On December 17, 1994, approximately 1420 central standard time, a Pitts S2SE, N604SB, was destroyed during a forced landing near Grand Prairie, Texas. The private pilot received serious injuries. No flight plan was filed and visual meteorological conditions prevailed for the local personal flight. The airplane departed Grand Prairie Municipal Airport (F67), Grand Prairie, Texas, approximately 1400, to practice aerobatics with another aircraft. The pilot reported in a written statement that after 5 minutes of practicing aerobatics, he "experienced a loss of power for approximately 2-3 seconds." After the loss of power he started to return to F67 and experienced another "loss of power." The pilot then "switched to the auxiliary tank and the engine caught and ran smoothly." After 3-4 minutes there was "another loss of power", at which time the pilot "switched back to the main tank." The engine "caught momentarily" and then "lost power again." After an unsuccessful restart attempt, the pilot "set up for a forced landing." The pilot of the other aircraft asked him where he was going to land. The pilot responded that he was going to put it in "this field" and then said, "I'm going to try to put it on this road." The airplane subsequently impacted in a soft, muddy field. The pilot of the other aircraft stated that the airplane "seemed to tumble" when it contacted the ground. After the accident, the pilot reported that as he was "setting up" to land on the road, he "observed vehicular traffic" on the road and "elected" to execute the landing in the field. Two successful engine runs were performed after the accident. The engine started normally on both runs and operated normally through ranges of 200 to 2800 RPM. Manifold pressures were observed to be normal and consistent throughout the RPM ranges. Magnetos had impulse during checks at 1500, 2000, and 2500 RPM. Fuel spills were observed at the accident site and ground scars were confined to an area within 20 feet of the wreckage.