|In Oz, during the years 1944 to March 1950, the skies above Melbourne were home to a homegrown fighter named the CA-15.
The following is an article by Felix Noble. 1997.
"On the afternoon of May 25 1948 a silver aircraft flew over Melbourne at an unprecedented 502mph. This aircraft carried a number of innovative design features, performed very well, and was considered by many people to be the ultimate piston engined fighter. The brainchild of Lawrence Wackett, head of the Commonwealth Aircraft Corporation (C.A.C) it was totally Australian in design and manufacture. It was the CA-15.
After the success of the Boomerang - albeit in a role other than it?s intended one - an order for a new fighter powered by a Pratt & Whitney R-2800 series radial engine was placed with CAC in February 1943. It was designated CA-15, and was to be a long range, high altitude, high performance fighter.
By May an engine had been obtained and a mock-up constructed. This was shown to the RAAF and upon approval the design was frozen. By June, plans for development and production were rapidly advancing and the P&W R-2000-21 engine was decided upon as the powerplant.
During this period Lawrence Wackett was touring extensively in the UK and the USA examining in detail their aircraft manufacturing methods and design philosophies. Upon his return in mid 1943 he recommended that the P-51 Mustang be license built here, and the CA-15 be developed "...as an exercise to keep alive the spirit of design, rather than as a war weapon for urgent development." To this end, some of the most promising younger design engineers were put onto the project and the whole thing given a low priority.
Also as a result of this trip Wackett decided to redesign the CA-15 as a low altitude fighter around the P&W R-2800-10w engine. There were two main reasons;
Firstly, he had become convinced that a fighter powered by a radial engine, even a turbocharged one, was more suited to low altitude work.
Secondly, he saw no advantage in developing an aircraft in competition to the Mustang which CAC was soon to start building. This change meant a large re-think in design, and was expected to delay production by about twelve months.
In August 1943 the RAAF issued specification no. 2/34 which covered the CA-15, and work once again advanced rapidly. By the end of the year an engine installation mock-up had been built, and detailed specifications were issued down to the smallest item.
Early 1944 saw rapid progress in the manufacture of prototype components and preliminary construction. An R-2800 engine was obtained in March, and in April the last major design feature was finished. This was an innovative integrated radiator system that served both the oil system and the intercooler. Calculations indicated that this would give better results than any other radial engine installation in the world.
Then on May 15 a cable arrived from the United States informing CAC that the R-2800-10w engine was no longer being produced. The replacement chosen was the R-2800-57w. This was a high altitude version of the motor, and once again necessitated a redesign. Work continued until by August, 75% of the detailed tooling and 85% of the assembly jigs had been completed. Then, again on the fifteenth, disaster, in the form of another cable, struck. This cable baldly stated that R-2800-57w engine delivery could not be guaranteed.
After much deliberation the Rolls Royce Griffon 120 motor was chosen in September. Before any major work could begin however the project was cancelled by the Aircraft Advisory Committee. Despite this, CAC continued with development at a much reduced rate, whilst lobbying fiercely for the projects re-instatement. It was granted on December 12 1944.
By January 1945 the Australian government had become tired of the whole project and supported it in a very listless manner. In contrast the British Air Ministry upon looking at the design was greatly impressed, and immediately lent the project two Griffon 61 motors for use until the Griffon 120 became available.
The motors arrived in April, and were in place in the airframe and run in December. The decision to fly the 61 series motor came when the production of the 120 series was cancelled due to the end of the war.
February 1946 saw the beginning of taxying trials for the CA-15, an aircraft that "...must be regarded as the leading example in proven technique in fighter design..."
Then after a few minor adjustments, the first flight of fifteen minutes duration was undertaken by CAC, and the aircraft logged 16.75 hours in the following twenty three flights. During this period a number of RAAF test pilots flew the aircraft. One commented "... The aircraft is easy to fly and has no apparent vices...The engine installation is very good, being by far the best Griffon i