On Monday, January 27, 2014 10:18:45 AM UTC-5, wrote:
Why aren't we all doing this?



http://youtu.be/Ln9fuR8uwIc?t=36m48s



Evan Ludeman / T8



I've been thinking about dynamic soaring a bit. (It's 5 below outside, and sick of finish height wars...) One thing that would help a lot is instrumentation. Dynamic soaring works, most basically, by pulling more Gs when the aerodynamic force vector (L+D) has a component pointing in the direction of motion. Then, pulling harder speeds the glider up. A sudden gust of lift, for example, rotates the relative wind so that pulling more g pushes the glider forward.



The trouble is, it's very hard for the human butt to detect this condition. Gs help, but you need to know a sort of total energy compensated g -- how much g should there be vs. how much is there. And even g isn't a perfect measure of what we're looking for.



The modern vario has the ingredients to detect this condition -- put gps, three axis gyros, magnetic heading, three axis g, airspeed and TE together, stir the pot and issue pull push commands (or feed them to the stick, but that's an extra project)



At a deeper level the modern vario could directly measure outside air movement. Compare GPS track with 3d relative air movement, and you know what the air is doing. (Plus a year's worth of filtering and adjusting...) This could tell us the air is going up long before it accelerates the glider up, the glider starts moving up, and the vario notices. That's the window for a dynamic soaring move.



In the same way the vario can detect sideways gusts, such as these shears near cloudstreets. Or guide you to backside of the ridge dynamic soaring by helping you to know when you're in the wind shadow.



The modern vario... Like the CN vario... Don't you work for CN? They keep sending my wild ideas to the spam filter these days...Something about "development budgets", "markets of one customer," "hare-brained schemes" and other business-ese



John Cochrane


Related, I suspect: the Katzmayr effect. This article describes what is essentially a dynamic soaring theory for the (at the time) puzzling phenomenon of reduced drag in an environment with medium frequency vertical oscillation.

https://ia600507.us.archive.org/10/i...9930081006.pdf

It might be that Gary's flying "on the edge of a cloud street" is the same sort of dynamic soaring, at larger scale, with much slower period and with pilot added variation in load factor.

Let's have the vario conversation off line.

Best,
Evan Ludeman / T8