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Motor specs look like a secret code: 2207, 1750 KV, 12N14P. Once you can read them, you can match any motor to the right props and battery and predict how a drone will fly before you build it.
Reading the stator size
The four-digit number is the stator size in millimeters. A 2207 motor has a stator 22 mm wide and 7 mm tall. A 2306 is 23 mm wide and 6 mm tall.
- Wider stators give more torque, which helps the motor change speed quickly. That’s good for quick corrections and handling heavier props.
- Taller stators give more top-end power.
- Bigger stators overall are heavier, so there’s always a trade-off.
What KV really means
KV is the motor’s unloaded RPM per volt. A 1750 KV motor on a fully charged 6S battery (25.2 V) would spin about 44,100 RPM with no prop. With a prop it spins slower, because the prop takes load.
KV doesn’t mean power. A high-KV motor spins faster at a given voltage but needs more current to make the same torque. The key rule:
Higher voltage pairs with lower KV. The motor’s top speed is set by KV times voltage, so you choose KV based on battery and prop size.
| Drone | Battery | Typical KV |
|---|---|---|
| 5-inch freestyle | 6S | 1700–1950 |
| 5-inch freestyle | 4S | 2400–2700 |
| 3-inch | 4S | 3600–4600 |
| 7-inch long range | 6S | 1200–1400 |
| Tiny whoop | 1S | 19,000–27,000 |
| 10-inch GPS quad | 4S | 880–1000 |
Poles and magnets
A spec like 12N14P means 12 stator poles (electromagnets) and 14 magnet poles. Most 5-inch motors use 12N14P. Betaflight needs the number of magnet poles (14 here) for RPM filtering to work correctly.
Matching motors to props
Props load the motor. A bigger or higher-pitch prop takes more torque to spin and pulls more current. Rules of thumb:
- Bigger props need lower KV or larger stators.
- More aggressive pitch needs more torque.
- Check the motor maker’s thrust table, which lists thrust, current and efficiency for specific props and voltages.
If a motor gets hot after a gentle flight, the prop is likely too much for it, or there’s a tuning problem. See the propeller guide.
Shaft, mounting and bearings
- Shaft size: 5 mm shafts are standard on 5-inch motors. Hollow titanium shafts are lighter and tougher.
- Mounting pattern: 5-inch motors usually mount with M3 screws on a 16×16 mm pattern. Small motors use 9×9 or 12×12 mm with M2 screws.
- Bearings: good bearings run smoother and last longer. Replace them when a motor feels gritty.
How to choose motors for a 5-inch
For most 5-inch freestyle builds on 6S, a 2207 or 2306 motor at 1750–1950 KV is a proven choice. Racing pilots often go slightly higher KV and lighter. Heavier cinematic builds lean toward wider stators. Shop 5-inch motors
Signs a motor is damaged
- It feels gritty or clicks when you spin it by hand.
- The bell wobbles, which usually means a bent shaft.
- It gets much hotter than the others after a flight.
- Visible scratches or burn marks on the windings.
A bent shaft can often be replaced. Damaged windings mean a new motor. See crash repair.
A worked example: estimating top RPM
Take a 1,750 KV motor on 6S:
- Full 6S pack: 6 × 4.2 V = 25.2 V
- Unloaded RPM: 1,750 × 25.2 = 44,100 RPM
- Under load with a 5-inch prop, real RPM is typically noticeably lower, and it drops further as the battery sags.
Now the same frame on 4S with 2,600 KV motors: 2,600 × 16.8 V = 43,680 RPM. Almost the same top speed, but the 4S version pulls more current for the same power. That’s why most 5-inch builds moved to 6S: lower current means less heat, less voltage sag and lighter wiring.
Motor weight and why it matters
Motors sit at the ends of the arms, far from the center. Heavy motors make the drone slower to rotate and stop, which affects handling more than the same weight in the middle. For a 5-inch freestyle build, motors in the low 30 g range each are typical. Racing pilots chase lighter options; cinematic builds tolerate a little more weight for smoothness.
Motor maintenance
- Check bell screws and the shaft clip regularly.
- Clean debris from the gap between bell and stator, especially after grass and sand.
- Replace bearings when they feel rough.
- Keep magnets intact. A cracked or loose magnet causes vibration and must be replaced.
Quick motor buying checklist
- Stator size suits your prop and frame
- KV matches your battery voltage
- Mounting pattern matches your frame (16×16 or 12×12, M3 or M2)
- Shaft size matches your props (usually 5 mm on 5-inch)
- Thrust table available for your prop
- Buy one spare
Frequently Asked Questions
What does 2207 mean on a drone motor?
It means the stator is 22 mm wide and 7 mm tall. The stator size affects torque, power and weight.
Is higher KV better on a drone motor?
Not by itself. Higher KV means higher RPM per volt. You choose KV to match battery voltage and prop size; higher voltage builds use lower KV.
What KV motor should I use for a 5-inch 6S drone?
Most 5-inch 6S builds use 1700–1950 KV motors. 4S builds of the same size usually use 2400–2700 KV.
How many motor poles should I enter in Betaflight?
Enter the number of magnet poles, which is the P number in the motor spec. For a 12N14P motor, that’s 14.