The nose down pitching moment of the wing increases as the square of the airspeed and is closely related to the camber of the wing airfoil. The down load on the stab that balances the pitching moment of the wing is inversely proportinal to the tail moment arm length. The pull up in the zoom just after release could produce a download on the order of 10 pounds. For slope racers with elevator to flap coupling, the down load on the stab in a tight turn could be even higher. For DSers pushing 200 MPH the down load could easily be in the range of 20 to 30 pounds.