change the rocket physics

i have been playing for a while and i have noticed a few things about the rocket physics. 1 every time i try building a 3 dimensional figure it spins out of control unless a put a rocket in the oposite direction. second even after resorting to building a long and flat type vehichle the rockets always make it lean to one side even though its balanced. i don't know this may be me  misbalancing something your are free to test it out if you want just give me some answers here. still great game.