Flying in Wind

Part 2: Handling Headwinds

by Dennis Pagen

:Most of us have experienced flying in headwinds because, right from the start, we learn to take off and fly forward in at least a trickle of wind. As we progress and fly higher, we still head into the wind toward our landing field. This practice continues until we learn to turn 90 degrees and more, set up landing patterns, and progress to soaring. So headwinds are our constant companions, if not our friends.

Here, we will look at stronger headwinds and tactics for tackling headwind flying in competition and general cross-country flight. Even if we never graduate to XC or comps, knowing headwind tricks will significantly improve the effectiveness and safety of everyday flying.

EXTENDING YOUR REACH We begin with a reminder of the techniques useful for penetrating a wind. Off the top of my head, I can recall six or seven cases of pilots not reaching their intended landing field due to headwinds (sometimes combined with sink). In areas where trees were plentiful, the result was landing in stressfully small spaces or grasping tree branches. Other times, the combo of headwind and sink resulted in barely making the landing field. I’ve been involved with a few such incidences myself over the years.

The first thing we can do in this case is to understand speed-to-fly concepts. Speed-to-fly is the principle that there is one speed (only) to fly for maximum efficacy (that is, best glide over the ground). This “best” speed varies with the type of glider, the wing loading, and the movement of the air (headwind, tailwind, crosswind, near calm, lift or sink). It would take pages to dive into this pool of knowledge (for this kind of knowledge, pick up a book on free flight), but for our purposes here, we can simply say: speed up in a headwind.

By the time we are flying high, we should all know that a glider (hang or para) has a maximum glide ratio airspeed. This airspeed gives the glider its best lift-to-drag ratio, which is also its best glide over the ground in zero wind. But in a headwind, flying at best glide speed will not result in the best glide over the ground. As noted above, how much you speed up depends on several factors. An easy rule of thumb is to add about half the speed of the wind to your best still air glide speed. For example, in a hang glider with a best glide airspeed of 27 mph in a 10 mph headwind, we would add 5 mph to 27 mph to get an ideal airspeed of 32 mph. In a paraglider with a best glide airspeed of 20 mph, you would add 5 mph to get 25 mph in a 10 mph headwind. These back-of-the-envelope ballpark figures are a reasonable starting point for the novice pilot. However, many pilots have instruments that calculate the wind as well as lift and sink with their GPS function and indicate the best speed to fly in the current conditions. However, conditions can rapidly change (for example, you fly into sudden sink or a headwind gust), so it behooves us all to be able to judge the conditions and quickly make an adjustment before the instrument can figure it out. It’s ideal to learn to feel the correct response rather than rely

To understand the concept of speeding up in a headwind, imagine flying straight into a wind equal to your flying airspeed. In this case, you will be descending vertically since your airspeed over the ground is zero. But if you speed up, you will make some progress over the ground, and thus your glide path is improved.

solely on your instrument. Staring at your instrument is dangerous in traffic and takes your attention away from the hundreds of little cues and clues about what is happening with the changing, churning air. All pilots should experiment with their glide ratios and airspeed in all different conditions at their local sites. Try flying out to the landing field and see how airspeed changes affect your glide path. With this practice, learn to judge the spot you will reach ahead of you as you glide. Another aspect of safe flying is being vigilant about the air’s changes as the day progresses. If you are soaring over launch, you can occasionally look at the wind indicators and how other pilots are progressing as they make passes in different directions. Also, you should fly defensively and always maintain a reasonable glide to your landing area. You can scout for alternative bailout areas as a backup, but having a cutoff point to initiate landing is most important. At our local sites, we have a cutoff point for new and intermediate pilots. At one site with a distant landing field, our rule is: leave for landing the instant you get below launch level.

On a recent flight, a couple of friends were 1,300 feet above launch when sink swallowed the area, and they were on the ground in minutes. They had to head out to land in this sink and a headwind. Fortunately, they had a good altitude buffer, but I have seen pilots in similar conditions where the landing field was beyond reach. With all the above in mind, be observant, leave plenty of margin for the unexpected, and learn to fly at the most efficient airspeed in various headwinds.

USING GIFTS OF LIFT Now we look at flying in headwind away from our primary (launch) mountain or hill while covering flat ground. Sure, we may be able to reach another mountain upwind, but generally, upwind flying will involve some flatland or mostly flatland flying. Pilots will often find themselves in such a situation when cross-country flying, whether it’s for competing or simply breaking the home binders and heading out for adventure.

Early on in hang gliding competitions (1981) and from the first XC paragliding comps, we began flying triangle courses. Such flight circuits bring pilots back to the launch area, so multiple days of competition have shorter retrieves.

PHOTO BY WILLY DYDO

Early on, pilots realized learning to fly some upwind paths was important. I remember big triangles in this era in Chelan, Washington and Lakeview, Oregon. Also, throughout the ‘90s, we had meets in the Sequatchie Valley, Tennessee, with multiple crossings of the valley (into the wind on half).

