On August 5, 1997, at 1355 central daylight time (cdt), a Champion 7KCAB, N5066X, operated by a private pilot, sustained substantial damage when on landing, control of the airplane was lost. The airplane subsequently nosed over coming to rest on its back. Visual meteorological conditions prevailed at the time of the accident. The aerial towing flight was being conducted under 14 CFR Part 91. No flight plan was on file. The pilot reported no injuries. The local flight originated at Hampshire, Illinois, at 1345 cdt. In his written statement, the pilot said that he was landing after towing and releasing a glider. "I landed to the west, runway 27, on the Sky Soaring [airport] grass strip and was slowing down to a speed at which the rudder had lost effectiveness. The airplane started a slight ground loop toward the right (north), which I corrected by use of the left heel brake. But, the airplane was still headed 15 to 20 degrees right of the runway centerline, toward a glider tied down on the north side of the field. I stepped on both heel brakes to stop the forward movement, and the airplane nosed over and ended on its back." The Federal Aviation Administration (FAA) inspector who examined the airplane, found the right wing broken at the wing root. The right wing tip was crushed in and aft. Both wing struts were bent inward. The engine cowling was bent upward and broken open. The engine and engine mounts were bent up and aft. One of the two propeller blade was bent aft at the tip. The spinner was crushed inward. The windscreen was cracked and pushed inward. The top of the rudder was crushed inward slightly. Flight control continuity was confirmed. No anomalies were found with the engine, engine controls, brakes or any other airplane system.