Brushless Motor Dynamometer from RCbenchmark

RCbenchmark dynamometer website

Please comment and send feedback below. A few months ago, I posted here asking if you would be interested in a dynamometer. I received quite a lot of comments. My colleague and I had the idea of a dynamometer for brushless motor after working over one month full time on a custom motor tester for our drone. We thought that there should be a better solution available on the market. Since there wasn’t anything, we have been working full time on that project, and we are ready to release the result of many iterations and prototypes!


Our dynamometer can fully characterize propellers, and brushless inrunners and outrunners up to 40A and 3kg of thrust. The tool measures thrust, torque, voltage, current, RPM, and it has a precision ohmeter to measure the motor's coils resistance. The data is saved to a CSV file manually or continuously. Here are the technical specs:

 Voltage (0-35 V)

  • Current (0-40 A)

  • Thrust (±3 kg)

  • Torque (±1.5 Nm)

  • Rotations per minute (up to 190000 erpm)

  • Motor winding resistance (0.003 to 240 Ohm)

  • Accelerometer on PCB

See the datasheet (PDF) for more information.


Our software is open source (link to the gitlab repository), and we are actively developing it. We hope it will be hacked and improved! It has safety cut offs (reduce your chance of burning your motor), a calibration wizard, unit selection, CSV export, and much more.  If you are curious, have a look at sample results of tests made with our dynamometer here.


At the time of writing we have 14 units left available at a reduced priced for the beta period. Please join us in this project and send us feedback in the comments below!



Charles and Dominic

Views: 2087

Comment by Thijs Sillen on August 30, 2015 at 6:05am

Use a PGA, will allow good resolution for small motors and allow higher currents :)

Comment by Dominic Robillard on August 30, 2015 at 9:15pm

@Thijs Sillen: we already use a PGA for the load cells, current, and voltage sensors. Making our unit support more power would make it more expensive as many components (connectors, hardware, electronics, shunt, etc...) would need to be bigger. Until we release a more powerful version you can always buy our device, hack our open source software and build your own hardware to support it :)

Comment by DG on September 6, 2015 at 8:05pm

Do you get different results when testing with the prop horizontal to the ground vs vertical?

Comment by Charles Blouin on September 7, 2015 at 6:17am

@DG We have not tested, although the device can be attach vertically or horizontally (nothing will prevent that in the firmware). If there is nothing in the way of the propeller (objects could cause ground effect), there should not be any difference between the two orientations.

In practice however, we install it the way you see it in the video for practical and safety reasons. If the prop breaks, it will be ejected along the disk of rotation. It is often easier to place a protection wall with the prop aligned horizontally.

Comment by Charles Blouin on February 8, 2019 at 9:20am

@Bjoern Kellermann 3.5 years, later, we deliver the database! The GUI can now upload data automatically. The database is still in alpha, but it is useable. We will implement more visualization features and a better UI and look soon.


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