How can I block collisions with hollow static mesh (inward normals)?

Hi folks, I’m new to UE4, although I’m very experienced with Unity and native game development.

I’ve imported a static mesh from Blender. The mesh is essentially a torus with inward-facing normals – it’s supposed to be a tunnel. Using this in the flying vehicle sample, my vehicle doesn’t collide with the tunnel walls, even if it starts inside. It does however collide with the blocks and other sample geometry.

As far as I can see, the only difference between the blocks that work correctly and my static mesh is that my mesh has no mass, and has inward-facing normals.

Any hints on how to get the vehicle colliding with the tunnel wall?

Thanks!