Motor Help

[keith4896]

Hi all,

I am trying to choose a motor for my air craft however i am stuck with complication of motor numbers. Can someone help me?

Alot of specification of the motor actually states four number before the motor can someone tell me what does these numbers means? I have been reading alot of articles on motor specification however none explain the numbers.

Example: C28-34 1120KV

What does this means and how does it affect the air craft ?

[JieZ]

Hi all,

I am trying to choose a motor for my air craft however i am stuck with complication of motor numbers. Can someone help me?

Alot of specification of the motor actually states four number before the motor can someone tell me what does these numbers means? I have been reading alot of articles on motor specification however none explain the numbers.

Example: C28-34 1120KV

What does this means and how does it affect the air craft ?

The first two numbers (28) is the diameter of the motor while the last two (34) is the length of it

[blueangel]

all else equal, a longer motor has more power.
all else equal, a bigger diameter motor has more power.
Kv is rpm per volt supplied.
lower Kv suitable for big props while high Kv for small props.

[keith4896]

Thank you, so in this case if I choose motor does that means i do need not have to have the same diameter and length of the original recommended one?

In this case, most of the motor that is bigger has a lower KV, so if i have a orignal motor that is 2208N 2200 KV and I change one that is C28-26-09 1900KV does that mean the new motor will be more faster?

[rayshaw23]

on the topic of motor... why does a higher KV suit smaller prop? or vice versa? thank you... newbie here...

[JieZ]

Thank you, so in this case if I choose motor does that means i do need not have to have the same diameter and length of the original recommended one?

In this case, most of the motor that is bigger has a lower KV, so if i have a orignal motor that is 2208N 2200 KV and I change one that is C28-26-09 1900KV does that mean the new motor will be more faster?

I think the new motor can go for a bigger prop which have more thrust.

[jansonfinn]

Hi all,

I am trying to choose a motor for my air craft however i am stuck with complication of motor numbers. Can someone help me?

Alot of specification of the motor actually states four number before the motor can someone tell me what does these numbers means? I have been reading alot of articles on motor specification however none explain the numbers.

Example: C28-34 1120KV

What does this means and how does it affect the air craft ?

I'm not sure if u have covered this.

Before u choose a suitable motor from those numbers, make sure that u match a motor which can support to your aircraft flying weight.

[keith4896]

It is ok to have a bigger and stronger motor right?

[blueangel]

It is best to get a motor somewhere in the recommended specification by the plane manufacturer. It may be wise to step up the power up slight but too big leap. Heavier motor need more power and thus bigger ESC and battery pack.

But then, if you though getting a light weight high Kv motor will be better because it is smaller and lighter and you start to you smaller propellers ( also you though small propellers can have more clearance during landing ) , you also getting nowhere because the air stream generated by the small propeller diameter will not be able to generate the power to push the plane forward because most of the air stream will be disturbed ( blocked ) by the fuselage.

Take for example :
you have a 3 inch diameter fuselage and your propeller is 3 inch length.. all the air being generated by the propellers are block by the fuselage.

Generally, I take the GWS planes as a guide of 1 meter span and 500 gram flying weight, 1200 Kv closely matches any 8X4 or 8X6 propellers. Full of power and full of speed... can go vertical climb.

[keith4896]

In this case am I right to say that around 1200 kv will be nice for gws model?? I am planning to get a e starter with brushless, have a 30a hobbywing esc. Which motor is recommended??

[wireless]

This motor is cheap and good, but may be too powerful for beginner I think.

Best pair with 9x6 or 9x8 propeller.

Get it from R o t o r H o b b y.





Outrunner Brushless Motor 1038KV
Turns = 8
Running-Light Current = 1.1A
LiPo Battery = 3-4 cell
Max Permissible Current = 25A
Running current < 20A
Weight = 68g
Shaft = Ø4mm
Max Pull = 1.2 kg
Propeller = < 10x7



List Price SGD 27.80


Website = http://shop.rotor.com.sg/show-detail.asp?prodid={7B99018F-7BF0-4049-A0C9-1832CE651065}&pn=1

[blueangel]

LiPo Battery = 3-4 cell
Max Pull = 1.2 kg

A bit over powered for a 500 gram plane. If you planning to get GWS or similar plane size / weight, I would recommend a motor that says 2~3 cell instead. My motor has about 700 ~ 800 gram.. more than enough.

[rayshaw23]

can i also advise that u might want to consider the dimension of the motor. u dont want to have a really long motor which expose too much motor shaft behind the prop, esp if u are going for scale or war bird... it might not be so visually appealling.

[rockinanko]

A bit over powered for a 500 gram plane. If you planning to get GWS or similar plane size / weight, I would recommend a motor that says 2~3 cell instead. My motor has about 700 ~ 800 gram.. more than enough.

i'm using this motor type for my SS too, it a 980kv motor mated with 10 x 4.7SF...just nice for the normal SS.

[keith4896]

Hi all, thanks once again. Went to rotor but the motor is out of stock.. Bought a 2830 1290kv 9t motor instead. Recommend prop is 9x5. May I know what does the 5 means?What kind of different will I see if I use a lower prop? What does the pitch makes a different ??