Choosing Quadcopter Motors Is Tricky

Quadcopter Motors Are Many and Varied

Without a motor – or rather, four of them – your quadcopter isn’t going anywhere. With the wrong motors, your aircraft probably isn’t going where you want it to either. Choosing your quadcopter motors then is a crucial part of putting together your DIY quadcopter. (I’m assuming you’re building your own machine, if you’re looking for advice on motors here.)

MultiStar 2209 V2
MultiStar 2209 V2

Propellers must be properly matched to your motors. Sometimes they are even sold as a bundle because someone else has done the work of finding the right pairing for you. However, in this article I’m just going to concentrate on the quadcopter motor itself.

As you’ll soon see, there are very many motors from which you can choose, but you can narrow your options with a little math and common sense.

How To Calculate Which Motor I Need for My Quadcopter

To keep your quadcopter aloft, something needs to thrust it into the air. That something is your motor (and propellers). So you need to figure out how much thrust you need based on the weight of your machine.

Assuming again that you’re building your own quadcopter, you probably realize that until it’s all put together, you won’t know exactly how much it weighs. Don’t worry, because you can estimate most of the weights and get close enough to determine which motors will be able to make it fly.

There is a “rule of thumb” that you may have heard or read elsewhere that says your (four) motors should produce twice the weight of your aircraft in thrust. So you calculate the thrust for a single motor by doubling the quadcopter’s (estimated) weight and then dividing by four. Another way to think of this is that a motor produces half of your machine’s weight in thrust.

I’ve seen math done that says the average quadcopter is likely to weigh around 1.3kg. That depends on your definition of “average”.

I’ve also seen the suggestion that, if you’re planning an aerobatic aircraft, you should get motors with a speed of about 1000-1400Kv. For larger quadcopters (or if you plan to carry a payload), look for 700-900Kv motors.

Quanum MT 5208
Quanum MT 5208

HobbyKing has a nice online tool for helping you find your motor. Not surprisingly, it’s called the HobbyKing Motor Finder. You can set sliders to limit the speed, weight, current, voltage, power, and several dimensions of your quadcopter motors.

The table below (which understandably will eventually become dated) shows some basic bits of data for nearly a dozen dozen motors, most of which you can find at HobbyKing currently. There is much more information available online for each motor, but this should help you get started. You might notice that, in general and as expected, as the weight decreases (i.e. the motor gets smaller), the speed increases.

Motors

MotorSpeed (Kv)Weight (g)
Aerodrive SK3 2822127531
Aerodrive SK3 2826124045
Aerostar 4340500220
Aerostar 4340720199
AX-2810Q75070
AX-400565059
AX-4008Q62088
Cobra 2204230025
Cobra 2204196023
Cobra CM2206200036
DYS BE 1806230018
DYS BE 1806-13230024
DYS BE 4114400146
DYS BE 4715330200
DYS BE 8108100240
DYS BE 8108135240
DYS BX 1306310013
DYS BX 1306230013
DYS BX 1804230016
Emax 1806228019.2
EMax MT1804248014
EMax MT1806228019.2
EMax MT2204230025
Emax PM1306280012.8
Emax PM1806230019
HobbyKing AP-0270002.3
Lumenier FX2206200032
MultiStar 1704190013.5
MultiStar 2204230024
MultiStar 2206215030
MultiStar 220998044
MultiStar 2209 V298048
MultiStar 2209120039.8
MultiStar 221398058
MultiStar 221680066
MultiStar 2216 V280083
MultiStar 231246063
MultiStar 281470099
MultiStar 2834800195
MultiStar 350864098
MultiStar 3508580102
MultiStar 3508700102
MultiStar 3508380102
MultiStar 352585058
MultiStar 3525750233
MultiStar 352565058
MultiStar 4010375128
MultiStar 4010485128
MultiStar 4010580128
MultiStar 4014400163
MultiStar 4014320163
MultiStar 4108480111
MultiStar 4108380111
MultiStar 4108600111
MultiStar 4112485147
MultiStar 4112320147
MultiStar 4112400147
MultiStar 4114320148.5
MultiStar 422088065
MultiStar 422065065
MultiStar 422539086
MultiStar 422561086
MultiStar 4230400138
MultiStar 4230630138
MultiStar 482257098
MultiStar 482239098
MultiStar 482249098
MultiStar 482269095
MultiStar 4830480154
MultiStar 4830420154
MultiStar 5008340163
MultiStar 5130570152
MultiStar 6135330230
MultiStar 6340230322
MultiStar 9225160329
MultiStar 922590401
MultiStar 9235100674
MultiStar Elite 2204230024
MultiStar Elite 221692058
MultiStar Elite 221692058
MultiStar Elite 231298058
MultiStar Elite 350826896
MultiStar Elite 400674093
MultiStar Elite 4114330152
MultiStar Elite 5010274211
MultiStar V2 2206215030
NTM Prop Drive 28-26100054
NTM Prop Drive 28-26110057
NTM Prop Drive 28-26A120057.6
NTM Prop Drive 28-3090066
NTM Prop Drive 28-3080065
NTM Prop Drive 28-30A110068
NTM Prop Drive 28-30S80065
NTM Prop Drive 28-30S90066
NTM Prop Drive 28-36220087
Outrunner 2725160035
Outrunner 2728100048
Quanum MT 1806230020
Quanum MT 2204230026
Quanum MT 2206200032
Quanum MT 2208180040
Quanum MT 2212100052
Quanum MT 222780068
Quanum MT 2814880100
Quanum MT 311047083
Quanum MT 350858092
Quanum MT 350870092
Quanum MT 3510700100
Quanum MT 3510630100
Quanum MT 3510360100
Quanum MT 4010580127
Quanum MT 4010475127
Quanum MT 4010370127
Quanum MT 4012480144
Quanum MT 4012340144
Quanum MT 4012400144
Quanum MT 4108370108
Quanum MT 4108700108
Quanum MT 4108580108
Quanum MT 4108475108
Quanum MT 5008335189
Quanum MT 5206320162
Quanum MT 5208360192
Quanum MT 5208335192
RCTimer 1806230018
RCTimer SL1804230016
RCTimer SL1806230018
RCX 1804240014
RCX H1306230012
SunnySky X2204230021
Tarot MT1806228018
Tiger MN1806230018
Tiger MN2206235030
Turnigy 420653068
Turnigy 420862084
Turnigy 5017620125
Turnigy 9014105420