On October 24, 2003, about 1824 eastern daylight time, an experimental (exhibition) Let NP Kinovice Z37A, N137MS, registered to and operated by a private owner as a Title 14 CFR Part 91 personal flight, impacted with the ground while entering the traffic pattern for the Blue Ridge Flightpark Airport, Oak Hill, Florida. Visual meteorological conditions prevailed at the time, and no flight plan was filed. The private-rated pilot reported serious injuries, and one passenger reported minor injuries, and the airplane incurred substantial damage. The flight originated from the Blue Ridge Flightpark, a few minutes before the accident. The pilot stated he was in slow flight at 250 feet above ground level in the traffic pattern on a heading of northwest, flying away from the runway when the right wing abruptly dropped. He first pushed the nose of the airplane forward, added power and opposite aileron, and then he applied rudder. He did not recover do to the low altitude. The FAA inspector who responded to the accident stated the pilot turned left base, for runway 18 when he noticed he was too close to the approach end of the runway. He elected to make a right turn to re-enter the traffic pattern. The airplane was on a heading of approximately 330-degrees when it stalled and spun to the right. During the uncontrolled descent the airplane rotated approximately 240 degrees before striking branches of a tree and then impacted the ground nose first.