I often notice that there's this kind of friction between the different air sports. Sailplane pilots versus hang gliders, versus paragliders, or rather the other way around, and then there are the model aircraft pilots in the way too. We're all operating in the same world, in the same medium, and there's such a great diversity where, in my opinion, you can learn a lot from watching each other, even in terms of understanding.
Podz-Glidz, the Lu-Glidz podcast. Stories from the cosmos of paragliding. Today with Paul Sehren and Lucian Haas at the microphone.
When you learn paragliding, you're quickly taught on the practice slope. To steer to the right, you simply pull the right brake—or control line—and for left turns, it's the left control line. That's how you actually get a paraglider around a corner, but from an aerodynamic perspective, this very rudimentary turning technique is anything but optimal. Paul Sehren recommends different control paths. Many years before he started paragliding, the now 61-year-old was involved in building model aircraft. His specialty, crowned with competition successes, is a particular class of free-flying sailplanes. They are optimized to stay in a lift independently without the remote-controlling hand of a pilot.
This requires a fine balancing of the center of gravity and wing chord, and that is exactly what you need to achieve when maneuvering a paraglider. Paul works part-time as a flight instructor at the Papillon flight school, but also in the DHV flight instructor training. There, he shares his deep insights into the aerodynamic peculiarities of paragliders, which he gained from model aviation. And that is exactly what this 45th episode of Putzglitz is about. Paul talks about, among other things, how you can refine your turning technique, why gliders basically do many things much better than their pilots, and how so-called active flying can, at best, be incorporated. And what passive flying should actually be called. This podcast contains quite a few "aha" moments.
Before we get started, I just want to briefly point something out once more. Putzglitz and the associated blog Lu-Glidz are available online for free, but they are part of my work as a freelance journalist, and therefore part of my livelihood. I would be very happy if you would help me as a supporter to maintain and expand this offer in its professional and ad-free form. How you can become a supporter is stated on the Lu-Glidz website—specifically, where you can sign up as a supporter. The contribution amount is completely up to you. If you're unsure how much you want to give, I recommend a non-binding 1 Euro per podcast episode and 2 Euro per reading month on Lu-Glidz.
Paul, where does your love for model aviation come from?
Yeah, well, I mean, I remember always being fascinated by flight. Anything that moved fascinated me. And I looked at that and it seemed obvious to get something into the air myself. And mainly through a school friend who had already started doing it a bit before, I came into contact with flyable things that you can also build yourself, with more or less success—at the beginning, certainly with much less success.
What was your first success? Like, when did you have that great experience where you said, "Hey, something I built is flying"?
Yeah, so it was just with this school friend back then, we had just cobbled some things together. But it didn't have anything special, nothing you'd really call a feat of engineering. And I took all the scrap parts home with me, tied onto the broomstick in some way. And then, by chance, probably the whole balance ratio, the equilibrium of forces of an aircraft, an aircraft, and the thing flew in our garden. And that was like a turning point for me where I said, wow, so no matter what it looks like, even if it's crooked, you can get something to fly.
But that was it. It was a simple glider. It didn't have a motor, just a broomstick with something as a tail fin maybe, but a wing. And you just let it go and it flew further than you could normally throw it.
Yes, and consistently. I mean, it was amazing. It wasn't just a ballistic trajectory, but really something you could call a flight. At least, that's how it seemed to me at the time, and that's when the spark was lit. That means the key experience...
...towards aviation, then you've probably tried a lot. A lot of things, just like it is in your youth, trying out all sorts of things. What did you learn about aviation just from trying things out?
learned? Yes, well, a lot of things came out of that—that precision does provide a certain advantage if you build things properly. There were also a lot of model kits back then, way more than today, where everything is more of a ready-made set. You had to get your hands dirty, and those were experiences in the sense of what you can create yourself. And you can even modify them, turn them into a sensible, cohesive build afterwards, and even fly them while preserving their value. I still notice that today. In my workshop in the back, there are model airplanes from that era that are still preserved and flight-ready. So that's really something that even has a certain sustainability to it.
Could you actually explain back then why your models flew? No, not really. It was... it was more of a marvel, the basic principles, like there being a center of gravity, or that you could adjust the vertical stabilizer somewhere so the whole thing stays in a straight flight and doesn't, well, pump—or stall, as they say today—or go into a ballistic trajectory, that you had several adjustment options. But it was more intuitive, and because I didn't understand it, I made the decision that I wanted to study aerospace engineering. So it was really the key to saying, I want to know why all this stuff actually flies.
But if I saw that correctly—I took a bit of a look at your CV—you had already flown these models around quite successfully before you studied aerospace engineering. You even won some real prizes with them, didn't you?
Yes, that also started relatively quickly. That was thanks to good instructions in a model building group that I joined with this school friend, and later continued in without him. These were model planes. They were also out at competitions, and that was interesting, because very sophisticated model types were out there and it was ultimately a replica of something that worked. That's also something that works quite well in aviation today, even in paragliding. If one person builds something and it flies, then the other person copies it. So the principle has been preserved. But back then, it was first about the experience: yes, take something that others can fly properly, then you'll get it too, even if you don't set it up yourself. All the things are reproducible, so the settings have to have a physical logical connection.
But knowing exactly why it worked like that was still rather unclear to me even until my studies. I might have developed a feeling or an idea about it, though.
And was your studies then basically a series of "aha" moments with what you already knew from practice, but then you'd go, "oh, so that's how it works"?
Exactly. Exactly. Just like you just said. That "aha" moment really happened then. To say, oh yeah, now a lot of things are becoming clear to me. Especially because the models—certain types of models at least—are in such a slow speed range where a lot of things wouldn't be explainable by all the other, yeah, theories that were emerging. For example, back then there was already this topic of air particles somehow splitting at the front and coming back together at the back, happy that they managed to master the path together somehow. And that was something where this depth—this physical depth—really fascinated me, because you could look very precisely, almost macroscopically, at the surface of a wing being flowed over, regardless of what kind it was.
And those were many "aha" moments as to why these slow devices could be flown so sensibly. Did you deal with paragliders during your studies as well? No, but quite spontaneously with the kite flying that was emerging at the time. That was really exciting. It was right around '78, '79, when the, well, Rugal kites were increasingly entering a quality seal process through approval by the German Aeroclub back then, and their flight capability first had to be proven. And yeah, I think I was one of the earlier pilots—my DHV number is still three digits—that I got back then.
