This article was originally posted on justACRO. I’ve made a few minor corrections to the translation for readability.
The Full Stall (stalling the whole glider) is one of the most important maneuvers, you have to practice it a lot if you want to learn other acro tricks. Many times when you make a mistake, there’s no other fast and safe way to get back control of the glider. It’s also a very good way to get to know the limits of your wing. By learning and becoming confident with the Full Stall, you will fly and do acro much safer!
To prevent riser twisting, set your harness to the full sitting position, open the chest strap as much as possible and put your legs under the harness. Take one wrap if the brake lines are long.
Slow down the glider to minimum speed by gently and symmetrical braking. When it’s stabilized above you (it doesn’t swing anymore), immediately pull down the brakes as much as you can. As the airflow on the whole glider is gone, the wing stalls and falls back behind you. Don’t be afraid, you will feel like somebody pull you back. KEEP the brakes locked at least until you swing back under the glider.
At the beginning the glider will pulse heavily (because you keep the brakes very deep) and it’s quite difficult to control the Full Stall like this. To stabilize it slowly and symmetrically release the brakes to around the level of your elbows (of course it really depends on the type of the glider and your brake setting!), until you notice the canopy calms down, doesn’t pulse anymore, the brakes don’t yank, and it’s much easier to keep them under control. This position is called Stabilized Full Stall. Now the glider is mostly opened, only the wingtips are collapsed and facing to the front, whilst you are flying backwards (almost as a Tail Slide). You may need a little bit of practice to find this point.
During the Full Stall if it is not stabilized, the glider is pulsing and the pilot also swinging a little bit underneath the canopy. When the glider is above, or a little bit in front of you, quickly release the brakes up to slightly braked position By this the glider starts to re-inflate and shoot forward as it picks up speed. Just after the glider started to surge, brake it carefully to prevent collapses. The more violent it shoots forward, the stronger you have to brake to stop it.
From a stabilized Full Stall, it’s very easy to exit, because the glider is smoothly over your head. Just release the brakes quickly, than control the following surge by gently braking.
If you see the glider will shoots forward asymmetrically, brake only the faster side (which is lower) until the slower one accelerates and comes down to the same level. Than stop it with symmetrical braking, as usual.
When the glider stalls because of your pendulum you will go further than your wing (the glider slows down faster than you can) and it will be far behind you for few moments. NEVER EVER RELEASE THE BRAKES WHEN THE GLIDER IS BEHIND YOU, BECAUSE THE FOLLOWING SURGE CAN BE SO STRONG, YOU CAN EVEN FALL INTO THE CANOPY!!! It’s easy to imagine why: the glider starts to fly and shoots forward very violently at the same moment you swing back from a big pendulum. This two effects together generates the dynamic movement, which can be easily strong enough to fall into, or even behind the wing!
It can also happens that one of your hands goes up unintended because of the heavy brakes (especially when the glider is pulsing). In this case you have to choose what to do. You can release the other brake immediately and lead out the Full Stall, or you can also try to pull it back quickly, but if you are not fast enough, the glider starts to Spin very fast and you can easily end up in a riser twist. Please read also the dangers of Spin and riser twisting. Anyway, the amount of the brake pressure during the Full Stall is various, from glider to glider.
Maybe the most critical part of the Full Stall is the exit. The glider has no horizontal speed (actually it’s even sliding backwards!) and it has to accelerate. Be careful, if you brake the glider too hard when it shoots forward, it can easily stall again (usually asymmetrically!), however if you don’t brake it enough you could get VERY big collapses and cravats! If you start to spiraling down with a cravatted wing, and you don’t have hundreds of meters below you, don’t hesitate to throw your reserve!
Don’t practice this manouvre if your glider is overused and its porosity is bad (anyway, don’t do ANY aerobatics with wings like that!), because you can easily end up in deep stall (parachutage) after the exit, especially if you release the brakes too slow, and you don’t let the glider to pick up speed! However if it happens, pull out your speed bar, or if it’s not prepared, gently pull forward the „A” straps with your palms to accelerate the glider and get out from the deep stall.
