According to the pilot, he did not align the airplane with the runway prior to applying power. Then, during the takeoff roll, the airplane drifted off the side of the runway, became airborne, impacted the grass area near the runway, and came to rest in a nose down attitude. A postaccident examination revealed that the airplane sustained substantial damage to the fuselage in the vicinity of the right main landing gear attachment point. The pilot did not report any mechanical abnormalities of the airplane to a Federal Aviation Administration inspector. The pilot had recently received a tailwheel endorsement.