It was really about being able to actually recognize that. Yes, for example, a sensibly shaped wing—the S-shaped wing, the S-shaped airfoil of a kite with a sensible twist—is flyable in the kite field just as it is in the model building field. And I then broke that down into models right away, showing how it's flyable with it, and first convinced myself that the inherent stability of an aircraft is actually there. This testing procedure, where you ultimately, for example, drop a kite off a bridge and it has to calm itself down a few times independently without influence and enter a stable, inherently stable flight state. That is exactly what models can do too, and for me, it was always a verification on both sides.
How did paragliding then enter your life?
Yes, much, much later through my family and, by extension, the kids. That was many years after my studies, and model flying was the main thing then. You could do that every now and then on the side, and it was great with the family too. And for us, the Wasserkuppe was a family vacation spot where we were very often. And it was funny to watch in the background, especially if you're flying on the northeast side of the Wasserkuppe—one half is for the model flyers, the "Abstruder Erhang," and on the other side, the kite flyers. And then suddenly, more and more colorful, yeah, model planes. Plastic bags that somehow managed to stay up in the air to some extent. At the beginning, though, it was really more about the "sink bag" thing, tumbling down and occasionally over the tree lines.
And over all those years, if you peek over there, I saw, man, they can even stay up there. So the performance of these paragliders kept getting better. As a glider pilot, you were back then rather always averse to those "rag-flyers," and that probably rubbed off on me accordingly. Nevertheless, because my family noticed I was looking over at the other side more and more, they said, "Now go do a trial course." And that was—I don't know exactly if it was 2000 or 2001—when I did my trial course up on the Wasserkuppe and for the first time again took off after many years of abstinence from "algae flying," and the addiction to algae flying was spontaneously there again in that moment. And it was clear, this is something that would excite me.
What I absolutely had to do was, and then a few years later, two or three years later, I did my first combined course there, which was basically the full commitment for my entire family, who then all followed suit one by one and still share this hobby with me to this day.
You say the whole family, your wife and your kids?
Four children. Yes, exactly. I have four sons. They are all relatively close in age. They all have model airplanes, so they probably caught this passion for flying from me. I mean, I didn't influence them much, but I don't think I could always hold back my enthusiasm for flying, and so the eldest did the combined course with my wife the very next year, and the other sons did it the year after that. And my youngest was even there during my first combined course. He showed me basically how the boot fits or where the hook scratched. So he showed me right away that you can actually get a plane off the ground without having to strain yourself.
And that naturally annoyed me terribly, and I always wanted to be better than him. So he was the one who, basically at the beginning, was totally indirectly cheering me on to keep at it. And I always tried to do my best as well. Yes. To have a five-minute lead in experience, speed, or distance over my sons. Did you keep that up until today? Yes. So, whenever I wanted to do something new, for example tandem flying, then another son would want to do it too, and then it was equalized again. But the flight instructor—they haven't done that yet. My second eldest, the kite flyer, is currently doing the kite flight instructor training. So that's the next one joining in.
Yes. But I still have those five minutes.
You mentioned earlier that when you were still actively flying kites, you always found it fascinating to see that these kites behave in a very similar way to your models, following similar aerodynamic balance laws or something like that. Are there things you can transfer from model aviation to paragliding?
Yes, well, there's actually quite a lot, especially the speed ranges. Yes. The range we move in with the paraglider is very close to the area where high-performance models are active today in competition, but also in the sport category, and the goal of staying up for a long time or covering a large distance, or the combination of both. That's exactly the same challenge in the field of model aviation, and there, they experiment with wing profiles, with spans, with weight, with wing loading, with new geometric approaches. The ones they have there, and a lot of it—especially in terms of flying, when you're flying thermals, for example—is transferable.
So ever since I've been paragliding, I know what thermals look like because I feel them myself. So I can see them better. That's an effect that stuck with me, and conversely, I've been able to transfer a lot from model aviation—how to keep my paraglider stable and self-centering in thermals, for example, without having to think about it myself. It's much easier than a kite, by the way, because I don't have to make many corrections; instead, through the strong twist that I can achieve accordingly using my body weight and control input, I have a device that stays in the thermals, circling on its own. And those types of model aviation classes are also the ones that my family and I fly, where models stay in the thermals for a long time, independently and without any influence from a remote control, and fly a certain distance using the thermal lift and the wind.
And that's something I can benefit from a lot when explaining things as a flight instructor—that turning is a very variant-heavy, but also sometimes nonsensical way of explaining how turns are still taught in training today. You pull right to go right, you pull left to go left. No, you actually have to react completely differently. You have to adjust the stagger meaningfully and not brake harder on the inside. And as a model pilot, you can understand that immediately. That's something that I definitely think is a good connection. There
I'd like to come back to that right away. But before that, the question: would you say that as a paraglider, you benefited more from your model aviation, or have you, as a model aviator, become significantly better through paragliding?
So both, both directions. I can say that quite clearly. I can't deny it at all. So I think that in the model aviation field, because I'm active in competition there, but not in the paragliding field, I've become more successful because this visualization in the head, at least of the thermals, is already a very important moment for me. In the other direction, I notice it much more, for example, in conveying aerodynamic topics and also in teaching students how to fly, that you can transfer a lot from the model aviation field—for example, in the model aviation field—and even show it haptically at times. So the understanding is much more meaningful than if you just, I don't know, draw some weird profile on a flipchart again and then desperately try to explain how flow and lift are created, but when you actually feel and see this lift and the flow yourself, that's something I always try to convey as well—that it's always the same medium we're moving in, perhaps not always a comparable scale.
But in certain areas, the scale is identical. And that's why you have to take certain peculiarities into account, like—well, maybe that's getting a bit too deep now—but the topic of low Reynolds numbers, for example, the second sound barrier of flight in general, what actually happens there, and that happens repeatedly in model flight. In paragliding, by the way, too, namely where our lines struggle through the air and create a huge amount of drag.
