I have a problem with UV-mapping. I cut some parts of my model loose, so I could unfold them easier. The problem is, that the texture now is applied on the wrong side of that specific part of the model. Essentially turning it inside out. 
These pictures show the problem.
Does someone know how to fix this? 
Select all the vertices and use Ctrl+N to recalculate the face normals.
If that doesn’t work, select the offending faces and W / Flip Normals.
Before doing these remove any duplicate vertices with W / Remove Doubles ann delete and faces that may be inside your mesh which could affect how the normals are calculated.
Ctrl+N seemed to do the trick!
Thanks for your help 