Frederick William "Gunner" Hill (24 February 1889 – 10 November 1959) is best known for his pre-war calculations that showed that the high speed fighters then being developed (notably the Supermarine Spitfire and Hawker Hurricane) would need to be armed with eight machine guns in order for them to become the potent weapons that were crucial to the victory in the Battle of Britain. Captain Hill's technical skills were important in arming aircraft in both World Wars. In World War I he trialled methods of mounting machine guns in aircraft, evaluated heavy aircraft guns including the 37mm Coventry Ordnance Works (COW) gun, tested ammunition to be used against Zeppelins including the Brock bullet and designed and developed aircraft gun sights. In the inter-war period he worked at the Air Minist