Relay box

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


Nov 10, 2009
Reaction score
Hi All
I am new to the site but have been building small scale rockets on and off for some time. I am getting back in and I am building my own control box. Can some one please tell me what the use of a relay box is for? And a good source to find a scamatic for one. Thank -you
Welcome to TRF :)!

A relay box resolves the problem of the resistance caused by the wire from the rocket preventing the igniter from firing. It is basically an extra box that is placed right next to the rocket that the battery, and the launch controller with its highly resistive wires, is connected to. This means that the distance from you to the rocket can be large (safety), but the distance from the battery to the rocket very short (less resistance). Check out for details on how to build one.

Hopes this helps :)