CAC Wirraway
The CAC Wirraway is a training and general purpose military aircraft manufactured in Australia by the Commonwealth Aircraft Corporation between 1939 and 1946. It was an Australian development of the North American NA-16 training aircraft. The Wirraway has been credited as being the foundation of Australian aircraft manufacturing.
When the name was announced on 6 April 1938, it was said to be "an Aboriginal word meaning challenge". The word presumably comes from Daniel Bunce's compilation Language of the Aborigines of the colony of Victoria, where Wirraway is glossed 'challenge; dare, to defy; incite, to stir up; menace, to threaten'.
During the Second World War, the Royal Australian Air Force deployed a number of Wirraways into combat roles, where they served in a light bomber/ground attack capacity, striking against the advancing forces of the Empire of Japan. While the type had been primarily used as a general purpose aircraft, being present in small quantities within the majority of front-line squadrons for these purposes, the aircraft was often pressed into combat when required. Typically, fighter versions of the Wirraway were operated over theatres such as New Guinea to perform ground attack missions and other Army co-operation tasks over extended periods until more advanced aircraft had become available in sufficient quantities. On 12 December 1942, the Wirraway achieved its only shoot-down of an enemy aircraft—thought to be a Mitsubishi A6M Zero at the time, but later determined to be a Nakajima Ki-43 Hayabusa—while flown by Pilot Officer John S. "Jack" Archer.
Following the end of the conflict, the Wirraway was operated for over a decade as a trainer by the RAAF, the newly formed RAN Fleet Air Arm, and the squadrons of the Citizen Air Force. During 1957, the last of the RAN's Wirraways was retired, having been replaced by the newer jet-powered de Havilland Vampire; as the CAC Winjeel came into squadron service, the RAAF phasing out its remaining fleet of Wirraways during the late 1950s. Officially, the last military flight to be performed by the type was conducted on 27 April 1959. Notably, the Wirraway had also functioned as the starting point for the design of a wartime "emergency fighter", which was also developed and manufactured by CAC, known as the Boomerang.
Development
Background
During the mid-1930s, some political leaders observed that both the Empire of Japan and Nazi Germany had the appearance of having been making strides towards a heavy preparedness for war, which in turn led to several other countries commencing their own preparations in response. However, in the case of Australia, the nation had no domestic aircraft industry, partially due to a historical preference for the procurement of both civil and military-orientated aircraft to be sourced overseas from manufacturers based in the United Kingdom, which had come about through strong political and cultural ties between the two nations. Around the same time, the Australian government decided to embark upon the development and expansion of the RAAF into a fighting force capable of defending the nation against external aggressors, in line with recommendations made by a formal evaluation compiled by Sir John Salmond in 1928. Allegedly, the move in Australia had been heavily influenced by a British decision taken in May 1935 to massively increase the front-line strength of the Royal Air Force.However, it was recognised that, while Britain had traditionally been the main source of aircraft for Australia, comprising around 50 per cent of all operational aircraft at one point, British industry was already coming under strain to meet the demands for the RAF, let alone satisfying major orders from other nations. Coincidentally, figures such as the industrialist Essington Lewis had taken an interest in the development of a domestic aircraft industry within Australia. These factors cumulated in a special conference held by the Australian government at which the first plans for syndicate-operated factories to produce both aircraft and aero engines were formulated. Accordingly, during early 1936, three Royal Australian Air Force officers, led by Wing Commander Lawrence Wackett, were sent on an overseas evaluation mission to inspect aircraft production in Europe, Britain, and the United States, as well as to support the selection of an aircraft design for local production in Australia.
In light of the industrial circumstances, the production of cutting-edge high performance fighter aircraft, such as the Supermarine Spitfire, were viewed as being too ambitious and a potential jeopardy to the whole venture. The government's position focused on the establishment of an industrial base capable of producing aircraft; thus, it was determined that the first aircraft to be domestically manufactured should be a reliable and established general purpose aircraft, while a long-term goal of proceeding to locally produce high-performance fighters would take around five years to attain. The question of what specific aircraft should be manufactured was a more complex question, as it was quickly recognised that there was no existing aircraft in RAAF service that was attractive to pursue local production of.
On 17 October 1936, with the encouragement of the Government of Australia, three companies came together to form a joint venture, registered as the Commonwealth Aircraft Corporation, which had the initial goal of assessing the viability for developing a self-sufficient aircraft industry in the nation. Early on, CAC set about planning for the establishment of both engine and aircraft manufacturing and testing facilities at Fishermans Bend, Melbourne, Victoria, purchasing tooling and equipment from manufacturers in both Britain and the United States. The newly formed company quickly decided that it would initially pursue the development and production of a single-engine armed advanced trainer aircraft, which would likely be a licence-built version of an existing aircraft. An investigation of various European and American-sourced aircraft was conducted to judge candidate designs for suitability.
