On aerotow in Oz in a Libelle std ( with ballast) behind
a Pawnee, the airspeed decayed to a value uncomfortably
close to stall; full back stick failed to hold the
the low tow position and I sank low enough ( with my hand on the (release)
that the rope contributed enough nose up to stabilise
the position using rudder and not ailerons to stay level.

It was later explained that the Pawnee ASI was kaput.
JMF