Sail Plane
Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor
Flight Crew Last 90 Days 50; Flight Crew Total 1250; Flight Crew Type 3
Situational Awareness
Conflict NMAC
Flight Crew Took Evasive Action
Human Factors
I was PIC in back seat of  glider on tow on climb out. This was a training flight with instructor in front seat. I was on tow behind a Pawnee. At around 1000 FT on a westbound heading I detected a biplane heading south at 1000 MSL; closure rate was significant. I called 'traffic' and released tow while turning hard right. The tow plane began a descending turn to the left and thereby probably missed impacting the southbound biplane. All airplanes made normal landings back at 1N9.
Glider pilot reported an NMAC while he was climbing out under tow from XLL.