Designed in 1915, The Fokker E1 was the first such fighter to develop a synchronized gearing system by which a machine gun could fire through a turning propeller. This was a dramatic step forward in military aviation. Prior to this, most aircraft had top wing mounted weapons. Clumsy to fire and difficult to property aim, The Fokker E1 solved this problem. Although developed as a trainer, it featured a revolutionary single (or bi) wing. The theory of single wing fighter was still many years away (but they were used as Trainers sometimes). With the German War effort dwindling down, several Squadrons were made airborne for combat duty. They performed moderately well.