On November 22, 1997, at 1102 hours mountain standard time, a Rans S91 experimental airplane, N9291T, collided with a dirt road following a loss of engine power at Phoenix, Arizona. The aircraft was owned and operated by the pilot/builder and was on its initial test flight following construction and certification. The aircraft sustained substantial damage and the pilot received minor injuries. The airplane departed Pinnacle Peak landing strip at 1002 for a local flight. Visual meteorological conditions prevailed. Following takeoff, the pilot flew for nearly an hour while exploring the handling qualities of the aircraft. After returning to the airport, the pilot made a pass over the airstrip to check controllability in the landing configuration. In his statement he reported that in initiating the missed approach he "applied full power and pulled to 55 IAS and 2.5G's at 300 feet agl . . .(then) I pushed over and reduced to 5000 rpm." At this point, the pilot noticed a loss of rpm, followed 5 seconds later by a complete loss of engine power. He turned toward a landing site, and at 10 feet agl started to flare for touchdown. The pilot stated that the airplane was not flying and he had no control of the aircraft. The aircraft touched down hard on the road. The pilot reported that the engine was free to rotate, with no evidence of internal failure. He believes the loss of power was due to a fuel system vent blockage.