Nicknamed “silent professionals,” America’s Special Operations Forces exist on the edge of war, moving behind and around front lines, preparing battles behind the scenes. They are as protected by obscurity as they are their own skill, which means that when they move around, it’s best if they can do it without any loud engines giving them away.
The Defense Advanced Research Projects Agency (DARPA), the Pentagon’s futuristic research wing, is making a silent motorcycle for the silent professionals. At a conference today in Tampa for Special Operations, DARPA showed off two different bikes.
The combustion engines are for when the bikes don’t need to be quiet. Running on fuel, they reach 80 decibels — somewhere between a vacuum cleaner and a garbage disposal. Running on just electric power, the engines quiet down to 55 decibels — roughly as loud as an office. That silence becomes stealth, allowing the bicycling Green Berets to travel unheard, provided there is any other ambient sound at all.
Read more at Popular Science