But back to model flying—if you say you compete in model flying competitions and that has made you more successful in paragliding in some way. But what types of model flying are we talking about, or what does a model flying competition even look like that you participate in? What do you have to do with your model specifically, where you say you can transfer something from paragliding?
Yes, it's a very, I'd say, special type of model flying. There are, in the model flying field, you could take almost 30 different types. This is one. These are models that, once they've been launched, may no longer be influenced by us. These models have a pre-trim. This trim must be set accordingly, for example, to achieve independent stable flight in the thermals. And they are simply boundary conditions that limit a certain starting altitude. For example, with the glider-like models, it's like this: the line with which they are launched is limited to 50 meters, and after that, the model must or should fly for a minimum flight time.
Everything below that is the point deduction that takes place. Everything above that isn't counted, and through a mechanical brake, the flight is then, yeah, ended and the thing tumbles down. With motor models, for example, it's the amount of energy you're allowed to provide at most—so with internal combustion engines, it's the runtime; with electric flight motors, it's the joules you can put in. That's another variant, for example. And there's a very special variant that I totally love, also free-flying; these are models controlled via the Earth's magnetic field. So that's very close to our slope soaring, and by the way, the Rhön is also the birthplace of this type of model flying. The models have the control head at the front, which aligns itself with the Earth's magnetic field, and depending on the slope gradient, wind strength, and wind direction, the model is set up so that it virtually
before the slope. So, "freely flying" means it stands there, and the magnet keeps steering the model back into the wind. So that's also a variant where you rely a lot on observation—what does the terrain look like, how is it shaped, what is the wind doing in that terrain—exactly the same observations that you actually make as a paraglider, which you can also use accordingly.
That means it's about the model staying in the air as long as possible. Exactly. And you're not controlling it with a remote, but you had to do it beforehand through constructive measures. Exactly. And adjust it accordingly and you look at how strong the wind is right now and all that. Exactly. How do I balance this now? And then you give it a push and say, now it has to stand there, and if I'm good and the wind is steady enough and a bit of luck on top of that or whatever. Exactly. I can win this competition.
Exactly. Yes. And that's just something that, I think, also simply shows the diversity. I often notice that there's this kind of competition in the air sports. So when a competition takes place, the sailplane pilots versus the hang gliders, those versus the paragliders, or rather the other way around, and the model aircraft pilots are also in the way. We're all moving in the same world, in the same medium. And there's such a great diversity where, in my opinion, you can learn a lot from watching each other, also in terms of understanding. And that's why I switch between different colors and would never let model aircraft stand against paragliding, which fascinates me like crazy. So that's a very good path for me. It's a source of possibilities, and especially in particularly bad times, like let's take Corona for example, or also winter times, early darkness, you can also fly in a room.
So that's also possible. You can really scale down the models to a minimum level and adjust them aerodynamically so that even flight maneuvers would be possible in my room.
But I'd still like to go back to the point you made earlier, namely this: we do paragliding. We have a wrong idea of how turns work best with a paraglider, and as a model aircraft pilot, you have a better theory. So, enlighten me. What should I do better, or what can I simply pick up from a sailplane model as a paraglider?
So, I'll start with the model and the mindset again. It's important there—if I can, for example, can you see the wing at that point right now?
I can see it. I
can it
can't see, but if something important comes up, I'll try to translate it.
Exactly. Anyway, by flying in a turn, we generally, once we're in the turn—so that's the current state—have the inner brake pulled in more and the outer brake released. That's already extremely sensible, and at the same time, we have our body weight on the inside. But if we, for example, only initiate the turn that way—now I'll make it very extreme. Like it might be taught in the first flights—we pull the inner brake, then two effects happen. The first effect is that the inner wing is pitched up more. Because of this, it gets more drag on one hand, which is good because we want to, so to speak, work around the drag, but it also gets more lift right at the beginning.
And that's something you can see very clearly in thermals technique courses, when people who have been flying for a long time even say, "Yes, I've been flying for a while. I keep falling out of the thermals." They keep consciously pulling themselves inward with the inside brake, and at the same time, instead of flying around, they get levered out because the higher angle of attack also creates a moment around the longitudinal axis. That's why, for example, initiating a turn is much, much more sensible if you—I'll leave out the body weight for a moment—initiate it by opening the outside brake. So, from a slightly braked state or a fully braked state, a straight flight, you open the outside brake, then it gets faster, which is good, and then the inside wouldn't be in the predicament of potentially stalling because it becomes too slow, but rather it stays ahead in terms of speed.
That's why this outside-braking curve flying is a very, very important and also sensible topic, and it has an immediate effect on thermals, even in circles, where you don't have this levering effect because you're simultaneously creating this levering effect around the longitudinal axis at that moment. The other thing is the topic of curve weight or weight on the inside of the curve. In hang gliding as well as in paragliding, it's often explained that because of this weight you put on the inside, the profile—meaning the entire surface—bends inward and then
somehow… Yeah, there's like a kink in there at the top and that somehow pulls you inward.
Yeah, exactly. So this kink is so minimal and tiny that it might contribute a certain amount to it. Ultimately, because I'm leaning toward the inside, towards, yeah, a higher wing loading on one half of the surface, also through a very spontaneous lean over, the following also happens. The wing loading on that side is higher, the wing sinks more. So higher wing loading also means more sinking. Because it sinks more in the forward speed, which it still stubbornly maintains, it basically happens that it has an increased angle of attack. Automatically. That leads, in turn, to a higher drag being created, but at the same time, there is sufficient lift for the wing not to want to lever back over to the other side.
At the same time, on the outside of the wing—where I've moved away from the path because I leaned toward the inside—I'm unloading the wing. That means it has a lower wing loading on the left side. A lower wing loading is a lower sink rate, and that leads to a longitudinal rotation. And that's something that... initiates the turn. Plus that cute kink, which adds a slight component to the inside of the wing.
But the turn initiation, if I understand you correctly, just means why my wing leans to the side, let's say. At the same time, I've at least learned that the higher the wing loading, the faster my wing flies, and the lower it is, the slower. So, that would actually mean that if I lean my weight in like that, my inside goes faster and my outside goes slower. So my turn would be turning outwards again, not inwards.
