CAC Boomerang

Background

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). After Tugan Aircraft Ltd was taken over that company's Chief Designer, Wg/Cdr Lawrence Wackett, became the General manager. Initially overseas designs were licensed, and then indigenous designs were developed. So in 1936 an Air Board Technical Commission visited the United States and negotiated a license to build the NA-16 for Australian use. The NA-16 was the first product of the North American Aviation Inc which had its initial flight on April 1, 1935. Trialed by the USAAC, the aircraft was put into production as the NA-19 (better known as the BT-9 Yale) and subsequently developed through a number of variants. This was followed by the BC-1 series of armed trainers (BC because there was budgeted money available for combat aircraft, but not trainers), also known as the Yale. In 1937 a single BC-1 type aircraft was constructed under the designation NA-33 and delivered to Australia.

In the hands of CAC, the NA-33 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. (North American went on to develop the Yale into the all metal Harvard which by the NA-88 or Harvard III was a very different aircraft). The last of 755 Wirraway was delivered in 1946.

At the end of 1941 as war broke out against Japan Australia was finding it difficult to obtain war material from Britain. 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 Japanese attacks on December 7 1941 Fred David, the Chief Designer at CAC had started conceptual work on an interceptor utilising Wirraway components to speed production. Detailed design began on December 21, 1941 under the supervision of Alan Bolton. Based on the design work, a RAAF order was made on February 2, 1942 for 105 fighters and specifying trials in three months. The first aircraft, serialled A46-1 by the RAAF was test flown by Ken Frewin on May 29, 1942, 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. (Although admittedly a pair of replica Boomerang wings have been trialed with success on a Harvard). 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 aircraft was delivered on July 15, 1942 and the first enemy engagement was by 84 Squadron on May 16, 1943 - less than 18 months after work on the aircraft began.

Boomerang development is designated under four basic models:

CA-12 Boomerang Mk.I designates the initial batch of 105 aircraft ordered. These were serialled A46-1 through A46-105 by the RAAF.

CA-13 Boomerang Mk.II designates a second batch of 95 ordered in 1943, and serialled A46-106 through A46-200 by the RAAF. This model featured various improvements devised through experience with the CA-12. Noticeable changes included the 'porcupine' flame damping exhaust (from A46-125) and wooden rather than aluminium wingtips.

CA-14 was the designation given to a single example built as a higher performance prototype incorporating a turbo-supercharger to improve performance at altitude. As noted below, this did not go into production. The aircraft was subsequently modified to streamline the airframe and the tail structure rebuilt giving squarer lines. CA-12 A46-103 was also utilised as a testbed in the CA-14 development. Following these changes, the CA-14 aircraft was then redesignated the CA-14A. The aircraft was serialled A46-1001

CA-19 Boomerang Mk.II designates the final 49 built, and serialled A46-201 through A46-249 by the RAAF. This model is essentially the same as the CA-13 but again featured slight improvements on the earlier model. From A46-211 on the standard fit featured an F24 camera mounted vertically in the rear fuselage.

One aircraft was reportedly modified by 1 APU as a two seater. The second seat inside the fuselage allowed an observer to be carried to record information during evaluation flights. As can be seen above, production amounted to 250 aircraft, with the last delivery being on February 1, 1945

The Boomerang was a product of its time and was not produced entirely in isolation. As noted above, the Wirraway was a parallel development of the Yale family which was used as a basis for the Boomerang. It is interesting to note that the Yale eventually resulted in the AT-6 Texan, and that family also spawned an export fighter with similar lines to the Boomerang. The NA-50 was a single seat fighter developed for Peru, which first flew on August 1, 1938. Seven were built and delivered by May 1939, and this was followed by the NA-64 of which six were produced for Siam (now Thailand). In transit by sea for delivery when Pearl Harbour was attacked, these aircraft were impressed for service by the US as the P-64. However all armament was removed and they were used as advanced trainers. A further aircraft designated the NA-73 was produced for the RAF who did not proceed with a production order.

Initial testing of the Boomerang was carried out by No.1 APU, and the aircraft entered service with No.2 OTU in October. The two months of testing had shown the design was basically sound, and 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 addition of turbo-supercharging was considered to address this, but as other aircraft (in particular the Spitfire VIII) became available work did not proceed. The aircraft was not considered to be a first-line combat prospect, but more suitable for advanced training and home defence. Two Squadrons (83 and 85) were in fact equipped for this purpose. With no other options available 84 Squadron did use the aircraft in Papua New Guinea in its designed role as an interceptor for an eight month period. Given the aircraft's limitations, CAC commenced work on a new fighter design, the CA-15. The Boomerang aircraft were the moved to other tasks. From mid-1943 the Boomerang replaced the Wirraway in the 'general purpose' role.

