UE4 doesn't import mesh correctly

I recently started to work on some graphics for my project and wanted to try them out.
There are some really interesting tutorials on flag- and wind-mechanics, and I tried to create my own in Blender (with sections, triangular modif. and so on) but once I import the model into UE4, the flags z-axis scales down to like 1/20 and I don’t know what I did wrong. It works fine with flags.fbx attached in some YouTube-tutorials.

Best ragards