Les, Could be… but it could also be a few other things. I have spent a lot of time on a Bagheera and haven’t noticed it as a problem. I like to do really big wing-overs and frequently watch my wing from tip to tip just to see where the loading is on the wing. I suspect I would have noticed and saw these small frontal closures as you describe. I have a feeling that the real answer would be the pilots themselves and how they were flying the Bag’s. If you tell me who the guy was I can give you more definite word on the pilot vs. wing issue since I know the Marshall boys real well… One of the things that I did notice about the Bag was what seemed like a lot of tension in the leading edge of the wing, which protects it from a lot of symmetric collapses, and helps speed the process of asymmetric recovery. It also gives the canopy a better shape and allows it to maintain a cleaner airfoil by reducing the flutter you get in the leading edge. It also helps keep the canopy from ballooning especially when giving a lot of brake input. I am going to make a guess that these guys were giving a lot of brake, not using a ton of body, and not giving enough outside brake during the dive after turning past the apex of the wing-over. Without going through the very specific details of properly executing a wing-over we should examine a couple of the basics.
First off a let me say this can be a potentially dangerous maneuver and a lot of pilots get hurt when learning the timing and mechanics of a wing-over… so remember altitude is your friend. Please don’t try this on your landing approach, or straight off launch because you want to impress the guys. I always hesitate to explain these kind of things because I feel it promotes the idea of doing them to the pilot. At the same time, if you are going to give it a go… better to know the right way to do it.
Okay wing-over mechanics, then where I suspect the guys are going wrong. This maneuver takes a lot of practice because the timing is counter intuitive. That’s what most guys don’t understand, they try to do it by feel which is wrong… unless you know the timing. Okay I am flying straight away from a cliff, hill, mountain, whatever, and I want to do big wing-overs. I first have to pick a point I can center myself on. Often people do asymmetric wing-overs because they will apply more brake or lean on one side than the other. I have my point and I am ready to go. BTW, this is how I do big wing-overs, I recommend we start on small ones. I will start my wing-over by turning to the right. Okay, I take a deep breath and relax… I crank the right brake hard and fast letting my left brake up almost totally. Just the lightest amount of pressure in the outside wing, so we don’t turn negative from a collapse on the outside. This throws my body to the right side of the wing, which I want to accentuate as much as possible. This also makes that initial turn and dive with my glider. My glider is picking up speed and my body is also building up potential energy. Now I look up at the outside (left) side of my wing, because I want to try and keep my head centered throughout the wing-over. Lot’s of guys lean their head to the right, which does two things. Number one it gives them the false impression that the are doing big maneuvers because their head is leaning with their body, so the are not seeing the horizon straight. This will make a bank angle of 30deg seem like 130deg. Secondly, they can’t see if the outside wing tip is about to collapse. I am looking up and waiting till the wing reaches the peak of it’s bank angle. Then I give a little bit more right brake to turn the canopy from perpendicular to the ground to facing the ground. This is just a little extra pop with the right brake that angles the glider so that it is facing and flying down.
Now my canopy is flying downwards fast, but my body is not positioned straight with it. I have a lot of energy built up with my body but I can’t use it yet. At just about the point I see the outside wing tip collapse, right after I pass the apex of the wing-over and have the wing slanted down facing the ground. I have to give my outside wing tip brake hard and fast (my left brake) to keep tension in the canopy (like a big pop), to slow my canopy down for a second so that my body can pass through and we have the extra speed and energy that my body has created. This pop will also get the canopy set for the hard left brake which I am about to do. Both hands raise a bit for a split second. Now I have to know my wing to do this and just before the wing starts to return the energy in straight and level flight, which it will seek to do, I have to drive the left brake down hard and fast, also throwing my body into the left side of the harness. Again I want to look up to make sure that the outside wing (now the right side) stays pressurized. Also look at your right hand for a split second and make sure that you have raised it up. A lot of guys get so excited, after the first turn they forget to raise the initiating break, which slows the wing down because we are increasing our drag. It also reduces our bank angle a lot. From this point, it is just the same as a right turn wing-over
