At 06:24 01 January 2011, Anne wrote:
On Jan 1, 12:38=A0am, Tony V wrote:
Bruce Hoult wrote:
....Since then I tow with the Pawnee horizontal stabilizer in the
same
position against the forward parts of the tug no matter what glider
I'm in and just ignore the horizon.

Yes, use the tug as a reference. Using the horizon doesn't work on
real
hazy days and it doesn't work in the mountains.

Tony V.

John Cochrane has the answer right, at least for standard class ships
like the Discus 2. I can verify that you run out of elevator control
at tow speeds significantly lower than the free-flight stall speed.
The reason is that the tow rope applies a downward thrust at the nose
- I have wing tip-camera video that confirms the tow rope has a
significant downward pull on the nose. I always try to stay away from
tow plane wash, so don't think that's a major component. I've never
experienced as marked a behavior in flapped ships, so I put it down to
AOA.

Mike


Possibly two (or more) different handling problems on tow then ...

1) Running out of nose-up elevator authority when in a 'high' high tow
position due to a combination of increased AoA required due to tug
downwash and downward force component from the rope + a nose down pitching
from the rope

2) degradation of lateral control due to changes in spanwise lift
distribution

I've certainly sparked some interest here - considering it's New Year
:-)