Motor Driven Shooter, Robot in 3 Days

**Ben_A** Sat Jan 25, 2014 5:35 pm

Everyone,

I have taken a look at the CAD files for the Boom Done, Robot in Three Days. It appears that the approximate gear ratio that they used for their motor driven catapult is around 10:1.

The top gear is 120 teeth with a major diameter of 9.68 inches in diameter. The smaller sprocket is not pictured in detail but I assume that it is the 1.6 inch diameter cylinder. Resulting in a 6.1:1 gear ratio.

The large pulley has a diameter of 5 inches and the small pulley has a diameter of 3 inches. this results in a ratio of 1.6667. The resulting overall gear ratio is 10:1.

Please keep this in mind when experimenting with our shooter.

- Ben