Simulate physics on skeletal mesh

Here’s the problem: [video]http://i.imgur.com/UAzfoyT.gifv[/video] The object doesn’t have any animations. Why is it jumping? Seems like a wind plays with it. How can I fix this?

I think it might have to do with your collisions, check whether there are any intersecting physics shape in your physics asset.
I think that would be the most probable cause for the “phantom forces” it is experiencing.