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Mini Quad Motor kv

Snarls

Gravity Tester
Mentor
#1
What are the advantages and disadvantages of a lower kv motor vs. a high kv motor for a mini quad. For instance, the Cobra 2204s come in 1960kv and 2300kv. I thought everyone was leaning towards 2000+kv, but then I saw that Charpu uses 1960kv Cobras in the latest FT episode. Are lower kv motors more efficient in producing thrust and higher kv motors better for raw speed? I get confused when it comes to motor specs and performance beyond the prop test tables.

Thanks!
 

narcolepticltd

I unbuild stuff regularly
#2
What are the advantages and disadvantages of a lower kv motor vs. a high kv motor for a mini quad. For instance, the Cobra 2204s come in 1960kv and 2300kv. I thought everyone was leaning towards 2000+kv, but then I saw that Charpu uses 1960kv Cobras in the latest FT episode. Are lower kv motors more efficient in producing thrust and higher kv motors better for raw speed? I get confused when it comes to motor specs and performance beyond the prop test tables.

Thanks!
He's likely using the 1960kv over the 2300kv if he's flying 4s... so like everything in this hobby "it depends" :)

If you're looking for a great 3s solution the 2204/2300kv motors are great, especially with 6x4.5 props.

EDIT: I just saw the video, and he's definitely running 4s (also running those same 6x4.5 HQ props)
 
Last edited:
#3
Motor Kv -- I had the same question as you when I started to design my first quad. I will give you my interpretation of what I have learned on this subject.

High KV motors spin fast, therefore they are more responsive and agile when used on a multi rotor. They are commonly used on the 250mm class of quads combined with small blades for fast FPV flying. use 5" to 6" props

Low KV motors spin slow , use larger props , give less vibration to the frame, less responsive to the sticks which make them great for aerial photography and video. The large props give alot of lift capability so they are better suited for heavy loads and they are the most efficient motors as they spin slower and draw less amps. Use 9" to 10" props

Mid KV range are in between the above parameters, using 7" and 8" props.

There is no really right or wrong motor setup, but I think using this guide line would give one the best flying experience when creating a quad for a specific purpose, IE: quad racing, FPV flying like charpu, aerial photography. Keeping in mind that the size of a quad coptor frame will determine the maximum size of props that can be used.

Larger props give more lift on less amps, going to 4s will give more lift on less amps as well.
 

jipp

Senior Member
#4
i won a motor,props, esc, prop saver off ebay for cheap money 3.50 ship to my door.

i too am confused when it comes to motors.. but your explanation helps a lot Harley.

i figure i could pick up 2 more of these for stupid money and build a really cheap tri-copter.

the specs on the motor are:

Specification Motor:
Name : A2212-KV1000 Brushless Outrunner Motor .
Motor for small fixed-wing , helicopter , Multi-axis aircraft .
Motor for ESC 20A - 30A .
Motor for 8045 , 9045 , 1045 propeller .
RC Pull weight : 300g - 900g .
Note : RC Pull weight Different , Optional ESC and propeller Different .
Internal Resistance : 230m¦¸ .
No load current / 10V : 0.4A .
Number of battery(Ni-MH) : 6-10 Ni-MH/ 2-3 Li-Po .
Current capacity : 12A / 60s .
Max efficiency : 80% .
Size : ¡é27.8 x 40 mm .
weight : 47g .

ESC
Name:HobbyFans 30A ESC
Output: Continuous 30A, Burst 40A up to 10 Secs.
Input Voltage: 2-3 cells lithium battery or 5-8 cells NiCd/NIMh battery.
BEC: 2A / 5V (Linear mode).
Max Speed: 210,000rpm for 2 Poles Outrunner BrushLess Motor, 70,000rpm for 6 poles Outrunner BrushLess Motor,35,000rpm for 12 poles Outrunner BrushLess Motor
Size: 51mm (L) * 25mm (W) * 8mm (H).
Weight: 25g.

it came with 4 props two 8", one 9", and a 10".

if i was to bid on 2 more of these ESC/motor deals.. would this make a slow flying tri-copter?
or should i just save this motor/prop for a foam plane..

that was my original plan, figured one of the FT plans would work with it if i won, which i did not think i would at that price.. and for the price what teh heck.. i figured the props alone were bidding. the price i won, seems to be the norm for this package. so for pennies i could get a power plant for a tri copter.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#5
Low KV motors spin slow , use larger props , give less vibration to the frame, less responsive to the sticks which make them great for aerial photography and video.
FYI, high kv motors and short rotors create more high frequency vibration. Low kv motors and long rotors create more low frequency vibration.

