The Slo Mo Guys, in association with (and sponsorship from) EA, produced a video where they recorded slow motion footage of a machine gun and propeller setup. They first recorded footage where the synchronization gear was active, a mechanism which timed a plane-mounted machine gun to fire in-between the arc of a propeller’s blades, making plane-mounted machine guns viable during the Great War. The second bit of footage has the synchronization gear turned off, and it resulted in 4 hits to the propeller blades.
Neat stuff.