![A pink camouflage patterned replica tank sitting in a yard.](https://www.popsci.com/wp-content/uploads/2019/03/18/HZ42SP4MWCE6IMIQTJ5JLU6ZPE.jpg?w=485)
![A pink camouflage patterned replica tank sitting in a yard.](https://www.popsci.com/wp-content/uploads/2019/03/18/HZ42SP4MWCE6IMIQTJ5JLU6ZPE.jpg?w=485)
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.
On parade day, it was no sweat to cruise 15 mph with a full load—just fast enough to escape the spectators Marshall was drenching with the cannon.
How it works
- Dept: You Built What?!
- Time: 11 days
- Cost: $3,000
Suspension and steering
The group cobbled together a steering system from an old Geo Metro and a Ford 150 pickup. But they built the frame and axles from scratch, to make sure those wouldn’t buckle under the tank’s enormous weight.
Power
Six old 10-speeds provided the pedals, cranks and bottom brackets. The group replaced the bicycles’ regular chainwheels with industrial-grade chains and sprockets to handle the increased load on the transmission.
Photo gallery
![Two men working on building the frame of a pedal-powered tank, while another man stands off to the side.](https://www.popsci.com/wp-content/uploads/2019/03/18/IRCETTEZL35Y37RGE6YZFLC2AE.jpg?strip=all&quality=95)
![A person welding the frame for a pedal-powered replica tank.](https://www.popsci.com/wp-content/uploads/2019/03/18/77RYMUPZIVG6BZD6YIAXIAELAE.jpg?strip=all&quality=95)
![The frame for a pedal-powered replica tank in a driveway.](https://www.popsci.com/wp-content/uploads/2019/03/18/XK5NYE6VAGJUHJNEKSN4NZGHPE.jpg?strip=all&quality=95)
![A transmission in a pedal-powered replica tank.](https://www.popsci.com/wp-content/uploads/2019/03/18/KG2AZHCFYPIRH4EHRSI5YQ4WPM.jpg?strip=all&quality=95)
![The chain drive inside a pedal-powered replica tank. Grayscale.](https://www.popsci.com/wp-content/uploads/2019/03/18/2BTGD5CUIGZGXEQ6UG2NIYRV34.jpg?strip=all&quality=95)
![A pedal-powered replica tank frame in a garage. Grayscale.](https://www.popsci.com/wp-content/uploads/2019/03/18/UVS4C62JE7WO7O5GRZ2UJXOZIU.jpg?strip=all&quality=95)
![The interior of a pedal-powered replica tank, showing the steering wheel and driver's seat.](https://www.popsci.com/wp-content/uploads/2019/03/18/ZLWQTN4US45Z6UBQ3YAE6Q6T7I.jpg?strip=all&quality=95)
![A group of men pedaling a replica tank frame down a street. Grayscale.](https://www.popsci.com/wp-content/uploads/2019/03/18/VEJIPJSRENQ7RDZOHJIGQKQP3Q.jpg?strip=all&quality=95)
![A group of men pedaling and pushing a pedal-powered replica tank frame down a street.](https://www.popsci.com/wp-content/uploads/2019/03/18/235WOBQ3VBR5EBUY5TV2SYHR3A.jpg?strip=all&quality=95)
![A pedal-powered replica tank frame in a garage, partially covered with cladding. Grayscale.](https://www.popsci.com/wp-content/uploads/2019/03/18/UR6E3IHHC2ZUB2LSFBM7L774MU.jpg?strip=all&quality=95)
![A replica tank cannon.](https://www.popsci.com/wp-content/uploads/2019/03/18/UZO7ROLMXHTVA2SKKCRHIHP2CQ.jpg?strip=all&quality=95)
![The interior of a pedal-powered replica tank, showing seats for the crew. Grayscale.](https://www.popsci.com/wp-content/uploads/2019/03/18/6ZDKZDDNEAJSNBHUAPAWZHMYRI.jpg?strip=all&quality=95)
![An unpainted pedal-powered replica tank on a city street.](https://www.popsci.com/wp-content/uploads/2019/03/18/2OAUVANILT6NRUDVB3QWBQMNYI.jpg?strip=all&quality=95)
![A group of men laughing as they pedal inside a replica tank.](https://www.popsci.com/wp-content/uploads/2019/03/18/VIMQCLQTNCGBWESKAPENF63J6I.jpg?strip=all&quality=95)
This story has been updated. It was originally featured in the October 2008 issue of Popular Science magazine.