Cutting Cooling Holes

Your nitro-powered RC car or truck is very dependant upon airflow reaching the motor head. While during the winter, you may be able to survive without a cooling hole cut in the body, you'll find that most of the year you'll end up overheating the motor if you avoid this crucial step.

When cutting a cooling hole, or holes, there are a few things you should keep in mind. So let me walk some things that will help you place the holes correctly, and still retain a strong body.

First of all, more is not necessarily better. When cutting a cooling hole in the front windshield, the last thing you want to do is to cut out the windshield in its entirety. This is a very common mistake. Typically, you'll only need a hole about 1/3 the size of the windshield, and you'll place it in front of where the motor resides. Not only that, but you should also keep the corners as round as possible. I normally use a hole saw, which cuts the hole easily and makes it a perfect circle as well, as illustrated by the example below of a hole in the windshield of a stock Revo body.

In the event you don't have access to a hole saw, you can use a hobby knife or lexan scissors. However I would suggest using a drill bit for the corners, and trimming between the holes. That will result in the corners being well rounded. This is illustrated in in the picture below.

It is also important to provide a proper exit path for the airflow as well. However, again proper strategy must be used as well. This is often complicated by the various bodies on the market. Generally, your exit path should be about twice the size of the entry opening. However, it's usually best to avoid cutting too far above the head as you want to make the air flow through the cooling fins in the motor's head. So while you can get away with trimming out the entire back window on a Jeep body if you have a tall cooling head, a smaller head may work better with only the lower half cut out. I recommend cutting as little as possible, and work from there. You can always take more off if needed. Some bodies, truck bodies for example, may provide enough outgoing airflow without needing to be cut at all.