Progression of the RC Mini Tank

 

This is the first servo based tank I built.

The idea to use servos to drive the tank came about in a most accidental way. Initially, I took apart a spare servo I had to reverse its direction. I needed a reversed servo for use in my Rover 6 Stampede, to steer the back set of wheels. I decided to try to change the polarity of the little motor inside the servo to accomplish this. Unfortunately this did not work since the pot needs to be changed too. However while I was tinkering with the servo I discovered that drive motor had a small amount of proportional control to its speed. It acted much like a motor with a speed control; with both forward and reverse to boot. After removing the devices that only allowed it to turn about 60 degrees, I reassembled the servo and now had a slow turning, but proportional and strong drive unit!

Here is the second mini tank built (actually an APC).

This tank initially was going to have a much different drive system than it ended up with. Like the first tank, it was going to be powered by two servos. However, the servos would then transfer power to a mini belt drive system that would speed up the tank. After some late experimentation, it was decided that the small belts (actually rubber bands) simply would not be able to proved sufficient torque.

To replace the original drive train, a Tamiya twin motor gearbox unit was purchased. It took up a lot less space and provided a solid power transfer, but a new problem arose of how to run the motors on it. There area a lot of RC car speed controls that would easily handle a small 110 sized motor, but cost now was an issue. Figure about $50 for a reversing, mini controller and then double that. For a while I didn’t know what to do. I didn’t want to spend that much money on the little tank, but I didn’t want to abandon the project either. Fortunately I found a site (robotmarketplace.com) that had exactly what I needed: a very small, dual motor speed controller for a reasonable price. With that last component the tank was completed.

This is the third version of the RC mini tank.

This is the design that the instructions will show you how to build. It is very similar to the first tank, but with a lot of simplification done to the chassis design. Practically all angles have been removed (except for two which are optional), and the chassis has been reduced to the minimum size to reduce weight and increase climbing ability. The only tools that are needed to build this are a saw and a drill. With some patience even a hand saw and drill will work on the wooden chassis.

Hopefully with the design being reduced to only the essentials, more people will be able to build one themselves. After all, that was the main reason for designing this version in the first place.