son_of_flubber wrote on 7/21/2020 3:47 PM:
Is close_to_terrain slope and ridge soaring unavoidable in big mountain terrain in SW USA, or can you opt out and stay 1000+AGL when using ridge, thermal, wave, and convergence lift?

I did six hours of dual close_to_terrain slope soaring at Omarama in February largely to see if the risk/benefit made sense to me in a best case scenario where all factors (aircraft,pilot,terrain,weather) are top shelf.

I understand that if you opt out of close_to_terrain soaring, you might also be opting out of the big OLC scores, and fly fewer days, but that's okay with me.

The situation we've been discussing is thermalling close to a mountain because
that's where the thermals are, with the intent of getting above the ridge and
thermalling higher. It's this need to stay in a small area (the thermal) that is
the problem: you can use figure 8s, but that often doesn't keep you in the best
lift.

Wave soaring generally doesn't put you in that situation, as the wave forms
downwind of the mountain; convergence also happens away from the mountain, so two
air masses can interact. Slope soaring usually means you have a mostly steady wind
against the slope, creating an updraft along the face of the mountain, so there is
no need to circle.

So, my experience is yes, most of the time I can stay safely away from the
mountain. The most likely time I use thermals below the mountain top is right
after launch, when I'm still low, and there aren't good thermals in the valley.

High desert pilots in the southwest US tend to fly ABOVE the mountains, but
New Zealanders (and pilots in some other mountainous areas) tend to fly AMONG the
mountains.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1