Now recommendations and tips on wing-overs… after coming out of that second turn, in this scenario the left turn… check your center point on the horizon and make sure you are still centered. Make sure that at no point during the wing-over do you hang onto the risers. I have seen guys do this and go from wing-over to spin. Always look at the canopy outside tip when you are learning the timing, because it is not natural. Most guys initiate the next turn, when the canopy is at the apex. This can be very dangerous and will usually result in a side slip with a huge outside collapse. Don’t forget to pop the outside brake once the canopy has passed the apex. This will slow the glider for just long enough for your body to swing through instead of fall through which most people do and screws up the wing-over momentum. When you start with wing-overs don’t do more than four in a row… as a beginner you will loose your equilibrium and start to get a little confused with out understanding why. Also try not to practice for more than 10-15minutes in a row as a beginner, because I guarantee in a few weeks you will be banking over 90 and this will also distort your equilibrium. The constant rush and drain of blood to and from the head also adds to dizziness, which can be very dangerous. Lastly, please, please, please don’t do this close to the ground. When you are learning the mechanics of it, you will have a lot of outside collapses, because your timing is off, you don’t give a hard enough pop, or an inside collapse, because you tried to give brake when the canopy was at the apex instead of past it… so you side slip. All of these can result in huge problems including spin, flat spin, cravatte, and pilot falling into lines. So give yourself plenty of space. Of all the maneuvers I see guys get hurt performing spirals and wing-overs lead the pack by a huge margin. I guarantee that while you are learning you will have some big collapses and you may need some time to recover. So Marshall guys probably did two or three things wrong. Not giving a little extra pop to get the glider turned downward after the Apex. This will often result in a collapse on the inside wing as the pilot falls downward past the glider, sometimes the wing will automatically try to return to equilibrium and level flight and will turn past the apex with the energy it has built from a previous wing-over, especially if the body is leaning into it. This could result in temporary loss of pressure along the leading edge as the wing charges downward and the pilots body is not yet on the same path. This leads to the second more likely occurrence, which is that the pilot did not apply enough outside break pressure after turning past the apex, to slow the glider momentarily as the pilots body regains downward momentum. This outside break and inside break will pull the tips back slightly as the pilot’s body catches up with the glider, which keeps the leading edge solid. Without this pressure, big frontal collapses are a possibility… or little ones as the Marshall guys may have demonstrated. Finally, they could have been using a ton of brake without much body involvement, which means they have to keep slowing their glider, then letting it shoot forward, without having drastic changes in their cg which would have kept the wing much more solid and efficient. These of course are just a couple of theories and I could probably come up with a few more. Tough to do without having seen it first hand. I don’t believe that these wing-over frontals where a result of a design flaw in the camber area, pressure center of the Bag. I tend to think it was more of a pilot error, or timing problem. Hope this helps, would love any feedback.
by Gabriel Jebb
Here are a few tips to help improve your thermal flying.
1. Listen to your variometer. As you hear its pitch increase, indicating stronger lift, straighten up your flight path a bit so that you fly deeper into the strongest part of the thermal. When your vairos pitch decreases, indicating weaker lift, tighten up your turn to get back to where you just came from. If your variometer indicates a constant rate of climb, circle as flat as possible.
Climb rate increases -> Widen your turn
Climb rate decreases -> Tighten your turn
Climb stays the same -> Turn as flat as possible
2. Fly with your GPS zoomed in to about 200m. At this setting you can easily see the circular track log left while coring a thermal. If you inadvertently drift too far in one direction and fall out the side of the thermal simply look at your GPS track log to guide you back into the thermal.
3. If you’re flying downwind and you enter a thermal start your turn immediately.The strongest lift is usually found on the upwind side of a thermal. By doing this you will avoid flying out the back side of the thermal and into strong sink.
4. If you are flying upwind and you enter a thermal continue to fly straight until you either fly into a strong core or fly out the front edge of the thermal. While flying upwind it’s no big deal to flying out the front edge of a thermal as you can simply make a 180 degree turn and with the aid of a tail wind fly back in the thermal.
5. If you need to reverse your direction in a thermal, wait until you are on the upwind side, then make your direction change by turning into the wind. If you end up flying out of the thermal it will be on the upwind side. As you complete your turn you will have a tailwind to help push you back into the thermal. See the illustration below.
5. Be aware of your chest strap setting while thermaling. In order to feel the thermals better, loosen you chest strap so that your carabineers sit farther apart. If the conditions start to get too turbulent you can tighten your chest strap up a bit which will dampen out the bumps.
There are a few other things to keep in mind in regards to chest strap settings.
- Less likely to getting riser twists.
- You will be able to feel the thermals better in your seat.
- If you take a asymmetric collapse it is even more important that you lean away from the collapse. If you don’t the wide chest strap setting will cause you to weight shift in the direction of the collapse, which will result in a significant change in heading and in most cases a more violent recovery.
- Dampens out the bumps.
- Turns less when recovering from a deflation (safer setting for beginners).
- More likely to get riser twists. Counter this by sitting up in your harness and being ready to turn with your glider if you feel a deflation is likely do to excessively turbulent air.
