Generally, the product title of FPV motors is fashioned by a bunch of two numbers. The primary one refers back to the dimensions of the motor and the second to the pace of the motor. Brushless motors have two fundamental elements: the rotor with everlasting magnets and the stator with copper coils. After studying to decipher the numbers on FPV motors, we’ll analyze two motors from LN-motor intimately.
The primary quantity has 4 digits (DDHH) and represents:
“DD” is the stator’s diameter (or width) measured in millimeters.
“HH” is the stator’s peak in millimeters.
For instance, the LN-motor FS2812 has a stator with 28mm diameter and a stator peak of 12mm. Greater motors have bigger magnets which are able to producing extra thrust.
The second quantity is “KV” and represents the variety of revolutions per minute (RPM) with no load when a one-volt is utilized to the motor’s terminals. Due to this fact, theoretically, the FS2306 2050 KV motor will run 50% sooner on a 6S battery than on a 4S one. Motors with increased KV are usually extra aggressive and power-hungry, whereas decrease KV choices are extra environment friendly.
LN-motor FS2812 and FS2306 overview
Disclosure: I obtained these FPV motors as a part of a product overview collaboration with LN-Motor. Though the motors have been provided without cost, all opinions on this article stay my very own, and the sponsor on no account influenced me.
LN-MOTOR is an modern know-how enterprise specializing in the manufacturing of brushless DC motors. “LN” comes from the Chinese language names of the 2 founders, Lin and Na. The corporate has 4 UAV motor ranges:
FPV
Multirotor
Fastened Wing
Educted fan
FS3115 900KV/1150KV
4214 400KV
FA2826 740KV
70mm 12-Blade3060-2000KV
FS2806.5 1400KV/1750KV
3115 1050KV
FA2820 870KV
FS2306 2050KV
2812 900KV/1150KV
FA2814 510KV
FS2207 1800KV
FA2216 2400KV
2806.5 1350KV
FA2216 2400KV
2307 1950KV/2600KV
FA2208 1100KV
2306.5 1800KV/1950KV
2307.5 1950KV
2207 1800KV/1950KV
2004 1800KV/2800KV
1406 4000KV
1303 5500KV
Final month, LN-Motor despatched me their newest FPV motor catalog (out there right here) to decide on those I would like for overview. I all the time wished to construct a 9-10″ long-range FPV drone, so I opted to check a set of FS2812 / 1150KV motors. As FS2306 motors are generally used for racing drones, and I take advantage of a lot of them, I additionally opted to check a set of 2050 kV. Each motors are packed in the identical kind of plastic container with foam padding. Within the heart of the 4 motors is a bag that features mounting screws and prop nuts. FS2812 is obtainable in black, and FS2306 in inexperienced and navy blue.
Whereas the smaller FS2306 adopts a unibell (one-piece rotor) design, the larger FS2812’s rotor is fabricated from two elements: a hoop with the magnets and a cap with the shaft. Sales space undertake 12N14P development, the place “N” represents the variety of coils and “P” is the variety of magnets.
LN-motor FS2812 1150KV
The LN-motor FS2812 1150KV is appropriate for 8 and 9″ long-range FPV drones. Many consultants say that 900KV would have been a extra acceptable alternative for a nine-inch. The motors weigh about 75 grams, together with the 25cm 18 AWG leads.
The bottom has a 19x19mm mounting sample with M3 screws. Wanting down on the motor, you may see that the motor has a hole shaft that saves some further grams. It makes use of 5mm propeller nuts.
FS2812 1150KV Technical parameters
KV
1150
N/P
12N14P
Shaft diameter
5mm
Stator diameter
28mm
Stator peak
12mm
Mounting sample
⌀19 M3
Weight
75 grams
Wires
3x250mm 18AWG
Resistance
64.2Ω
Voltage
3-6S
Max Energy
1595W
Max Present
66A
Effectivity (g/W)
1.93-3.87
Max thrust
3230grams
I plan to make use of these motors on an iFlight Chimera9 ECO body with MasterAirScrew 3MR 0945 glass fiber composite propellers. Based on the producer specs, utilizing GF8045-3 propellers and 6S LIPO (24.1V) at full throttle, the thrust is round 3000g. For extra check knowledge, test right here.
LN-motors FS2306 2050KV
I obtained inexperienced+crimson FS2006 motors, however navy blue+pink choices are additionally out there. These motors are appropriate for five and 5.5″ propellers. Adopting a light-weight unibell design and a hole shaft, they weigh simply 36 grams, together with the 15cm 20AWG wires. They’ve a 16x16mm M3 mounting sample.
When choosing motor KV for five″ racing drones, 1500-2000KV is designed for 6S, whereas 2300-2800KV is acceptable for 4S. The 2050KV is the center approach, appropriate for 4S and 6S batteries.
What’s bizarre is that solely three from the 4 motors have been printed with mannequin quantity and KV worth -one motor was unlabelled.
Based on the producer’s check outcomes, utilizing GF51466 propellers and 6S LIPO (22V) at full throttle, the thrust is round 1865g. For extra check knowledge, test right here.
FS2306 2050KV Technical parameters
KV
2050
N/P
12N14P
Shaft diameter
5mm
Stator diameter
23mm
Stator peak
06mm
Mounting sample
⌀16 M3
Weight
36 grams
Wires
3x150mm 20AWG
Resistance
64Ω
Voltage
3-6S
Max Energy
1030W
Max Present
46.8A
Effectivity (g/W)
1.81-3.18
Max thrust
1868grams
How do you select the best motor measurement in your body?
Earlier than selecting a motor, it’s essential to have no less than a tough thought of the dimensions and necessities of the FPV drone you propose on constructing. Matching your body wheelbase with the propeller measurement is obligatory. For instance, you may’t bodily set up a 5″ prop on a 100mm measurement body.
Wheelbase
Propeller measurement
Motor
KV
65-150mm
3″ and smaller
1003 – 1306
3000-10000KV
150-180mm
4″
1806, 2204
2600KV – 3000KV
180-220mm
5″
2205-22082305-2306
2300KV-2600KV
220-250mm
6″
2206-2208, 2306
2000KV-2300KV
250-280mm
7″
2506-2508
1200KV-1600KV
280-420mm
8 and 9″
26XX28XX
1200KV and decrease
420mm+
10″ and bigger
32xx and larger
1200KV and decrease
You’ll want the estimated complete take-off weight (together with battery and digital camera) to calculate the minimal thrust required in your motors. Usually, a 2:1 thrust-to-weight ratio could be sufficient, however for racing and freestyling FPV drones, you will have no less than a ten:1 ratio.
For instance, when you have a 500g racing quad, the full thrust generated by all motors must be no less than 5kg. That’s greater than 1 kg thrust produced by every motor.
To drive a brushless motor, you’ll want an ESC (digital pace controller). Generally used ESCs on FPV drones have rankings from 10 to 100A, and it’s essential match them with the motor’s energy wants. For those who drive FS2812 motors with 214-1300W energy with 20A amper ESC, this can final solely a second -when you push the throttle increased, it can smoke and burn out.