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Old 02-09-2007, 08:21 AM
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Default RE: Electric motor help

RPMs per volt.

Depending on your application (geared, direct drive, inrunner, outrunner ) you will need this info.

For example:
On a recent 40 size model I just finished I wanted to use an outrunner motor with a 12x8 or 12x10 prop turning ABOUT 8,000 - 9,000 rpm to generate the thrust I needed.

Using other criteria I determined the wattage of the motor I needed.

Then I determined I would need to use a 4 cell lipo battery (14.8 volts) for this motor. Dividing the rpms by the voltage I determined I needed a motor that had a kv between 540 and 608 rpms per volt to provide the rpm range I wanted.