Thrust Measurement Device

[JasonK]

I rigged up a thrust measurement device on my bench, do you see any issues with how this is setup?

 

[Arcfyre]

I like the idea, but you're basically limited to testing prop sizes that fit between your uprights. If you rotate the motor mount assembly by 180° and mount the prop in a "pusher" configuration, you can test any size prop you want. As an added bonus, it will be easier to change out the props as well.

 

[Merv]

Your setup should work.

 

[Aireal Anarchist]

I like the idea, but you're basically limited to testing prop sizes that fit between your uprights. If you rotate the motor mount assembly by 180° and mount the prop in a "pusher" configuration, you can test any size prop you want. As an added bonus, it will be easier to change out the props as well.

less thrust in the pusher config....one of the members tested pusher vs tractor and there was a 10mph difference

 

[JasonK]

Your setup should work.

thanks, I already figured out that 'lifting' didn't work because of the air coming off the prop would push back down on the sensor countering much of the thrust. I verified by changing the distance the prop was off the bed and got different reading.

at least now I can test the various motors/props that I have and see if I can work out some combination that gets me my needed static thrust (hovering/vertical take off).

 

[joji]

This is super clever, I never thought about measuring thrust like this! Very cool!

 

[PsyBorg]

I might rethink the single beam mounting of the motor. I would think things could get quite dramatic should the motor decide to rotate on that axis mid full pull test.

 

[tamuct01]

From a safety standpoint, it would be best to have a setup where you can read the output of the scale while not standing in the prop arc. Should the prop fail during a test, you have a chance of catching a blade in the chest with that setup.

 

[JasonK]

From a safety standpoint, it would be best to have a setup where you can read the output of the scale while not standing in the prop arc. Should the prop fail during a test, you have a chance of catching a blade in the chest with that setup.

how often do people have props fail on these tiny motors?

 

[JasonK]

I might rethink the single beam mounting of the motor. I would think things could get quite dramatic should the motor decide to rotate on that axis mid full pull test.

if I was testing larger motors that would make sense, however the 'biggest' motor I have, the most thrust I have got out of it was ~400g and it stayed pulling straight down (slightly different build, ended up with 2 sticks as I was worried the motor might snap the stick with the flex in it).

 

[PsyBorg]

how often do people have props fail on these tiny motors?

Depends on what make of prop and type materials.. To me gemfan props break if you look at em funny as they are super solid and brittle where as others like the V1s v2 are nearly made of rubber...

I have cracked Gemfan hubs just snugging down the nyloc nuts enough so the hard material didnt slide on the motor bell.