On August 11, 2005, approximately 1630 central daylight time, a homebuilt McCain RV-8 single-engine airplane, N2071D, was substantially damaged during a forced landing following a loss of engine power near Stephenville, Texas. The private pilot/owner, the sole occupant of the airplane, was not injured. A flight plan was not filed and visual meteorological conditions prevailed for the personal flight conducted under 14 Code of Federal Regulations Part 91. The cross-country flight originated from Clark Field (SEP), near Stephenville, Texas, at approximately 1630 and was en route to the Brownwood Regional Airport (BWD), near Brownwood, Texas. In a telephone conversation with the NTSB investigator in charge (IIC), the 500-hour pilot stated that he departed SEP and was in cruise flight when he experienced a loss of fuel pressure, with a subsequent loss of engine power. The pilot turned on an electrically driven fuel pump and switched fuel tanks several times. The fuel pressure or engine power were not regained. The pilot initiated a forced landing. During the forced landing, the airplane impacted trees, coming to rest in a clearing. Multiple attempts to obtain a completed Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) from the pilot were unsuccessful. Examination of the aircraft by a Federal Aviation Administration (FAA) inspector revealed structural damage to the wings and fuselage. The two wing fuel tanks had been breached by the accident, but the right tank still contained approximately half of it's total capacity. Inspection by an airframe and powerplant mechanic of the airplane's fuel system, including the fuel pumps, lines and selector valve did not reveal a reason for the reported loss of fuel pressure. At 1645, the automated weather observing system (AWOS) at SEP reported wind from 170 degrees at 13 knots gusting to 16 knots, visibility 10 statute miles, clear skies, temperature 90 degrees Fahrenheit, dew point 63 degrees Fahrenheit, and a barometric pressure of 29.94 inches of Mercury.