On November 6, 2016, about 1600 central daylight time, an Zenith 801 homebuilt, experimental airplane, N801KJ, registered to the pilot, was destroyed by a postimpact fire after it impacted the ground while on approach to Runway 18 at the Northport Airport (WI38), Royalton, Wisconsin. The private pilot, who was the sole occupant, sustained minor injuries. The local personal flight was being conducted under the provisions of Federal Code of Regulations Part 91. Visual meteorological conditions prevailed throughout the area and a flight plan was not filed. The flight originated about 1530 from WI38. The pilot reported that he had built the airplane over the last 14 years. The airplane was approved for a 40-hour testing period on May 12, 2016, when it received it's continuous airworthiness inspection. The airplane was flown by the pilot on the day prior to the accident and he reported no mechanical anomalies. The pilot provided a detailed account of the day's flight and accident on NTSB Form 6120. He reported that the purpose of the flight was to practice stalls and how the airplane responded. On the first flight of the day, the airplane stalled with full power at 38-39 mph, neither wing stalled first, and the flight was straight and stable. He landed with full flaps on the grass runway, and took off for more testing. He then performed a successful full-flap engine idle stall. The airplane stalled at 28-29 mph, both wings stayed level, and the airplane flew straight. He performed a tough and go landing, took off, and established the airplane on downwind, about 1,000 feet AGL, to set up for a full flap landing. He lowered the flaps and set the engine power to idle. The pilot discovered that the control stick would move, but he had no control of the airplane. The stick would move, but the airplane could not be controlled. The airplane impacted the ground and the pilot did not remember the crash. Neighbors helped to evacuate the pilot from the wreckage and local responders transported the pilot to a hospital. There were no eye-witnesses to the accident, however, a neighbor reported hearing the airplane and thought that he heard the engine backfire. The airplane was totally consumed by a post-impact fire. An FAA inspector examined the wreckage, but due to the extent of fire damage, it was not possible to determine any pre-impact anomalies with the engine, flight controls, or flight control surfaces. The pilot reported that he did not believe that the airplane stalled. The pilot also stated on NTSB Form 6120, that the 5-point harness that he installed on his homebuilt airplane probably saved his life.