 ", with their own money) as a two-seat light bomber; although the bomb load of 570 lb (259 kg) was the same as the Hart, the reinforced fuselage and wings allowed the P.V.4 to dive with this load.The P.V.4 was first flown from the Brooklands airfield on 6 December 1934.The Bristol Pegasus III engine was initially used, but this was changed to the Pegasus X in 1935.