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Old Mar 30, 2007, 07:51 PM
Planes from 1oz to 55lb's
simo10's Avatar
USA, FL, Orlando
Joined Aug 2004
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My new test stand measures effciency by using torque and rpm measurements.

I just built a new test stand that measures efficiency of the whole powertrain (including prop!!) by measuring torque and rpm. When all the units are converted to SI, Grams of torque to Newton/meter and rpm to radian/second (rad/s) all you have to do is multiply the revolutions by the torque and it gives you output in watts! Then just divide Output/Input and you will get a percentage.

I will get pics up in a few minute, let me find the camera.

simo10
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Old Mar 30, 2007, 08:08 PM
Planes from 1oz to 55lb's
simo10's Avatar
USA, FL, Orlando
Joined Aug 2004
1,278 Posts
Here are the pics. The entire motor rotates on an old crankshaft and 2 bearings. The connecting rod is used and that pushes down on the scale and measures torque.

RPM's, amps, volts, estimated efficiency, time, and watts are measure by the E-meter. Please realize it still needs a little more work and an extra scale so I can measure thrust as well. The pictured balance will eventually go between the support brace and the base and move with the stand.

simo10
Thanks for checking out my project,

If you have any questions please ask!!!
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Old Mar 30, 2007, 08:11 PM
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Fountain Valley, California
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I don't think I've seen a test stand to measure torque before...intriguing.

Will
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Old Mar 30, 2007, 08:16 PM
Planes from 1oz to 55lb's
simo10's Avatar
USA, FL, Orlando
Joined Aug 2004
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Inspiration came from this guy

http://www.unitedhobbies.com/communi...ts.asp?TID=308
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Old Mar 30, 2007, 08:18 PM
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Nice. I look forward to your tests. Any chance there'll be a video?

Will
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Old Mar 30, 2007, 08:27 PM
jrb
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Edina, MN, USA
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Very nice!

Though, but you can only get total system efficiency if you measure both thrust and velocity off the back of the prop.
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Old Mar 30, 2007, 08:38 PM
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That motor is GINORMOUS! What was it used in?

Will
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Old Mar 30, 2007, 09:42 PM
jrb
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Edina, MN, USA
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Assume you mean my motor?

Its used for prop testing – 22” shown.

Since its synchronous, its rpm remains constant!

Tells a lot about props (dia & PITCH) when run at constant rpm.
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Old Mar 31, 2007, 06:51 PM
Planes from 1oz to 55lb's
simo10's Avatar
USA, FL, Orlando
Joined Aug 2004
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A few tests with a park 480 1020kv with a 10x7 prop, tested with a 3s 3300 20c pack and a CC60. Remember the efficiency is for the WHOLE power system, so naturally, it's a little lower than what it is spec'd at.

Have fun!
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Old Mar 31, 2007, 06:58 PM
Planes from 1oz to 55lb's
simo10's Avatar
USA, FL, Orlando
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and i finally mounted the scale correctly. I have a lab quality 10kg 2gram resolution scale coming for thrust measurements.
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Old Apr 07, 2007, 11:02 AM
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Blackpool, Great Britain (UK)
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Quote:
Originally Posted by willhaney
I don't think I've seen a test stand to measure torque before...intriguing.

Will
Then you have not searched this website.
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Old Apr 07, 2007, 11:05 AM
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Quote:
Originally Posted by peterangus
Then you have not searched this website.
Never thought to.
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Old Apr 07, 2007, 11:07 AM
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Quote:
Originally Posted by simo10
A few tests with a park 480 1020kv with a 10x7 prop, tested with a 3s 3300 20c pack and a CC60. Remember the efficiency is for the WHOLE power system, so naturally, it's a little lower than what it is spec'd at.

Have fun!
The efficiencies you quote in post #9 are motor efficiencies.
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Old Apr 07, 2007, 11:32 AM
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What's up peterangus?
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Old Apr 07, 2007, 12:56 PM
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Dr Kiwi's Avatar
Chattanooga, Tennessee, United States
Joined May 2003
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Here is a picture of my thrust stand modified as a crude Torque Measuring rig.
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