Sorry to keep playing devil's advocate but I don't see any advantage at all in using a drone instead of streamers.
Streamers arrayed downslope will indicate not just the strength of an approaching thermal, but the location of its center, its speed of approach and its width.
How many launches have adequate arrays? In my experience, very few. This is pilot error on a grand scale.
In much of my Owens Valley flying, I could find neither a flying partner nor driver, so I ended up launching alone into very active air.
How to survive this was my utmost priority. The broad array of streamers was vital.
I also used an Alan Fisher Thermal Snooper in later years. This worked in concert with the streamers.
I constantly and consistently launched alone from mountains that frightened many visiting pilots.
And I remain convinced that they placed themselves at greater risk launching from their home sites in a crowd than I did launching in Owens Valley alone.
In "Explorations with the Thermal Snooper" (SSA Soaring Magazine, Aug 1987), I recalled my first take off with the instrument.
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From the summit at 9140 MSL (Measured from Sea Level) the view is inspiring - all the more so because Mazourka is the only mountain launch in Owens Valley to offer an unobstructed view in all directions. Just east of Mazourka, the main spine of the 11,000+ MSL Inyo Range marches north to descend into the rolling hills of Westgard Pass, then rises again as the great White Mountains. Westward, the raw granite spires of the Sierra Nevada rear from the valley floor to form an unbroken wall, reaching over 14,000 feet. Between these awesome ranges the boulderstrewn alluvium, pockmarked by magenta cinder cones and scarred with tortured fields of dark lava, is cut by narrow, brush-choked streams that gurgle from every canyon only to be seized by the Los Angeles Aqueduct, leaving the meandering Owens River to struggle pitifully southward alone in a futile attempt to moisten the red eye of Owens Dry Lake.
The day was extraordinary. A broken cloud street of the classic type with flat-bottomed, underdeveloped cumulus had established itself along 100 miles of the Inyo-White range. Cloudbase beckoned a mile above Mazourka. Across the valley, the crest of the Sierra was laced with a narrow and continuous band of cloud. Only the tallest snowcapped peaks pierced the cloudtops.
At the north launch point on Mazourka summit the wind was light to moderate (5 to 15 mph), driven from the north but veering due to thermal cycles, resulting in a predominant northeast wind with an occasional west. But every few minutes the wind would straighten and hold north, the optimum direction for launch, for 20 seconds or longer. Several gaggles of ravens and hawks, the lords of Mazourka, drifted on thermals above me. I decided to set up.
The glider I'd chosen for this flight was a Pacific Wings Express "Racer," a fast European design that had carried me 178 miles great circle distance from Horseshoe earlier in the season.* My hook-in weight of 215 pounds resulted in a wing loading of nearly 2 pounds per square foot, and therefore demanded an aggressive thermalling technique with tight turns centering the core for effective altitude gains. Because of this, I felt the Express would be ideal for testing the Thermal Snooper.
I clamped the Snooper to my instrument mount and turned it on. It's "beeps" and "boops" were easily discernible from the "chirps" and "buzzes" of my variometer. I assumed the Snooper would quiet down after the circuits normalized - but it didn't. That was my first surpise.
Instead of remaining silent like my vario, the Snooper was giving me a running commentary about the quality of thermal cycles rolling through launch. When a freshening breeze began to tease the first flag 100 feet down the mountainside, it would begin to "beep" hesitantly. Then as the nearer flags became agitated, the "beeps" would increase excitedly. If the thermal was centered and all the flags stood out from the north, the Snooper would fall silent. But when the flags skewed off to the east or west as a thermal passed to the side, the Snooper would immediately follow its "beeps" with a series of low "boops."
Fascinated, I stood at takeoff for 20 minutes. For each cycle that passed through, the Snooper gave an indication of it's size by the duration and frequency of it's "beeping." A few "beeps" meant a small, short-lived thermal. Many "beeps" told of the arrival of a large thermal. At some point during each thermal's passing, the Snooper would begin to "boop" - a few "boops" for small thermals, many "boops" for large thermals. It was obvious that these "boops" warned of the "downside" of the thermal's cycle.
Years of observation have led me to attribute the majority of takeoff accidents in thermal conditions to pilots launching into the tail end, or down-side, of thermaI cycles. It took a lot of practice to read thermals accurately, and some pilots just never became adept at it. Now here I was with a tiny instrument clearly identifying both the up and down sides of each cycle! I was impressed. Even if the Thermal Snooper didn't do anything else, it promised to make mountain flying a lot safer.
But surely, if it could read thermals on the ground, it could read them in the air. I eagerly shouldered the Express. When the Snooper announced another large cycle, I was airborn by my fourth step. The air was straight, smooth, and lifting. The vario began "chirping." The Snooper fell silent.
When I am first to launch, I never attempt to work the occasionally treacherous takeoff thermal. It has never proved necessary for me in the Owens because there is always another just as good nearby. So I flew fast and straight away from launch - and out of the thermal lift. The vario went silent and the Snooper began to "boop" just like it had on the ground during a down-cycle. With the gentle ridge lift helping sustain me, I turned to seek out the resident "thermal snake" on the knife-edged western shoulder of Mazourka Peak.https://web.archive.org/web/20120101172100/http://www.cometclones.com/illusion.htm----------------------------------------
My point in this is that it doesn't matter what technology is available. Most pilots aren't going to use it because it's too much trouble or it's too expensive or they don't know how to do it or it's too time-consuming or they don't recognize its importance. Therefore hang glider pilots are going to continue to periodically die launching into thermal conditions. For no good reason.
Wishful thinking is a powerful drug. And it's free.
Hang glider pilots are going to keep dying. Forever. But you don't have to be one of them.
And for God's sake, will people stop calling for the cutting down of trees that aren't in the way?! Am I the only one with a concept of beauty in this sport? If you don't have the skill or ability to avoid the tree, you shouldn't be there. You are the problem, not the tree.
In the early '80s, after my friend Keith Davis killed himself by flying square into the beautiful dead snag off below and off to the south of the take off track at Walt's Point while looking down at his harness instead of paying attention to where he was flying his topless Dawn, an idiot from Lone Pine convinced the Forest Service to let him cut the tree down. That was the tree that ravens would land on when they waited for lifting thermals cycles in front of launch. I had watched them for years and used their flight as an indicator of the best time to launch.
Babies who are over their heads flying hang gliders in the wrong places need to understand that somebody else doesn't make it safe for you to fly the Big Air.
You make it safe. You and you alone. It's never any other way.
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