DH110
Quite right, dbboy, about the DH110 at the 1952 SBAC display. The down-going wing produces a higher angle of attack and hence incremental lift somewhere near the quarter-chord point, whereas the deflected aileron produces a bigger down-force nearer the trailing edge. The resulting nose-up moment twists the wing, and might well break it. In addition, of course, an insufficiently stiff wing may lead to an aeroelastic divergence and hence certain wing failure.
Interesting that the DH110 had carried out an identical display all week, and had not come to grief during that rolling-out, pulling-up manoeuvre. However, on the final day the reserve aircraft was used and this lacked an experimental wing fence that was fitted to the first. The wing fence, although being tried for aerodynamic reasons, had the additional structural effect of stiffening the wing in torsion. Its absence on the aircraft used on that final day was enough to make a tragic difference to the outcome of the manoeuvre.