just out of curiousity, if i upgrade my blade to brushless using this http://www.helidirect.com/product_in...oducts_id=1524 motor with 9t pinion, what Amp do i need for a esc? eflight recommend a 20amp for their 4100kv, some gone with 25, some even gone with 35A, what should be sufficient?

i used to run a 25A esc until a few weeks ago, after i hooked up my wattmeter to my 4100kV w/8T and got 9A at full collective (+12 degrees pitch); this was at the battery, with a long can geared brushless tail spinning ~half speed, so the main motor was probably drawing closer to 6A. ever since i've been running a 10A esc to save weight.

haha, thx, so even teh 20A is overkill what was the 4100kv's no low current draw? the motor above is 2.6A. just trying to get some states so that if i ever decide to go bl, i'll know what esc to get.

opened up my manual and found this:
himax 2015 4100kV:
no load current = 0.80A
efficient operating current = 5-12A
recommended esc = 10A

looked a bit more and saw this:

himax 2015 3600kV:
no load current = 0.54A
efficient operating current = 3-8A
recommended esc = 8A

2.6A is a high no load current. don't know a whole lot about brushless terminology, but i guess higher no load current means more current is required to spin same RPM without a load. so i think lower no load current = higher efficiency, but not sure if things change a lot when the motor is loaded.[]

hope this helps.

just found this link if your curious:

[link=http://davesrcflight.mysite.wanadoo-members.co.uk/frame_pages/electric_flight_frame4.htm]http://davesrcflight.mysite.wanadoo-members.co.uk/frame_pages/electric_flight_frame4.htm[/link]

i guess Rm (winding resistance) is also an important factor when comparing motors. that page explains a bit more about brushless theory and gives a few equations to go with it. may or may not help, but it's good info to know anyways. i found out i was wrong about no load current. apparently it's independent of rpm or voltage. interesting huh?

hmmm...0.58 no load current?! that's pretty good, i've read somewhere else that even though no load resistance is independent of everything else, a lower no load current will usually make a better motor, the eflight's 4100 has a no load current 1A. i guess 2.6A is VERY high then... no wonder it's dat cheap thx, i was just trying to get some data.

Chopperdudes,

I have the same motor on my CP Pro and use the Sonix 18A esc.

The motor runs cool to warm and the esc is barely warm after 8 minute flights. That motor has plenty of power with the 9t pinion. With my Futaba 6exh radio, I really have to lower the throttle curve. If I run the high end at 100 %, I'm pretty sure the head would explode. It also runs fine with the stock radio.