Both are bad for accelerometers, but low freq is much much worse. Therefore, low kv motors and long rotors are more likely to cause vibration problems than high kv motors and rotors. This is one reason why low kv motors and larger copters require more maintenance. You MUST balance low kv motors and rotors particularly if you want to shoot jello free video.

I don't bother balancing 2300kv motors with 6" rotors. A little foam or some O rings on the flight controller fixes the issue on the little motors.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#6
i won a motor,props, esc, prop saver off ebay for cheap money 3.50 ship to my door.

i too am confused when it comes to motors.. but your explanation helps a lot Harley.

i figure i could pick up 2 more of these for stupid money and build a really cheap tri-copter.

the specs on the motor are:

Specification Motor:
Name : A2212-KV1000 Brushless Outrunner Motor .
Motor for small fixed-wing , helicopter , Multi-axis aircraft .
Motor for ESC 20A - 30A .
Motor for 8045 , 9045 , 1045 propeller .
RC Pull weight : 300g - 900g .
Note : RC Pull weight Different , Optional ESC and propeller Different .
Internal Resistance : 230m¦¸ .
No load current / 10V : 0.4A .
Number of battery(Ni-MH) : 6-10 Ni-MH/ 2-3 Li-Po .
Current capacity : 12A / 60s .
Max efficiency : 80% .
Size : ¡é27.8 x 40 mm .
weight : 47g .

ESC
Name:HobbyFans 30A ESC
Output: Continuous 30A, Burst 40A up to 10 Secs.
Input Voltage: 2-3 cells lithium battery or 5-8 cells NiCd/NIMh battery.
BEC: 2A / 5V (Linear mode).
Max Speed: 210,000rpm for 2 Poles Outrunner BrushLess Motor, 70,000rpm for 6 poles Outrunner BrushLess Motor,35,000rpm for 12 poles Outrunner BrushLess Motor
Size: 51mm (L) * 25mm (W) * 8mm (H).
Weight: 25g.

it came with 4 props two 8", one 9", and a 10".

if i was to bid on 2 more of these ESC/motor deals.. would this make a slow flying tri-copter?
or should i just save this motor/prop for a foam plane..

that was my original plan, figured one of the FT plans would work with it if i won, which i did not think i would at that price.. and for the price what teh heck.. i figured the props alone were bidding. the price i won, seems to be the norm for this package. so for pennies i could get a power plant for a tri copter.
1000kv motors that weigh 47 grams each will make for a mid sized copter. It won't be good for racing but will do some moderate acro AND it can lift a copter up to 1300grams or so. The ESCs are pretty large and I don't know the firmware on them. I suspect they are not made for copters and probably have some pretty slow firmware. If you can, flash these to Simon K or BlHeli depending on the chipset and your copter will be MUCH more responsive.

This set up should work well with a FliteTest kit.
 

jipp

Senior Member
#7
1000kv motors that weigh 47 grams each will make for a mid sized copter. It won't be good for racing but will do some moderate acro AND it can lift a copter up to 1300grams or so. The ESCs are pretty large and I don't know the firmware on them. I suspect they are not made for copters and probably have some pretty slow firmware. If you can, flash these to Simon K or BlHeli depending on the chipset and your copter will be MUCH more responsive.

This set up should work well with a FliteTest kit.
yeah, it is a large ESC. the props are good quality tho.. im thinking FT plane would be best use for this. then i do not have to worry about what firm wear is on it.

what FT air frame do you think this combo would work well. i will only have to buy the battery, as i have all the tools ( even a nice glue gun i bought just for building, then i found multirotors section and my interest has moved, hah ), foam ,electronics,etc to scratch build a FT plane.

no matter what, it looks like its a compromise.. between flight, jelly.

chris.