"Frank Whiteley" wrote in message
oups.com...
While cruising, one wing raises and the other lowers, left or right?
For discussion's sake, let's say the right wing's up and left wing
down. This can be caused by lift at the right wing, or sink at the
left wing.

When we have good thermal indicators in clouds, most of the time while
heading for that marker we encounter sink upon entering the thermal,
and sink again on exiting it on the next cruise.

So a down wing may well indicate that the thermal is just a bit further
in that direction. If you turn towards the raised wing, you may, as
Bill points out, also find the thermal about half the time, but the
thinking is that you've already flown past the core and will take two
or three turns to center. Or, you won't find the thermal, as it was
toward the down wing. By turning toward the down wing, you'll find the
thermal, or not. If not, you continue the turn through 270 degrees and
fly back to the raised wing indication which should be nearer the core
than if you'd originally turned that direction.

The concept is that you will reduce uncertainty in locating the thermal
initially and core more quickly at least half the time and that the
strategy saves 15-30 seconds or more per climb, or quite a lot during a
XC event. Perhaps a winning strategy.

Frank Whiteley

Or, as I've seen in OLC .igc files by top pilots, fly straight through the
thermal to evaluate it, then turn 270 degrees AWAY from the side where they
think the thermal is and then reverse turn direction thus placing the final
circle two turn diameters back on track offset to the side where the
strongest lift was. The emphasis seems to be good thermal selection vs.
fast centering.

Alternatively, at least one pilot will sometimes perform what must be a
modified Immelmann since the course reversal, as seen on SeeYou's map view,
is a zero-radius turn while gaining 800 feet in the pull-up. This entry
showed an 80 knot IAS reduction in 12 seconds.

However, it's more likely these guys don't use any specific maneuver - they
just KNOW where the lift is and they're not shy about going for it.

Bill Daniels