Commonwealth Aircraft Corporation

The CAC Files: CA-1

CA-1 was the contract number allocated to the first order for Wirraway aircraft, an Australian-built version of the North American Aviation NA-16-2K advanced trainer and basic combat aircraft.

Development

Specifications

Service History

Production Summary

References

Side-view of the CA-1 Wirraway (as produced by the factory) showing it's distinguishing features including:

• Corrugated skin on the vertical stabilizer (at least the first 5 aircraft, and maybe as many as 20 also had corrugated skins on the horizontal stabilizer)
• Antenna mast in front of the windshield
• Open rear end of canopy section above the observer's seat
• Twin fixed Vickers Mark V .303 machine guns synchronized to fire through the propeller, with leather boots protecting the trigger motors
• Single Vickers Gas-Operated .303 Mark 1 No. 1 machine gun on a flexible mount in the rear cockpit
• Single air-cleaner intake under the engine cowl
• Cowl cut away next to the exhaust outlets

A total of 40 Wirraways were produced under the CA-1 contract, with CAC construction numbers 1-40 and RAAF serial numbers A20-3 to A20-43

Development

The development of the Wirraway is inseparably linked with the birth of the Commonwealth Aircraft Corporation.

During the mid-1930s several business leaders and politicians realised that Australia lacked the ability to produce modern military aircraft, and this may leave the country in a vulnerable position if war broke out and traditional supply sources were cut. Until that time, the fledgling RAAF had relied upon British companies to supply all of it's aircraft, in line with government policy of the time, and Australian companies were only capable of assembling small numbers of aircraft from parts or carrying out repairs. So in co-operation with the government, a group of business leaders (including Essington Lewis from Broken Hill Proprietary, Laurence Hartnett from General Motors Holden and William Robinson from Broken Hill Smelters) formed a syndicate in February 1936 to study whether it would be possible to develop a self-sufficient aircraft industry in Australia, based on local raw materials and industrial facilities. The announcement predictably drew the consternation of aircraft producers and politicians in Britain, the British Board of Trade expressing on February 20th that it was "strongly opposed" to the move. The involvement of an American corporation (General Motors, through it's part-ownership of General Motors Holden) also became an issue, with the British military refusing to allow British companies to divulge any technical secrets to an Australian company which was partly owned in the US.

At the same time as announcing the formation of the syndicate, the companies sent a technical committee of three experts (Wing Commander Lawrence Wackett, Wing Commander Herbert Harrison and Air Commodore Arthur Murphy) on a tour of Britain, Europe and the United States to select an aircraft design for CAC to produce. The committee met with aircraft and engine companies in England, Germany, France, The Netherlands, and Czechoslovakia, using the following guidelines as they considered designs which may be suitable for production by a new company in Australia:

• Not too complex for production by a newly-established company and suppliers with little or no aircraft manufacturing experience;
• Manufactured using techniques which can be applied to a range of other aircraft;
• Manufacturing should maximise the use of jigs and tools, so that in an emergency it could be produced by a semi-skilled labour force;
• Incorporate design characteristics which were expected to become more prevalent in future types, such as all-metal and stressed-skin construction

In fact the leadership of the syndicate fully expected that the first design selected for manufacture by the proposed company would be a general purpose or training type, rather than the latest fighter or bomber aircraft.

The technical committee left Melbourne for their tour on February 19th 1936 and returned on July 14th. On returning from their tour, Wackett reflected that in his opinion the RAF was "in the front rank" of air forces around the world^[1]. However the committee unanimously recommended the new NA-16-1A design from the recently formed North American Aviation Incorporated (NAA) in California, together with the single-row Wasp radial engine from the new Pratt & Whitney Aircraft Company in Connecticut. This selection caused further uproar in the United Kingdom, where it was expected that a British design would be selected for production by the new company. The committee were asked to re-consider their selection by the Air Board (the controlling body of the RAAF), and during October and November 1936 the British government exerted much pressure on the Australian government to reverse the decision. But following an explanation of the facts behind the decision the Air Board threw it's support behind the selection.

Further controversy followed when it was revealed that General Motors (the US parent of General Motors Holden) also held 30% of the shares of NAA. Despite the technical merits of the NA-16 design this was a clear conflict of interests and GMH offered to withdraw it's interest in CAC, but eventually remained involved with a smaller share-holding. The technical skills in light manufacturing which GMH could bring to the project were critical to it's success.

