The problem of perfecting a machine gun that would synchronize its firing with the rotation of the propellers was the assignment given to Anthony Fokker. In two days the Dutch engineer had improved on Garros' innovation considerably. Fokker Eindekkers were armed with synchronized Spandau machine guns and roamed the skies virtually unopposed for a while. German aces such as Immelman and Boelcke led a reign of terror in the skies, known as the Fokker Scourge. But, as things went in that war for control of the air, the Allies weren't too far behind in making an answer to the Fokker Scourge. A little while later the Allies came up with a synchronized gun designed by Georges Constantinesco

During the month before the outbreak of the war, Raymond Saulnier had been working on an interupter gear that would allow a machine gun to be fired through the propeller arc. He had grown impatient with hang-fire failures so he attached steel deflection plates on the propeller where the bullets passed through the arc. The military lost interest in his idea once the war started and made Saulnier return the machine gun he had borrowed. After a few months into the war, all the pilots were unanimous in their desire for fixed machine guns facing forward that they could shoot in the direction they were flying. Lieutenant Roland Garros, who had been a famous stunt pilot before the war, came to Saulnier and had steel deflector plates attached to his propeller blades and a fixed machine gun mounted in front of the cockpit. The interrupter gear was not installed, Garros relying on the steel plates to ward off the bullets that hit the airscrew. At the end of March Garros took to the air, and in just over a fortnight he had shot down five German planes. On April 19, though, he was brought down by enemy ground fire while strafing an infantry unit near Coutrai. His attempts to set fire to his plane (as all pilots did when they crashed landed in enemy territory, so the enemy could not get their hands on their technology) were unsuccessful and his modified airscrew was quickly in the workshop of Anthony Fokker.