Hey @wbleier ,
Thanks for posting on the Forum.
As you see in the image below, the custom pressure boundary condition is only applied to the outlet face in your project. This is an incorrect setup. It might be helpful to look at the finished drone tutorial project to visualize the faces to which this boundary condition was assigned. Only if you apply it to all the outer faces of your domain, does it make sense to use it to represent static conditions.
However, that is not the only thing that is wrong with the setup. The mesh is really big and has a quality outside of the recommended range which causes the simulation to diverge leading to similar issues as this forum post.
Some more help:
Let us know how it goes! 
Best,
Satvik