On December 3, 2016, about 0851 eastern standard time, an Arion Aircraft LLC, Lightning LS-1 airplane, N218D, impacted soft terrain during a forced landing following an inflight loss of engine power near Goshen, Indiana. The pilot and his passenger were uninjured. The airplane sustained substantial fuselage damage. The airplane was registered to and operated by the pilot under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Day visual meteorological conditions prevailed for the flight, which did not operate on a flight plan. The flight originated from the Goshen Municipal Airport (GSH), near Goshen, Indiana, about 0840 and was destined for the Ankeny Regional Airport (IKV), near Ankeny, Iowa.According to the pilot, he contacted the flight service station for a weather briefing along his route of flight to IKV. He conducted a preflight inspection of the airplane. About 0825, the pilot loaded the airplane and started it to allow it to warm up. About 0830, the airplane was taxied to runway 27. The pilot performed flight checks that allowed the operating temperatures to continue to warm and he "ran the carburetor heat again just prior to departing." About 0835, he departed from the runway on a 270 heading. The climb to cruise at 2,000 feet was normal and he subsequently transitioned to cruise. About 9 to 10 nautical miles from GSH the engine started to run "rough" and the pilot applied carburetor heat. This did not improve engine performance, so he decided to return to GSH where he started to line up for a downwind for runway 27. The engine continued to sputter with carburetor heat applied. Engine "power was very poor" and the airplane was losing altitude rapidly. The pilot then thought that the airplane may be able to make runway 9. He subsequently realized the airplane was too low for that approach and with little power, the airplane would not be able to make the field where it would end up in the trees or fence short of runway 9. The pilot spotted a clear field that he could turn into and have an up wind landing. He called common traffic advisory frequency at GSH about 0852 and announce a mayday call that indicated where the airplane was landing. The pilot performed a soft field landing approach and slowed as much as possible heading back on 270 heading. He knew that the fields were recently tilled and would be very soft and muddy due to recent rains. The pilot attempted to fly just above the surface as long as possible and keeping the nose up. On landing the gear dug into the very soft plowed field and the airplane continued forward on its belly. The pilot indicated that it was a very short amount of time from when he "called in and actually landed the plane." At 0853, the recorded weather at GSH was: Wind 260 degrees at 5 knots; visibility 10 statute miles; sky condition overcast clouds at 2,800 feet; temperature 1 degree C; dew point -3 degrees C; altimeter 30.33 inches of mercury. The temperature and dew point spread were plotted on a carburetor icing probability chart. Their intersection was within the serious icing at any power setting envelope. A Federal Aviation Administration Inspector conducted an on-scene investigation of the accident airplane. He established flight control continuity existed. He observed that the fuel filters, one for each tank, were mounted in the aircraft cabin under the seats. The filters appeared clean and contained a liquid consistent with 100 low lead aviation gasoline. Some engine components sustained impact damage and the engine could not be test run. However, no preimpact anomalies were detected.