Tuesday, February 21, 2012

Mountain Thermals 102 with videos

Below are 3 videos on mountain thermals. They show and discuss "Plumes", triggers, winds and flow. Pay attention to the one on the wind impact on a thermal. Where the strongest part of the plume could be. The cross section on a thermal is also showing how important the bank angle is.
The bank angle gives a greater risk of increasing sink rate of the modern glider versus a few knots of airspeed. Realizing this, the sink rate from a 35 to 40 degree is not really that much as when compared to a 45 degree to 60 degree bank. Our data shows this. When we look at the diameter of a thermal, say 700 ft, its what we are discussing, as getting as reasonably as close to the rising plume. What our data shows is 45 kts and 40 degrees keeps us close to the rising plume which then results in our best climb. Ah, my glider and what yours is, is again "What is, is."
When we spoke in our last post, we are trying to get this one thought going. After you see the cross section of the plume you will now understand where we have been headed.
Also, when your cruising, scanning the approaching cloud looking for the plume area that's active might be a better idea. Staying current on the direction of wind and where the thermal could be, then planning on a upwind entry, not finding it, then traveling downwind under cloud could produce less sink as to a tailwind advantage of travel. Just thoughts, that's all. "What is, is."
What the 3 videos below will do for you is as you shrink the ALPS( boy am I going to get nailed their, "#711 shrunk the Alps.") and turn them into hills, then valleys, then to the plains, to the ridges of Reedsville, you now have a better picture as how important triggers are. This will point in a direction of where "plumes" maybe. Certain parts of our country have different trigger features which will give a better chance of finding thermals. Research this area of your charts before going to play might be the best idea. Even goggle earth can help.
A short address on birds. If you see the bird after you enter the thermal, you have seen him or her to late. We need to train our eyes to always graze the area we are going to, to see signs which might have thermals. We do this by practicing. Thier are ways to do this but discovery will be your find!!!!!! By constant surveillance of the surrounding area, we train our eyes to see birds circling,etc. After awhile, you might be surprised at how much you can really see.
Birds are lazy, that's why they use thermals, as it gives them a free lunch. But when they glide away, they could pick a path you might consider when you leave the climb your in. Also moisture is not a requirement for streeting of lift. Thats a thought for varying your crusing path when in the"blue".
Also, on the You Tube page where these 3 videos are, is a video on centering of lift. It might be something you wish to watch, but I would give it great thought if I would choose that way. Your thoughts on how to center and how you do it is again "WHAT is, is". When your practicing centering that thermal, just reduce your stress, about how the top guns can do it in one turn or less. When that happens its like winning the lottery. As re centering is required during the climb using the smoothest control inputs possible which will give the least drag.
Whats coming next will be a series of 7 videos. They run about 45 minutes total. So maybe plan ahead. They show a story which some of you may already have seen.
I'll post that shortly, as I need to stay focused on where we are at.
Remember, this is not only to be of what some find as useful, but to get others to acquire thoughts which may lead to a better air adventure.
A friend showed the path to these videos as others were planned.
XCkelly is not me. Thanks Paul Cordell.
#711 reporting.