When crabbing is done all of the airplane controls will typically be in a neutral (centered) position. If you wanted to fly a ground path that went exactly North but had a wind that was out of the East (from the right) you would need to turn the nose of the plane a few degrees right (into the wind) to maintain the desired ground track. The amount of deviation depends upon the speed of the plane and of the wind and the relative angles.

In full scale, and in severe conditions, this could mean that to see where you are actually going you would have to look out the side windows. That would be a LOT of wind of course and a slow plane.

In full scale "crab angle" is also the difference between "course" and "heading".