The gyroplane was substantially damaged when it rolled onto its left side during landing. The gyroplane's main rotor struck the runway causing the cabin enclosure to roll over about two times before coming to rest on its right side. The pilot reported that the approach was normal with touchdown on both main wheels. He stated that he reduced power and then felt the right main wheel come off of the ground. He stated that he attempted to correct by moving the cyclic control to the right and forward, but the aircraft proceeded to roll to its left. The wind conditions reported were from 20 degrees right of runway heading at 15 knots gusting to 21 knots.