An FPV motor listing gives you two numbers that matter most: a four-digit size and a KV rating. Once you can read those, choosing a motor becomes a short process.
What the size number means
A 2207 motor has a stator 22mm wide and 7mm tall. The stator is the fixed core carrying the copper windings, and its size sets how much torque the motor can make.
- Wider stators give more torque, which helps spin bigger props.
- Taller stators give more power at high RPM.
- Bigger always means heavier, and weight costs agility.
Decimals work the same way. The RCinPower GTS V3 1404.6 has a 4.6mm stator height, about 15% more volume than a standard 1404 in the same footprint.
What KV means
KV is how many RPM a motor tries to spin per volt, with no load. It says nothing about quality or power on its own.
A 1800KV motor on a fully charged 6S pack (25.2V) has a theoretical no-load speed of about 45,000 RPM. Real RPM with a prop fitted is lower.
This is why KV and battery are chosen together. Higher voltage means you need lower KV to reach a similar RPM. A motor with too much KV for its voltage pulls more current, runs hot and can burn out.
Which motor for which build
Tiny whoops (1S)
Very small motors at very high KV, because 1S gives so little voltage. The BETAFPV 0702 comes in 25000KV, 30000KV and 36000KV. See our tiny whoop guide.
2.5 to 3-inch cinewhoops and micros
Usually 1303 to 1804 size. The GTS V3 1404.6 shows how KV follows voltage: 3850KV for 3-4S, 2850KV for 4-6S.
5-inch freestyle and racing
Usually 2207 size. On 6S, look around 1700-1950KV. On 4S, look around 2300KV and up.
- iFlight XING-E Pro 2207: 1800KV, a durable budget choice rated 2-6S.
- T-Motor Velox V3 2207: 1750KV for smooth flying, 1950KV for more acro, 2050KV for extra punch.
- MadMotor BSC 2207.5 V2: 1777KV to 2111KV with a titanium alloy shaft.
7-inch long range
Larger stators and lower KV to swing bigger props efficiently. The GEPRC EM2807 1350KV is built for 6-8 inch props on 6S. Check the prop's recommendation too: the Gemfan Flash 7040-3 is tested up to 1500KV.
Four things to check before you buy
Mounting pattern
The screw spacing must match your frame's arms. Common patterns in our range include 16 x 16mm on 2207 motors, 19 x 19mm on the EM2807, 9 x 9mm on 1404 size, and three M1.4 screws on a 6.6mm circle on whoop motors.
Shaft size
This decides which props fit. Most 5-inch and 7-inch motors take 5mm props, while micro motors use a 1.5mm or 1.0mm shaft. The BETAFPV 1102 has a 1.5mm shaft and will not take props with a 1.0mm hole.
Cell rating
Some motors are rated across a range and others for one voltage. Use the motor's stated rating, not a guess from its KV.
Pack quantity
Many motors are sold singly, so you need to order four. Others, such as the BETAFPV 1102 and 0802, come as a set of four. Check before adding to cart.
Frequently asked questions
Is higher KV better?
No. Higher KV is only faster at the same voltage, and it draws more current to get there. The right KV is the one that suits your prop and battery.
Can I mix motors on one quad?
Avoid it. All four motors should be the same model and KV. If one dies and you cannot match it, replace the set.
Why are my motors hot after landing?
Warm is normal. Too hot to hold suggests too much KV for the voltage, too large a prop, or a tuning problem. Land and find the cause before flying again.
Not sure which KV suits your build? Email info@aeroflow.in with your frame, battery and prop size and we will suggest a match.