Generally, the product identify of FPV motors is fashioned by a gaggle of two numbers. The primary one refers back to the dimensions of the motor and the second to the velocity of the motor. Brushless motors have two important components: the rotor with everlasting magnets and the stator with copper coils. After studying to decipher the numbers on FPV motors, we are going to 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 top in millimeters.
For instance, the LN-motor FS2812 has a stator with 28mm diameter and a stator top of 12mm. Larger motors have bigger magnets which can be 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% quicker on a 6S battery than on a 4S one. Motors with larger KV are typically extra aggressive and power-hungry, whereas decrease KV choices are extra environment friendly.
LN-motor FS2812 and FS2306 evaluate
Disclosure: I acquired these FPV motors as a part of a product evaluate collaboration with LN-Motor. Though the motors had been supplied totally free, all opinions on this article stay my very own, and the sponsor under no circumstances influenced me.
LN-MOTOR is an revolutionary expertise 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-Blade 3060-2000KV |
| 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 want for evaluate. I at all times needed 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 exploit lots of them, I additionally opted to check a set of 2050 kV. Each motors are packed in the identical sort 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 on the market 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 manufactured from two components: a hoop with the magnets and a cap with the shaft. Sales space undertake 12N14P building, 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. Trying down on the motor, you’ll be able to 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 top | 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. In accordance with the producer specs, utilizing GF8045-3 propellers and 6S LIPO (24.1V) at full throttle, the thrust is round 3000g. For extra take a look at knowledge, test right here.
LN-motors FS2306 2050KV
I acquired 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 deciding on motor KV for five″ racing drones, 1500-2000KV is designed for 6S, whereas 2300-2800KV is acceptable for 4S. The 2050KV is the center manner, appropriate for 4S and 6S batteries.
What’s bizarre is that solely three from the 4 motors had been printed with mannequin quantity and KV worth -one motor was unlabelled.
In accordance with the producer’s take a look at outcomes, utilizing GF51466 propellers and 6S LIPO (22V) at full throttle, the thrust is round 1865g. For extra take a look at knowledge, test right here.
FS2306 2050KV Technical parameters
| KV | 2050 |
| N/P | 12N14P |
| Shaft diameter | 5mm |
| Stator diameter | 23mm |
| Stator top | 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 on your body?
Earlier than selecting a motor, it’s necessary to have not less than a tough concept of the dimensions and necessities of the FPV drone you intend on constructing. Matching your body wheelbase with the propeller measurement is obligatory. For instance, you’ll be able to’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″ | 2205-2208 2305-2306 |
2300KV-2600KV |
| 220-250mm | 6″ | 2206-2208, 2306 | 2000KV-2300KV |
| 250-280mm | 7″ | 2506-2508 | 1200KV-1600KV |
| 280-420mm | 8 and 9″ | 26XX 28XX |
1200KV and decrease |
| 420mm+ | 10″ and bigger | 32xx and greater | 1200KV and decrease |
You’ll want the estimated complete take-off weight (together with battery and digicam) to calculate the minimal thrust required on your motors. Usually, a 2:1 thrust-to-weight ratio could be sufficient, however for racing and freestyling FPV drones, you will have not less than a ten:1 ratio.
For instance, if in case you have a 500g racing quad, the full thrust generated by all motors needs to be not 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 velocity controller). Generally used ESCs on FPV drones have rankings from 10 to 100A, and it’s good to match them with the motor’s energy wants. Should you drive FS2812 motors with 214-1300W energy with 20A amper ESC, this may final solely a second -when you push the throttle larger, it can smoke and burn out.
