On April 24, 1997, at 0900 central daylight time (cdt), a Cessna 185, N4641E, sustained substantial damage when the airplane flipped over during landing near Pella, Iowa. The pilot was attempting to land on a private airstrip at a farm when the accident occurred. The commercial rated pilot was uninjured in the accident. Visual meteorological conditions prevailed at the time of the 14 CFR Part 91 flight and no flight plan had been filed for the local flight. The pilot was attempting to land the airplane on a plowed field which had been rolled. Before attempting to land at the airstrip the pilot reported that he and the owner of the aircraft walked and drove on the landing area. The pilot reported that he was landing the airplane to the west using 30 degrees of flaps. During the landing roll the pilot reported that the airplane's wheels began to drag heavily, and the airplane flipped over on its back. The pilot said during a telephone conversation after the accident, that even with full up elevator input applied he was unable to stop the airplane from flipping over. The pilot did not report any mechanical malfunctions with the airplane or its engine. The airplane's left wing skin, left wing spar and propeller were bent. The vertical stabilizer and rudder were crushed.