The pilot stated that he was conducting, night takeoff and landings. During the first landing, he flared too high and landed hard. The airplane veered off the runway, hit a drainage ditch, and nosed over. The pilot did not report experiencing any flight control or mechanical anomalies with the airplane during the landing. Examination of the airplane by a Federal Aviation Administration inspector revealed that the firewall and wings were substantially damaged. Winds about the time of the accident were light and variable.