 The second aircraft, the F2 ("A78-2"), was significant in that it was powered by the more powerful Rolls-Royce Nene jet engine, rather than the standard Goblin unit.All of the 80 F.30 fighters and FB.31 fighter-bomber Vampires that were subsequently built by de Havilland Australia were powered by Commonwealth Aircraft Corporation (CAC) versions of the Nene engine manufactured under licence at their facility in Melbourne.The Nene required a greater intake cross-section than the Goblin, and the initial solution was to mount auxiliary intakes on top of the fuselage behind the canopy.