On July 12, 2018, about 1625 eastern daylight time, an experimental amateur-built Whittman Tailwind, N619NT, impacted terrain during a forced landing following a total loss of engine power near Orient, Ohio. The airplane sustained substantial damage to the fuselage. The private pilot/airplane owner and a flight instructor were uninjured. The airplane was registered to the previous owner and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as an instructional flight that was not operating on a flight plan. Day visual meteorological conditions prevailed at the time of the accident. The local flight departed from the Bolton Field Airport, near Columbus, Ohio, about 1610. The pilot, who was the airplane owner, stated the flight was a familiarization flight for him for the purpose of meeting insurance requirements. The flight instructor stated the preflight and runup for the familiarization flight was normal. After the departure and level off at 2,000 ft msl, the engine began to "surge and then quit running". He turned on carburetor heat and the fuel pump, but engine power was not regained, and the propeller kept windmilling. He then performed a forced landing to a field. The flight instructor did not provide his total flight time in the accident airplane make and model in his National Transportation Safety Board Pilot/Operator Aircraft Accident Report, Form 6120. The flight instructor entered "all types" in the flight time matrix of Form 6120. The flight instructor's experience in the accident airplane make and model was unknown. The pilot stated the airplane was equipped with an unconventional mixture control that was improperly used during flight and caused the engine to quit running. The pilot's recommendation was: "Better and more thorough cockpit familiarization would have prevented the accident from occurring." According to the Federal Aviation Administration inspector from the Columbus Flight Standards District Office, the post-accident examination of the airplane revealed the mixture control had been modified from its original configuration that was opposite of a configuration in which a full forward position of the mixture control would have provided a full rich mixture. As a result, the fuel was inadvertently cut-off during flight. There were no other mechanical anomalies reported that would have precluded normal operation.