brushless motor selection question

[mountaindewdude76]

I'm curious to know how to select, with confidence, an appropriate brushless motor for my scratch builds. How is this done? I believe that I understand what the "kv" rating means. Higher "kv" means more speed, less torque/power. Lower "kv" means more torque/power but less speed. However there are so many different sizes of motors, how to select one for my scratch builds?

Any help will be appreciated.

Thanks in advance!!!

 

[earthsciteach]

I can't adequately explain the "how," but when in doubt I consult Jeff at www.HeadsUpRC.com. I prefer to order from them because their service is top notch and they have a flat rate shipping fee of $2 for all but large items (those are $4). If you give them the weight of your plane, wingspan and desired performance, they will recommend a motor/esc/prop combo for you.

To learn the "ins and outs" of power system selection, this is a great resource: http://www.wattflyer.com/forums/showthread.php?t=18521

 

[pgerts]

You must know the size of you plane.
Best is to compare with another similar plane and get what is recommended.

There are lots of recommendations of how many watts/wieght depending on the style of flying from oldtimer-scale-slow to the extreme 3D or racing planes.

KV is only interesting to compare when comparing motors in the same power range and same battery.

a big 200 KV motor will give you a lot more speed om a big plane with 12 cell LiPo battery than a 2000 KV motor vill give you on an indoor plane with 2 cells.