On August 7, 1995, at 1730 central daylight time, a Schempp-Hirth Ventus A, N307L, was substantially damaged following a loss of control near Rocksprings, Texas. The airline transport rated pilot received minor injuries. The glider was being operated as a personal flight under Title 14 CFR Part 91. The flight originated in Uvalde, Texas, at 1345. Visual meteorological conditions prevailed, and a flight plan was not filed for the round robin flight. During a telephone interview with the investigator-in-charge the pilot reported that when he attempted to accelerate to glide airspeed he experienced problems with elevator control. He had to apply full elevator before the glider would respond to control inputs. It also responded "very slowly" to the elevator control inputs. The pilot further reported he was going to land on a ranch road; however, because of the control problem he elected to bail out. The glider impacted the ground in a level attitude damaging the fuselage, horizontal stabilizer, and canopy. Examination of the glider by a Federal Aviation Administration inspector revealed that the Mylar tape, which was used as a gap seal for the elevator, had partially separated.