Title summarizes the problem: I've built at least 7 different rocket designs - some from old templates that I know worked before, some brand new - and every single one of them has a massive stability issue. Right around 10k meters up from launch, the rocket will tumble end-over-end, no matter what I do, or change. I've checked everything I can think of: weight distribution, where thrust is actually being applied, RCS, no RCS, fins, no fins, solid boosters, liquid engines, every possible combo of thing I could think of. I did have ONE rocket that mostly flew stable, but I can't figure out why it does, or why all the others do not. At first I thought maybe the rockets I was building with the AI pilot were wonky (and they still may be), but even manually piloted rockets have this problem. Any ideas?