On November 23, 1996, at 1010 eastern standard time, a homebuilt EAA Biplane, N818Z, was substantially damaged during an aborted takeoff at the Williamsport-Lycoming County Airport (IPT), Williamsport, Pennsylvania. The private pilot was not injured. Visual meteorological conditions prevailed for the personal flight that originated at IPT. No flight plan had been filed for the flight conducted under 14 CFR Part 91. In the NTSB Form 6120.1/2, the pilot/owner stated that after he completed the preflight, he started the engine by hand propping, and then climbed into the cockpit. He further stated, "It was cold and I closed the canopy to keep the wind off me, but did not lock it! Taxied to [runway] 12, received takeoff clearance after run-up, and still neglected to lock canopy. About rotation speed, the canopy slid back, caught my headphones, and held my head back. Lost directional control, went off the runway and flipped tail over, upside down..." According to a Federal Aviation Administration Inspector, examination of the airplane revealed that the canopy locking mechanism functioned properly.