1. When thermalling, fly deeper in the brakes.. almost carabiner level. Better pressurizaton, less pitching, occillations. I was flying right through a bunch of the juicy stuff and getting tossed over the waterfall on the backside.
2. When on speedbar, fly with your fingertips on the stabillos. “Checking” the glider with the stabillo lines in the event of a frontal is apparently a better method than Ds or toggle pressure… all the comp pilots were talking about this “new” technique.
3. Search upwind for the thermals and don’t be afraid to push out front. The “yo-yo” technique was mentioned quite a few times, i.e. drifting with the core then pushing back out front if you fall out of lift.
~ Chris C.
So you’ve found your climb – now what’s the best way to use it?
by Jay Rebbeck, Published: 27-Aug-01 X-C Magazine
Centering thermals efficiently, and climbing quickly, are probably the most fundamental skills you need to soar successfully. Even a small improvement in your technique could easily mean an extra few hundred feet in every thermal – or thousands of feet in a typical XC flight of, say, 10 thermals. Come the end of the day, this might even make the difference between getting home and landing out. In a competition, what you gain in improved climb rate could well equate to the points separating the winner and mid-table obscurity.
Before you even reach a thermal, you can start building a mental picture that will help you center and climb quickly when you get there. Typically, you will be approaching a cumulus hoping to climb. You can improve your chances of finding a thermal by assimilating all the experience gained on that day to guess where the thermal might be in relation to the cloud. While on some days, thermals appear to form randomly, there are others when you can find them quite reliably. For example, if a strong wind and bright sunshine were feeding a cloud from one direction, you would expect to find the thermal on that same side.
As you approach the area where you expect the thermal to be, hold your brakes very lightly. Other than maintaining a good lookout, you should be totally focused on feeling which side the thermal is. If the thermal feels strong enough, turn towards the wing that’s lifted.
After you have rolled and turned into the thermal, one of two things might happen: If the lift steadily improves, great. But what should you do if the lift drops into sink?
The answer depends on how good the surge felt and how desperate you are to climb. If you weren’t confident of the lift when you started to turn and the clouds ahead look good, then simply roll out and get going – if you’ve got the height. However, if the surge felt smooth and solid, but you turn into sink, then you’ve probably turned the wrong way. At this point FORGET any distractions about what techniques to use, and resort to a mental picture. Logically, the quickest way back into the center is to do a tight 270° turn, and then re-center. This maneuver brings you back to where you would have been if you’d turned the right way in the first place! You’re now in a position to maximize your climb.
Despite the enormous importance of climbing quickly in thermals, this is one of most controversial topics in free flying. Most people want to be taught a prescriptive technique for thermalling, and this is where the confusion begins. There are two widely-taught techniques, but they appear to be completely contradictory. The tighten on the surge theory says that when the vario indicates the greatest climb rate, you should increase the angle of bank. In apparent contrast, the second theory says you should widen out when encountering the strongest lift. So how do we resolve this contradiction? The answer is that both theories are right, but they are appropriate in different situations.
TIGHTEN ON THE SURGE
So, having positioned your glider in the thermal, how do you establish yourself in the center and optimize your climb rate? The answer is to use the tighten on the surge technique: when you feel the thermal pushing solidly, or the vario indicates the strongest lift, you should tighten the turn and dig the wing into the thermal. Most pilots don’t turn tightly enough, but of course, if you only tighten up in lift you’ll end up in a spiral dive! To prevent this, when the vario indicates weaker lift or sink, you should widen the turn out to anticipate banking and pulling into the next surge.
The importance of tightening on good surges was brought home to me during the 1997 World Air Games in Turkey, where I was competing in the gliding section. Climbing in hot, blue thermals with massive gaggles in identical-performance gliders, often the only way to achieve an advantage on anyone else was simply to get stuck right in to the core of the thermal. The pair of flying French pilots who went on to win always managed to center on the strongest cores.
WIDEN OUT IN THE STRONGEST LIFT
Tightening on the surge is the technique for staying centered in one core of a thermal. So what is the role of the opposing technique of widening out in the lift? Quite simply, this should be used when you think there is a developing core nearby. But how can you recognize this emerging fresh bubble?
Having centered on one core, there are a few tell-tale signs: first, the average rate of climb drops off and, second, the thermal seems much stronger on one side than the other. Another core has formed, is bumping up the side of the one you are in, and the outflow from that bubble is interfering with yours. Sometimes this is marked by birds or other gliders circling, or tendrils being sucked into cloudbase nearby. In any case, the solution is simple: widen out in the strongest lift, wait a few moments, and then tighten up in the emerging bubble. Then continue to stay centered in the new pulse of lift using the tighten on the surge technique.
