On May 1, 2005, approximately 1900 central daylight time, a single-engine Lancair Legacy homebuilt experimental airplane, N204RH, registered to and operated by the pilot, was destroyed during a forced landing following a reportd loss of engine power while maneuvering near Nacogdoches, Texas. The airline transport pilot and pilot rated passenger were not injured. Visual meteorological conditions prevailed, and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 personal flight. The local flight originated from the A. L. Mangham Jr. Regional Airport (OCH), near Nacogdoches, Texas, approximately 1845. The 20,000-hour pilot reported in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that he was maneuvering at an altitude of 700-800 feet above ground level (agl), when the "sound of the engine suddenly changed" followed by a loss of engine power. As the pilot pitched the airplane up, "to trade airspeed for altitude," he verified the throttle, propeller, and mixture control positions. The pilot stated that he switched from the right fuel tank to the left fuel tank and cycled the throttle, but the engine continued to lose power, as he initiated a forced landing to an open field. As the airplane touched down, the main landing gear "sheered off" and the airplane skidded to a stop in an upright position. Subsequently, a post-crash fire ensued and both occupants evacuated the airplane. The pilot added that about three to four minutes prior to the change in the engine sound, he verified on the engine monitoring instrument that all indications where within the green bands. Examination of the airplane by an Federal Aviation Administration (FAA) inspector, who responded to the accident site, revealed that the fuselage and inboard portions of the airplane were consumed by the fire. The wreckage of airplane, which had accumulated approximately 30.1-hours since new, and the Teledyne Continental Motors IO-550-N13B engine which had accumulated 23.7-hours since new, were recovered to the facilities of Air Salvage of Dallas, near Lancaster, Texas, for further examination. Examination of the engine was conducted on June 9, 2005, at the facilities of Teledyne Continental, of Mobile, Alabama, under the supervision of an NTSB representative. The examination revealed that rotational continuity was established throughout the engine and accessory gearbox when the propeller was rotated by hand. The top and bottom sparkplugs were removed and when compared to the Champion Aviation Check-A-Plug Wear Guide (Part Number AV-27), displayed signatures of normal operation. All six cylinders remained attached to the crankcase and were fire damaged. Cylinder #1, #2, #3, #4, #5, and #6 pistons, rings, pins, and connecting rods remained intact and free of anomalies. The crankshaft and counterweight were free of anomalies. The reason for the reportd loss of engine power could not be determined.