On June 16, 2004, about 1130 Pacific daylight time, a Stewart Rocky 162F helicopter, N717CS, lost engine power and was substantially damaged during a forced landing near Hood River, Oregon. The helicopter is owned by the pilot and was being operated as a visual flight rules (VFR) flight under the provisions of Title 14, CFR Part 91, when the accident occurred. The airline transport pilot, the sole occupant of the helicopter, was not injured. Visual meteorological conditions prevailed and a flight plan was not filed for the flight that originated from the Ken Jernstedt Airfield (4S2), Hood River, Oregon, at 0945. In a written statement dated June 16, 2004, the pilot reported that while flying at 2,200 feet mean sea level he noticed a low RPM needle and warning light, a high manifold gage indication, but no LOW FUEL warning light, which would indicate approximately 3 gallons of fuel remaining. The pilot further reported that he tried adding throttle and reducing collective, but when this did not correct the problem he assumed he had lost engine power. The pilot stated that he then made an immediate 180 degree turn and performed an autorotation to a large hay field, "...which was about 4 feet high and thick." The pilot further stated that the landing went well until the helicopter slowly rotated towards the nose and the main rotor blade made ground contact. The helicopter subsequently rolled over on its left side. The pilot related that during a post accident examination he dipped the right tank and found no fuel present. At the request of the NTSB investigator-in-charge the pilot also drained what fuel remained from a common drain into a jar which measured approximately 3 inches in diameter. The total amount of fuel drained into the jar measured about 1 inch, equating to approximately 4 to 6 ounces according to the pilot. The pilot reported that during the day it was taking higher power settings to lift off and hover due to the warmer weather. The pilot further reported, "I just miscalculated my fuel. I think I ran out of fuel."