Like many aircraft initially considered less than successful, the Boomerang found its niche in another roles - particularly army cooperation and ground attack. The sparkling low level performance of the Boomerang combined with a tough structure was ideal for this alternate role. 4 and 5 Squadrons operated the Boomerang in Papua New Guinea and the Solomon Islands. In the tactical role, as well as strafing (armament being four .303 machine guns and two 20mm cannon) 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 four 9kg (20lb) smoke bombs carried under the centre section to mark targets for RNZAF Corsair fighter-bombers. The aircraft could also carry up to a 227kg (500lb) bomb on the centreline. Other operations, like convoy patrol were common. A number of aircraft were written off in training and many operational losses were in crashes and landing incidents. The latter reflect the nature of the airstrips being used. The aircraft were often stripped of parts and subsequently dumped. One (A46-88) was shot down by US ground fire, and another (A46-136) was damaged in an attack by a P-38 flown by Lt G.R. Johnson. One aircraft from 5 Squadron RAAF (A46-189) was lost when it crashed on the target while marking it during an operation with 24 Squadron RNZAF Corsairs .

As an interim aircraft the Boomerang was phased out of service rapidly following the end of the war, most gone by 1946. The Wirraway was to serve much longer, having been put back into production until 1946, (as noted above) and used as a trainer. Many Boomerangs were stored, but most were eventually sold for scrap by the early 1950's. A single example (A46-30) remained essentially intact having been used as a stand in for Lockheed Altair VH-USB 'Lady Southern Cross' in the movie 'Smithy'. The aircraft which had spent its entire service with squadrons within Australia was donated to the Australian Air League in 1946, and it was displayed in Sydney until 1964. By then its condition had deteriorated and it was relocated to RAAF Williamtown where it was restored by 481 MU and displayed as a gate guard. In 1977 it was again refurbished and then displayed at the Australian War Memorial Museum until 1994. It is now at the RAAF Museum at Point Cook.

Although A46-30 was for many years the sole example of the type, the Boomerang has made a comeback in the past 20 years. A number of restoration projects has seen the number of almost complete examples expand rapidly in the past few years, with many more as long term projects. Currently the only airworthy example is A46-206 VH-BOM (more on this below), but three more examples are progressing toward airworthiness in Australia: A46-117 registered as VH-ZOC by Alan Arthur of Mathoura, NSW in February 2001, A46-122 registered as VH-MHR by Matt Denning of McDowell, QLD in November 2001, and A46-54 which Greg Batts of Brisbane has in hand (registration VH-MHB reserved). Another example, A46-165 is under restoration to airworthiness by Kermit Weeks in Florida. Other museum exhibits, projects, and partial survivors include A46-3 (South Australia Aviation Museum), A46-25 (Moorabbin Air Museum), A46-47 (Darwin Aviation Museum), A46-55 (R. Lee), A46-67 (C. Jamesson), A46-77 (G. Batts), A46-92 (R. Provan), A46-101 (D. Baxter), A46-124 (Darwin Aviation Museum), A46-142 (D. Brown), A46-144 (L. Long), A46-166 (D.Brown), A46-174 (K. Weeks), A46-249 (R. Hourigan). For a complete list of CAC Boomerang aircraft and known details see the ADF Serials listing.

Apart from combat operations with the RNZAF in the Solomon Islands, New Zealand's connections with this distinctly Australian type have been limited. However a number of aircraft, or more accurately five part aircraft have reached New Zealand shores. The aircraft were part of the collection gathered by Charles Darby and N.M. 'Monty' Armstrong in Papua New Guinea while working with David Tallichet in the early 1970s. The aircraft were all 4 Squadron aircraft that had been written off in wartime crashes:

CA-13 A46-115 (c/n 938) was delivered to the RAAF in August 1943. Reportedly crashed on landing at Cape Gloucester on June 12, 1944

CA-13 A46-117 (c/n 940) was delivered to the RAAF in August 1943. Served with 4 Squadron coded QE-F. The aircraft was involved in several incidents including being being holed by shrapnel and a refueling fire. It was written off after a crash on landing at Nadzab on August 9, 1944.

CA-13 A46-174 (c/n 997) was delivered to the RAAF in January 1944. Reported to have been severely damaged in a crash on landing at Cape Gloucester on May 18, 1944 which damaged the wing leading edges and fuselage, and severely damaged the top engine cowl, and tail surfaces.

CA-19 A46-205 (c/n 1028) was delivered to the RAAF in June 1944. The aircraft was written off in a landing accident at Wau on August 27, 1944 when it overshot and hit a truck.

