A62 CAC CA-15
At the time of its construction the CAC Boomerang mounted the most powerful power-plant in Australia - the licence-built 1,200 hp Pratt and Whitney Twin Wasp R-1830 radial engine. The combination of the Twin Wasp and the sturdy design of the Boomerang resulted in a highly manoeuvrable fighter aircraft.
In fact, the Boomerang's tests in 1942 were so promising that plans were initiated to design an improved version with a more powerful engine. However, subsequent investigations revealed that the basic Boomerang airframe would not take the extra weight without considerable modification and so the project was cancelled.
Nevertheless, the RAAF requirement for a long-range, medium altitude, high performance fighter still remained. Throughout 1943 and 1944, conferences were held between the RAAF and CAC, and in 1945 the CAC design was accepted for the specification under the company designation CA-15.
The CA-15 airframe was originally designed to use a radial engine, the 2,300 hp Pratt and Whitney R-2800 with a turbo-charger. However, this particular engine became unavailable at the time and, late in 1945, it was decided to fit an in-line Rolls Royce Griffin Mk 61 as an interim measure pending the interaction of a Griffin with a three-speed supercharger.
Another program centred around the armament installation and various combinations of 20mm cannons and 0.50 machine guns were considered before it was decided to produce the first aircraft with six 0.50s with provision for 250 rounds per gun.
The CA-15 was the second fighter to be completely designed by CAC and, in comparison to its predecessor, the tubby Boomerang, it had an exceptionally pleasing appearance. The aircraft was rolled out in 1946, and taxiing tests commenced on 12 February 1946.
Test pilot Jim Schofield carried out the first flight on 4 March 1946, and company tests continued until the end of June. On 2 June 1946, the CA-15 was allocated to the RAAF as A62-1001, and on 27 June 1946 the aircraft was delivered to No 1 Aircraft Performance Unit at RAAF Laverton.
Familiarisation flights were carried out, and calibration and performance tests were commenced with APU pilots Wing Commanders J.H. Harper and G.D. Marshall, Squadron Leaders D.R. Cuming, G.C. Brunner, C.W. Stark and G.H. Shields, and Flight Lieutenant J.A. Archer.
The tests continued until the CA-15 was forced to crash-land due to hydraulic failure on 10 December 1946. The aircraft was extensively damaged, and in June 1947, it was returned to CAC for repairs. Meantime, plans were underway to introduce jet-engined fighters to replace the RAAF Mustangs, and the CA-15 project lost its original priority.
Consequently, almost a year elapsed before A62-1001 was delivered back to the RAAF on 19 May 1948. A limited test-flying program continued until 1950 when it was decided to cancel any further development. On 1 May 1950, the CA-15 was transferred from Aircraft Research and Development Unit to No 1 Aircraft Depot for conversion to components.
In retrospect, the CAC CA-15 (which at one time was unofficially known as the CAC Kangaroo) was quite a remarkable aircraft. In addition to its thoroughbred lines, it possessed a flying performance well in advance of many contemporary fighters.
APU pilots found the CA-15 a pleasant, uncomplicated aircraft to fly with no apparent vices. Climbing and range trials were well up on expectations, and maximum speeds of 448 mph at 26,400 ft in combat power and 432 mph at 32,700 ft compared favourably with fighters of similar design and power rating. Although superseded by the Vampire and Meteor, the CA-15 was, nevertheless, an outstanding aircraft that was a credit to Australian designers and technicians.
TECHNICAL DATA: CAC CA-15
Single-seat, interceptor fighter, with provision for extra wing tanks or wing bombs for escort or fighter-bomber duties. All-metal stressed-skin construction.
One 2035 hp Rolls-Royce Griffin Mk 61 with two-stage two-speed supercharger.
Span 10.97 m (36 ft); length 11.03 m (36 ft 3 in); height 4.34 m (14 ft 2 in).
Empty 3420 kg (7540 lb); loaded 5597 kg (12 340 lb).
Max speed 721 km/h (389 kt); Maximum rate of climb 1520 m (4900 ft)/min; Service ceiling 39,000 ft (11 887 m); Normal range 1850 km (1000 nm).