Floating

You all probably know something about my game RaceCraft by now. Try the attached scene. Even if you fly skillfully you're bound to topple over somewhere. I need to find a way to make the craft more stable, so it won't tip over at all, or make it have a self-righting mechanism. Or both. Here's the code I wrote for floating:

Code (csharp):

1.  
2. function FixedUpdate () {
3.     if (Physics.Raycast (transform.position, Vector3.down, 3)) {
4.         rigidbody.AddForce (Vector3.up * 4.6);
5.     }
6.     var accel = Input.GetAxis ("Vertical") * 2;
7.     rigidbody.AddRelativeForce (0, 0, accel);
8.     var h = Input.GetAxis ("Horizontal");
9.     transform.Rotate (0, h, 0);
10. }

EDIT: Actually, FreezeRotation seems to have solved it (duh), but you can still play the buggy web player if you want. lol