Soaring Is Learning
Soaring is about learning all the time. Here are some tips on becoming a better soaring pilot. Brought to you by Southern California Soaring Academy.
Soaring is about learning all the time. Here are some tips on becoming a better soaring pilot. Brought to you by Southern California Soaring Academy.
My first unsupervised solo was also the perfect occasion for a premature display of the arrogant conceit that tempts all pilots, and has shortened more than a few careers. It would be inaccurate to say I failed to secure the rear cockpit, because I did start to do exactly that, but was so anxious to get going I consciously chose to not bother. After all, there’d be nobody
dying there anyway.
Once aloft and drunk on adrenalin, I got into fooling with something I’d not yet experienced to any satisfaction, zero G. What unmitigated fun! Zooming up and over, floating like an astronaut, then diving for speed to pull up again, to the left, to the right, time after time, transformed me into a giggling kid jumping on his bed with no one there to yell, “Stop that!”
Then when it came time to reestablish full control the rudder pedals were mysteriously jammed. Whoooda thunkit? Well, only one pedal was stuck, but that’s like saying you have only one flat tire on your bike. A quick glance over my shoulder confirmed the rear cushions were no longer where I saw them last. One or both had found their way to the worst possible place, and someone had to do something about it.
After unbuckling and twisting around to reach back, I had to reverse my shoulders and scrunch between a crosswise middle bar of the canopy’s frame and the canopy itself, squirming to grasp that cushion and knock it clear. Meanwhile, what little contact I had with the controls became more random than effectual. What could be worse?
It was while I was laid out with my chest on the aft panel, facing backward and down, that the unpiloted vessel decided to hit turbulence, inducing an open-ended episode of what could most generously be called ‘unstable’ flight. Oh yeah. Whaatta ride. Each time it got too spooky I’d absently kick the stick some opposite way, obsessed far more with grabbing at that obstruction. But abrupt movements of the stick caused rapid reorientation of the cockpit — while within that same small space my spacewalker’s inertia remained independent… caroming off of basically everything. All this spawned a very rational terror of clumsily knocking the canopy open from either side and being sucked away by its frame engirdling my torso!
What would you do in that situation? (Saying you’d never allow it to happen doesn’t help, BTW.) It’s no trifling boast to suggest I may be the only fool ever to smack a canopy with his back in flight and live to describe what that’s like. Spoiler, it sucks if you really wanna know.
I did manage to put a fingertip on the cushion, but couldn’t knock it free. Then craning my neck to get an eye on it – and God this is the most embarrassing – I saw what I’d known all along but stupidly ‘overlooked’ in the heat of fluster: a Blanik’s cockpit is entirely open down there, front to back! I could/should have freed that obstruction with a flick of the wrist right at first, so easy even an idiot can do it.
Sheesh! All I’d accomplished so far were horrific cramps in my neck and shoulder, some well deserved bruises, and a mysterious laceration on my pinky. But smearing blood everywhere was the least of worries.
This poor bird had been out of control now for approximately ever, don’t forget… and still was. Long past time for somebody to reclaim the driver’s seat. In a surprisingly few fierce seconds I somehow unwound my feats of contortionism without further injury, eventually coming to rest on my belts, pulling a whole lot more than zero G in a steepening bank and feeling quite naked.
It still took both hands to fish those harnesses out from under and properly secure them, so this struggle was not yet won, but the irrepressible vigor of youth again prevailed and I had things relatively under control in time for a normal landing. Imagine though, if I’d been even more foolish and crawled even further aft of my station. I was barely heavy enough to fly solo without ballast as it was, and climbing halfway into the back, in a glider that spins aggressively when it’s told to… could have made news in more than the local paper.
I’ve flown solo only rarely over the last few decades, but usually in two-seaters on return-to-service flights, et cetera, and not one single time since that undocumented spacewalk have I been even tempted to fly without securing everything in the aft cockpit beforehand. And it seems to be working too, ‘cause I’m still alive!
Spur-of-the-moment with a girlfriend, we were up in cloudless December wave. It was so balmy on the ground we hadn’t thought of wearing jackets. Direct sunlight can keep a cockpit comfy in winter if you don’t fly too fast. Besides, without oxygen we wouldn’t be going very high.
It was grand as ever of course, but what should we do to keep it interesting?
