On September 9, 2005, at 1350 central daylight time, a Dixon RV-4, N9120Q, piloted by a private pilot, was substantially damaged during a forced landing following a loss of engine power near Grafton, Illinois. Visual meteorological conditions prevailed at the time of the accident. The personal flight was operating under the provisions of 14 Code of Federal Regulations (CFR) Part 91 without a flight plan. The pilot sustained minor injuries. The flight departed Batesville Regional Airport (BVX), Batesville, Arkansas, at 1200 and was enroute to Whiteside County Airport (SQI), Rock Falls, Illinois. The pilot reported that after passing the St. Louis metropolitan area the engine "started missing" and eventually "went dead". The pilot stated that he performed a forced landing into a soybean field and nosed over during the landing rollout. The pilot told a Federal Aviation Administration (FAA) inspector that he had descended to 2,000 feet mean sea level in order to avoid the St. Louis Class B airspace. The pilot reported that after passing St. Louis he started to initiate a climb when the engine began running rough. The pilot stated that he switched fuel tanks, checked the magnetos, and applied carburetor heat to no avail. The engine was test run during a post-accident examination. The engine started and ran at idle for a period of five minutes with no anomalies. The engine subsequently ran at 2,100 rpm with no anomalies. The gascolator and carburetor inlet screen were contaminated with fragments of a red fabric-like substance, according to the mechanic who examined the airplane after the accident. The red fragments were similar to a shop-cloth or scotch-brite abrasion pad.