At 14:36 14 October 2004, Todd Pattist wrote:
(Chris OCallaghan) wrote:

If you are opposite
(180) a glider and it's climbing better, steepen your
bank through 90
degrees of turn, then shallow out for several seconds
to shift your
circle to the side of the thermal where you saw the
better lift.

I wouldn't do this.

When I'm sharing a thermal with another glider at the
same
altitude I'm trying to figure out two things - 1) 'where
is
the best lift?' and 2) 'what is the other glider going
to
do?' The first question is answered by watching the
other
glider's relative climb rate. The second is usually
signaled by the changes he makes in bank angle.

I have to recognize that the other pilot may not agree
with
me where the lift is strongest. I also keep in mind
that
he's trying to answer the same two questions I'm trying
to
answer, so my actions signal to him my intentions,
just as
his actions signal his to me. The first pilot to
adjust
his bank is signaling where he wants to move the center.

I think it works better for each glider to flatten
towards
the core to move the center. I'm not against tightening
in
the core, a bit, but that method should be used with
more
caution as it tends to put the gliders closer. I'm
against
tightening in the sink first, then flattening as it's
likely
to confuse the other pilot and delay the cooperative
process
of moving to the center of the lift.

If I see a pilot steepen in sink, I'm immediately concerned
he thinks the lift is stronger there. However, if
he waits
90 and flattens on the heading towards the core, I'm
reassured that he's either leaving and not a problem,
or
more likely, he agrees with my conclusion on where
the core
is.



If a pilot is alone and thinks he's found the core,
he'll
typically steepen his bank. It keeps him turning in
the
core and it moves the center of the circle closer to
the
core before the pilot opens up a bit. If he doesn't
steepen
in the core, but recognizes the sink side first he'll
typically open up the bank first and fly towards the
core.
Thus, with two pilots in the same circle negotiating
as to
where to move the core, it's the first to change his
bank
that signals where he thinks the core is.

If I'm coming into the strong core, I desperately want
to
tighten, so I'm closely watching the glider on the
weak
side. If I see the pilot steepen there, I'm immediately
concerned he thinks the lift is stronger there. However,
if
he waits 90 and flattens on the heading towards the
core,
I'm reassured that he's either leaving and not a problem,
or
more likely, he agrees with my conclusion on where
the core
is, and I'll expect him to tighten as he reaches the
core.

Bottom line,
Todd Pattist - 'WH' Ventus C

Let's hope you two guys don't meet up in the same thermal!
I believe we have the makings here of a two-party
system on thermalling. Let's hope it doesn't get vicious.

Some of us don't even have a theory; we just blunder
around.