Glider pilot reported an near midair collision while he was climbing out under tow from xll.

Attributes
ACN	1278488
Time
Date	201507
Place
Locale Reference	XLL.Airport
State Reference	PA
Environment
Light	Daylight
Aircraft 1
Make Model Name	Sail Plane
Operating Under FAR Part	Part 91
Flight Phase	Initial Climb
Flight Plan	None
Aircraft 2
Make Model Name	Small Aircraft
Flight Phase	Cruise
Flight Plan	None
Person 1
Function	Pilot Flying Trainee
Qualification	Flight Crew Commercial Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 1250 Flight Crew Type 3
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 300 Vertical 0

Narrative:

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.

Original NASA ASRS Text

Title: Glider pilot reported an NMAC while he was climbing out under tow from XLL.

Narrative: 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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.