On July 31, 2002, at 1100 central daylight time, an amateur-built Jackovich Pitts S1D, N29FJ, owned and piloted by a commercial pilot, was substantially damaged during a forced landing following a complete loss of engine power. The pilot departed the Davenport Municipal Airport (DVN), Davenport, Iowa, at 1030 cdt and was practicing in the local area when the engine and propeller both stopped during a stall. Attempts to restart the engine were not successful. An emergency landing was executed into a bean field approximately 7 miles north-northwest of the Davenport Airport. The flight was being conducted under 14 CFR Part 91 and was not on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot did not report any injuries. In his written statement, the pilot reported entering a departure stall at a relatively steep attitude and with full power applied. Just prior to stall, he reduced power to idle. As the airplane stalled, the nose dropped "rapidly and vertically through the horizon". The pilot stated "I believe the aircraft may have had some reverse direction relative wind producing what some ... refer to as a 'whip stall'." Both the engine and propeller stopped completely as the nose dropped through the horizon, according to the pilot. Attempts to start the propeller windmilling were not successful. The pilot, then, proceeded "in best glide profile" to his selected forced landing site. Post-accident examination revealed no anomalies with the engine. The pilot stated that the engine and aircraft were performing normally during the flight prior to the stall. Although the propeller was damaged during the landing, engine continuity was verified through rotation of the crankshaft. The piloted noted that the engine was modified to exhibit an enhanced compression ratio (10.5:1) and the propeller installed was a wood core, composite construction. In addition, due to weight and balance considerations, an engine starter was not installed in the aircraft. Approximately 8 gallons of fuel were found in the fuel tanks. No evidence of fuel contamination was noted.