Figure 8 VS circling

[Jonathan St. Cloud]

Virtually all my glider time and heck fixed wing and rotary wing flight time 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 figure 8's waiting to circle until he was several hundred feet higher than the mountain. I have certainly flown enough figure 8's but I also will circle 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 few 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.

[Michael Opitz]

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

[JS[_5_]]

I'm guilty of a lot of rock polishing. It's not always easy to tell if the air is going to stay friendly.

Once transitioned too soon from figure 8s to circles at the Switchbacks near Lone Pine. It seemed like the thermal had broken off the hill. First turns were good, then the bottom fell out while facing the mountain. Accelerated towards the rocks. Turned low, out of there! Back to figure 8s somewhere else.
In 2011 we lost Jerry Snedden in pretty much the same spot.

A somewhat similar transition from smooth lift to AAAArgh recently occurred at Ely, with a good outcome for the pilot but not the glider.

Last year at Nephi, Uys showed us the trace from an experienced friend he lost in ZA. Figure 8s, circles, spin, the trace stopped moving at ground level.

Without knowledge of either accident, shortly after getting to the Inyos I turned for home the day Steve Fossett disappeared. Also gave up on the day we lost Geoff Loyns. The air both days was not friendly.

Keep this stuff in mind, keep the speed up and a way out.
Jim


On Friday, July 21, 2017 at 8:46:07 AM UTC-7, Jonathan St. Cloud wrote:
> Virtually all my glider time and heck fixed wing and rotary wing flight time 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 figure 8's waiting to circle until he was several hundred feet higher than the mountain. I have certainly flown enough figure 8's but I also will circle 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 few 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.

[Tango Eight]

One of our newer XC pilots came back from the (NH) White mts with cockpit video showing an uncommanded, 180 degree turn *into* the mountain. He was well above the ridge line, cruising straight ahead, mountain on the right, flying about 50 kts (too slow!). Then the left wing comes up, he applies full left stick as this happens and that darned glider gets forced around a tight right turn anyway. As the glider turns through 90 degrees -- now facing the mountain but above ridge line, he regains control continues the turn until parallel to the ridge, mountain on the left. Just a typical Summer day, no crazy weather. It takes no imagination at all to figure out how this would have played out had the rocks been close aboard.

That mountain demands your reverence, respect and deep suspicion.

See Henry Coombs, Sep 84 Soaring Mag, "That Beautiful Mountain and Her Sinister Trap".

I fly a lot of figure 8s.

Evan Ludeman / T8

[[email protected]]

Yup I had that recent incident reported by one of our club members in mind as I read this thread. I wasn't there so I don't know exactly what happened. But he was not circling (until forced to by the air). Not even a figure-8. Just cruising along the ridge. What was needed was more airspeed, and good thing there was enough distance and altitude. The location (Mt. Lafayette) is a picturesque knife-edge ridge that is perpendicular to the typical winds, and a short distance downwind from another parallel ridge. And both ridges are neither straight nor smooth. I've experienced all kinds of strange air currents in the valley between them. I stay out of there unless I can stay well higher than the top of the ridge, but that alone is not enough.

[Charlie M. (UH & 002 owner/pilot)]

OK, my experience is "eastern mountains" high is a lot different than out west.
When low and no clue on winds, I do eights until above terrain.
Most manuals will say the same.
As you get up, wind gradient may increase causing more downwind drift to granite.
So......leave an out.
FWIW.....