The pilot of the experimental, amateur-built airplane reported that he attempted to take off on a grass portion of his property that extended about 1,000 ft before reaching power lines. During takeoff on an approximate 130° heading, he noticed the airplane was not climbing fast enough to clear the power lines. He pulled up "hard" to clear the power lines but stalled the airplane. The left wing dipped down, and the airplane impacted the ground. The right wing separated from the fuselage, and the empennage was crushed behind the wings. Both main landing gear separated from the fuselage, and the nose landing gear folded back under the engine compartment. The pilot reported that there were no preimpact mechanical malfunctions or anomalies with the airplane that would have precluded normal operation. He added that he thought the wind was swirling and that the airplane may have encountered some wind shear. The recorded wind at an airport located about 13 miles west of the accident site, about the time of the accident, was from 320° at 4 knots.