On August 27, 2007, about 1830 central daylight time, an unregistered Quicksilver GT500, two-place airplane, piloted by a private pilot, sustained substantial damage on impact with terrain during takeoff from a private airport near New London, Wisconsin. The personal flight was operating under 14 CFR Part 91. Visual meteorological conditions prevailed at the time of the accident. No flight plan was on file. The pilot sustained serious injuries. The local flight was originating at the time of the accident. The pilot stated in his accident report that a new engine was installed on the accident airplane and that he was performing a high speed taxi on a 1,000 foot runway. The pilot, in part, reported: [The] airplane [unintentionally] took off too close to end of runway to land and stop. I made the choice to fly the airplane, make an approach [and] land. Airplane could only maintain 40-45 mph (stall 35). I was [losing] altitude and attempted to land in hay field. Plane [stalled] about 20 [feet] off the ground. Right wing hit first then nose. The pilot's safety recommendation stated, "Pilot should make sure airplane is in safe condition before attempting flight."