This is a Knex battlebot that is around 1.5ft long and 1ft high.
It is powered by the large silver motor (Terrain Trekker I Think).
The motor powers both the wheels and the blade on the front. On the wheel axis is a small pulley that has a rubber band on that links up to another pulley on the blade axis. Making it power both.
The batteries in my motor are very old so the motor isnt at it's strongest (shown in the video)
Also, there are 5 red cogs at the ack as a counterweight. Without them, the blade becomestoo heavy and it tips over.
The video of it working is here:
Tell me in a comment if you want me to post.