With all that in mind, we began to practice. The way I did it locally was to try to reach a mountain upwind across a 5-mile valley. The idea was to tag that mountain, soar it to gain altitude, and return to launch. At first, the task was difficult, but with loads of practice, I learned to use lift lines and streets. These factors are the main components to successful upwind flying. Lift lines occur when little convergences well up or thermals get strung out parallel to the wind. Such lines of lift are often very weak, but they greatly enhance your glide path or can even give you a magic carpet ride. Of course, when there are lift lines, there can be compensatory sink lines or random blots of down air. Practice is necessary to develop the skill to instantly recognize such lines of lift. Also, you want to learn to stay in the line as you progress into the wind by altering your path to one side or the other if the lift dwindles. With practice, you can get good at making the most of lift lines.

Cloud streets (thermal streets when there are no clouds) can present even stronger lift in a line parallel to the wind. Cloud streets are common in the eastern U.S. and anywhere cold fronts move through. With the presence of clouds, they are easy enough to see, and often cloud shadows can help you determine which cloud line looks best or continues the longest. Of course, when there is solid cloud street action, there will be sink streets too. In such conditions, it is doubly important to be in the line of the lift and stay in this line when flying upwind.

THE SAWTOOTH The final factor is patience with a capital P. In a pure headwind (no lift), if we are gliding upwind a long way, especially high above the terrain, it can seem like we are hardly progressing. In these situations, pilots tend to gradually fly a little faster when things don’t seem to be moving until they are flying faster than the best speedto-fly. Think about this factor, recognize it, and prevent it by learning efficient flying techniques long before you glide into a strong headwind with lots of altitude. In truth, this outcome is so common among new pilots on their first high flight that it has a name: dive syndrome.

When flying cross country using thermals or any other source of lift, our flight path resembles a sawtooth zig-zag pattern with the teeth pointing up. The reason for this flight path is that when we find a thermal and climb, we drift with it downwind—away from our goal upwind. Then we eventually leave the thermal to glide into the wind at a (hopefully) flatter path to find the next thermal. With the next thermal, we repeat the process. In this manner, we gradually “sawtooth” our way upwind. Of course, the stronger and higher the thermals and the lighter the wind, the easier it is to progress upwind in this manner.

One trick of the technique is to know when to leave each thermal to maximize your forward gain. The longer

you stay in a thermal, the higher you may get, but often the lift slowly diminishes, and you may rise into a higher headwind. Both of these factors tend to lose position, as you drift more and more downwind with each circle. In fact, given each day’s wind profile and thermal behavior, there is an ideal height to leave the thermal. This ideal cannot be determined without knowing the details of the conditions. Still, it is important to remember that there is an ideal, and we should experiment enough in our upwind flying practice until we can judge, as best as possible, when to leave a thermal to glide upwind. In general, most inexperienced pilots stay in the thermals too long in a headwind. In competitions, we often fly with other pilots nearby, so by paying attention, we can quickly learn what strategies provide the best results. In one competition, pilots can learn skills that may take a year of flying on our own to acquire.

From personal headwind experience, and that of many others, I can report that it can be very disheartening to see your hard-earned distance fritter away as you circle backward in the thermal or watch your altitude dwindle as you glide into the wind searching for a savior shot of lift. And that’s where the patience comes in. It can sometimes be astounding how much ground you cover when thermaling and flying on a downwind course. But it is negatively impressive how much ground you don’t cover when sawtoothing upwind. But good pilots do it often with success. So train your patience as you train your thermal and best gliding skills. Perhaps by the time we are flying upwind in comps or choose to do so on our own, we have already become adept at thermaling and gliding, so the main thing to think about and work on is patience.

Here are a few anecdotes relating to flying headwinds and lines of lift. In Chelan, on a long triangle with the last leg into the wind, only one pilot made goal. He did it by heading a bit off course to the north to reach a band of clouds promising better lift and thermal blocking of the wind. In Brazil, I once flew 15 miles straight at a very fast speed without losing altitude in a convergence line. In Texas, I flew about 20 miles along course line in a cloud street. In Florida, I cruised along a lift line approximately 3,500 feet off the ground when it quit, and I wandered to the side. In massive sink, I tried to cut sideways to get some relief, but I lost it all and was soon grounded in angst.

Closer to home, I once had to cross from one street to another and lost 3,000 feet in the crossing. On one task in Florida, pilots braved a horrendous headwind (more than predicted), and many of us went down, zig-zagging back and forth. I was with my Brazilian friend, Conrad Heilman, when we picked up some scrabbly lift about 500 feet off the ground. We drifted back with it, barely climbing, and I eventually left it, thinking we were losing too much ground. I flew forward looking for better prospects but was soon landing and thinking that no one would make goal in such conditions. Later, I learned that our shaggy thermal eventually turned on about a mile downwind. Conrad got very high and continued to make stuttering progress to reach goal. Only a few made it that day, and I relearned my lessons when flying in a headwind: practice patience, patience, patience.

PHOTO BY WILLY DYDO