The pilot/builder had recently completed constructing the experimental amateur-built airplane and had successfully flown for about 15 hours over three days. On the day of the accident, he had completed seven takeoffs and landings and was preparing for another takeoff in the tailwheel-equipped airplane. According to the pilot, he aligned the airplane with the runway heading to take off. As he slowly applied engine power, the airplane began to turn “hard” to the left. The pilot attempted to add right rudder input to correct the left turn, but the airplane continued to the left, exited the runway, and ground looped in the grass. The pilot estimated that the airplane traveled a total of 235 ft down the runway from where power was applied to where the airplane came to rest. The airplane sustained substantial damage to the right aileron and empennage during the runway excursion. The pilot examined the airplane after the accident and found that the left wheel was “hot” difficult to rotate. He disassembled the left wheel and brake system and observed that there were significant grooves in the brake pads and debris lodged within the brake rotor.