Yes, but the reinforcement comes in because the higher the angle of attack, the greater the increase in drag. That means the inside wing remains braked. That's exactly the big advantage. The outside wing is in a range—because you've put the brake into the trim range—where it's significantly faster. You notice that too if you release the brakes too early, for example during takeoff, then the glider overshoots. So this increase in speed that comes in is enormous. And now something actually happens. We always think we're flying the turn because the inside brake is pulled harder and has more drag. But it also has more lift, and it needs that for the lower speed on the inside of the turn. If it didn't have more lift, we would fall into a spiral dive. And a sailplane flies like that too, so one should also look into other types of manned sport aviation.
A saw-tooth flyer initiates the turn by applying the rudder pedals. This creates rotation around the vertical axis. As a result, the outer wing gets more lift because it speeds up as it moves over the vertical axis. The entire wing rotates around the longitudinal axis, and now the saw-tooth flyer has to support it, even taking the aileron in the opposite direction. That means they take the aileron down on the inside and up on the outside and support the inner surface. And that is exactly what we do with the paraglider. We support the inner surface by using our body weight. We initiate the turn properly and brake harder on the inside than on the outside. It is exactly the same as how my models are set up for their free flight, by the way: a stronger angle of attack on the inside, a lower one on the outside, and a trim that pushes it into a turn direction—specifically on the side where the angle of attack is higher.
I hope I didn't make that too complicated to explain.
I hope people can somewhat imagine that. It wasn't complicated. But you also said earlier that when flying such turns, as a paraglider pilot, you shouldn't necessarily just keep pulling and holding that inside brake, but that you could actually stay in the turn even with relatively free brakes. How does that work?
Yes, so you can stay in it if you maintain the asymmetry caused by the different pull on the inside and outside brake. For example, to fully take the thermals, meaning to use them at their optimum, the inside of the turn has to be braked enough so that the inside wing is in the area of the least sink. Anything more or less than that is simply much worse on the polar. You sink much faster and wouldn't be optimally using the wing where the inside area of the wing—namely the core area of the thermals—is. And the turn control is performed essentially, unless you have to deal with some disturbances at the same time, only through the outside.
So, since I took this over from my model plane, I fly like this in normal thermals. I set my inside brake to the minimum sink. That's the amount of pull I need. That's then hooked in on the inside. I don't do anything else there. And the outside maintains the bank angle simply by increasing speed, by letting out more. And the inside supports the area of minimum sink.
No matter what the thermals are like. That's your basic position. But that would mean there are probably gliders that have a tendency to circle tighter than others in this position. Because other things also come into play, like how the brake input from the rear distribution is set up and so on.
Next. Yes, but it's important that you work with the outside brake accordingly. So that's the part—if you noticed it was spiraling in too steeply, that would be exactly the point where the outside brake doesn't have to be opened all the way anymore. So you use that braking effect at least, and then also take the body weight off the inside again. So the higher sink on the inside is shifted back toward the center more neutrally. But it's really helpful; you don't have to think about moving inward at all. That's locked in, unless a collapse occurs. Then both hands go down. And otherwise, when I fly into the thermals, it's the same. Where it levers me up, the hand goes relatively spontaneously into that brake position of the least sink, and the outside opens for me, and I just let myself dive into the thermal, and the thing bites really hard forward into the thermal.
And then you apply the outside brake a bit again to catch that bite, just as much as is necessary, and then you let the glider run and circle in that position.
Yes. The classic thing with, let's say, strong wind drift is that because the glider has such a high surface area, as soon as it's tilted in the air, I have to constantly realign the glider with the wind whenever I notice I'm being blown away. In the area where I'm flying against the wind again, I straighten up a bit and let it bite into the thermals from the front again, so to speak. But in normal, I'd say, weather conditions with relatively low wind drift—meaning a constant wind drift that isn't blowing away—I don't actually do anything. I just let it run and enjoy it, just making sure that I maintain my control pressure.
If the glider circles on its own, like your model, which you set up somewhere so that it stays in the air as long as possible—how do you, or how does the paraglider, ensure that it doesn't fall out of the thermals? Now, leaving wind drift out of the equation entirely, because this is simply a stationary thermal. Why isn't the glider pushed out of the thermal? Rather, why does it stay in? At least according to your idea or your experienced theory? Now explain it to me. The experienced practice.
exactly. So, definitely with the models. And now let's take this ideal case. Our thermal tube just goes straight up. So we really have no change in the local lateral displacement. And let's imagine now that the thermal component gets stronger the more you get into the middle of the thermal bath. That would be the ideal case. It doesn't exist, but it's relatively close. If we are already in the area, so in the lift-proximate area, and the glider—I'll give an example—let's say we have stronger thermals on the right than on the left. So it's unevenly distributed. The inner wing, we're already curving to the right and now we're entering the area on the right where the rising air mass is.
Then the following happens: right where the rising mass is ascending even more strongly, the angle of attack increases significantly again. We are already in a relatively high angle of attack range. We might have entered it because of a stronger thermals component. This means the increase in drag becomes disproportionately larger than the increase in lift again. But the outside is not yet affected by this strong lift component at that point. And at the same time, it's also at a shallower angle of attack. This means the glider immediately pushes around with the stronger lift. And that's what causes this automatic circling. Do that
all gliders, based on your experience? Or are there gliders that can do this much better than others? And what do those gliders that can do this particularly well look like?
I notice that A-gliders handle it more easily than a high-performance one. I fly both. I fly a C-glider, including the new Cayenne. And for my wife—my wife flies an A-glider, for example. It's the Raccoon released by Papillon. So, a light glider. And with that, it's exactly that kind of fun. I just hang onto it. That works with my Cayenne, but it has a tendency to want to fly straight ahead. It's its cross-country flight wing. So it's not designed for turning and thermals in the same way that an A-glider would simply do it better. Although with the A-glider—I wouldn't generalize—the more, for example, with Nova gliders where the sides go down very sharply, I get a rudder effect that comes along with it.
If it's not shaped in that exact way, it can also lead to a counter-reaction. You often see that with those low-profile, angular gliders, where they even want to turn in the opposite direction during a collapse. And that's something that works against them in the so-called derivatives. But the normally shaped, nice paraglider, without the edges being pulled down strongly, reacts best to that. So a deep, stubby wing rather than a highly extended wing.
