CAC, under Sir Lawrence Wackett, began work on its own design, hoping to out-perform the Beaufort by building a machine that could serve as both a torpedo-bomber and dive bomber. To keep down weight, Wackett dispensed with traditional self-sealing fuel tanks and opted to make the wing cavities liquid-tight, and thus serve as fuel storage. The Australian Government was initially uninterested in the CAC design. However, in mid-1940, cut off from the supply of British-made components for the Beaufort program (thanks to a British embargo on the export of aviation products, due to the need to maximise British production during the Battle of Britain), the Australian Government ordered a prototype of the CAC design, even before the Royal Australian Air Force had expressed a view about the machine. This prototype CA-4 took to the air on 19 September 1941. The CA-4 was a low-wing, twin-engined, multi-role bomber with a crew of three. It was armed with four nose-mounted .303 calibre machine guns and two remote-controlled twin machine-guns barbette mounted at the rear of the engine nacelles. It could carry either bombs, bombs or two torpedoes. It was originally powered by two Pratt & Whitney Twin Wasp R-1830-S3C3-G radials. Unfortunately, the novel fuel tanks never proved reliable, and in January 1943 the CA-4 prototype was completely destroyed in a mid-air explosion, probably due to a fuel leak.