The NA-16-1A was a two-seat basic training (BT-type) aircraft design developed from the NAA NA-16 demonstrator. The NA-16 was the first aircraft designed by NAA, developed as a private venture aimed at export markets as well as the US military. The NA-16 first flew on April 1st, 1935 in an open cockpit configuration with fixed landing gear, powered by a Wright R-975 radial engine. Marketing brochures produced by NAA at the time showed a planned range of aircraft based on the NA-16 which included a 2-seat bomber (with longer wing-span), a single-seat fighter (with reduced wing-span) and options for retractable landing gear^[2]. NAA entered the NA-16 in a competition for a Basic Trainer aircraft run by the US Army Air Corps at Wright Field in May 1935, and although the NA-16 did not win the competition an order for 42 BT-9 aircraft resulted due to it's good performance and possibly the political clout of General Motors.

Earliest ancestor of the Wirraway - the North American NA-16 private venture basic training aircraft. The NA-16 demonstrator NX-2080 is shown here in it's original form with open-cockpits and powered by a Wright R-975 engine. Note how the R-975 engine was arranged with the exhaust collector ring in front of the cylinders. (San Diego Air & Space Museum archives)

The project to develop the NA-16-1A for CAC was given the NAA accounting code NA-32, so as well as it's official NAA designation of NA-16-1A it was also known by this NA-32 code. To confuse the situation further, the popular press in Australia shortened the official NA-16-1A designation and referred to the design as simply the NA-16 (even though this was actually a different aircraft). The NA-16-1A was almost identical to the NJ-1 (NA-28) advanced training aircraft ordered by the US Navy and the Y1BT-10 (NA-29) demonstrator developed for the Navy by NAA. It featured fixed landing gear, a single gun firing forward through the propeller, a rear-firing gun on a flexible mount in the observer's cockpit and the more powerful R-1340 Wasp engine from Pratt & Whitney (the engine supplier favoured by the US Navy).

During the later half of 1936 the original three syndicate members were joined by Imperial Chemical Industries A.N.Z., the Electrolytic Zinc Company of Australasia and The Orient Steam Navigation Company and the creation of a company to produce aircraft and engines was initiated. The Commonwealth Aircraft Corporation Pty. Ltd. was registered in Victoria in October 1936^[3].

In January 1937 the Lyons government defended it's action in selecting the NA-16-1A design with a statement by the Minster for Defence Archdale Parkhill justifying the selection of the NA-16-1A on the grounds of urgency and the lack of a suitable British design.

On January 7th 1937 the Air Board sent a letter to CAC advising that the government was prepared to order 40 NA-16 type aircraft, assuming that prices and terms could be agreed. The letter backed up the decision by the government:

"You are aware that is has been the policy only to use approved types of British aircraft and engines for the equipment of units of the Royal Australian Air Force and for this reason the Government has given serious consideration to your proposals which involve the introduction of foreign, in preference to British, types of aircraft and engines. Owing, however, to the abnormal position now being experienced in the British aircraft industry it is agreed that the proposals submitted by your Company offer the most satisfactory means of establishing the industry expeditiously and on a sound basis."

On the basis of this letter, CAC set about organising materials, machinery, suppliers and a workforce to commence production of the NA-16-1A.

CAC ordered one NA-16-1A aircraft for evaluation purposes. North American Aviation produced this aircraft under the accounting code NA-32. Only one NA-16-1A was produced, with the NAA serial number 32-387. This photograph shows the NA-16-1A is shown in California prior to delivery to Australia. Image copyright expired, courtesy of the San Diego Air and Space Museum archive.

Lawrence Wackett returned to the United States in March 1937 to make arrangements for licensing the NA-16 design to CAC and to purchase production equipment for the new CAC factory, which was under construction. On his arrival he discovered that since his first visit, NAA had developed several improvements to the NA-16 series (including retractable undercarriage and a more powerful engine and a range of armament options) which changed the character of the aircraft from a "basic trainer" (BT) type to a "basic combat" (BC) type. Adding these improvements to the basic design under the project accounting code NA-33, resulted in a new design that was designated NA-16-1K by NAA. Wackett left the US with license rights for CAC to manufacture either of the NA-16-1A (NA-32) advanced trainer or NA-16-2K (NA-33) basic combat designs. The license deal signed on March 10th 1937 included a fee of US$100,000 for the two designs, US$30,000 for the specifications and manufacturing data, a US$1,000 royalty for each of the first 25 aircraft produced and a US$600 royalty for each of the subsequent 75 aircraft produced.

