On May 29, 2004, at 0730 central daylight time, an unregistered Zorn EAA Sport Bi-Plane, collided with the terrain following a loss of control during initial climb after takeoff from a private airstrip in Mazon, Illinois. The pilot received fatal injuries and the airplane was substantially damaged. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions without a flight plan. The flight originated just prior to the accident. A witness reported, "I saw the plane come over the trees and it waivered and nose dived into the ground." Another witness reported the airplane appeared to be "performing maneuvers in the air above the crash site." The pilot's wife reported the pilot purchased the airplane in the fall of 2003. She reported that her husband had just finished assembling the airplane and the accident occurred during the first flight. She stated her husband was having some oil problems and he was going to test fly the airplane. According to the Grundy County Sheriff's Department Report, the pilot towed the airplane to a farm that had a grass airstrip the night prior to the accident and that the pilot left his home at 0600 on the morning of the accident to work on the airplane. The pilot's wife told the sheriff's department that her husband was "going to taxi the plane and complete short take-offs and landings to test the plane and engine." The airplane came to rest in an open field. The nose of the airplane impacted the terrain and came to rest in a near vertical position. The fuselage and empennage folded inverted over the cockpit. Both lower wings were uniformly crushed rearward. The wreckage was examined by a inspector from the Federal Aviation Administration Flight Standards District Office in West Chicago, Illinois. This examination failed to reveal any engine or airframe failure/malfunction which would have resulted in the accident. The pilot's wife stated she did not have any pilot or aircraft logbook records. The airplane did not have an airworthiness certificate. No records were located to indicate that the airplane had ever been registered. The original builder of the airplane was contacted and he stated he and a partner began building the airplane between 1968 and 1970. He stated the unfinished airplane was put in storage and his partner sold it 15 to 20 years ago. He did not know who bought the airplane. He stated the airplane did not have any skin on it and the engine was not installed when it was sold. The pilot held a private pilot certificate with a single-engine land rating. This certificate was issued on July 1, 2002. The pilot also held a third class medical certificate which was dated July 8, 2003. The medical certificate contained the limitation "Holder shall wear corrective lenses." On the application for this medical certificate, the pilot reported having 150 hours of flight time, 20 of which were in the previous 6 months. The weather reported at the Joliet Regional Airport (JOT), Joliet, Illinois, at 0805, was clear sky condition, 10 statue miles visibility, winds from 110 degrees at 5 knots, temperature 12 degrees Celsius, dewpoint 7 degrees Celsius, altimeter setting 29.99 inches of mercury.