On April 17, 2012, at 1600 central daylight time, an experimental amateur-built Heiser Pulsar XP, N912RV, sustained substantial damage during a hard landing after a loss of power during takeoff from runway 17 at the Ducote Air Park (TS65), San Angelo, Texas. The sport pilot, the sole occupant, received minor injuries. The airplane was registered to and operated by the pilot under the provisions of the 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The airplane was departing TS65 on a local flight. The pilot reported that he and the airplane had not flown in four months, so he wanted to fly and get current in order to carry passengers. He reported that he pulled the airplane out of the hangar and completed a detailed preflight inspection. He added fuel to the right tank bringing the total fuel in the right tank to 6 gallons and 3 gallons in the left tank. The fuel tanks held 9.5 gallons each. The engine start, taxi, and run-up were normal. After checking the ignition systems, he increased engine speed to 4,000 rpm to raise the oil temperature to 120 degrees Fahrenheit. About 4 minutes after engine start, he taxied onto the runway and departed. He reported that the airplane climbed to about 50 feet above ground level when the engine started to lose power. He started a right turn to make a short traffic pattern and land, but the engine had a total loss of power after the airplane had turned about 30 degrees. He executed a forced landing to a flat wheat field and the airplane landed hard, which resulted in substantial damage to the wings and fuselage. The fuel tanks, fuel lines, and fuel strainer were checked for debris and water contamination but none was observed. The engine driven mechanical fuel pump was tested and it operated normally. Air was blown through the fuel system to determine if there was a blockage in the system. When air was blown into the right fuel tank and through the fuel system, no blockage was noted. When air was blown into the fuel line that attaches to the engine driven fuel pump back through the fuel system, the air was blocked. It was determined that air could pass through the Facet 12V electric fuel pump in the direction of flow from the fuel tanks to the engine, but not from the engine back to the fuel tanks. When the electric fuel pump was removed from the airframe, air could travel through the electric fuel pump in both directions. The Facet 12V electric fuel pump was removed from the airframe and was tested at an airplane component repair facility. The pump was tested on a fuel bench and it operated normally, pumping between 110 to 130 pounds per hour. The 100-horsepower Rotax 912 XP engine was shipped to a Rotax distributor for examination. The engine was placed on the engine run stand, and it operated normally delivering takeoff power. The examination of the airplane revealed that the outboard section of right wing fuel vent was blocked by debris. About a 4 inch section of the blocked fuel vent line was removed and sent to the component repair facility for examination. Fuel was introduced into the line and a minimal amount of fuel flowed through the line. The blockage was removed from the line, which measured about 1/4 inch wide at its widest and about 1/2 inch long.