At 15:46 21 July 2017, Jonathan St. Cloud wrote:
Virtually all my glider time and heck fixed wing and rotary wing
flight
tim=
e has been in the mountains of the West. Was looking at multiple
traces
of=
a a well known pilot that anytime he was below the mountain tops
he used
f=
igure 8's waiting to circle until he was several hundred feet higher
than
t=
he mountain. I have certainly flown enough figure 8's but I also
will
circ=
le low next to a mountain (Sierra's, Whites and Inyo's) to climb up.
I
was=
wondering if some other experienced mountain flyers could weigh
in on the
=
safety of thermaling next to a mountain vs using figure 8's until
clear of
=
the top. If I am flying along a range and hit lift, I all usually take a
f=
ew figure eights until I know the local wind eddies and lift patterns,
then=
I transition from figure 8's to circles, clearing each turn well
before I
=
am committed to completing the turn. thanks for your comments.


It depends.. If you find good enough lift to circle in - far enough
from the mountain face, then OK... BUT, in a lot of places, especially
in Europe, the best orographic lift is in a very thin boundary layer
sheet which clings very close to the surface as it crawls up the slope.
In this process it picks up more heat from the rocks as it moves over
them, and accelerates, thus causing the lift to get stronger until the
rising air gets to the summit (or intermediate trigger point) and
breaks free. This boundary layer is very thin, so the best way to
utilize it becomes ridge flying, which includes figure 8's. If you try
to circle, you will be "half in, half out", and turning towards the slope
that close in (and in sometimes very turbulent air) will be
dangerous. If you happen on a thermal which has broken free due
to being triggered off a lower intermediate peak, and you have
enough spacing, that's another matter.... In order to best utilize
orographic lift below ridge top height on bigger mountains, one has
to fly close to the rocks. That's just the way it is... It is what the
books say, and also what I have found in my personal experiences at
WGC's in Rieti, and Austria, and at several nationals at Minden..

RO