That means the aspect ratio plays a part. The more elongated it is, the more it says, I want to fly straight. And the less it is, then the canopy curvature probably also plays a role in that. Yes,
Exactly. Exactly. What's the general relationship there? The more curved, the more it turns? Yes, you could put it that way. Just say that, although there's also something else to consider: the washout—meaning the more curved and more washed out the glider is at that point, the property could be improved by that. As long as it's not, let's say, like a Susi from Nova, which is heavily braked or curved down at the corner. But in the broad sense, it really is as you can assume, exactly, that a normally curved glider, and rather an A-glider with a lower aspect ratio, supports this turning behavior more positively than a stretched wing.
If you look at hang gliding, for example,
the kite flying gear that's designed for distance is mostly more like the paragliders, like when you look at an Atrus, or rather a turbulence-free glider. They have these VG. That's exactly what they use additionally; they tension the VG so that the glider—the glider, I'm saying glider—is largely, well, really strong and stiff, so it's no longer as easy to turn. As soon as the VG is loosened, it's the case that because of these turns—and the shift in the center of gravity at the same time—the inner curve also leads to a significant increase in drag as well, just to be able to take the turn accordingly even more sharply. At the same time, the projected area is reduced on the inside of the turn, and that also leads to a rotation, mainly around the vertical axis plus a longitudinal axis rotation.
So, more span, less turning; less span, better turning.
Why is such aerodynamic theory, which you already knew very well from your model flying and then transferred to paragliding, why is it actually taught so little or not very deeply in paragliding instruction, where once you've understood such simple tricks, you'd say, yeah, that makes sense, then I'll fly it like that. But why is it such a minor topic?
Yeah, well, I think it's always the issue of how quickly and easily you can provide those first successes. Especially when I think about basic training on the slopes, the pilot and the student aren't really settled into the harness yet. They can't really fly by controlling the curve. So they'll be levering a lot with the control lines. That's something that, unfortunately, ends up becoming ingrained. At the flight schools where I work occasionally, it's like we also make sure to say, yeah, so in the high-altitude training at the latest, we're curving now—how you actually curve properly. That's something that's being included more and more in the training, and that's a good thing. But this old "I want to go right, I pull right, I want to go left, I pull left" just stays in the head way too much.
And you notice that especially in advanced courses, with participants who have been flying for, let's say, five or ten years—they just have this control technique ingrained and they pull on the inside. So I did an exam last year, I'm also out there as an examiner for the DHV from time to time, and I witnessed how a student during the exam, during the initiation of the figure eight, brought an A-glider into a heli because he wanted to initiate the turn. And that was exactly this issue: it's supposed to be somehow fast, within the 30 seconds. And then he's really working with force, and I measured that with him afterwards. I always have force gauges with me for my training sessions, where I just want to know: do people even know what two kilos or one and a half kilos actually are? And I have them pull the two kilos with such a force on those spring scales, just without looking.
The tendency is around three and a half to four kilos. That's what gets pulled because no one can explain two kilos. You have to meet that requirement at that point too. And with a spring scale like that, you can simulate it very well. And with this colleague, whom I also did it with—the one who went into the heli during the exam—he pulled five kilos. It almost pulled the spring scale out of my hand. And we practiced a bit more with the spring scales, and the next day he passed the exam. But I also gave him some advice on his way out: it's very important that he learns to fly turns. So not just using inside brakes, which then really get into the flow behavior. And I believe this understanding of stall, angle of attack—that's something that has to be clear, what kind of danger zone you're putting yourself in if you only work within the inside brake range.
You just gave two kilos as a requirement. Yes, you should pull two kilos there. Is that really a typical measure for paragliding?
Yes, for an L-glider that fits. I mean, you could say that fits for many gliders. The more modern the gliders become, the less it fits. So those control forces are significantly lower, which you need to be in the minimum sink. For an S-glider, I'd say one kilo. That's the order of magnitude, depending on what kind of mass is actually hanging under it. So in the lower or upper weight range. For the M, S, and M gliders, it's one and a half kilos. The main thing, and that's actually enough, is this feeling when I just let my hands and my arms hang, so I really let a weight hang on it and let it work on that and say, okay, that's completely sufficient.
With that mass on it, we're actually in the minimum sink. So it's about feeling. It makes much more sense, and I always do this with new gliders of mine when I try something new again, to take my sledge with me to that spot and, in absolutely calm air in the morning and maybe also once in the evening, but rather in the morning, I try to find the minimum sink using the GPS accuracy, when it's completely still and the ground speed is approximately the same as what I'm doing right now and there isn't much thermal activity yet. So, at what position on my control line is that, and what force is it? And then I try to fulfill it and hold that force. That is exactly the force with which I maintain my internal strength again when circling the thermals, no matter where it has to be positioned.
And this force is then correspondingly important to maintain. Mhm.
Would that be something you'd recommend to everyone? Flying with a spring scale? Yes.
So, if you dare, yeah. I mean, I don't think five euros for a feather scale is too much of an investment. But it would give you a good feeling for what the minimum sink actually is, or what two kilos even are. I'd really start with that beforehand, because for me, it's shocking how much the—well, students, but also flight instructors—I try it with my colleagues too, what two kilos or one and a half kilos are. So there are very interesting variations. Whatever comes out clearly, basically, you see it differently on the left and right. So either this way or that way. Everyone has their favorite side. And it's about a 500-gram to one-kilo difference, which are pulled differently by both hands on the feather scale.
And your head says it's the same thing you're seeing. What's your favorite side? I'm, yeah, strangely enough, I was a right-hand turner in hang gliding. In paragliding, I'm a left-hand turner. Even though I'm right-handed.
But you feel the two kilos less on the left. So you mean you'd have to pull more to get to those two kilos. And do you prefer to fly into the side that you pull harder?
Yeah. Why? Well, yeah, I'd say that's the case 90 percent of the time. If I notice there's an asymmetry, I'll ask, and then someone will say, "You're probably a left-hand turner" or "You're a right-hand turner." And that's true in most cases. It really is, like, I have to pull on it. And then it's really about getting that "enemy flying" out of there. But this experimenting—really, when you're flying in calm air and even if you're already quite far along in your flying—I find that gliders are wonderful for trying those things out with yourself and your aircraft, to get to know them better. And if you make the physics, at least the minimal understanding that's necessary—which isn't much—visible, for example through a force meter or force zones, then that will help too.
