CAC Woomera

In early 1939, the Australian Government ordered large numbers of Bristol Beaufort bombers, with major components to be built in a variety of locations, including railway workshops, and in doing so it by-passed the local aircraft company, the Commonwealth Aircraft Corporation.

CAC, under Sir Lawrence Wackett, began work on its own design, hoping to out-perform the Beaufort by building a machine that could serve as both a torpedo-bomber and dive bomber.Ewer 2009 Chapter 6 To keep down weight, Wackett dispensed with traditional self-sealing fuel tanks and opted to make the wing cavities liquid-tight, and thus serve as fuel storage. The Australian Government was initially uninterested in the CAC design. However, in mid-1940, cut off from the supply of British-made components for the Beaufort program (thanks to a British embargo on the export of aviation products, due to the need to maximise British production during the Battle of Britain), the Australian Government ordered a prototype of the CAC design, even before the Royal Australian Air Force had expressed a view about the machine.Ewer, 2009, p169 This prototype CA-4 Wackett Bomber took to the air on 19 September 1941.{{cite book|last1=Wilson|first1=Stewart|title=Military Aircraft of Australia|date=1994|publisher=Aerospace Publications|location=Weston Creek, Australia|isbn=1875671080|pages=216}} The CA-4 was a low-wing, twin-engined, multi-role bomber with a crew of three. It was armed with four nose-mounted .303 calibre machine guns and two remote-controlled twin machine-guns barbette mounted at the rear of the engine nacelles. It could carry either {{convert|500|lb|abbr=on}} bombs, {{convert|250|lb|abbr=on}} bombs or two torpedoes. It was originally powered by two Pratt & Whitney Twin Wasp R-1830-S3C3-G radials. Unfortunately, the novel fuel tanks never proved reliable, and in January 1943 the CA-4 prototype was completely destroyed in a mid-air explosion, probably due to a fuel leak.

With a re-designed tail and rudder, and an improved nose armament of two 20 mm cannon and two .303 (7.7 mm) calibre machine guns, the CA-4 became the CA-11 Woomera.

Faced with the crisis caused by the Japanese entry into the war in December 1941, the RAAF accepted the design even before testing was complete, and ordered 105 examples of the CAC bomber on 8 March 1942. However, after the loss of the CA-4 prototype, the redesigned CA-11 did not fly until June 1944. By the time production was due to commence, the dive-bombing concept had fallen into disfavour and the RAAF was filling the light bomber/reconnaissance/strike role with British-designed Bristol Beaufighters (which were being made in Australia by the Department of Aircraft Production); US-made bombers, including the B-25 Mitchell, had also become available. Consequently, the original Woomera order was reduced from 105 to 20. After the first CA-11 flew, the whole program was cancelled and the production capacity set aside for Woomeras at CAC was switched to P-51 Mustang fighters. The only completed CA-11 Woomera, A23-1, was stripped for parts and scrapped in 1946.

On 15 January 1943, the prototype CA-4 Wackett Bomber, A23-1001, crashed on a test flight to assess powerplant performance and evaluate aerodynamic effects of a new fixed leading edge slat. During the return to the CAC airfield at Fisherman's Bend, the pilot, Squadron Leader Jim Harper, had detected a fuel leak in the port Pratt & Whitney R-1830 engine. As the problem worsened he attempted to shut down the engine, feathering the propeller; however, the actuation of the feathering switch caused an explosion and uncontrollable fire. The three-man crew subsequently attempted evacuation at {{convert|1000|ft|m}}, yet only Harper succeeded in parachuting free, while the CAC test pilot Jim Carter and power plant group engineer Lionel Dudgeon were both killed. The airframe subsequently impacted {{convert|3|mi|km}} south-west of Kilmore, Victoria. The wreckage was recovered and used for components.Isaacs, p. 58.

