Chapter 04 · Components
The cheap part that changes flight the most
Changing props is the easiest, cheapest way to change how your drone flies: more power, more smoothness or more flight time.
How to read them
A 5.1 × 3 × 3 prop (or “51303”) has a 5.1-inch diameter, a 3-inch pitch and 3 blades. The pitch is the theoretical distance it would move forward in one full turn, like a screw going into wood.
More pitch
Higher top speed and more thrust at high speed, but higher consumption and hotter motors.
Less pitch
Smoother, more efficient and more precise at low speed. Ideal for learning and for cinematic flying.
Bigger diameter
More thrust and efficiency, but the drone has to be bigger and responds a little more slowly.
Number of blades and shape
| Blades | Character | Use |
|---|---|---|
| 2 blades | The most efficient, less grip | Long range |
| 3 blades | A balance between grip and efficiency | The standard for freestyle and racing |
| 4 or more | Lots of thrust from a small diameter | Cinewhoops and heavy small drones |
Rounded tips (bullnose) give more thrust but are less efficient than pointed ones.
Spin direction: props in and props out
Two props spin clockwise and two anticlockwise to cancel out the torque. Looking at the drone from behind:
Props out
The front props spin outwards over the top. They throw less grass and dirt towards the camera. The most common setup for freestyle.
Props in
Betaflight’s default setup. If you run props out, enable the reversed motor direction option.
Maintenance
- Replace them if they’re bent, cracked or nicked: they vibrate and pollute the gyro signal.
- M5 lock nuts done up firmly, without overtightening.
- Small drones use press-fit mounting or small screws (T-mount).
- Always carry spare sets: they’re the number one consumable.
Never fit the props for bench tests or while in Betaflight. A 5" prop at full throttle cuts.