We decided to angle crosswind toward a lenticular sixty miles east. Getting there was easy and surprisingly quick with a quartering tailwind, though flying away from the sun made it chillier than we liked. That lennie appeared to be growing toward us – or did it just seem so the closer we came? Either way, the wave was stronger there and we regained lost height before arrival.
With sundown due around four-thirty I thought of turning back. (‘Too late already,’ chuckles Bad Angel under his hoary breath.) For the first time in forty miles I looked over my shoulder… Oh boy.
The lenticular had been growing, and now reached clear across, connecting to the local wave we started from. The whole system had been powering up all along, and already we had more energy between us and home than could quickly be disposed of, with too little daylight left to fly that far. And now that tailwind component would be reversed, too. (Good Angel whimpers, Bad Angel laughs out loud.)
Bright side? Being way too high and short on time each require the same solution: push over and GO — FAST as you and your bird are willing. Soaring’s ultimate luxury in one way of thinking.
We could no longer see the ground where we were going. The sun was down down there, yet still blinding us. Our crab angle had us pointing directly at it as shadows lengthened below, dissolving into a gray abyss, so we pegged trusty old Zero One Mike at 100 knots indicated, straight toward where I thought the airstrip should be. Lift on the way was just plain ridiculous. We rose for a while to nineteen thousand feet, where 100 knots indicated means 158 MPH true airspeed. Where cold-shrunken canopies leak very thin air and the setting sun is frigid, not romantic.
Guessing five miles, out we slowed briefly to pop full spoilers, then resumed our dive into what by then was late dusk, down through rotor and even more unwelcome lift, still racing hard against darkness. Good thing we weren’t landing off-field; approaching our unlit strip, perception of depth and distance (through a tinted canopy) would have been even scarier without the familiarity of local features.
And after all that, mm-hmm, just one more anticlimactic landing.
This story has no surprise ending or punchline. The lesson isn’t how to get away with such foolishness, it’s that you might not! If we’d gotten back ten minutes later the landing would have been less ‘safe’ by an order of magnitude. Twenty minutes, we may have never found the airport.
It was early spring, well into thermal season, and perhaps the last day of winter-like weather. Most thermals were being blown apart by a strong north-northwest wind, and any that did rise only added to the roughness of erratic rotor. No clouds other than cirrus, so if there was good stuff above this disorganized junk we’d have to find it by braille. The wind aloft was steadily increasing as we climbed, yet when it finally began to smooth out up near 10,000 MSL, the ‘wave’ yielded scarcely more than zero sink. With no visible markers, all we could do was gently feel around for more, the way you noodle for catfish, careful not to get bit.
Once established in fully uniform flow, we did the old thing where you hover at zero ground speed precisely as possible and note what the ASI says. That number plus two percent for every thousand feet MSL yielded an ambient wind of sixty knots, triple the theoretical minimum for wave. So why so flat? My guess, this oblique wind direction and that non-linear topography upwind of us would generate no wave at all if the wind were any less. Big energy, weak lift. Like sipping from a firehose.
To go anywhere but backwards we’d have to fly faster, but even a small increase in sink rate risked losing altitude and falling out of what little lift we had. Too slow put us in reverse and too fast meant going down. Call it the ‘coughing corner’. Fair enough. So play the cards you’re dealt, invent some way to make use of this particular set of problems, and you might learn more in half a day than whole weekends of booming thermals.
We were situated a mile off the flank of Bear Mountain, west of Tehachapi, and this wave’s axis ran north to our one o’clock as we faced the wind. We nibbled side to side in our crab, experimenting with minuscule changes in pitch, and even goofed at leaning forward or pulling our feet back in unison to effect CG and find some kind of sweet spot. Little in the way of repeatable results of course, but every effort contributed to improved results, and glacial gain into the wind was our meager reward. (One of the few times I’ve found staring at the vario more useful than staring at my belly button!)
It took almost two hours to creep fifteen miles upwind, finally nearing 11,000 MSL above the hills south of Lake Isabella. Peeking across it into the mouth of notorious Kern Canyon is where the lift finally began to improve — from almost one knot, that is, to almost two…
This was starting to look like a rare opportunity we might never have again. Imagine: not running along the east-facing crest that’s a world renowned drag strip for gliders, but straight up-river into the Sierra high country’s very gut! Problem was, it took us so long to get just this far, and there weren’t many hours of daylight left. Beyond Kern Valley airport in the mouth of the canyon, there’d be nothing even remotely landable across countless square miles of steep mountain wilderness, higher and higher the further you go.