That's also the same thing in the area of active flying. So, for me, that's always been an issue as well.
Our glider canopy is always stable if we manage to keep that control pressure constant. For example, in a slight sink, if you want to fly down with it. When the air gets turbulent, you always hear about active flying. Actually, for me, at that point, it's completely passive flying. If I were to just hang one and a half kilos of weight on my brake lines now, I could really fly like that, with my arms crossed, letting the glider do the work, because the weights would always pull exactly what needs to be pulled. So, this truly unconscious thing—I don't have to work against it, but my weight is on the—in the worst case, if you were to steer like that, in the steering grip position, on the lines, and my arms are the weight. And if that moves, then it moves, and I move with it, not against it.
And that's something we also try to balance out with this spring cart. To say, "Look, I'm pulling, creating some turbulent air, and working with the spring cart. Tell me about your last vacation and then a poem." And at the moment it happens unconsciously, it's really like you just let your hands go loose like a marionette. The only active part is actually when you notice everything is getting very, very soft; then I think it's already quite helpful to really clearly guide your hands downwards on the side where it's getting soft, or on both sides, until the control pressure is back and slowly moves back up into the working position.
What you just described was like a dry run that you do with your students. Have you actually tried this theory in the air—where I just hang two kilos of weight on my brake lines and they do it on their own—have you practically tested if that works? It works. It's like an autopilot.
So it's really that good. The problem is just if a situation actually arises in very turbulent air where you have to fear a collapse, you might be moving a bit faster with your own reactions, noticing it's getting soft, than the weight can pull it down, because you can approach it with a higher speed or a mechanical advantage. So the weight just adds up, right? Exactly, exactly. Because it has its inertia at that point. But in the normal flight range with reasonably usable turbulence, it really works. So just take two weights, one and a half kilos or two bottles, carry them under your arm, hang them on, and then out in front of the camera and take photos. That would be something.
I haven't filmed it yet. I should do that sometime. That's a good suggestion.
Yeah, that would be a nice image, I think. So if you just say, "Hey, watch out, I've got this photography aid here, I'm hanging my two kilos on each brake line again. The wing is now flying in autopilot mode. I can take wonderful photos now and everything works perfectly." Yeah, exactly. Maybe you could also just hook in some springs at the bottom of the carabiner, like those standard two-kilo preload springs that you pull in with them, or not?
Yeah, but that won't work because depending on the heavy movements, the area where those two kilos or one and a half kilos—regardless of what weight we agree on—can be further up or further down. So feeling that weight, the weight alone, does it automatically. Or if we unconsciously just move with the control line, we do that unconsciously. And it can also happen, for example in strongly rising air, that my two kilos are up here. And if you were to fix it with a spring downwards, you would have exactly that amount of slack we have on the paraglider restricted and would enter the collapse zone. So it has to be free. It really has to run freely through the pulley.
That means, if you were to transfer that, you could basically build something like a dry training device for every paraglider pilot, where you'd say, look, here there's a...
whether it's pneumatic or whatever, a control where you say, okay, you have to stay in this two to two and a half kilo range or something like that. And if you go out of it, it makes a loud beep. And then you've lost a point or something. And then it wobbles around and you have to stay in this range. You could really train your own muscle memory there perfectly. Yeah,
Yeah, definitely. I mean, I think everywhere I've used it, it's been an "aha" moment for the students. Even with the student flight instructors, it's always a funny game to realize that the human body initially resists it—you're reacting instinctively. By doing this visualization and just going along with it, getting it out of your head, what really helps is talking about your vacation or something. Just not thinking about it anymore, so that it happens automatically, just like when you couple.
Now we've talked about active flying. We've talked about turning. What other aerodynamic insights have you brought over or gained from model aviation, where you'd say it's an aerodynamic concept that is sometimes really misunderstood or explained incorrectly by many paragliders, students, or maybe even instructors?
One topic that really... yeah, that's my pet peeve, when I hear people trying to explain why lift is generated and doing it so painstakingly—far too painstakingly—with flow on top and bottom and Bernoulli and Venturi, trying to represent it like, because the air is faster on top and it's a low-pressure zone, for whatever reason, but there's apparently a low-pressure zone and that's why it goes up. This entire knowledge of aerodynamics is so complex, it's so deeply difficult to understand what actually happens in that near-surface area and above it, especially at different speeds, at certain sizes, at different temperatures and at different altitudes.
I think that's always a slippery slope that people get led down, and I'd describe it like this: from my experience, the description always implies that only a wing profile that is significantly more curved on the top than on the bottom is capable of flight. But if we look closely at our paraglider profile, it has a curvature of about one to two percent. That's practically nothing. It's almost as curved on the bottom as it is on the top—okay, I'm exaggerating a bit—but just as curved as the top. If you had put this profile on the paraglider upside down and made the angle of attack a bit larger, or the incidence angle—which is related to the angle of attack size—the profile would still fly. Even a sailplane, which has a more semi-symmetrical, even a convex curved profile, if I flip it onto its back and adjust it accordingly, I can get that thing to fly just the same.
So it has nothing to do with the profile shape or it being more curved on top than on the bottom. That's why an aerobatic plane can fly on its back, or a normal glider, which can also fly in thermals, can fly on its back and won't, so to speak, enter a stall because the lift in that direction would suddenly become significantly stronger. That's why it's important for me to explain the relationships between the forces here. This is easier, it's measurable, it's demonstrable, and with the topic of angle of attack, because angle of attack affects us again and again. This is something we have to watch throughout our entire flight, to ensure that it's always in a sensible case, in a sensible range, that we never enter an angle of attack range that is too high, where the flow can stall.
and our plastic-filled wing then collapses in on itself. The other way around is the same: if we fly too fast, i.e., in an angle of attack range that is too low with the speed bar, which would be structurally possible in principle—we would just close the vent at the bottom, where the fresh air and the stagnation pressure, the internal pressure, build up, and have the stagnation pressure on the upper surface of the wing. The thing just won't fly. So it's always about the angle of attack in every area during landing. It's about when I'm in a turning flight, when I initiate turns, that I always, for example, also make sure that I keep the inside—as well as the outside—always exactly in this sensible angle of attack range. That's why my approach is always to go over the top, leaving the flow on the outside out of it.