;{{AUS}}

• Royal Australian Air Force

File:CAC Woomera.svg

{{Aircraft specs

|ref=War Planes of the Second World War: Bombers and Reconnaissance Aircraft, Volume SevenGreen, 1967, p. 16.

|prime units?=imp

|crew=3

|capacity=

|length ft=39

|length in=7

|length note=

|span ft=59

|span in=2.5

|span note=

|height ft=18

|height in=2

|height note=

|wing area sqft=440

|wing area note=

|aspect ratio=

|airfoil=root: NACA 2218.5; tip: NACA 2209{{cite web |last1=Lednicer |first1=David |title=The Incomplete Guide to Airfoil Usage |url=https://m-selig.ae.illinois.edu/ads/aircraft.html |website=m-selig.ae.illinois.edu |accessdate=16 April 2019}}

|empty weight lb=12765

|empty weight note=

|gross weight lb=

|gross weight note=

|max takeoff weight lb=22885

|max takeoff weight note=

|fuel capacity=

|more general=

|eng1 number=2

|eng1 name=Pratt & Whitney R-1830-S3C3-G Twin Wasp

|eng1 type=14 cylinder air-cooled radial piston engines

|eng1 hp=1200

|eng1 note=

|prop blade number=3

|prop name=constant-speed propellers

|prop dia ft=

|prop dia in=

|prop dia note=

|max speed mph=282

|max speed note=

|cruise speed mph=184

|cruise speed note=

|stall speed mph=

|stall speed note=

|never exceed speed mph=

|never exceed speed note=

|minimum control speed mph=

|minimum control speed note=

|range miles=2225

|range note=(with external tank and one torpedo)

|combat range miles=

|combat range note=

|ferry range miles=

|ferry range note=

|endurance=

|ceiling ft=23500

|ceiling note=

|climb rate ftmin=2090

|climb rate note=

|time to altitude=

|lift to drag=

|wing loading lb/sqft=

|wing loading note=

|fuel consumption lb/mi=

|power/mass=

|more performance=

|guns=

• 2 × .303in (7.7 mm) Browning machine guns in the nose
• 2 × 20 mm Hispano Mk II cannon in the nose
• 4 × .303 Browning machine guns in two rear-firing remotely controlled barbettes
• 1 x .303 Vickers K machine gun in a ventral position

|bombs=

• 4× 250 lb (113 kg) bombs internally in engine nacelle bays
• and 4× 500 lb (224 kg) bombs
• or 2× 45 cm Mk XII, Mk XV or 57 cm Mk 13 aerial torpedoes mounted under the fuselage
• or 1× torpedo and 1× {{cvt|293|impgal|l USgal}} external fuel tank mounted under the fuselage

|avionics=

}}

{{Portal|Aviation}}

{{Aircontent

|related=

|similar aircraft=

• Arkhangelsky Ar-2
• Junkers Ju 88
• Kawasaki Ki-48
• Martin Baltimore
• Petlyakov Pe-2
• Savoia-Marchetti SM.85
• Tupolev Tu-2
• Yokosuka P1Y

|lists=

• List of aircraft of World War II

|see also=

}}

{{reflist}}

• Ewer, Peter. Wounded Eagle: The Bombing of Darwin and Australia's Air Defence Scandal. Sydney: New Holland, 2009. {{ISBN|978-1-74110-825-5}}
• Green, William. War Planes of the Second World War: Bombers and Reconnaissance Aircraft, Volume Seven. London: Macdonald, 1967. {{ISBN|0-356-01477-0}}.
• Isaacs, Keith. "Wackett's Wonder". Air Enthusiast Quarterly, No. 1, n.d., pp. 52–65. {{ISSN|0143-5450}}

{{Commons category}}

• [https://web.archive.org/web/20120208043500/http://www.adf-serials.com/2a23.shtml adf-serials.com, 2003, "ADF Aircraft Serial Numbers RAAF A23 CAC CA-4/CA-11 Woomera"]
• [http://www.pidgeon.info/comans/war-time-plane-crash-bylands-vic-1943/ War Time Plane Crash, Bylands, Vic. 1943]

{{Commonwealth Aircraft Corporation}}

{{ADF aircraft designations}}

Woomera

Category:1940s Australian bomber aircraft

Category:Low-wing aircraft

Category:Aircraft with retractable conventional landing gear

Category:Aircraft first flown in 1941

Category:Twin piston-engined tractor aircraft