The NA-16-1A arrived in Australia in August 1937 and made its first flight on September 3rd in the hands of Squadron Leader F.R.W. Scherger. Flight tests at Point Cook continued until September 15th.

In late September 1937 CAC submitted a proposal to the Air Board that the RAAF should purchase the NA-16-2K aircraft rather than the NA-16-1A, since it could carry out advanced training duties as well as basic combat duties with it's expanded capabilities. The Air Board asked CAC to provide one of each design so that comparative performance tests could be carried out to justify the extra cost of the NA-16-2K, which was being offered by CAC at £8,098 (compared with the NA-16-1A at £7,200).

The NA-16-2K arrived in Australia in mid-November.

CAC also ordered one NA-16-2K aircraft for evaluation purposes, produced by NAA under the accounting code NA-33 (serial number 33-388). It arrived in Australia in November 1937. This photo shows the NA-16-2K in California prior to it's delivery to Australia. The NA-16-2K featured retractable landing gear, a geared engine driving a three-bladed propeller at 66.6% of the crankshaft speed and several other improvements over the NA-32. Image copyright expired, courtesy of the San Diego Air and Space Museum archive.

On January 14th 1938 the Air Board wrote to the Defence Department to inform the Minister that trials of the two aircraft confirmed the NA-16-2K had superior performance and more desirable features. The Air Board recommended that the NA-16-2K design (stressed to a safety factor of 8.5 at an all-up weight of 5,500 lbs) should be put into production. This was agreed by the Minister of Defence, H.W. Thorby in a Ministerial Minute on January 20th:

"I approve of the Air Board's recommendation that the type of aircraft to be ordered should be the N.A. 33. There is no objection to the Company being advised accordingly, but before the order is confirmed at £8,098 each for the machines and £2,200 for the spare engines, I desire the Air Board to furnish all evidence it is able to obtain supporting the reasonableness of the prices quoted."

Following this decision, the RAAF requested the Contracts Board to place an order with CAC (the order also included 10 spare Wasp engines). The unit price for each aircraft was £8,098 and the total cost for the order was £349,920.

A copy of Contract Demand T.374 issued by the RAAF on March 15, 1938 to the Contract Board. Based on this request, the Contract Board then negotiated the actual order for the first 40 Wirraway aircraft with CAC, which would be produced under CAC's internal project code CA-1.

A detailed analysis of the prices quoted for the NA-33 aircraft was conducted, comparing them against prices for imported Hawker Demon aircraft. The results were presented in a Department of Defence Ministerial Minute on May 5th 1938:

Demon Landed cost ... £5,850 excluding duty, but including special armament, navigation and wireless equipment to the value of £281. Total ... £5,580

Wirraway Price quoted by CAC ... £8,098 Plus special equipment, navigational and wireless equipment to be issued by the Department ... £450 Total ... £8,548 Less special features included in the Wirraway but not in the Demon, vide paragraph 6 of Air Board Minute of 15/3/38 the value of which I am advised by the Air Board is in the region of  ... £1,600 Less additional equipment over and above that included in the Demon and assessed by the Air Board at ... £170 Total ... £6,778

In view of the fact that the performance and type of construction of the Wirraway are superior to the Demon, it appears that the quotation of £8,098 for the Wirraway is reasonable, particularly as it will be manufactured locally. The Air Board's recommendation is accordingly approved, and authority is given for the order of 40 aircraft , at £8,098 each, and 10 spare engines, at £2,600 each, to be placed with the Company for early delivery.

The choice of the name "Wirraway" (from the Woi Wurrung language group of the local Wurundjeri Nation, meaning "to challenge" in English) for the new aircraft was officially announced to the public by the Air Board on April 7th 1938, stories appearing in newspapers the following day.