First of all, because it flies—even a board flies. And it doesn't have a profile to begin with. And yeah, how can you explain that when he says, "Well, it flies," but then why does only the paraglider profile fly? And it's still so weirdly curved and has a hole in the front.
So, that's something you can describe more so through force measurement. And for me, it's very important—a colleague of mine, who is an engineer, and this is a bit of an exaggeration now, but he lived over 130 years ago, Otto Lilienthal, didn't deal with airflow, but only with measured forces. And that's what led to humans being able to fly. That's completely sufficient to explain it. And there, you can simplify the physics. Forces
So, if I take a plate, as you're saying, and shape it into an airfoil—so basically just place a door against the wind in a positive position—then the wind pushes against it, and the air is diverted downwards, which then creates the lift.
Yeah, well, I wouldn't really explain it that way with the air, but what you would see as an effect is that a tilted door, if moved against an air mass at a sufficiently high speed and in a sensible state of equilibrium, will fly—a brick will too. So, ultimately, that's also possible. Even a flat plate has a polar, it has a CACW curve. And by the way, when you design an aircraft today, you actually start with the flat plate. And with the airfoils, you can significantly improve the lift-to-drag ratio, but that only accounts for maybe 20% of the performance increase, plus the change in characteristics.
There are profiles that react critically to changes in the angle of attack. There are profiles that are much, much more forgiving. For example, thick, comfortable profiles. Strangely enough, we have those exactly with the paraglider. The faster the C-glider, for example, the glider becomes, we also see that the profiles simply get thinner. At that point, they start to get fussy. So, ultimately, the profile only influences a large part of the flight characteristics. The basic portion of the lift is simply created by some surface being positioned at a meaningful angle of attack against the air. And because of that, there is naturally a flow around it. And you can try to describe that afterwards. It's just different. That's why a single-skin glider flies too. It doesn't have a profile. So, in that case, the particle principle can't really be explained correctly anymore, why the air particles at the top and bottom at the back at the same time...
Yes, the rest of the airfoil figures that out. Yes, yes, exactly.
That's one way to explain it. Yeah, I mean, air particles are intelligent. They get the message. They say, "He's flying a single-skin, but we're going to help him anyway." So, I'd say the air is being friendly.
Yeah, exactly. It's very friendly. I mean, it forgives a lot, even a single-skin. No, I fly a single-skin myself too. It's just great. Especially in the model aviation field, in my remote-controlled, so with radio control, there's been an incredible amount of cross-pollination in recent years regarding the single-skin area and the mantra-an area. Model flyers, for example at Swing, started with that back then. This device caused a stir among model manufacturers. By now, the scene has become huge, to the point where German championships are already being flown in these classes with single- and hybrid-skin models. And they're really high-performing. I also always take a model single-skin with me for training, for example, and send it out beforehand to see if the air is clean or if the thermals are already lifting.
And if it's carrying, then it gets swept away again and I'll follow it with my glider. Or if it's that turbulent, I'll just have another coffee.
But the single-skin has a motor on the back so it can land back with you at the top, right? No,
No. I have both with motors, but I also have free-flying single-skins without motors. Exactly. But
Remote-controlled? They're remote-controlled, yes. That means you send it out and if it stays up there, you say, "You guys can go flying too?" Yes, exactly. Is that enough if you say, "If my glider stays up there, then it's enough for us too?" Can you just transfer that like that? If the glider flies, then we can definitely fly too?
Yeah, so with my single-skin, the motorized one in particular, it has a pretty high wing loading. If it still climbs without the motor, then it's fine for all of us too. It might even be almost too much. And the other single-skin, for example, which I fly without a motor—if that sinks and I have to go pick it up somewhere below the slope, I won't have any time to provide flight supervision anyway, so no one can fly. So it's not useful in that situation either.
But these are really good precursors. And yes, in the paragliding scene, there are quite a few paragliders. For example, Manu Nübel, he also comes from that scene. He's experimented quite a bit with it. And he's a very good model pilot and paraglider. Hannes Vadder, for example, too—they're also out there as test pilots for the Single-Skin model gliders. So there's a lot of cross-pollination, especially very intense regarding this type of flying. And easy to pack, that's great too. No one can complain that the vacation luggage becomes too big because of a model aircraft in addition to the paraglider. Instead, it's just a smaller pack.
Now you have these remote-controlled model aircraft. But you've also mentioned several times that you work as a flight instructor, so you have these students on the radio. I'm jumping off-topic a bit now, but to move forward: to what extent do you sometimes, as a flight instructor, when you have your students in flight or something like that, basically with models...
...work? Well, I have to admit, it's almost a one-to-one feeling in that regard. I mean, it's manned model flights, ultimately, that are taking place. It has helped me immensely, for example, with the topic of landing field instructor. Every model pilot who flies remote-controlled model aircraft has to estimate height, speed, and the landing field to ensure the model lands there, because at the edge there could be, I don't know, tall grain. And then the model is unfortunately either gone or damaged. So you want to come down exactly there. That's exactly the task you have as a landing field instructor: getting someone there and giving them the ideas on how they can ultimately estimate that height as well.
And for me, it's really effective as a model aircraft, what I see, which just sometimes leads to the fact that the radio connection and the reaction to the radio signals on my model are often better than the student's. Probably faster and more precise then. Yeah, right. So I have it more in my hands. I then have to try to use verbal communication to bring the student's wishes, his direction, and his reaction into harmony. That's a bit more difficult than via radio control.
But in the end, you bring it in just the same way you bring in your model. Exactly, just like that. I
I assess it the same way. So that's the basis for me. Just the same, even in thermals technology courses, for example,
when I send the participants into the thermals, it's like when I send a model airplane to a spot where I see, ah, it lifts off, it goes. And now, right or left, that's something that really comes from the model aviation field.
And for me, that's just another variant of remote control in the truest sense of the word, yeah.
So, does that mean model aircraft pilots are better flight instructors?
