The pilot completed some dual flying earlier in the morning in another pilot's gyrocopter. About 10 hours dual flying had been completed with this other pilot over recent weeks. He then decided to make a solo flight in his own single place gyrocopter. The intention was to fly eight to ten circuits and low passes along the airstrip to get the feel of the aircraft. The first circuit appeared to proceed smoothly at an altitude of about 250 feet above the ground until the turn onto final approach. When that turn was started the aircraft assumed a reasonably steep nose down attitude. Engine noise remained constant until the aircraft hit the ground tracking about 15 degrees to the left of the landing direction. A detailed wreckage inspection did not reveal any pre-existing defect that may have contributed to the accident.