On 11 April 1952, the second prototype WB215 made its maiden flight, after modifications to the fuel system. It was fitted with more powerful RA.7 Avon engines with thrust each, rather than the Sapphires that had been originally planned; it also featured more rounded air inlets, replacing the narrow slot-type intakes of the first prototype, in order to feed sufficient air to the more powerful engines. The short delay until the second prototype became available meant that loss of the prototype did not compromise the development schedule.