sgt peanut

I have recently decided to get a new brushless motor for my recently repaired plane, and i came to the conclusion that i have no idea how brushless motors work. First of all, how do you determine the sise of your aircraft? I dont want to buy a motor that's physically too big or too small for the airframe. Secondly, what does Kv stand for? I assume the more Kv the more power the motor has, thus how do you figure out which prop to put on it? I do know that brushless motors need brushless esc and the amps on the 2 entities have to match. So yeah.... how do i figure out which motor and prop to get ?

andrewtexas123

A good place to start would be the weight of your aircraft and look at specs of different motors to see what they pull. Most places online will have different charts of what the motor will pull with certain props and battery's.. We need more spec's on the plane to help you find the right motor prop set up.

Is it a trainer, sport, 3D, ect.?
Whats the wing size?
What plane is it?
Weight?

The higher the kv is the more speed it is going to have there for you are gonna want to run small props at high speeds (Ducted fans, pusher jets, and so on) the lower the kv the more torque it will have and with more toruqe it can spin bigger props look for something around 1300kv asuming its a trainer.

Andrew

brett65

My Feedback: (18)

Check the sticky at the top, its for electric newbs, guess how I know! http://www.rcuniverse.com/forum/forumid_102/tt.htm

There is a lot to the electric planes, but they aren't difficult to put together after you figure out what you need.

redfox435cat

kv stands for thousands of revolutions per volt. high kv rating does not mean more power

high kv ratings like small props at higher rpm and pull less amps. lower kv ratings pull more power and swing bigger props slower. The motor is based off size, kv rating and power rating in watts and current rating in amps

There are allot of ways to look at the what size motor to get of motor to get

usually your 480 brushless system is about a 480 sized moroe and would power a 40 sized plane 3.5 to 5 lbs.

sgt peanut

I tried to check out that link but could not find anything i could use (or perhaps understand).
andrewtexas123 asked the dimensions of my plane, well here they are:
Wingspan: 1000mm (37.8 inch)
Length: 835mm (30.8 inch)
Flying Weight: 700g (20 oz)
Speed Controller: 25A Brushless ESC
Servo: 3X 9g high speed micro servos
Battery: 11.1V 1300mah Li-Polymer
http://www.nitroplanes.com/20ar2f4uco3d.html
Thanks for the Kv information, but how do i know what i want:? Should i go with a higher Kv motor and a smaller prop, or a lower Kv motor and a bigger prop? The plane has plenty of power, i want to upgrade because I want it to go faster, however i dont think the design of the nose will allow for a small prop. (check out the link)

sportrider_fz6

if you want more performance try a two blade prop first. they are more efficient. from there try bumping up the KV a bit.