I have one of the old Hangar 9 piggyback setups. In fact, I just put together an old Superstar to carry it (and turned it into a utility plane with bomb drop and everything
I also modified an old Wild Hawk I have into a glider... pulled the motor and speed controller and lightened it up. I'll be testing it today if all goes well.
The Superstar trainer has an OS 50SX on the front. I tested it yesterday and it had no problem carrying a full 24oz bottle of water up... and subsequently dropping it...