If you want to crash a local parade of human-powered vehicles and soak unsuspecting onlookers in water or vaporized hot dogs, a pink camouflage tank is a pretty good craft to do it in. At least that’s what 30-year-old Philadelphia gearhead Vin Marshall thought when he persuaded nine of his friends to build the 2,000-pound replica, complete with a functioning pneumatic cannon.
The trick was moving the tank using muscle alone. Computer models showed that it could fit hardware for six pedalers and yield about 1.5 horsepower. That’s not enough to move tank treads, so the team used wheels instead. Then they gave it bicycle-like gearing to get more power from less exertion. A salvaged rear differential (which allows wheels to spin independently) from an old truck axle made turning more efficient.