Quick Answer

It is completely normal for motors on a Betaflight drone to spin at slightly different speeds when armed and on the ground. This is a sign that the flight controller's stability system (the PID controller) is working correctly. It is actively trying to keep the drone perfectly level, even in response to microscopic tilts. You should only suspect a fault if a motor stutters, won't spin at all, or if the drone flips on takeoff.

The Explanation: Your Drone Is Trying to Balance

Think of your drone's flight controller (its "brain") like you are trying to balance a stick on the palm of your hand.

• Your Brain = The Drone's Flight Controller
• The Balancing Stick = The Drone's goal to stay perfectly level
• Your Hand's Tiny Movements = The motors spinning at different speeds

When your drone is armed on the ground, its highly sensitive gyroscope sensor detects that the surface isn't perfectly flat. It senses a tiny tilt. To correct this non-existent "instability," the flight controller commands a motor on the opposite side to spin up slightly to try and level the craft.

Since the drone is on the ground and cannot actually move, all you see is one motor spinning faster or slower than the others. This is the PID controller doing its job perfectly.

When to Suspect a Real Problem

The normal balancing behaviour described above is very different from a genuine motor or ESC (Electronic Speed Controller) fault. You should investigate a potential hardware issue if you observe any of the following symptoms:

• No Spin: One or more motors do not spin at all when the drone is armed.
• Stuttering or Twitching: A motor appears to stutter, twitch erratically, or sounds "gritty" when you turn it by hand (always with the battery disconnected!).
• Flip on Takeoff: The drone immediately and violently flips over as soon as you apply enough throttle to take off.
• Excessive Heat: One motor or ESC becomes significantly hotter than the others after a short flight or test.

The Solution: How to Properly Test Your Motors

The only way to confirm if your motors and ESCs are working correctly is to test them individually, without the influence of the PID controller. This is done safely within the Betaflight Configurator.

To isolate and test each motor, please follow our definitive step-by-step guide. This procedure will walk you through the process safely.

• KB Article Link:
  How to Correctly Test Motors and ESCs in Betaflight

Key Takeaway: Seeing motors spin at slightly different speeds on the ground is usually a good sign. If you have any of the "real problem" symptoms, use the linked testing guide to diagnose the issue accurately.