Prior to the commencement of hostilities the Allies in Malaya and Singapore had four fighter squadrons: 21 and 453 RAAF, 243 RAF, and 488 RNZAF. They were equipped with the Brewster Buffalo B-399E, a plane that aviation historian Dan Ford characterized as pathetic. Its engine had fuel starvation problems and poor supercharger performance at higher altitudes. Maneuverability was poor and the engine tended to overheat in the tropical climate, spraying oil over the windscreen. In service, some effort was made to improve performance by removing the armour plate, armoured windshields, radios, gun camera, and all other unnecessary equipment, and by replacing the .50 in (12.7 mm) machine guns with .303 in (7.7 mm) machine guns. The fuselage tanks were filled with a minimum of fuel and run on high-octane aviation petrol where available.