Following on P3's post, this isn't hypothetical in the sense of depending upon some new technology. Thanks to the FLARM folks, the data on glider altitude and position are already available. Everything else is number crunching.

Forget crude displays of climb rate by blip. The first task is to write the code that creates a lift strength vs. height band profile for a thermal (already done for the SN10 years ago) based on the gliders who have been climbing in it. It's not just a snapshot; the software can keep track of anyone in a thermal as long as they're in range.

Then project the future thermal position for wind drift (already available in some nav software). Then project the arrival height at each thermal based on the MC setting (same as arrival height over a waypoint, adjusted for fact that this waypoint moves in the wind). Presto, a display of all the thermals within X miles (X depending on antenna design and placement) with lift profiles and arrival heights.

The next, only slightly more difficult, step is to add an indication of thermal life cycle: i.e., how long has it been there and are climb rates increasing or dying.

So as I top out in my thermal, I'm presented with a handful of alternatives, for each of which I know how far away it is, how high I'll be when I get there, where that arrival height is within the thermal lift band, and the likely lift strength, with an indication of whether I'll arrive before the thermal dies. And all of that will be updated while I'm on the way, of course.

The next step is to offer a recommendation on when to leave the current thermal (which has its own lift-height band and life cycle profiles) in order to reach the next thermal.

The next step is to automatically adjust the MC setting for the projected lift strength for each target thermal, because that's what MacCready theory needs to work well. Yes, for the first time (except for team flying), we'll have a good idea of what the strength of that next thermal is so we don't have to guess. And so what if the gliders marking the next thermal depart before you arrive? The nav system will direct you into the best part of the thermal.

The next step is to optimize the recommended path along the next five or so miles of the course line. Some thermals will justify a larger off course excursion than others. Let the computer calculate when. A little more difficult but it's still just number crunching.

And thanks to the software we'll all have, there will tend to be more gliders in each good thermal so the profile info on those desirable "destinations" will be better, although I can adjust my course to bump the weak thermals, as well. It's not too much of a stretch to think about deriving some airmass movement information by comparing the actual glide tracks of cruising gliders with what they should be given the average performance at a given speed. Exploiting lift streets--the holy grail of fast flying--will become a lot easier when they're painted on the nav screen, on which more and more of my attention will be focused.

This isn't science fiction. The software guys who jump on the FLARM bandwagon will soon have an "amoeba" of reachable thermals to go with their amoeba of reachable landing sites. I'd be shocked if most or all of these features aren't available by next contest season.

Full disclosu although I'm sold on the safety benefits of FLARM after one contest, I resisted the transition to GPS loggers for years because I believed it would eliminate the need for an important soaring skill (navigation). So I guess I'm hardly in a position to be critical now, at another critical juncture. But somehow I think there's more philosophical opposition to making it significantly easier to leech--as FLARM does--than to making it easier to fly without being able to use a map. We've decried leeching since the arrival of large numbers of composite sailplanes in the 1970s equalized the fields and made it possible for less skilled pilots to blindly follow [and I mean that literally; there are some funny stories about leeches who grimly trailed leading pilots who wandered off course accidentally] more skillful pilots all the way around a task.

Various solutions have been proposed over the years to address leeching. In this case, stealth mode offers an easy way to blunt most of the impact. Will we have another challenge in a future era of ADS-B? Probably. But that shouldn't stop us from addressing this thorny situation now.

Just my opinion based strictly on the competitive aspects. UH's post provocatively addresses the safety angle.

I agree this is a good discussion.

Chip Bearden
ASW 24 "JB"
U.S.A.