On May 30, 1998, about 1500 eastern daylight time, a Cessna 170B, N3099A, was substantially damaged during an intentional ground loop during the landing roll at the Weltzien Skypark (15G), Wadsworth, Ohio. The certificated flight instructor (CFI) was not injured, and the commercial pilot/owner received minor injuries. Visual meteorological conditions prevailed and no flight plan was filed for the instructional flight conducted under 14 CFR Part 91. The flight originated from Weltzien Skypark, about 1400. The pilot/owner stated that this was his Biennial Flight Review. After takeoff and completion of air work and maneuvering in the local practice area, the pilot and CFI returned to the airport and landed. The pilot reported that after landing, the CFI recommended that he perform a short field, power off landings. The pilot reported that after two unsuccessful attempts, the CFI stated, "let me show you how to do it." The pilot also stated that while on final during the next approach, the CFI stated, "guard the controls." The pilot said that he was confused by that statement, but "placed his hands and feet near the controls to follow the CFI's inputs." The CFI reported that he used 40 degrees of flaps, and had 70 mph on the airspeed indicator, when he flared the airplane. The airplane then touched down on its main landing gear, and when it started to drift right, the CFI applied left rudder. He stated that the left rudder only traveled about 1 inch. He continued to depress the left rudder, when "all of a sudden, it seemed to let go," and full left rudder deflection occurred. The CFI stated that the airplane immediately went left and "with little runway remaining and the surrounding obstacles, he felt his only option was to kick full right rudder and intentionally ground loop the airplane." The pilot stated that he did not feel any binding, and his hands and feet were only "near the controls, not on them." He said that he felt the right rudder being applied, and when the tail wheel came down, the nose of the airplane went right and the empennage of the airplane swerved left. The airplane came to a stop 90 degrees right of the runway heading. The pilot stated that he had not been able to fly with any consistency for the last two years. He reported that the last annual inspection on the airplane was completed in December, 1996. The CFI had accumulated 4,769 flight hours, and 36 total hours were in make and model (tailwheel) airplane. The CFI had "0" hours in make and model during the last 90 days. A Federal Aviation Administration (FAA) Inspector stated that the left landing gear was collapsed underneath the fuselage and the left wing and propeller were damaged from contact with the runway. On June 4, 1998, two FAA Inspectors examined the airplane. They reported that floor panels were removed, and the rudder cables were verified intact and properly installed. They stated that they found no "witness marks" of the rudder cables binding or rubbing, and all flight controls moved freely. The Airport/Facility Directory listed the runway as 2,360 feet long and 37 feet wide, and stated no touch and go landings.