At 12:27 06 January 2011, cernauta wrote:
On Wed, 05 Jan 2011 17:52:28 +0000, Doug Greenwell
wrote:


Did you notice any kind of change in elevator control force before you
hit
the stops?

i didn't notice, I was probably busy trying to keep altitude behind
the tug

Did you experience this effect with any specific type of tug? Derek
Copeland has decribed a similar loss of elevator authority when towed
by
a
motor glider.

Andreas says that it's much less likely to happen bihind a
motorglider, however.
In my case, I'm not sure, it may have been both times a Robin dr400.

I think the "descending airmass" theory by Andreas is the easiest to
understand and believe. It explains both the running out of elevator,
and the poor lateral control (when not perfectly centered behind the
tug, or because of the increased AoA at the tips)

aldo cernezzi
-
www.voloavela.it
the italian gliding magazine



Yes - it's really difficult to explain in words, but Andreas'
description is good without being too technical.