Weird animation effect

Hello, I’m trying to make an animation of a rotating aircraft propeller but I’m getting some weird displacements of the blades.
The following video illustrates the problem:

The first bit is the animation played through the animation window, the second one is when the game is running. The animation is all being made in unity.
I really don’t know what’s causing this…

Thanks you for all the answers but I was being a bit stupid here…
Since both engine are the same (same model) I just duplicated the one that was functioning well and adjusted it to fit the other side of the airship.

Did you animate these in Unity? You need to combine all those propeller meshes into one mesh, and center the transform. That is, all the propeller blades must be one object for it to work. Don’t be making the blades children of a propeller blades GameObject. That could work if all your blades were symmetrical, and if you made sure that the transform (the colored arrows) were in the center…I say just don’t animate weird stuff like that. Also make sure you are animating globally, not locally, if you know what I mean.