Perhaps no other combat aircraft in history can match the reputation of the Spitfire. In the eyes of the British public, the performance of this aircraft, more than any other factor, decided the outcome of the Battle of Britain and changed the course of WW2. The first all-metal fighter produced for the RAF, the Spitfire was noted for its sleek design and unique thin, oval wings. While the Hurricane evolved from a biplane design, the Spitfire was designed as a monoplane from the start. And while the Hurricane outnumbered the Spitfire in 1940 and shot down more German aircraft, the Spitfire captured the imagination of the British people. Originally based on a design for a record-breaking racing seaplane, the first Spitfire prototype flew in 1936. Thought its complex design delayed initial production, the first Spitfires (Mk I), were delivered to RAF squadrons in 1938. The first seventy-seven aircraft had two-blade fixed pitch propellers, and succeeding aircraft were fit with three-blade two position propellers, thereby raising its ceiling by 7000 ft and improving climbing and diving. Later modifications included the addition of a high visibility bubble cockpit hood and extra armour protection. The Spitfire Mk I first saw action in October 1939 at the Firth of Forth in Scotland, where 2 RAF squadrons intercepted Ju 88 bombers and shot one down.