On September 18, 2011, approximately 1540 central daylight time, a Mark Divita RV-8, N98D, experienced a loss of directional control on landing, and subsequently ground looped at the Lancaster Regional Airport (LNC), Lancaster, Texas. The commercial pilot was not injured. The airplane sustained substantial damage to the fuselage. The airplane was registered to and operated by the pilot, under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed and a flight plan had not been filed for the local flight. The flight had originated from LNC at 1535. According to the pilot, during the landing rollout on runway 13, the airplane began to swerve to the right. The pilot attempted to arrest the swerve by applying left rudder pedal and left brake to no avail. The airplane exited the right side of the runway and subsequently ground looped. The pilot reported that the winds were from 190 degrees at 8 knots. The pilot further reported having 420 hours of tailwheel fight time, with approximately 400 of those hours in a Pitts Special from 2006 to 2011. A postaccident examination of the airplane, by the National Transportation Safety Board (NTSB), investigator-in-charge (IIC), revealed that the tailwheel assembly, tailwheel steering arm, and rudder stops were all in working condition. However, when combined together, the resulting configuration allowed the tailwheel to unlock and fully swivel, 15 degrees prior to the rudder reaching full travel in either direction.