Installing a Failsafe

Anyone who runs a nitro truck is aware of the danger of a runaway. If the batteries are low, you run into radio interference, or run out of radio range, the servo will continue to do the last thing you told it. More often than not, it's full speed ahead. This can cause many problems, such as a full speed crash or a blown motor. A failsafe takes over when these conditions occur and returns the throttle servo to a preset position. So instead of running away, the truck's throttle will return to neutral or apply the brakes.

Installing a failsafe is easy. I chose to use the Dynamite Race Guard. I also have a review of this failsafe here. When installing the failsafe, I wanted to try to make it fit in the stock receiver cover so that it was protected and my T-Maxx would have an uncluttered look. Here's the procedure I used.

First I removed the antenna tube and receiver cover.

Then I removed the throttle servo plug, which in most cases is the Channel 2 slot.

To make the assembly easy to reinstall in the cover, I decided to attach the failsafe to the receiver with some double-sided tape as shown below.

Then I attached the female end of the failsafe, to the failsafe itself, with more double-sided tape.

Now all I had to do was to plug the servo's plug into the female end of the failsafe, and plug the failsafe into the Channel 2 slot of the receiver. After this I turned the radio and receiver on to ensure they were working properly and set the failsafe according to the directions. Instead of choosing to return the throttle servo to a neutral position, I set it to have some pressure applied to the brakes. This way if I was running downhill when the failsafe took over it would bring my truck to a gentle stop. Returning the servo to the neutral position would allow the truck to continue to coast, and wished to avoid that scenario.

To test the failsafe's actions you can simply switch off the radio while leaving the receiver on. When you turn the radio off, the throttle servo should immediately move to the position you adjusted it to when you followed the instructions to set the failsafe.

Now comes the tricky part. Putting it all back in the receiver cover. Try and keep the wires on top of the receiver and not the failsafe. There isn't going to be any room between the failsafe and the receiver cover. Gently push the receiver and the failsafe back into the cover. Make sure you don't pinch any wires and that they all exit the box at the appropriate notch on the side that faces the front of the truck. You want the receiver to be close to level with the bottom of the cover before placing it back on the truck.

Once you've installed the electronics, place the cover back in it's respective place and tighten the screws down. Follow that up with a quick test of the failsafe and the electronics and if everything looks good you're ready to go!!!

Despite the benefits of a failsafe, it will not protect you if power is cut off suddenly. Examples of this would include, the power switch accidentally moving to the off position or the receiver pack coming unplugged. So to offer the best protection against a runaway truck, you should also install a throttle return spring which would cover those circumstances. For more information, see my section on throttle springs.

Below is a list of failsafes that should work well with your T-Maxx. However, not all of these may fit into the stock receiver box.

• Dynamite Race Guard Fail Safe
• Dynamite Race Guard Micro Fail Safe
• Futaba FS-1 Fail Safe
• KO Propo
• OFNA Fail Safe
• Venom Fail Safe

As of the time of this writing the Dynamite Race Guard does not have a copy of the instructions available online. Since I run this failsafe and have a copy of the instructions I have made a copy available for anyone who may need it. To view this document you will need to use the Adobe Acrobat Reader which can be downloaded for free. Click here for the instructions.