Essentially several key elements are required:
At the moment I am in the building stage of this rig and I am outlining some of the design considerations here. After testing I'll also start to post results from the dyno testing.Mechanical arrangement
How do you know what is the optimum prop selection for the motor you have? Traditionally you could either rely on manufacturers data for a small selection of props or invest substantial time and money in a motor dynamometer. Using this arrangement and simple (cheap) hand-held instruments you can characterise motor efficiency, thrust and power for most common propellers.
The mechanical arrangement and strain gauge installation is shown below:
The theoretical considerations of the torque are shown below for torque:
The theoretical considerations of the force are shown below for thrust:
So from measurements from these two bridges the force (P) in Newtons and torque (T) in Nm can be calculated. But this isn't the whole story; the measurements we really want are:
In order to make these measurements the following considerations must be made: