(W.I.P.) Quadcopter

Well, I made a Quadcopter. Except, it seems to like tilting to the right for no apparent reason. If any of you want to take a look at it and would be willing to help figure why it's tilting to the right and how to combat the issue, I'll post the .bsg below.

WebM (direct watch link on MediaFire) here.

BSG download here.

It controls simply through the arrow keys. Forward is forward, back tilts back, etc.

Side note: If we could directly post embedded WebM's, that'd be great.
The tilting to the right is from some crazy physics due to your 4 rotors being mini spinning gyroscopes. If you steer forward it will veer right, if you steer right it will veer backwards, and so on. A simple fix is to have two of them spinning in the opposite direction to cancel out the force.
From the initial version the tilting issue can be fixed while maintaining the same controls.

For the two rotors that are at the front and back controlled by up/down, hover over the blades, wheels, and saws, and press F once for each to reverse their directions. That will change the direction the saws spin, the direction the blades get lift from, and will swap the wheel controls for the new spin so it still works the same.