According to the pilot in the tailwheel-equipped airplane, he landed on the turf runway and the airplane began to drift left. He made a right rudder pedal input that did not counter the left drift, and he adjusted his foot on the right rudder pedal so that he could apply differential braking. However, he reported that, "my shoe was caught between the rudder pedal and the sheet metal fairing on the floorboard that covers the rudder pedal bell cranks," preventing him from applying differential braking. The airplane exited the runway to the left, ground looped to the left, the right main landing gear collapsed, and the right wing struck the ground. The airplane sustained substantial damage to the right-wing spar and right aileron. The pilot reported that there were no pre-accident mechanical malfunctions or failures with the airplane that would have precluded normal operation.