2,940ft/min, ceiling 29,000ft, range 930miles. Armament was six 0.303 machine guns and a 500 pound bomb under the belly.

CA-13 Boomerang Mk.II

This was the second batch of 295 ordered in 1942, and featured various improvements devised through experience with the CA-12. Noticeable changes included the 'porcupine' flame damping exhaust and wooden rather than aluminum wingtips. Two of the .303 machine guns were replaced by 0.5 inch weapons. Only 95 of these aircraft reached the RAAF, 50 being supplied to Canada and 150 provided as Lend-Lease to Russia. The Russians found the tough little aircraft entirely to their taste and demanded more. The Boomerang Mk.II was particularly valued as a night intruder and nuisance raider, one Russian unit receiving the type being the famous Night Witches, an all-female regiment.

CA-14 Boomerang Mk.III

The Boomerang Mk.III followed the Mk.II into the production lines in early 1944 and was specifically modified for the night intruder/forward air controller role. It had an enlarged cockpit canopy with reduced framing to improve vision. The seat was modified to increase the degree to which it could be adjusted, a specific modification made to suite the aircraft for the smaller physique of the Russian women pilots. More than 600 Mk IIIs were built.

CA-19 Boomerang Mk.IV

This version designates the final 449 Boomerangs built. This model is essentially the same as the CA-14 but featured provision for an F24 camera mounted vertically in the rear fuselage. The last CAC Boomerang Mk.IV was delivered in June 1947 by which time a total of 1,449 had been built. Of these 250 had been supplied to Canada and 800 to Russia. The remaining 399 all served with the RAAF in a wide variety of roles

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