So, I was watching PBS's Nazi Mega Weapons, and they were discussing the V-1 terror drone when they said something that made me scratch my head. They said that the Nazis initially had problems with the compass that facilitated navigation because of magnetic interference from the metal in the V-1 chassis. The part that confused me is that they solved this problem by encasing the compass in a wooden shell. I didn't think that an insulator could stop magnetic field lines. In fact, I'm pretty sure of it, unless we can make monopoles now. Any speculation on how this worked, or if the show meant something else when they said this?