Video - Synchronized machine gun

In the spring of 1915, the German army was equipped with the first true fighter aircraft, the Fokker Eindecker ( monoplane ). What made it successful was the forward firing machine gun that shot between the aircraft’s propeller blades, without hitting them. The Museum of Aviation and Space in Ottawa, Canada has a working model of this gun on display, so we went there to find out how it works.

Rénald Fortier, Curator - Aviation & Space Museum Ottawa, Canada :

"They were some patterns before the First World War. French, German possibly British or Russian but there were some research done on the concept, because there were machine guns mounted on airplanes before the start of the First World War.

Fokker was the first company to put a synchronized machine gun on an airplane and put that into service. That is the beginning of the fighter aviation. The first fighter plane, one could argue that was it. The Fokker Eindecker of 1915.

Having a machine gun that can fire through the propeller certainly has great advantages. It allows you to use a fairly small airplane, faster, more agile, better performance for aerial combat. The way it works, it depends on the system of course, but the early ones stand to be mechanical.

What we have here is a model of a Fokker synchronizing gear that was made by the museum. The synchronizer basically is a mechanism that allows the machine gun to fire. It sorts of connect the engine and the machine gun. The basic system is quite simple. The engine is connected to a cam wheel, a wheel that is not perfectly circular. It has a little bump on it. So every time the engine turns about 1,200 to 1,300 times a minute, the bump hits a little vertical rod, which pushes a horizontal rod. Having the pilot pressing the trigger mechanism on its control stick brings pieces together. It completes the circuit and that fires the machine gun. So if the pilot presses the button and the mechanism is not engaged, nothing will happen. If the mechanism is engaged but the pilot does not press the trigger mechanism nothing happened. It’s the combination of the pilot and the mechanism, working together that will fire the machine gun between the blades of the rolling propeller.

The Germans were the first to actually put a synchronized gear on an airplane and use it in combat. The French had used something different. They had used armored propeller with deflectors, so the machine gun would be firing at the propeller. When it hit it, rather than going through the blades, metal deflectors would sort of deflect the bullets hopefully all of them in some other directions. The system was a bit crude, not very effective, potentially rather dangerous."

The Germans kept their technological lead in this area until mid-1916; after which, the French and the British developed their own systems to counter the technological advance of the Germans.