On November 30, 2019, about 1000 eastern standard time, a Yakovlev Yak 52, N52CY, was substantially damaged during an off-airport landing after experiencing a loss of engine power enroute near Wrightsville, Georgia. The flight instructor and private pilot sustained minor injuries. The airplane was registered to and operated by the flight instructor as a Title 14 Code of Federal Regulations Part 91 personal flight. Day visual meteorological conditions prevailed, and no flight plan was filed. The flight originated from Waycross-Ware County Airport (AYS), Waycross, Georgia about 0915 and was destined for Kaolin Field Airport (OKZ), Sandersville, Georgia. The private pilot, seated in the rear seat, reported this was the second day of a cross-country trip to move the recently purchased airplane to Tennessee, from Florida. He reported that the flights the day prior were normal, and the accident flight takeoff and cruise progressed normally, until about 10 minutes from OKZ. While cruising at 3,500 ft mean sea level, there was a sudden heavy vibration from the engine that lasted about 5 seconds and resulted in a complete loss of engine power. He added that there was no indication that something was wrong with the engine, prior to the heavy vibration. The flight instructor reported the same heavy vibration and loss of engine power, and added that the vibration was so heavy, that an engine gauge fell out of its position into the back of the instrument panel during the event. He immediately took the flight controls and adjusted the throttle but received no response from the engine. He then attempted an engine restart, but when he engaged the starter, he saw one propeller blade remained fixed in the airstream. The flight instructor reported he then turned the airplane left to align with a long farm field, and while on final approach about 500 ft above ground, he extended the landing gear, which resulted in the airspeed decaying rapidly and a further increase in the descent rate. Subsequently, he reported that as the airplane entered the landing flare, it was "out of airspeed," and shortly after the nose wheel touched down the airplane nosed over and skidded to a stop. According to a Federal Aviation Administration (FAA) inspector who examined the airplane at the accident site, the airplane came to rest upside down. The fuselage, empennage, and wings sustained substantial damage. Flight control continuity was confirmed to all surfaces. Oil spray was observed on the underside of the fuselage. When the propeller was moved by hand, it was revealed that the engine had seized and would not rotate. Further examination of the engine by a National Transportation Safety Board investigator revealed that thick black oil was present in the engine. The spark plugs were dark in color. The propeller blades sustained impact damage. Inspection of each cylinder with a lighted boroscope found that the cylinders were very dark in color and oil soaked. The No. 5 cylinder exhaust valve was damaged and had the appearance that the valve seat dropped into the cylinder. Metal pieces were also found inside the No. 5 cylinder. According to FAA airman records, the private pilot had ratings for airplane single and multi-engine land, and instrument airplane. He completed the FAA basic medical certificate course October 21, 2019. His most recent flight review was completed on November 19, 2019. He reported a total flight time of 1,920 hours, of which 4 hours were in the accident airplane make and model. In the past 90 days, he reported a total flight time of 4 hours. According to FAA airman records, the flight instructor held an airline transport pilot certificate with a rating for airplane multi-engine land and a commercial pilot certificate with ratings for airplane single-engine land and sea, and glider. He held a private pilot certificate for rotorcraft-helicopter. He also held a flight instructor certificate for airplane single and multi-engine, instrument airplane, and glider. He did not hold a medical certificate. He reported a total flight time of 3,805 hours, of which 4 hours were in the accident airplane make and model. In the past 90 and 30 days, he reported a total flight time of 20 hours and 7 hours respectively. According to FAA airworthiness and airplane maintenance records, the 2-tandem seat former Union of Soviet Socialist Republics (USSR) aerobatic trainer was manufactured in 1988 and was powered by a Vedeneyev M14P nine-cylinder radial engine. The propeller was a wooden Vperod V530TA-D35. The most recent 100-hour inspection was completed on November 1, 2019, where the maintenance entry stated that the engine oil and spark plugs were replaced. There was no mention of an inspection of the engine cylinders. According to the flight instructor, the airplane had not flown for a "couple of years" prior to the 100-hour inspection and repositioning cross-country flight. At 0955, the OKZ hourly weather observation, about 12 nautical miles north of the accident site, included wind from a heading of 210° at 4 knots, visibility 10 statute miles, overcast ceilings at 3,100 ft above ground, temperature 16°C, and dew point 10°C.