On Sun, 5 Aug 2018 19:49:46 -0700 (PDT), wrote:

Have there been stall spins during an aero tow?

Today, I had a very scary aero retrieve. From being towed to fast to-to slow. Anyways the scaries
part was when, the tow plane started to climb and to slow. The indicated speed on the glider
was 50 knots and decreasing. The glider kept slowing down and sinking under the tow plane
into the wake. By this time the glider felt extremely sloopy and it felt like it was ready to drop
into stall. Fortunately as I felt the wing wanting to drop, the tug leveld some and got back to
a decent speed.

Yes I did radio the pilot askig for 20 indicated more. And I was attempting to release when
I hit the wake, but the release on the standard cirrus is far, and my extention had moved
from my legs.

If I understand your situation, what you describe is not unique to the
Standard Cirrus, but is a common experience when an aerotow gets too
slow, though most often experienced with a heavy ballasted glider.

The question usually comes out something like "I can fly my glider in
free flight at x knots (e.g., 40 kts), why does it feel difficult to
control and ready to stall at x+y knots (e.g. 50 kts)?"

This topic was widely discussed on r.a.s. in the 2010-2011 time frame.
The best explaination I saw came from Gary Osaba in his post on
1/1/2011.

To summize (Gary, sorry if I am not doing justice to your post) was
that the effect was due to the combination of the downwash (not the
prop wash!) aft of the towplane wing, combined with the fact that in
most cases, since the towplane has a shorter span than the sailplane,
the sailplane's outer wings (i.e, the ailerons) lie outside this
downwash field.

The impact of the downwash on the inner portions of the sailplane wing
is that the glider must be flown at a higher angle of attack than
would be experienced in normal free flight. To compound the issue, the
outer wing ailerons are not in this flow field, but in effect are in a
higher angle of attack than the inner wing. Essentially over-twisting
the outer portions of the wing (the exact opposite of what would
normally be done to prevent tip stalling and loss of aileron control).

The solution is obvious, the towplane must fly faster. This theory
only helps explain why the sailplane feels so close to loss of control
when on a tow comfortably above its free flight stall speed.

Anyone interested can do a search on Google's r.a.s archive using a
search term "poor lateral control on slow tow" (don't use the quotes
in the search, however).

https://groups.google.com/forum/#!searchin/rec.aviation.soaring/poor$20lateral$20control$20on$20slow$20tow

Hope this helps explain your experience.

Bob