Selection
The aircraft selected by CAC was the North American Aviation NA-16, upon the recommendation of Lawrence Wackett. The selection was heavily fuelled by the relatively low level of difficulty involved in the manufacture of both the airframe and its Pratt & Whitney R-1340 Wasp radial engine. The application for the NA-16 was often viewed as being suitable for the trainer aircraft role, but that it could also play some role as a fighter-bomber as well, although there were doubts voiced by senior figures over its combat suitability. The selection was not without controversy as some voices within the Australian government were keen for aircraft manufacturing and development to be kept within the Commonwealth of Nations. In 1938, an inspection by Sir Edward Ellington of the then in-development Wirraway in 1938 led to him to express his opinion that the type should only serve temporarily in combat roles, and that the choice should be delayed to await the testing of a suitable British aircraft for the mission.Nevertheless, the proposal of producing a modified variant of the NA-16, known as the Wirraway, received official approval. During 1937, CAC was informed to prepare for the production of an initial batch of 40 aircraft, if the type proved satisfactory. In late June 1938, the Australian government announced that it had placed an order for 40 Wirraways; it stated at the time that the price involved was competitive with comparative imported aircraft. Ellington's report on the aircraft's suitability was hotly contested, especially by the Australian Air Board, which had been subject to considerable criticism by Ellington; the board defended the Wirraway as being the best available aircraft in its class.
During 1937, production licences for the type were obtained from North American Aviation along with an accompanying arrangement to domestically produce the Wirraway's Wasp engine from Pratt & Whitney. Additionally, a pair of NA-16s were purchased directly from North American to act as prototypes. The first of these two aircraft was the fixed undercarriage NA-16-1A ; the second was the retractable undercarriage NA-16-2K. These two aircraft were also known by their NAA project accounting codes sometimes leading to confusion; these accounting codes were used internally by NAA to track their projects and were not the actual aircraft model numbers. During August 1937, the NA-16-1A arrived in Australia and, following its re-assembly, flew for the first time at Laverton on 3 September of that year, exactly two years before war was declared on Nazi Germany by the United Kingdom and France. During September 1937, the NA-16-2K arrived in Australia and likewise flew shortly afterwards. These aircraft were given the RAAF serials A20-1 and A20-2 within that organisation's numbering system.
Production
The NA-16-2K model was the type selected for initial production. The design featured several detail and structural changes, such as provisions for the fitting of a pair of forward-firing guns instead of the NA-16's single gun, and the strengthening of the tail and wings to better facilitate dive-bombing operations. Other modifications included the adoption of a single gun set on a swivelling mount to the rear of the cockpit, along with the installation of cameras and radio sets. On 27 March 1939, the first CA-1 Wirraway, RAAF serial A20-3, performed its maiden flight. This aircraft was subsequently retained by CAC for evaluation and trials for a number of months; on 10 July 1939, the first pair of Wirraways to be delivered to the RAAF, serials A20-4 and A20-5, were received by the service.By the outbreak of the Second World War, the RAAF had received a total of six Wirraways. Early on, it became clear that CAC's rate of manufacture of the airframes outstripped Australian capacity to produce the Wasp engines to power the type. During 1940, having observed an excess of Australian capacity, Britain issued an offer to procure any Wirraway airframes that could be produced that had not already been allocated to fulfil RAAF orders, intending to fit US-built Wasp engines to power them. This led to the placing of an initial British order for 245 aircraft, the last of which was to be delivered before the end of 1942. During October 1940, this order was expanded to cover 500 aircraft, 300 of which being scheduled for delivery during 1943. While these orders were ultimately unmet due to the implementation of the extensive American-led Lend-Lease arrangement, the British government did finance the procurement of aircraft for Australian use within the Empire Air Training Scheme.
Forty CA-1 Wirraways were constructed before the improved CA-3 variant entered production. Although there were detail changes to the design, the change in designation had more to do with the next batch of Wirraways being built to a different government contract than any real difference between the two sub-types. During February 1942, the Australian War Cabinet issued its approval for the production of 105 Wirraway interceptors as "reinsurance against inability to obtain fighter aircraft from overseas". Around this time, the War Cabinet also decided to reject an order for 245 Wirraways that had been received from Britain. In July 1940, at which point the United Kingdom was the sole European nation fighting against German in the war, the Australian Government issued a statement advising that "from this date onward Australia can rely on England for no further supplies of any aircraft materials or equipment of any kind.
The CA-5, CA-7, CA-8 and CA-9 models were all broadly similar to the CA-3; only the CA-16 variant featured substantial design changes; amongst other purposes, several wing modifications had been made to allow for the carriage of a heavier bomb load, along with the addition of dive brakes for dive-bombing. Sets of 'dive bomber' wings were built under the designation of CA-10A, and retrofitted to CA-3s, −5s, −7s and −9s; 113 Wirraways were converted. Production of the type continued even after the end of the Second World War. In July 1946, CA-16 A20-757, the last aircraft to be built of a total of 755 Wirraways, was delivered to the RAAF.