The remains were all located at Nadzab, a large collection of aerodromes about 30km inland from Lae in the Markham river valley. Presumably a Repair and Salvage Unit (RSU) team had a hand in the aircraft disposition as Nadzab is in the order of 250km from Cape Gloucester (at the western end of New Britain Island). The aircraft had already been partially stripped (as was typical of war wrecks on airstrips). Nearly 30 years in a tropical environment had also taken its toll. A46-115 and A46-205 had some fuselage structure plus cockpit fittings and some panelling. These two were fuselages only. A46-174 was the most intact and had a centre section but was mising wings, tail surfaces, landing gear, instruments, and armament. Only components were recovered from A46-117 and the crash damaged tubular steel structure was abandoned along with another unidentified Boomerang cockpit section from which some items were recovered.

The remains of A46-174 were held by Charles Darby in Auckland for some time with the intention of restoration. They were eventually passed to Kermit Weeks for inclusion in his restoration of A46-165. Mr Weeks had acquired the restored fuselage structure of A46-165 in 1987. The aircraft project is now approaching completion in the United States. Some parts (like the hydraulics access door) have also gone to Matt Denning and have been incorporated into his restoration of A46-122. The other aircraft remains were held by N.M. 'Monty' Armstrong. I have no details on their ownership changes, but some components formed the basis of the restoration of A46-117 which was mentioned above. To the best of my knowledge the fuselage structure of this aircraft was not recovered from PNG.

One further, and complete Boomerang has visited New Zealand. This is CA-19 A46-206 (c/n 1029) VH-BOM which was imported temporarily to appear at the 2001 Classic Fighters Air Show at Omaka. The remains of the aircraft were acquired by Guido and Lynette Zuccoli in 1989, who then had the aircraft restored by Sanders Aircraft Technologies at Chino. A civil engineer and native of Morbegno Italy, Guido had emigrated to Australia in 1961 and set up his own engineering business (Steelcon). Having become enamoured with flying in the late 60's he later caught the warbird bug and set up AEROTEC in Darwin and Toowoomba. A46-206 made its first post-restoration flight at Darwin with Guido at the controls on October 3, 1992. Subsequently the wings used in the initial restoration (based on T-6 structures but heavily modified) were replaced with examples built in Australia to the original design and containing a number of original components. The modified aircraft flew on December 29, 1993. During WWII the aircraft had served with 83 Squadron RAAF coded MH-Y. 83 Squadron initially provided home defence for Brisbane before moving to Milingimbi and Gove in the Northern Territory. The restored aircraft was also repainted to an early period two-tone scheme wearing its original codes, and modern nose art as 'Milingimbi Ghost'. The aircraft has subsequently had the scheme modified to a later period with the removal of the red from the roundels and the tail surfaces painted white (illustrated below). Unfortunately Guido was killed in a flying accident on March 6, 1997. His wife Lynette has maintained the couple's collection (including a Fiat G-59 and a Hawker Sea Fury) at Toowoomba, and it was through her kind permission that the aircraft was brought to New Zealand. A46-206 was transported to Port Nelson aboard the Roll-on Roll off carrier Rotoma on its own undercarriage but with the wings removed. The vessel arrived on March 28, 2001 and the aircraft was unloaded the next day, before being towed to Nelson airport on the 30th. After reassembly the aircraft was test flown on April 7th, and then proceeded to Omaka on April 12th, with the airshow being held over the weekend of the 14th-15th. After the show the aircraft was promptly disassembled and freighted back to Australia within a week. It is interesting to note that Chief Pilot Wayne Milburn is originally from Nelson, New Zealand. He has also converted AFC pilot Rex Dovey on the type - they must be among the very few New Zealanders to have flown the Boomerang.

Thanks to Charles Darby, Matt Denning, Darren Crick, Gordon Clarke, and the other correspondents who have helped with details for this page! Special thanks to Lynette Zuccoli for bringing the aircraft to New Zealand, and whose kind permission allowed me to get the cockpit pictures.

Last Update:- 19 June, 2002







Technical Data

Accommodation : 1

: 1 Dimensions Span : 10.97m (36'0ft) Length : 7.77m (25'6ft) Height : 2.92m (9'7ft)

Weight empty : 2,437kg (5,373lb) max : 3,742kg (8,249lb)

Power Plant : 1,200hp P&W R-1830-S3C4G

: 1,200hp P&W R-1830-S3C4G Performance :

: max speed : 491km/h (305mph)

: 491km/h (305mph)

max climb : 2,940ft/min (896m/min)

: 2,940ft/min (896m/min)

ceiling : 29,000ft (8,845m)

: 29,000ft (8,845m)

range : 1,490km (930miles)





Images





Close Up

Remember to let me know if you have a request for an image of a particular part of the aircraft. But as this type is not resident in New Zealand requests may take some time to process.







© 2002 Phillip Treweek, all rights reserved