Post-war, Wackett was one of just 21 officers who formed the nucleus of the new Royal Australian Air Force (RAAF) in 1921. He had a strong belief in the need to develop an indigenous aircraft industry and completed a Bachelor of Science degree at the University of Melbourne, then had two years of advanced training in aircraft design under Frank Barnwell, designer of the F.2 Fighter aircraft that he had flown while serving with No. 3 Squadron AFC. He entered and won second prize in the 1924 Low-Powered Aeroplane Competition (held at Richmond in December that year) with his first design, the Warbler. This was a parasol wing monoplane powered by an engine also of his own design, the Wizard, a two-cylinder horizontally-opposed monosoupape-type pusher engine developing .