like hazel in the early 1930s making such an important contribution to our later success in the battle of britain, which was vital to this country's survival. the calculations carried out by hazel and her father resulted in both spitfires and hurricanes being armed with eight rather than four guns. over the next six years, as britain headed towards war with nazi germany, the planes were tested and put into production. each gun carried just 300 rounds. it took around 15 seconds for them all to be fired. it meant that every bullet had to count. the spitfire was a nimble aircraft, perfect for dog fights, and their pilots loved them. so, you'd got three german fighters that day? 98—year—old squadron leader allan scott flew both spitfires and hurricanes.