1   Motor

1) Motor KV Rating

KV rating is super simple: it’s how fast a motor spins (in RPM) with 1 volt, no propeller attached (that’s “no-load”).

Example: A KV800 motor hits 800 RPM on 1V. Crank it up to 10V? 8,000 RPM—easy math!

Lower KV = slower spin at the same voltage, but more “muscle” (torque). Perfect for big propellers.

Higher KV = faster spin at the same voltage, but less torque. Only works with small propellers—no heavy lifting here!

Relatively speaking, a lower KV value indicates higher efficiency.

For aerial photography, low-KV motors paired with large propellers are preferred. The lower RPM results in higher efficiency and reduced vibration—all highly advantageous for this application. Quadcopter Battery, Motor, and Propeller Selection and Matching

2) Motor Model

Motor models like 2212, 3508, 4010 denote the diameter and height of the motor's stator (note: this refers to the stator, not the rotor).

The first two digits indicate the stator diameter, while the last two represent the stator height, measured in millimeters.

Larger first digits mean a wider motor, while larger last digits indicate a taller motor.

Generally, a thicker stator provides greater torque (more power). Height selection depends on the chosen frame.

3) Motor Efficiency:

— Typically, currents between 3–5A offer high efficiency

Efficiency is labeled as: g/W (grams per watt)

Motor power and pulling force are not directly proportional. For example, 50W may produce 450g of pulling force, but 100W might yield only 700g instead of 900g.

Specific efficiency values can be found in the motor's efficiency chart. Most motors achieve peak efficiency between 3A and 5A current. During normal flight operations, maintaining efficiency within a reasonable range effectively ensures flight endurance.

Using the Langyu X3508S-700KV motor (see image below) as an example: paired with APC1147 propellers and a 4S battery at 5A current, it achieves 8.1g/W efficiency and generates 600g thrust. For a quadcopter, this yields a total thrust of 2.4kg.

For a 4S 5000mAh battery, accounting for various factors that halve performance, flight time should still exceed 30 minutes. We observe that at 5A current, the motor operates at 2/5 of its maximum thrust (1500g), delivering 600g of thrust—a point where flight performance is optimal.

4) Motor Selection Guidelines

Guideline 1: Total airframe weight should remain below 2/5 of the motor's maximum power rating.

Many beginners in aerial photography opt for 2212 motors. Why? Most beginner tutorials reference 2212 motors.

For beginners, 2212 motors are indeed suitable.

But let’s be real—2212 motors just don’t cut it for aerial photography. They’re total lightweights: once your quadcopter tips past 1.5 kg, those motors start gasping for air. And here’s the thing—most beginner aerial photography setups weigh 1.5 to 2 kg! I’ve heard folks argue, “Wait, Brand X’s 2212 motor says it can push 830 grams max! Four of ’em add up to 3320 grams—why can’t they lift my rig?”

Fair question—but here’s the catch: those motors aren’t just spinning to keep the drone hovering. They’re pulling triple duty the second it leaves the ground! The lift they make has to do four big jobs at once: lift the drone up/down, tilt it forward/back (so you can fly ahead or reverse), lean it left/right (for side-to-side moves), and fight wind or make quick adjustments (so your shots don’t turn into a blurry mess). It’s not just about “can they lift the weight”—it’s about having enough leftover oomph to keep everything stable when the wind picks up or you need to nudge the drone into position. Those 2212s? They’re already maxed out just holding a 1.5+ kg rig up—add any wind or maneuvering, and they’re toast.

Here’s a simple rule I’ve learned from years of tinkering: use about 2/5 of the total lift for just going up and down. Save the other 3/5 for all the other stuff—wind resistance, turning, tilting. Why? Because if you use too much lift just to stay airborne, when the battery starts to die (and trust me, it always does), the motors won’t have enough power left to keep the drone stable. Next thing you know, it’s a crash landing.

Let’s make this concrete with an example. Take four 2212 motors—super common in hobby drones. Together, they can push up to 3320 grams (that’s their maximum thrust). So the drone’s total weight should be no more than 2/5 of that—1328 grams. Go heavier than that, and you’re asking for trouble. Those motors will be working overtime, which means:

Worse battery life (they’re burning power faster)

More vibration (2212 motors—especially budget ones like Langyu or XXD—have terrible dynamic balance. Crank ’em up to high speed, and the drone shakes like a leaf)。

A flight controller that’s struggling (it can’t compensate for the vibration or lack of power)。

I learned this the hard way. My first quadcopter had 2212 motors and a gimbal, and it weighed around 1800 grams—way over the limit. As soon as it took off, it shuddered like crazy. Even a light breeze would send it wobbling out of control. After crashing it three times (don’t ask how much that cost in parts), I started testing different weights. Below 1400 grams? Smooth takeoffs, stable flight. Above 1500 grams? It was like trying to fly a brick—crashes were almost guaranteed.

So remember: when picking motors or building a drone, don’t just focus on maximum thrust. Leave room for the unexpected—wind, battery drain, last-minute moves. Your drone (and your wallet) will thank you.

Experience #2: Always verify motor specifications via datasheets. Avoid any product lacking this documentation.

Quadcopter motors are predominantly external rotor (ER) designs. Internal coil windings indicate a stator configuration. Many unscrupulous manufacturers label their motor models as out-runner types. One careless glance and you're deceived. For example, a certain 4006 motor priced around 65 yuan. But what you get isn't a genuine 4006 motor—its stator is actually a 3506. Or take a certain 4225 motor priced around 110 yuan; its internal stator is actually a 3508. These motors typically lure buyers with low prices and falsely inflated specifications. They suffer from poor workmanship, terrible dynamic balance, low efficiency, inconsistent performance, and unstable operation.

Stay vigilant! Motors are critical for aerial photography!!! Always buy from reputable brands to ensure quality. For your drone's safety, splurge a little! (Reputable brands provide complete efficiency charts and full-throttle temperature data. Ignore any that lack efficiency charts or refuse to disclose full-throttle temperatures.)