The ability to re-center quickly can sometimes be the key to competition success. On a critical day in the Junior Gliding World Championships in Holland, I was able to gain enough height on the gaggle in just one thermal to make it home as the sole finisher. What made the difference that day was simply that I re-centered efficiently and caught a short-lived bubble which the rest of the gaggle missed. That turned out to be the last thermal of the day, giving me enough height to glide home over the unlandable forest, while everyone else hit the deck the wrong side of it.
There is a strong correlation between the width of a cumulus and the number of bubbles feeding that cloud. For example, when arriving under a vast cloud street you should expect loads of bubbles and will probably need to widen out into wind frequently when you feel a fresh surge. On the other hand, climbing under the last isolated cloud of the day, you are likely to have to rely on simply tightening on the surge to get you home.
Whichever style you adopt, if you want to climb fast, you have to keep working it all the way to the top! You’ll also need to be planning where you’ll go when you leave the lift.
An air mass is any large volume of air having a relatively uniform temperature and water vapor content. A front is simply the boundary between two air masses. When a cold air mass pushes into a warm airmass, we call the boundary a Cold Front. When the warm air pushes forward, we call the boundary a Warm Front.
Cold fronts typically come from the north and move in a southerly direction. They tend to pass quickly, usually within a few hours. As a cold front passes, it plows under the existing warmer air rapidly lifting it and often times generating thunderstorms.All pilots should be very cautious when flying in pre cold frontal conditions. Beginning pilots should wait for the front to pass.
Post cold frontal conditions are generally unstable and great for soaring.
Warm fronts typically come from the south and move northwest. They move more slowly sometime staking several days to pass. The less dense and therefore lighter air tends to ride up and over the already present cooler air mass.
Because of the slow movement of a warm front, it is often possible to predict its approach a day or two in advance by noting a gradual increase and lowering of the clouds as illustrated below.
The passage of a warm front is not typically a good time to fly.
Structure of the Atmosphere / Density Altitude
To understand the weather it helps to know a little about the air. Air is simply a gas comprised primarily
of nitrogen and oxygen and a variable amount of water vapor. Air has mass and weight. At sea level
where the air is most dense it exerts a pressure of 14.7 pounds per square inch.
Air density is affected by altitude, temperature, humidity and pressure. Air density alters wing
performance. The higher the altitude, temperature or humidity the less dense the air will be and the faster
you will have to move to generate lift.
For every 1000ft of altitude you gain, the air density drops approximately 4%.
For every 5ºF increase in temperature, the air density will drop 1%.
The amount of water vapor a mass of air can hold depends on its temperature. As air heats up it is able to
hold more water. Low relative humidity means that the air at its current temperature could hold a lot more
water. When the temperature of an air mass drops, its relative humidity increases and when relative
humidity reaches 100%, water condenses and a cloud is formed.
Humid air is lighter then dry air and therefore has a tendency to rise just as when air is heated.
Solar Heating and Circulation
Solar heating and the resulting high and low pressure systems causes all atmospheric circulation. The sun
heats the ground, which heats the air above it. Different surfaces heat up at different rates. Some examples
of terrain that heat up slowly are water, snow, green grass, and forests. Examples of terrain that heat up
more quickly are asphalt, dry fields, dark soil and dark rocks.
As air warms up it expands, becomes less dense, and tends to rise. When warm air rises, cooler air moves
in from the surrounding areas to replace it.
So what is a thermal anyway? Well it’s pretty simple, a thermal is created when the sun heats the earth which in turn heats the layer of air directly above it. As this layer of air warms up the molecules spread out causing it to become less dense and therefore lighter than the air surrounding it. When the temperature difference becomes great enough the air breaks away from the surface and begins to rise, much like a hot air balloon.
However as a thermal begins to rise the surrounding air pressure decreases which allows it to spread out and now it’s temperature begins to drop. This drop in temperature do to a decrease in air pressure is known as Adiabatic cooling.
As long as the air temperature inside the thermal remains higher than the temperature of the surrounding air the thermal will continue to rise.
To read more information about thermals and paragliding weather in general see Understanding the Sky by Dennis Pagen.
When flying in a thermal it is very helpful to have a reliable vario like the Flytec 6005.