On August 20, 2011, at 1045 eastern daylight time, an experimental amateur-built American Autogyro model Sparrowhawk, N2631B, was substantially damaged during takeoff from Delaware Municipal Airport, Delaware, Ohio. The non-certificated pilot/owner and passenger sustained minor injuries. The gyrocopter was registered to and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91. Day visual meteorological conditions prevailed for the flight, which was operated without a flight plan. The flight was originating at the time of the accident and the intended destination was Newark-Heath Airport, Heath, Ohio.The pilot reported that he had been receiving instruction toward a pilot certificate, but had not obtained a student pilot certificate. He noted that although he had a pilot-rated passenger onboard, he was still acting as pilot-in-command and was flying the gyrocopter when the accident occurred. He stated that during initial climb from runway 28, about 20-30 feet above the ground, he noticed the gyrocopter's airspeed was lower than intended and the gyrocopter began to drift to the right. He attempted to increase airspeed by lowering pitch, but the gyrocopter landed hard and rolled over onto its side. The fuselage, tail, and main rotor were substantially damaged during the accident sequence. The pilot stated that although there were no engine anomalies during pretakeoff operations, it could have been running at a reduced power setting during initial climb. He noted that the engine throttle was found selected to about 80 percent power after the accident; however, he was unable to determine if it had been inadvertently retarded from a full power setting during the flight, or as he egressed from the gyrocopter after the accident. A witness to the accident reported seeing two similar gyrocopters depart in succession. The first gyrocopter was flown by a certified flight instructor and was followed by the accident gyrocopter. The witness reported that the accident gyrocopter's ascent after liftoff was steeper than the preceding gyrocopter. The accident gyrocopter climbed about 30 feet before it entered a descending right turn. The gyrocopter collided with the ground in a nose low attitude and subsequently rolled-over onto its left side. A postaccident examination conducted by Federal Aviation Administration inspectors did not reveal any mechanical malfunctions or failures that would have precluded normal operation of the gyrocopter. The main rotor blades exhibited rotational damage. No mechanical anomalies were noted while the engine crankshaft was rotated. All three composite propeller blades exhibited rotational damage consistent with engine operation at the time of impact. At 1053, the airport's automated surface observing system reported the following weather conditions: wind 180 degrees at 3 knots; visibility 10 miles; clear skies; temperature 25 degrees Celsius; dew point 20 degrees Celsius; altimeter setting 30.01 inches of mercury.