RideTest

What can you do when you have an old and almost broken powerpod, a bad weather outside and one hour sitting at home? In this article I use very basic and FT friendly materials to make a simple RC car to have fun at home. 

The biggest problem about making this possible using an RC plane motor is reduction. An RC motor usually has a high rotation speed determined by the KVs. But cars have a high mass and the wheels usually spin much slower than a propeller does. What we need is to convert down all that speed into torque to move the car mass at slow speeds. Here I show a cheap idea to convert your old powerpod into an RC car gear.

The basic needed intems are:

• 1 old power pod with a motor
• 1 old servo
• 1 tail wheel (or you can make one)
• 7x10 inch sheet of foam
• a scrap piece of foam to make wheels and gears
• 2 office rubber bands
• 2S battery

In the table* bellow, I made the calculations of how much I would need to reduce the motor rotations to get a maximum speed of 25km/h using a 800kv motor (slowest I had) with a 2 cell battery. Then I planned the wheel sizes as you can see in rows 8 to 11.

 *the table is in the metric system

 The main functionality is very simple and is detailed in the illustrations bellow. First let us take a look at the gearbox seen from behind.

Gluing a piece of straw to the power pod, we can make a rotating axis with a barbecue skewer. A piece of foam should work fine as stopper. The yellow dots simbolize where the rubber band comes in and out the wheels. The left wheel is linked to the motor and the right wheel to the front wheels.

The front wheels are illustrated next.

The motor has the 1.5cm wheel and is linked to the 3cm wheel though a regular office rubber band. Make sure the motor wheel is well aligned with the gearbox'es 3cm wheel. Then, the 1.2cm wheel, glued in the same axis (see gearbox image), is connected to the 2cm wheel with the same kind of rubber band. In this last link, the rubber band passes through a hole cut into the foam made clearer in the final picture. This last 2cm wheel is already attached to the front wheels axis (see front wheels picture). Finally I usued a standard tailwheel to make it steerable. 

In the picture above we can see how the motor is aligned to the gearbox. The motor on the front also helps the traction on the front wheels. Hint: use a folded sandpaper to make a groove into the foam of the wheels to guide the rubber bands so they do not fall off.

In the picture we also see the layout and also the extra stuff I added to have fun. A camera, a transmiter and a spearker. If you just playing at home you can simply attach your cell phone and make a call through skype(or something similar) and drive around using a video call. That is why there is a speaker: so that you can have a louder phone and you can talk to whom is wandering around. 

In the next picture you can take a first glance at the setup and how it can look like.

Check the video and you will see some of the fun capabilities of this RideTest!