On August 1, 2004, approximately 1625, a Drzymala RV-4 single-engine homebuilt airplane, N7XD, was substantially damaged during a forced landing following a loss of engine power near Collinsville, Texas. The private pilot and the passenger were fatally injured. The airplane was registered to and operated by the pilot. A flight plan was not filed for the cross-country flight that originated at the Allen County Airport (K88) near Iola, Kansas, about 1400, and was destined for the Ironhead Airport (T58) near Sanger, Texas. Visual meteorological conditions prevailed for the personal flight conducted under 14 Code of Federal Regulations Part 91. The pilot departed from Sanger, Texas, on July 24, 2004, and flew to Oshkosh, Wisconsin, to attend the Experimental Aircraft Association's annual fly-in event. He was returning from the fly-in when the accident occurred. A witness observed the airplane flying in a southwesterly direction approximately 200 feet above the ground. The engine was not operating. The airplane then made a 90-degree turn to the east, and descended in an approximate 45-degree nose down attitude. The airplane came to rest upright on the front lawn of a private residence. A Federal Aviation Administration (FAA) inspector, who responded to the accident site, reported that the fuel tanks were empty and not breached. The tanks appeared to be dry, and no residual fuel was found in the main fuel line from the fuel pump to the engine. He also reported that the airplane sustained structural damage. The flaps were set approximately 5-10 degrees, and flight control cable continuity was established for all flight control surfaces. The airplane was powered by an overhauled 180-horsepower Lycoming O-320-E2A engine that was installed just prior to the trip to Oshkosh. There were no logbooks for the engine, which was part of the purchase agreement. Examination of the airfame logbooks revealed the last annual inspection was performed on June 21, 2003, and the airplane had accrued approximately 40 hours since that inspection. Fuel receipts were obtained from locations along the pilot's route of flight. Based on these receipts, it was calculated that the newly installed engine burned approximately 11.5 gallons of fuel per hour. The total fuel capacity of this airplane was 32 gallons, of which, approximately 31 gallons were usable. The pilot purchased 24.6 gallons of fuel in Iola, Kansas, at 1343. The pilot's wife reported that her husband called her just before 1400 and told her that he would be departing soon. The accident occurred approximately 1625. The pilot held a private pilot certificate for airplane single-engine land and was also a certified airframe and powerplant mechanic. His last Federal Aviation Administration (FAA) third class medical was issued on June 11, 2003. At that time, he reported a total of 625 flight hours. At 1653, the automated weather observing system at the Denton Municipal Airport (DTO) near Denton, Texas, located approximately 28 nautical miles south of the site of the accident, reported wind from 100 degrees at 8 knots, visibility 10 statute miles, clear skies, temperature 93 degrees Fahrenheit, dew point 68 degrees Fahrenheit, and a barometric pressure setting of 29.99 inches of Mercury.