Always remove the props before you plug in a battery to test motors. The Betaflight Motors tab docs and every build guide repeat that for a reason.
What Betaflight expects by default (props in)
On a standard Quad X mixer with Motor direction is reversed turned off, Betaflight expects this layout (rear of the quad toward you, looking down):
| Motor | Position | Spin (props in) |
|---|---|---|
| 1 | Rear left | Clockwise |
| 2 | Front left | Counter-clockwise |
| 3 | Rear right | Counter-clockwise |
| 4 | Front right | Clockwise |
Oscar Liang's takeoff troubleshooting guide lists the same directions. A short mnemonic for props in: the front prop tips move toward the camera (inward), and the rear tips move toward the tail.
That pairing cancels yaw torque in a hover. Two motors spin CW and two spin CCW so the frame does not twist under the motors the way a helicopter without a tail rotor would.
CW and CCW props: match the motor, not the bag label alone
A bag of four FPV props is usually two clockwise (CW) and two counter-clockwise (CCW). Each prop only produces useful thrust when it spins the way it was designed for. Put a CW prop on a CCW motor and the blades push air the wrong way: the quad may refuse to lift, or it flips on takeoff.
The reliable check is the blade profile, not the printed letter:
- The leading edge (the edge that cuts into the air first) sits higher on the blade.
- The trailing edge sits lower.
- With the prop on the motor and turning the correct way, that higher leading edge should face into the direction of travel of the blade, and the prop should push air down.
Printed markings help once you know the brand's convention, but they are inconsistent across manufacturers. Oscar Liang notes that some hubs print "R" for reverse/CCW and leave CW unmarked. iFlight's Gemfan example labels the CW prop with an "R" (for example 51377R) and the CCW prop without it. Treat the letter as a hint, then confirm with the leading edge and a hand spin that pushes air down.
Also check top versus bottom. Oscar Liang's propeller guide: the top is often glossy with model text near the hub; the bottom is matte. Upside-down props produce little or no lift and can flip the quad on takeoff.
Props in vs props out
Props in is Betaflight's default: front props spin toward the camera. Props out reverses every motor so the front props spin away from the camera.
Neither setup wins for every quad. Oscar Liang's January 2024 comparison and the Betaflight Motors tab docs put the trade-offs like this:
| Props in (default) | Props out (reversed) | |
|---|---|---|
| Debris | More dirt thrown at the camera lens | More dirt thrown at the FC/ESC stack |
| Whoops / small quads | Fine | Often preferred: better control in tight turns, less prop wash |
| 5" freestyle | Oscar Liang is happy to keep the default | Benefits are less noticeable; you must re-enable the reverse flag after a fresh Betaflight flash |
| Branch / gate hits | Props can dig in | Props more likely to glance off |
| Turtle mode | Normal | When upside down the props run the opposite way relative to the lens, so the camera gets dirtier during a flip |
Betaflight's Motors tab notes that pilots use props out to keep debris out of the camera and that it also helps against prop wash on smaller craft. BETAFPV's whoop docs recommend props out for many of their micro builds and show the same three-step switch: mount props for the reversed pattern, reverse the motors in the ESC or Motors wizard, then enable Motor direction is reversed.
For cinewhoops with odd flight behaviour, Oscar Liang suggests trying the other orientation; it often fixes the oddities.
Switching a build to props out
Turning on Motor direction is reversed alone does not reverse the motors. The Betaflight reversed-motor wiki is explicit: that flag only tells the mixer how to command yaw. The motors still have to spin the other way in hardware or ESC firmware.
Steps that match Oscar Liang and BETAFPV:
- In Betaflight Configurator, open the Configuration (or Motors) mixer section and enable Motor direction is reversed. Save and reboot.
- Remove the props. Plug in a battery and use the Motors tab Motor direction wizard (Betaflight 4.3+) to reverse each motor that does not match the props-out diagram, or reverse them in BLHeli / ESC-Config / by swapping any two of the three motor wires.
- Fit CW and CCW props to match the new spin directions. For props out the CW/CCW positions swap relative to the default map.
- Confirm every motor pushes air down with a correct prop before the first flight.
Three ways to reverse one motor
Oscar Liang lists three options when a motor spins the wrong way on the Motors tab:
- Motors tab wizard (Betaflight 4.3 and later). Props off, battery plugged in, open Motor direction under the quad diagram and follow the prompts. No soldering and no separate ESC app.
- Swap any two of the three motor wires between that motor and the ESC. Which pair you swap does not matter; the spin reverses either way.
- ESC firmware. BLHeliSuite32 for BLHeli_32, or ESC-Config for BLHeli_S: Read Setup, set Motor Direction to Reverse (or back to Normal), Write Setup. Do not set 3D mode unless you intend to fly 3D.
If motors use fixed-direction threaded shafts and prop nuts that self-tighten only one way, reversing spin without swapping motors can loosen nuts in flight. Self-locking nylon nuts and a pre-flight prop check reduce that risk; Oscar Liang still prefers matching thread direction to spin when the hardware allows it.
Quick checks before the first hover
Work through these with props off until the last step:
- Motors tab: each slider spins the motor shown in the diagram (use Reorder Motors if the order is wrong).
- Spin direction matches props in or props out, and the reverse flag matches what you built.
- Props on: CW/CCW match each motor, glossy/text side up, leading edge correct, nuts tight so the prop cannot turn on the shaft.
- Hand-spin each prop and feel downward wash.
If it still flips after that, move on to board alignment, motor order and the rest of Oscar Liang's flip-on-takeoff checklist. Wrong props and wrong spin direction are still where most first flights fail.