In March 1964, with the Mirage fighter being delivered to the RAAF, the Melbourne based Commonwealth Aircraft Corporation presented its idea for a locally designed and manufactured, advanced supersonic aircraft designed to meet both flying and weapons training needs.
The basis of the project was that there was no type with this dual capability available anywhere in the world.
In the 1960s, it was also seen that there was a huge gap between flying jet trainers and modern high speed fighters.
This difference involved more than just speed; the flying characteristics of supersonic delta wing fighters were quite different to the subsonic trainers then available.
The original design featured a double delta wing powered by a single GE – J85 engine, and the design was advanced to the stage of constructing this full size mockup, and then revised to incorporate the Rolls Royce RB172 Adour engine.
The aircraft was to feature Martin Baker ejection seats and be capable of carrying a load of 1815 kg on four wing and two fuselage hardpoints.
The RAAF jet trainer requirement was eventually fulfilled in 1967 by Macchi Trainers licence built by CAC, and a number of 2 seat Mirages built by GAF in Melbourne, resulting in the CA-31 project being cancelled, effectively ending CAC’s indigenous designs.