On July 6, 2016, about 1530 eastern daylight time, an experimental amateur-built Glasair, N67WH, was substantially damaged following a forced landing following a total loss of engine power near Maynardville, Tennessee. The private pilot was not injured. The airplane was registered to and operated by Mainpro Inc. under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed about the time of the accident and no flight plan was filed for the flight that was destined for Clermont County Airport (I69), Batavia, Ohio. The pilot flew from I69 to DKX earlier in the morning without incident and he was returning to I69 when the accident occurred. He reported that the preflight inspection, taxi, and runup were normal and the climb to 5,500 ft mean sea level (msl) was uneventful; however, while passing through 5,500 ft msl the engine oil temperature was getting high, so he elected to level off for a few minutes to let it cool down. About 5 minutes later, he resumed his climb to 7,500 ft msl and while passing through 6,000 ft msl, the engine "blew." He stated that the engine "broke" and started to shudder "like it was out of balance." In addition, smoke started filling up the cockpit. The pilot declared an emergency, shut down the engine and scanned the area for a suitable place to land. While descending through 4,000ft msl, he reported the terrain was hilly and unsuitable for landing to the north, but to the south it was less congested and a better option for landing; the road was a two-lane state highway. After turning and getting established on a final approach to the southbound lanes of the highway, the pilot noticed electrical transmission wires crossing the road about 80 feet above ground level. The pilot pushed the stick forward and flew under the wires by going into an abrupt descent, then attempted to flare for landing, but the airplane "pancaked" onto the road, collapsing the main gear and shearing off the nose gear. The airplane skidded about 200 feet before coming to rest on a business property adjacent to the road. The pilot held a private pilot certificate with ratings for airplane single-engine land and instrument airplane. His last flight review was completed on July 20, 2014. He held a third-class airman medical certificate issued on April 21, 2015. The pilot reported 2,055 hours total time with 1,320 of those hours in the same make and model as the accident airplane. In addition, he reported 42 hours and 24 hours in the previous 90 and 30 days, respectively. According to FAA airworthiness and airplane maintenance records, the two-seat, low wing, retractable tricycle landing gear airplane was manufactured in 1991 and was issued a special airworthiness certificate for experimental amateur-built aircraft. It was powered by a Lycoming IO-360, 200-hp engine and equipped with a Hartzell two-blade constant speed propeller. The engine had accumulated 680 hours of operation since overhaul and 25 hours since the last condition inspection on April 15, 2014. DKX was located about 15 miles south of the accident site. The DKX weather at 1353 included wind from 240° at 10 knots, visibility 10 statute miles, few clouds at 3,400 ft, temperature 31°C, dewpoint 19 ° C, and the altimeter setting was 30.03 inches of mercury. An inspector with the Federal Aviation Administration (FAA) responded to the accident site and examined the wreckage. The airplane and all major components were accounted for at the scene. There was substantial damage to the underside of the fuselage where the landing gear had collapsed. Both blades of the propeller were bent aft and that engine case was breached. Oil streaks were observed on the underside of the engine cowling and fuselage. Subsequent examination of the engine revealed engine case was breached above the No. 4 and No. 3 cylinders. Fragments of the case material were discovered in the engine baffle. Some corrosion was present on the mounting surface of the cylinders. The No. 3 cylinder exhibited damage to the connecting rod where it attached to the crankshaft and had fractured off completely near the wrist pin. The No. 3 cylinder skirt base was damaged at two points perpendicular to the wrist pin. The remainder of the connecting rod sustained damage and was deformed and bent back toward the crankshaft. The No. 4 cylinder was jammed and canted several degrees and could not be removed from the case but a visual inspection from the opposing cylinder revealed internal damage to parts of the connecting rods and engine case. The No. 1 and No. 2 cylinders showed no damage to the piston, rods, cylinders or surrounding case. Automotive spark plugs and a wiring harness were observed on the bottom cylinders and no engine data plate was found on the engine.