Deviations from the drive data can occur due to:

- changing propeller design (e.g. GM)
- different propeller shapes
- different centre section dimensions/offset centre sections
- different air density
- different controllers
- timing settings
- measuring shunts (series resistor voltage drop)
- Wear of punching tools for the motor laminations - Burr formation
- Batchwise small changes in motor KV
- Use with low C rate battery