The aircraft collided with the ground while performing aerobatic maneuvers. The pilot had scheduled a number of aerobatic flights for various people. During the last flight of the day, the aircraft crashed in an alt open, plowed field. Weather was not a factor. The aircraft impacted the ground in a 30 degree nose down attitude and traveled forward 35 ft after impact. The empennage was not damaged. The wings were destroyed but remained attached to the fuselage. The aircraft remained upright. The engine remained attached but the engine mount was collapsed. The floor and the landing gear were collapsed. The integrity of the flight control system was established. There was no evidence of an in-flight failure of the structure or powerplant. The occupants had worn their seat belts and shoulder harness which were intact. Both occupants received fatal traumatic injuries. There was no evidence of pre-impact factors which might have detracted from the pilot's ability to operate the aircraft. The toxicological reports for both occupants were negative for drugs and alcohol.