High pitch noise

[KAD4555]

Hello to all, just received my first drone which is a phantom 3 standard. First few short flights did not notice anything that seems odd. Today during one of the flights I could hear a high pitch noise while the drone was in flight. After running the battery down I brought the drone inside remove the blades and started it back up. At idle no noise running very quiet. At a higher speed it seemed that each engine had a high pitch sound. Is this just the RPM's of these motors or is there an issue with the motors. This is a used drone, thank you for your suggestions.

 

[N017RW]

Hello to all, just received my first drone which is a phantom 3 standard. First few short flights did not notice anything that seems odd. Today during one of the flights I could hear a high pitch noise while the drone was in flight. After running the battery down I brought the drone inside remove the blades and started it back up. At idle no noise running very quiet. At a higher speed it seemed that each engine had a high pitch sound. Is this just the RPM's of these motors or is there an issue with the motors. This is a used drone, thank you for your suggestions.

Common sound and discussion.
Look for threads titled 'whistling noise' or similar.

 

[GrammatonxXXxCleric]

My P3A/P's also make the noise. Normal.