On July 9, 2002, at 1500 central daylight time, a Piper PA-J3-C65, N7744B, sustained substantial damage during landing roll when it veered off the left side of runway 27 (2,450 feet by 135 feet, turf) and impacted a ditch. The certified flight instructor (CFI) and student pilot were not injured. The 14 CFR Part 91 instructional flight had departed the Sparta Community-Hunter Field Airport (SAR), Sparta, Illinois, on a local flight. Visual meteorological conditions prevailed and no flight plan was filed. The CFI reported that the flight was an introductory tail wheel instructional flight. He reported, "Student pilot flew aircraft under my direction through several flight maneuvers for initial orientation. He also approached the airport for our initial landing on runway 27 at SAR. Upon turning final for the runway I took full control of the aircraft to demonstrate a 3 point landing. All went well until aircraft started an uncontrollable right turn on the runway. I applied full opposite control but was unable to recover so I chose to initiate a go around but could not gain flying speed before encountering a drainage ditch adjacent to the runway. Power was removed and aircraft was damaged in the drainage ditch."