I have also tried this with several gliders. The IS28B2 Lark was the most
interesting. As long as the CG was near the middle of the allowable range,
it would circle first to the right reaching about a 45 degree bank in
several turns and then reversing the turn direction and going to 45 degrees
the other way for a while before reversing direction yet again. This
circling to the right and then to the left would continue until the pilot
took control.
I have no idea why it would do that but it was interesting to watch.
Bill Daniels
"Pete Brown" wrote in message
...
Michael:
What you are talking about is generally referred to as
benign spiral descent mode. It may allow you to get down
through the clouds if you are trapped above them in wave.
Here's what you do.
1. Point glider into wind
2. Open dive brakes
3. Trim for slow flight
4. Hands and feet OFF controls and stay OFF until VFR.
This procedure is not be suitable for stabilator aircraft or
aircraft with flaps only for glide slope control. I also
wouldn't try it unless you know you are within the CG envelope.
We did this in a number of aircraft, including a Blanik L-13
and found that the nose would bob a bit and the aircraft
would eventually enter a spiral but the airspeed would
remain in a safe range and the turn would not tighten beyond
a certain degree of bank. It would oscillate in pitch and
roll but ours would stay well within safe limits.
However, yours may act differently. Before you have to use
this in a an emergency mode, try it in your own aircraft in
good weather with lots of altitude to see what your glider
does. It should not exceed 30 deg. in pitch or 60 deg in
roll. Try it first from level flight and then from steeper
turns and see what happens.
It may be a lifesaver sometime and its fun to try in good
weather.
Pete
MHende6388 wrote:
I was taught during wave training that all sailplanes, properly trimmed,
when
you let go of the controls, will seek a gentle banked circle to one
direction
and maintain that attitude, even in light turbulence.
There must be great variation from one a/c to the next with varied CG
and trim
settings.
What experiences have others had and with which makes and models?
Thanks,
Michael
--
Peter D. Brown
http://home.gci.net/~pdb/
http://groups.yahoo.com/group/akmtnsoaring/