A number of changes to the NA-16-2K design and equipment fit-out were implemented as it was put into production. These included:

• Tubes in the rear fuselage for releasing parachute flares;
• The addition of a second forward-firing machine gun in front of the pilot (earlier versions of the NA-16 family - such as the NA-18 of 1935 - already featured two forward-firing machine guns). The guns were changed from US-built Browning models to 0.303" calibre Vickers Mark V. A large magazine holding 1,200 rounds (600 for each gun) was installed just aft of the firewall below the guns, which required relocating the hydraulic fluid header tank to the port side of the fuselage beside the rear seat;
• Addition of a chute and box to catch and store shell casings (on the NA-16-2K the shell casings were ejected via a chute on the starboard side of the forward fuselage). The box was in the centre of the wing, in front of the forward spar and between the wheel wells. It was emptied after every flight if the forward guns had been fired;
• Modifications to the rear gun-mount (in the NA-16-2K the rear gun could be stored under a hatch in the rear fuselage top decking);
• Changes to the exhaust system (two outlets instead of 1);
• Modifications to the air cleaner for the oil cooler and cold carburetor air;
• Addition of bomb slips in the outer wings, along with control panels in both cockpits and wiring required for electrical bomb release;
• Changes to the drawings to use BA (British Association) metric screw threads for small fittings rather than US standards;
• It has also been noted elsewhere that the design was strengthened to allow for dive-bombing (evidence supporting this suggestion has not been found); and
• Many other small detail changes

In July 1938 Sir Edward Ellington (Inspector General of the Royal Air Force) submitted a report on the capabilities of the RAAF to the Minister for Defence, Archdale Parkhill. Ellington had been asked to provide an independent view of the RAAF, and among the content of his report was criticism of the selection of the NA-16-2K design which was then under construction at CAC's plant in Fisherman's Bend:

"I understand that it is intended to use it in replacement of the Demon as a fighter-bomber. I consider that the Wirraway should be regarded as a temporary expedient... it can only be regarded as an advanced training aircraft."

He went on to suggest that the choice of a new type (to be produced instead of the Wirraway) should be delayed until a suitable aircraft had been tested in Britain. This suggestion almost marked the end of the Wirraway project, as when the report was released to the public by Prime Minister Lyons in September 1938 there was a great deal of speculation in the press that the Wirraway would be cancelled, or at least no more orders would be placed beyond the initial order for 40 aircraft. The Canberra Times reported on September 2nd 1938 that "fighting aircraft" would be built by CAC instead of more Wirraway trainers^[4]:

This will mean the cancellation of an order which the Commonwealth Government had intended to lodge early next year for 60 or 70 additional Wirraways. In reaching this decision the Government has been influenced by the statement by the British expert, Sir Edward Ellington in his report on the R.A.A.F. to the Prime Minister (Mr. Lyons) that the Wirraway has insufficient speed for a fighter, but is quite suitable for training".

As it turned out, the Government did not accept Ellington's recommendation, and additional orders for Wirraway production continued after the CA-1 order.

Apart from constructing a new factory on a green-field site, CAC needed to develop an entirely new supply chain for highly advanced materials and components from scratch for the Wirraway project. This is one of the most significant elements of the work which the CAC team led, and is largely unrecognised. Newly qualified suppliers included:

• Australian Aluminium Company producing sandwich "Alclad" aluminum sheet;
• The Australian Forge and Engineering Pty. Ltd. in Lidcombe, NSW, supplying a range of forgings;
• Stewarts and Lloyds in Newcastle, NSW, producing forged cylinder blanks for the Wasp engines;
• De Havilland Australia in Bankstown, NSW, producing Hamilton Standard propellers under license;
• British Tube Mills in Adelaide, SA, producing chrome-molybdenum alloy steel tube for the framework;
• James N. Kirby Pty. Ltd. in Sydney, NSW, making undercarriage castings

Of course this new supply chain could not ramp up all of these these new technologies in time for production of the first aircraft, and a number of the first aircraft off the production line were assembled using many imported components from NAA.

As the first Wirraway was nearing it's first test-flight, public interest intensified and newspapers reported progress on a regular basis. The first flight was announced for March 25th 1939, but problems with the landing gear caused a delay of two days. When the Wirraway made it's first flight it is obvious that the undercarriage doors were not fitted.

Just over one year after contract demand T.374 was issued, the first CAC-built Wirraway took to the air on March 27th 1939 in the hands of CAC test pilot Hubert Boss-Walker.

