Gmod Physics Questions

I’ve been trying recently to rig up thrusters to just counteract the combined weight of the thruster(s) and connected object(s). However, so far all that has happened is either there is no lift or too much lift never a hovering type effect. I have also noticed in these attempts that when items are lifting off, even from a completely flat surface, they start leaning to one side or another and start to turn and eventually spin in circles… Can someone help understand why this happens?

Because it’s Source?

Use Hoverballs?

It is not perfect for physics.

I realize all these things but i want to know more about it than just, use hoverballs, for the sake of hoping to make vehicles capable of hovering.