I don't know about winch launch, but this looks like just an exciting
launch, with a 7500 lb gross wt. glider:

http://www.pointvista.com/WW2GliderP...rretrieval.htm

wrote:
In our winch clinic last week, the paraglider folks we shared the dry
lake with, seemed surprised we could get something as big as a Blanik
off the ground with a long steel cable.

Their tandem instructor asked our CFIG, "what was the largest gross
weight sailplane ever ground launched". Never really thought about it
before.