On October 30, 2005, at 1515 eastern standard time, an Enstrom F-28A helicopter, N266Q, owned and piloted by a private pilot, was substantially damaged during a forced landing shortly after departing Portland Municipal Airport (PLD), Portland, Indiana. Visual meteorological conditions prevailed at the time of the accident. The personal flight was operating under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91 without a flight plan. The pilot and passenger were not injured. The flight's intended destination was a private airstrip near Woodburn, Indiana. The pilot stated that he landed at PLD to refuel. The pilot noted that the engine did not sound normal during shutdown. The pilot stated that during a postflight inspection he noted the engine oil quantity was six quarts low. The pilot stated that he called his mechanic who told him, "If it holds power, it is okay to fly it." The pilot reported that he added six quarts of oil before restarting the engine. After engine startup, the pilot walked around the helicopter and noticed smoke emanating from the engine compartment and heard the engine misfiring. The pilot stated that he brought the helicopter into a hover to see if the engine would sustain power. After hovering briefly, the pilot departed on the accident flight. The pilot reported that the helicopter experienced a total loss of engine power during climb out and an autorotation was performed into a cornfield. The pilot stated that the loss of power occurred about 1 mile north of the departure airport at about 1,300 feet mean sea level. The pilot stated that he was unable to maintain directional control during landing due to the soft ground condition and the helicopter slid approximately 100 feet and turned about 190 degrees to the left. The pilot reported that the main and tail rotors contacted the ground, but the helicopter came to rest in an upright position. A witness reported seeing the helicopter on the ramp with the engine running. The witness stated that there was someone standing near the tail rotor talking on a cell phone and another individual looking at the engine. The witness reported that there was smoke coming from the engine compartment and that the engine was misfiring at idle power. The witness stated that the helicopter then departed with smoke trailing from the helicopter. An inspection of the engine revealed that the number two cylinder connecting rod had separated from the crankshaft. There were two holes in the crankcase, located at the top and bottom of the number two cylinder. The number two connecting rod was protruding from the hole located at the bottom of the number two cylinder. The rod cap, cap bolts, and bearing material were not recovered. The number two crankshaft journal surface was smooth, shiny, and did not show any evidence of heat discoloration.