One Foreign Materiel Exploitation (FME) story during the war involved the synchronized machine gun. French pilot Roland Garros and his mechanic armored his prop with steel plates to enable a machine gun fire through it. He said about one in 10 bullets would ricochet. Garros downed several German aircraft with it before going down behind enemy lines. The Germans tried to copy his design with disastrous results because the French used copper-jacketed bullets and the Germans used steel-jacketed ones that shattered the wedges and the props. Anthony Fokker’s engineers fully realized the idea of the mechanically synchronized machine gun to fire through the prop. They made it work thanks to basic engineering and more dependable German ammunition. The Fokker Scourge ensued, where the Fokker Eindecker fighter wreaked havoc on Allied aircraft for a number of months. The British also developed mechanically synchronized gear, but took a different approach as well. Using the Theory of Sonics developed by Romanian physicist George Constantinescu, they used vibrations transmitted through a mixture of kerosene and oil to outperform mechanical systems. As a bonus, when German engineers tried to copy it they failed, believing it was a simple hydraulic system. The truth remained a secret until after the war.