The first CAC-built Wirraway (A20-3) on the day of it's first flight, March 27th 1939. Notice the lack of undercarriage doors, armament and antenna mast. Image copyright unknown, linked from the Owen O'Malley & 462 Squadron website.

By the declaration of war on September 3rd 1939, the RAAF had taken delivery of 7 Wirraways.

A flight of three CA-1 Wirraways (A20-4, A20-10 and A20-11) of 22 Squadron near Point Cook. Note the original style air cleaner (single intake) under the cowl. The closest of these three aircraft, A20-10, is held in the collection of the Australian National Aviation Museum in Moorabbin, Victoria. Although it appears to have a 2-bladed propeller, Wirraway aircraft were fitted with 3-bladed propellers - the appearance is only a photographic illusion. Image linked from the RAAF historical image archive.

Specifications

A dramatic picture of preparations for a night flight in a CA-1 Wirraway showing the single air intake for the oil cooler under the cowl. Note also that there is no air intake on the upper starboard side of the cowl (in the 10 o-clock position when viewed from ahead). The ribbed housing for the propeller reduction gears is also prominent on the Pratt & Whitney Wasp engine. Image copyright expired, courtesy of the AWM archive.

CA-1 Service Use

The first CA-1 aircraft delivered to the RAAF were A20-4 and A20-5, handed over on July 7th 1939. Deliveries continued until the last CA-1 (A20-43) was accepted on February 21st 1940.

RAAF strength of CA-1 Wirraways peaked at 39 aircraft (since A20-20 was struck off charge while other CA-1 aircraft were still being delivered). The last CA-1 to be struck off charge by the RAAF was A20-13 on May 3rd 1960, so CA-1 Wirraway aircraft were operated by the RAAF for a total of 22 years and 2 months.

CA-1 Wirraway aircraft served with 22 different RAAF units, including the following:

• 1 Squadron
• 2 Squadron
• 12 Squadron
• 21 Squadron
• 22 Squadron
• 23 Squadron
• 25 Squadron
• 54 Squadron
• 120 Squadron (Netherlands East Indies)
• 452 Squadron
• 457 Squadron
• 2 Service Flying Training School (Forest Hill)
• 3 Service Flying Training School (Amberley)
• 5 Service Flying Training School (Uranquinty)
• 7 Service Flying Training School (Deniliquin)
• Advanced Flight Training School
• Advanced Aerial Gunnery School
• Central Flying School
• Richmond Station Headquarters
• Advanced Flying & Refresher Unit (Deniliquin)
• 2 Operational Training Unit
• 8 Operational Training Unit

One CA-1 (A20-28) was converted to CA-20 specifications and served with the RAN Fleet Air Arm and one (A20-31) was allocated to the United States 5th Air Force for a period of time.

Of the 40 CA-1 aircraft produced, 14 were destroyed in crashes (including one lost on a ferry flight from Port Moresby to Tanamerah) in which 21 airmen lost their lives.

Production Summary

The following table provides a summary of all the aircraft produced under contract CA-1^[6]:

References and Footnotes

1. "IN FRONT RANK."The Canberra Times(ACT: 1926 - 1954) 14 Jul 1936: 1. Web. 22 Mar 2012 <http://nla.gov.au/nla.news-article2421840>
2. Hagedorn, Dan. North American NA-16/AT-6/SNJ (WarbirdTech Volume 11). North Branch, MN: Specialty Press, 1997. ISBN 0-933424-76-0. Pages 10-11
3. "AIRCRAFT BUILDING."The Sydney Morning Herald (NSW : 1842 - 1954) 18 Sep 1936: 11. Web. 22 Mar 2012 <http://nla.gov.au/nla.news-article17279448>.
4. "WIRRAWAYS ORDER ABANDONED FOR NEXT YEAR." The Canberra Times (ACT: 1926 - 1954) 2 September 1938: Web. 1 April 2012 <http://trove.nla.gov.au/ndp/del/article/2467911>
5. RAAF Operations Record Book Form A.50 for 12 Squadron, September 1938; National Archives of Australia
6. RAAF service cards for Wirraway aircraft, National Archives of Australia, Series A10297 Block 107

For additional detailed information regarding the Wirraway, go to the Wirraway Technical Details page