On December 16, 1998, at 1131 Pacific standard time, a Elliot RAF 2000 gyroplane, N797X, sustained substantial damage during a hard landing at Walla Walla, Washington. The pilot, the sole occupant, was uninjured. There was no fire, and no report of an ELT actuating. Visual meteorological conditions prevailed at the time of the accident. No flight plan was filed for the local flight. The pilot reported that he was practicing taxi tests after just installing repaired rotor blades and propeller. On his fourth high-speed run, the gyroplane lifted off to approximately 20 feet in altitude. The pilot stated that he closed the throttle and the gyroplane touched down on its tailwheel, then its main gear. The pilot stated that while still moving forward with the front wheel elevated, a slight wind gust caused the gyroplane to veer to the right. The pilot stated that he instinctively pushed left rudder, noting that at such slow speed, the rudder is ineffective, however, it does turn the steerable nosewheel to the left. He stated that when back pressure was released on the stick, the nosewheel touched down in a left-turn direction, causing the aircraft to roll over due to the sudden turning action.