Basic R/C Rubber Tread Tank

My current solution for a rc vehicle I can drive in grass up to around 6" tall while still doing ok on smoother surfaces. Overall design objective was a simple setup with a modest overall cost (especially if you have a few makeblock parts already).

Tank uses two brushed high turn 555 motors running on 3S. Unit is about 250mm (10") long with an overall weight around 1.3kg (3 lbs) and top speed of 18 kph (11 mph). Practical speeds in grass are limited by the lack of suspension, tread slip on the grass, and retention of the rubber track - but it is at least 10 kph (5-6 mph).