On May 22, 2011, at 1630 mountain daylight time, N457CF, an experimental Flournoy MR S1S airplane, ground-looped during landing on Runway 15 at Meadowlake Airport (KFLY), Colorado Springs, Colorado. The airplane was registered to and operated by the commercial rated pilot, who was not injured. Visual meteorological conditions prevailed and no flight plan was filed for the local flight conducted under 14 CFR Part 91. According to the pilot, after a normal touchdown, he felt the tail drop about 6-inches followed by a loud grinding noise. As the airplane began to decelerate, it began to yaw to the left. The pilot applied full right rudder and right brake, but was unable to stop the yaw to the left. The airplane continued to rotate to the left and began to bounce/skip to the side and roll. The lower right wing struck the ground and the engine came to an abrupt stop. The pilot reported that the right main landing gear strut, entire brake assembly, wheel, tire, and wheel pant were damaged. The lower right wing tip and aileron sustained substantial damage from impacting the ground. The tailwheel separated from the airplane and there was substantial damage to the rudder and aft section of the fuselage. The propeller was also damaged. An inspector with the Federal Aviation Administration (FAA) performed an examination of the airplane and discovered that the tailwheel spring attach bolt had pulled through the fuselage structure where it was mounted. The bolt was intact and there was no obvious damage to the threads. It could not be determined as to why the bolt separated. Weather at Meadowlake airport at 1630 was reported as clear skies, visibility 10 miles, and wind from 100 degrees at 5 knots.