So no, it felt like a gorgeous trap, too easy and too tempting. Unique and spectacular as such an adventure would be, we could think of many better ways to die. Especially so early in the season. It may have been mere cowardice, but we’d pushed our luck enough for this sortie and it was time to turn back.
Whereupon we instantly acquired every advantage. The comparative quickness of our retreat should be no surprise, but was nonetheless a marvel to behold. We now had a ripping tailwind, and still that same weak but consistent lift. Because we were returning to land anyway, most of our height was energy we could afford to splurge. Plus our destination, Mountain Valley Airport, now lay almost directly downwind, which meant no more crabbing as we slid diagonally over the wave’s broad crest into inevitable sink, which in this case also served our interest. Even capping our speed at ninety indicated out of respect for turbulence on the way down, our achieved ground speed was, honest injun, 200 MPH, and four minutes later we were ready to enter the pattern!
That’s why some of us find winter soaring in southern California even more fun than summer, and you don’t need oxygen or a heavy coat.
At the risk of insulting your intelligence, however, here’s some sage advice. Best be cautious about quicking the downwind leg first in such a gale, especially on days that end early! We’ll discuss that temptation of fate next week, reprising another true tale from several years ago.
We all hear lots of talk about wave lift in praise of climb rates, preposterous smoothness and all the rest, yet seldom much mention of wave sink. That’s understandable, but sink is always half of any big picture. Open and endless as wave lift may feel, it’s normally sandwiched between sink of similar volume and strength, upwind beyond the trough and probably downwind behind the crest. And once you’re in it, wave sink feels plenty open and endless too.
In wave sink, whatever your achieved climb rate has been, the corresponding descent will feature an equivalent vertical speed downward plus the 100+ fpm aerodynamic sink rate you had while climbing — think carefully about this, or you won’t believe it. That’s if you remain at the low-end speed you maintained while climbing, and almost anything you might want to do in sink necessitates higher airspeeds.
Theoretically, wave requires at least twenty knots of wind across the hilltop that generates it (and on wave days, 60-knot winds aloft are not rare). For this discussion, let’s stipulate an achieved climb of 5 knots in ambient wind of 30 knots. Response to the equivalent sink, by itself, will roughly double speed-to-fly, and penetrating to the next lift upwind will demand also adding half the headwind. This puts you up around maneuvering speed in any glider, and quickly compounds to 15 knots DOWN, maybe more…
To estimate achieved glide during a wave penetration, subtract the approximate headwind from your airspeed and divide that by the total rate of descent. Example: 75 kts airspeed minus 30 kts headwind equals 45 kts ground speed — and if you’re coming down at 15 knots, you get an achieved glide of 3/1. This is not an exceptional situation; it’s ordinary in wave soaring. For stronger conditions or low performance gliders, the numbers will be MUCH WORSE!
Having fun yet?
Gliding downwind in wave sink is a very different story. Moderate sink in a tailwind of thirty or less requires only moderate increase in speed, which an old-fashioned MacCready ring will give you. For stronger tailwinds and the heaviest sink it gets numerically complicated, but going downwind in wave usually doesn’t take long, whatever the situation, and by the time you calculate exact speed-to-fly, that question may be moot.
Gliding crosswind in wave sink is just a bad idea for almost any purpose, unless you’re intentionally letting it cast carry you down to wherever you wish to go. But this brings us to using wave sink for descent, which can be an efficient, entertaining, and educational way to finish a flight. There are many ways to do this, some not at all recommended, while some are lots of fun. Here’s just one.
Imagine a free standing lenticular, say four thousand feet deep. Climb by its windward face to just a few hundred feet higher than the top, then turn and glide downwind toward it, still slowly rising as you approach the crest. From horizontal flow there, you drift into the reciprocal of all that lift, so softly you may never feel the vertical transition from huge up to huge down. Proceed a few moments further as the cloud below drops away, and once your vario’s pegged on down, turn back into the wind again to face the falling cloud like a helicopter autorotating before a waterfall! Cool stuff, so long as there’s some clear route to safety — or a convenient harmonic waiting a few seconds further downwind…
Now you want a real challenge? Rassle rotor beneath that cloud (bladder permitting), all the way upstream to the windward side again, and climb from there back up into the wave you started from. For that achievement I always award myself an imaginary lennie pin. An inverted one of course, pewter, not brass!