motor KV

[goly]

hi there

i am trying to understand the motor specs
what effect does the KV value on the brushless motors?
when should i choose one KV over other value?
what effect it has on the prop selection?

[Callardo]

Heya

I am only a newbie myself ... my first post, so I am sure some one can explain a bit better than me

As i understand it KV is the measure of RPM per volt ... so a 900 kv motor would spin at 900 rpm at 1 volt

Smaller motors tend to have higher KV than the larger ones and less torque

Lower KV motors are larger but have more torque

As for prop selection .. I haven't a clue yet ... But i assume you would use a low KV motor on bigger props ?

I am sure there is some real geeky equations you can do to find out the correct prop size for motor size and weight of aircraft plus what you would like to achieve ... top speed, lift etc ....

[drg964]

I see Bruce is starting to cover this topic in his latest youtube channel

http://www.youtube.com/watch?v=JQkTm-vuFGI&feature=youtube_gdata