A20 CAC Wirraway
In 1936, Wing Commander L.J. Wackett led a mission abroad to select a general purpose aircraft for manufacture by the newly-formed Commonwealth Aircraft Corporation (CAC). The mission unanimously recommended the North American NA-33, and plans were made to produce a modified version to be known as the Wirraway (Aboriginal for 'challenge').
While the CAC buildings were being erected at Fishermens Bend, two aircraft were shipped from America for evaluation and the first, a fixed undercarriage NA-16, which overseas became known as the Yale, arrived in mid 1937 and was transferred from CAC to the RAAF on 2 February 1938. The second aircraft, a NA-33, arrived late in 1937 and was taken on charge at No 1 Aircraft Depot from CAC on 8 November 1938. For some time, these two aircraft remained un-numbered, but later became A20-1 and A20-2 respectively. In June 1940 the two aircraft were transferred to the Engineering School as instructional airframes.
Subsequent to RAAF selection, the NA-33 was ordered by other air forces and it became known as the Texan in America and the Harvard throughout the British Empire. The Australian Wirraway version was modified for operations, and the NA-33 single wing-gun was replaced by twin synchronised guns in blast troughs above the fuselage, plus a flexible gun in the rear cockpit. Camera and radio installations were introduced, and the wing and tail units were redesigned and strengthened for dive-bombing in later variants only.
The first Wirraway, A20-3, was test flown by Flight Lieutenant 'Boss' Walker on 27 March 1939, and the first three RAAF Wirraways were accepted in July 1939. By December 1940, seven aircraft were being delivered weekly, and by September 1941, 45 Wirraways per month were coming off the production line. The initial orders for 620 aircraft were completed by June 1942, but limited production continued until 1946 when the 755th Wirraway, A20-757, was delivered. CAC designations for Wirraway orders included CA-1, -3, -5, -7, -8, -9, -10 (a bomber version which was cancelled), -10A (dive bomber), and -16. The designation CA-20 covered the conversion of Wirraways for the RAN.
In 1940-41, camouflaged Wirraways were deployed to forward bases in Malaya (No 21 Squadron) Rabaul (No 24 Squadron), and Darwin (No 12 Squadron). On 6 January 1942, Flight Lieutenant B. Anderson of No 24 Squadron became the first RAAF pilot to engage in air-to-air combat in the South-West Pacific, when his Wirraway intercepted a Kawanishi (Mavis) flying-boat over Rabaul.
Two weeks later, on 20 January 1942, the Rabaul Wirraways achieved immortal fame when eight aircraft, including A20-177, piloted by Sergeant W. Hewett, courageously engaged a force of over 100 Japanese fighters and bombers. Although hopelessly outclassed by enemy aircraft, the Wirraway remained in the front line as a stop-gap fighter, and on 26 December 1942, Wirraway history was made when Pilot Officer J. Archer, in A20-103, succeeded in shooting down a Zero fighter near Gona.
Wirraways served mainly with Nos 4, 5, 12, 14, 21, 22, 24, 25, 54, 60, 78, 82, 85 and 87 Squadrons, although most squadrons had Wirraways on strength at one time or another. In addition, the aircraft was used extensively for the Empire Air Training Scheme, and many Australian fighter pilots learnt their trade in the Wirraway.
The Wirraway continued to serve as a trainer and communications aircraft until 1959 and of interest is the fact that a Wirraway was used in 1947-48 by No 81 Wing while on duty with the British Commonwealth Occupation Forces in Japan.
Today, restored Wirraways can be found on static display and in the air all around Australia. These examples are on hand to remind us of the first Australian mass-produced aircraft - a tribute, in one respect, to Sir Lawrence Wackett, who had the foresight and ingenuity to provide Australia with an efficient aircraft in a time of need.
TECHNICAL DATA: CAC Wirraway
Two-seat general-purpose monoplane, of all metal stressed-skin construction.
One 600 hp (Pratt and Whitney licence) Wasp - nine cylinder air-cooled radial engine.
Span 13.10 m (43 ft); length 8.48 m (27ft 10 in); height 2.66 m (8ft 9 in).
Empty 1811 kg (3980 lb); loaded 2991 kg (6595 lb).
Max speed 354 km/h (191 kt); Rate of climb 594 m (1,950 ft)/min; Range 1158 km (625 nm); Ceiling 23,000 ft (7010 m).
Twin synchronised 0.303 guns mounted above fuselage, and one manually operated rear cockpit 0.303 gun. Light bomb load carried externally beneath wings.
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