On August 3, 2022, about 1010 central daylight time, a Vans RV-10 airplane, N255CP, was substantially damaged when it was involved in an accident near Hurst, Illinois. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 post-maintenance test flight. The pilot, who was also the airplane owner, reported that he finished an annual inspection and engine condition inspection about two weeks earlier, on July 20, 2022, and intended to complete a test flight before the airplane was sold. He completed an extensive engine ground run with no anomalies noted. After takeoff, he climbed the airplane to 8,500 ft mean sea level (msl) (about 8,100 ft agl), flew for a few minutes and confirmed that all instruments showed normal indications. He reduced engine power and started a slow descent to 3,000 ft msl (2,600 ft agl). When he leveled the airplane and advanced the throttle, “the engine started running rough,” so he applied carburetor heat and turned on the fuel boost pump, but the engine roughness did not improve. He maneuvered for an emergency landing but was unable to glide to the nearby grass strip. The airplane landed hard in a bean field and came to rest upright. The pilot stated that after the accident, the left fuel tank contained 9 gallons of fuel and the right tank contained about 19 gallons of fuel. The carburetor bowl also contained fuel. The responding Federal Aviation Administration (FAA) inspectors reported that the airplane sustained substantial damage to the engine mounts and fuselage. Before the FAA was notified of the accident and could examine the airplane, the pilot had already recovered the airplane to a hangar, removed the engine cowling, drained the fuel tanks, checked the carburetor bowl, and pulled the ignition leads and spark plugs. The FAA inspectors interviewed the pilot, who stated that he could not remember exactly when the engine stopped running, but that the propeller stopped rotating about 300 ft agl and that he did not shut down the engine. The pilot stated that the airplane had not been flown for about a year and that the fuel in the fuel tanks was the fuel that had been in it when it was flown last. A new carburetor was installed in June 2021, because the pilot previously had similar engine issues that resulted in a loss of power. The pilot thought the engine issues were due to carburetor icing. The airplane was equipped with a Dynon electronic flight instrument system (EFIS) and its recorded data was provided for the investigation by the pilot. The airplane was operating in an environment conducive for carburetor icing at glide and cruise power. The airplane was not made available for a detailed examination and the pilot did not submit the National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident Report Form 6120.1.