Thats what systems like Traxxas telemetry does. It reads motor RPM, as well as other parameters, but, only if you have all of the corresponding parts, and a sensored motor, and, with a bluetooth link module, you can read it in real time from a smartphone. I dont have the Traxxas system, but, a...
I dont know why you would want all that on a Redcat Volcano, but, multiple companies make systems that do what you are looking for. Traxxas has a system (Traxxas link, and Traxxas Telemetry) that does RPM, temp, speed, and a bunch of other parameters, and can even be set up to link to your phone...