On May 16, 1998, about 1300 eastern daylight time, a homebuilt Rans S-12, N91337, was substantially damaged when it impacted terrain shortly after takeoff from the Holly Springs Airport (80VA), Gum Spring, Virginia. The certificated private pilot was not injured. Visual meteorological conditions prevailed and no flight plan had been filed for the personal flight destined for the Warrenton Airpark Airport, Warrenton, Virginia. The flight was conducted under 14 CFR Part 91. In a written statement, the pilot said he had flown the airplane on two flights earlier in the day and experienced no problems. He then departed runway 24 at 80VA, a 2,000 foot long turf runway. During the initial climb, approximately 250-300 feet above the runway, the engine sputtered and recovered. A second later the engine sputtered again; however, it did not recover. The pilot said the engine continued to run, but produced "very little power." The pilot then turned back towards the airport and attempted a forced landing to the runway. The pilot further stated: "...In my attempt to land, I made the turn with a sharp attitude of descent to maintain sufficient airspeed so that I did not stall. I completed the 180 degree turn and was successive in partially flaring the aircraft just before hitting the surface. I was at approximately [a] 30 degree angle to the [runway]..." Examination of the wreckage by a Federal Aviation Administration Inspector revealed that the rubber intake hose which extended from one of the carburetors to the engine was loose and partially disconnected.