RC Motor Dynomometer (Dyno)

The 3D print files for my RC Motor Dyno project - code and other files will appear at the project's Github page.

Discussion of the dyno project will be on the thread at RC Tech.

Aim
So what is it then? It's an inertial dynomometer (dyno) which measures the rate of accleration of a known mass with a known moment of inertia. By measuring the rate of accleration and multiplying it by the moment of inertia, we get torque, and from there via another equation, power.

Steps
Two major milestones for the project for me:

1. Get something working that I can use to test motors in Simple Dyno

2. Do the measuring myself and build a GUI/app around this

How will it work?
I'd like to measure 3 parameters

1. ESC Input Voltage

2. Current drawn

3. RPM (and by calculation from this, acceleration) using a hall sensor detecting the change in magnetic flux as the magnets on the inertial flywheel passes over it.

Progress so far:
I've designed and 3D printed:
- The inertial flywheel pieces
- The assembly housing (with hall sensor mount, the mount will change slightly to improve it)
- The assembly lid
- A spacer piece to get the motor plate to the correct height to allow a flexible coupling to fit between the flywheel and the motor shafts
- The motor plate

The Flywheel
The Flywheel is reasonably simple, it's a D-shaped M6 rod, 100mm long, around which is fitted 3D printed assemblies housing and clamping 2x M20 washers (they weight approx 60g each). All up weight of the flywheel assembly is 201.4g. EDIT: I need further testing to confirm the ideal weight. I may make some spacer pieces which can be inserted in place of one of the M20 washers.

The idea is to run the motor, capture the acceleration and RPM of the flywheel via the hall sensor, and to calculate torque and power. In the 1st step, I'll do this with Simple Dyno, in the 2nd step, I'll write the program to do this part too. I want to be able to do calibration runs so if someone builds themselves with a slightly different flywheel mass, they can get accurate readings.

Printed in PLA 1.75mm. 

Quite a lot of M3 screws are needed of varying lengths as well as some M3 flat nuts. M3 x 10mm thumbscrews are a quality of life addition to aid quick assembly/disassembly.