Measuring Brushless Motor's Thrust,Amps easily

by Amit RC | September 13, 2017 | (4) Posted in How To

In this article I show you How to measure Brushless Motor's Thrust,Amps & watts at the same time. 

For this you need to have Kitchen Weight Scale and a Power analyser or watt meter. 

Its very important to know the exact thrust and maximum amps drawn by the motor so you will know which ESC & Prop can be used with the motor.

This test lets you know which prop to use for what thrust and which prop is the efficient one.

Advantages of this measurement test are -  

1. You can decide what size prop & pitch is best for motor.

2. you know which esc to use .

3. Before scratch building or designing a new rc plane model, quad you know your motor's thrust capabilities.

4. You become sure that you will not overburden the esc and the current.

5. you can estimate flight time.

So to do this measurement, you will need to attach brushless motor on weight scale in the center. I used cello tape or packing tape.

Don't worry, its not going to come off because motor will be pushing on weight scale and not pulling.

Important things to do - 

 Motor must be in Pusher Configuration.

Prop must be balanced before the test. If not balanced, it will have crazy vibrations and you know, vibrations are not good..

Calibrate the ESC correctly.

Then connect your ESC power cable on Power Analyser's  "Load" side.

Then connect  Power Analyser's Input side to Lipo battery. This should power everything ON.

Then slowly raise throttle upto 25% and observe the Thrust on weight scale and respective current,watts on Power analyser.

Similarly increase throttle at 50 %, 75 %, 100 % and observe the readings.

Its that simple. Now you have all the thrust,current,watts readings with you.

I hope this article helps you. 

Happy flying.


mikeflight on September 19, 2017
Great idea and great video. Measuring thrust your way will be very accurate. Thanks for sharing.
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Amit RC on September 27, 2017
Thanks. Glad that it helps.
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thenated0g on September 19, 2017

Great setup, nice and simple. I would recommend a couple Indents in the article though.
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Amit RC on September 27, 2017
Yes.Its very simple. Appreciate your input.
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Mach60 on October 27, 2017
So, the scale is zeroed first and the indicated weight is the thrust in grams? If I have a 800 g plane and the thrust is 800 g, then I have a 1:1 weight to thrust ratio...correct? Thanks for putting this information out there.
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Amit RC on October 27, 2017
Yes you are correct.Thrust in grams & scale zeroed first. Cheers. Happy Flying.
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Measuring Brushless Motor's Thrust,Amps easily