Yes, I think they definitely have an advantage because they can really estimate everything regarding altitude much better. I consider that part especially essential to convey, because it's quite a bit of practice that they can pass on. For example, why do you do a landing pattern at all? How can you estimate landing altitudes? Even when I fly to a model airfield, we have a landing circuit where you have to fly against the crosswind and the final approach, partly to be in clear flight operations, but also to lose altitude sensibly and bring speed, altitude, and the landing point into as good a harmony as possible. And I believe that's something where a paraglider instructor who flies models has a huge advantage, at least at the beginning of their career.
You're not a full-time flight instructor. You've worked for an automotive supplier for 30 years, but interestingly, you told me that you took a sabbatical in 2015. And during that time, you only worked as a flight instructor. How did you experience that? Is being a flight instructor something you'd say, compared to your other job, is something you'd always like to do? Or is it more like, for one year I thought it was great, but that dream many people have of becoming a flight instructor or something, isn't necessarily what you'd want to have as a dream job for a long time?
Yeah, well, it's ambivalent. Maybe that's how you could put it. From my working life perspective, it was the most work-intensive period. I never would have thought that. I had so much fun that I actually forgot what the working hours were, for example, because it starts in the morning, continues during the day, and then in the evening it continues again in cheerful groups. So, a pilot is then among pilots. You can't separate that. So this separation of job and your own leisure time with your own hobby, that just doesn't work at that point. And that's the other ambivalent part. Your own flying eventually came to short shrift. I noticed that too. So that's a big danger, that as a flight instructor you're then just standing at the start and at the landing field, maybe especially during the best times, and looking after others while not being in the air yourself.
You have to see it that way. And the other thing—well, yes, maybe because of my life path so far and my other hobbies—the financial part is of course manageable. I don't think that with a family and, let's say, bigger ambitions that you have to fulfill in your own life and your surroundings, like the style of house construction, you can just easily manage that. It's quite a challenge. But in terms of feedback, of the sense of achievement from the profession, I've never experienced anything like that again, not even in all the years before and not even in my last years now at the same automotive supplier,
...where I still work, it's just such an incredibly satisfying activity. So from that perspective, I can only recommend it. However, from my point of view today, it might not be feasible permanently, or maybe only at intervals or in conjunction with another job. But that's my personal experience and perhaps also my history in this area.
Well, you're also active in the field of training with your current employer. And are there things where you'd say, from experience, that this is something completely different? It probably involves a lot of technical and other training and stuff that an automotive supplier has all there. But are there things where you'd say, based on what I experience in my normal job, how training works there? Is there anything where you'd also say, like how I transferred things from model aviation to flying or saw how it can be done better? Are there things where you'd say, you see something where paraglider training could somehow be improved? With some ideas that come from this professional world?
Yes, well, I think a major helpful contribution from the professional world I'm currently in to the world of training is that training today is no longer about the instructor standing at the front and the poor trainees sitting at the back, with the instructor showing and drawing on a blackboard while they diligently write along, or standing at a machine doing some kind of practice or test pieces. Instead, it's increasingly about the topic of personal responsibility and introducing the trainees to the learning topics, the learning themes, and also the learning methods. And I believe being a flight instructor is really about much more than standing on the slope and showing PowerPoint slides during the theory session; it really has a lot to do with haptics as well. I'm experiencing that in technical training too, especially now during the Corona times with home offices.
You can do a lot of things theoretically, but you have to be able to touch the things. And I think it's very important that we make the things we might not be able to explain completely tangible. And to make it as haptic as possible. Flying itself is a very haptic process afterwards, in any case from takeoff to landing. But what happens in between, and similar to my force measurement units, I think that's an idea you can get across. What is also being incorporated more and more into training today, for example, is the topic of virtual and augmented reality. That is also something I can very well imagine in the glider area in the future. So, meaningful simulators that are more than just the harness hanging in some frame, where you can actually feel more, see more of what is happening around you.
For example, in our welding training, we work with Augmented Reality. We're also already using Virtual Reality in areas where the machine, the operation, and the instructions all happen right there on the spot. I can easily imagine that something like that would be useful. Of course, I think it's a very complex area for such a specific topic as aviation, especially in paragliding. But the big players are setting the example for us. The passenger pilot flies for several hours in a simulator. The military pilot today mainly learns a lot in a simulator first. And I think we can convey a lot of understanding and feeling there in the end, too. I think we can definitely benefit from a piece of that.
What would probably make sense then is if the respective flight instructor actually stands right next to them and can say directly: what can you do better at this point? That's something many people who are doing their training, of course, have had their high-altitude flights brought down, were instructed during landing and so on. But when they start flying themselves, many flight conditions, especially in thermal air or something like that, everyone has to work that out for themselves emotionally and they get very little direct feedback saying, hey, there's your stall. But did you see it? You let it progress way too far. If you just briefly brake with your hips two seconds before and then let go again, everything would be smooth sailing.
...basically been. Yes, so I think that's maybe more in the direction of flight school training concepts. I might be a bit [biased] there because I don't run a flight school myself, but rather enjoy collaborating in that area. Yes, it's also a topic that schools do today, namely this coaching, accompanying them, the VIP schools, or whatever you want to call them. And I think it's good if you also provide that along the way and say, okay, let someone give you feedback after a certain amount of time. Where have you reached? So, I mentioned it earlier as a side note, but especially in thermals technique courses, I often see such ingrained, hard-wired behaviors that are incredibly difficult to get out of, but are error-prone. And that's something where a lot...
I think that along the way, things could have been adjusted and worked on so that flying actually remains fun. Especially this thing where I fall out of the thermals or I fly through the landscape with lines that are braked way too much, and on top of that, in the worst glide ratio and sinking areas. So, those are different things. A bit about starting. So, starting is a topic where, for example, those who got their license six or seven years ago, in my opinion, have to relearn how to start, because the newer gliders they are flying now—most of them anyway, once they eventually switch their glider—can be started in a completely different and much easier way. And that running away from the glider and stumbling down the slope, which unfortunately we still see,
that you could avoid that, in order to significantly reduce the risk of accidents.
Did you need something like refresher courses or up-to-date courses, or whatever you want to call them, where they say, "Hey, every five years, get yourself up to speed on the latest technical standards regarding control techniques, launch techniques, glider technology, and so on." Yeah,
Absolutely. Especially when you look at glider development, specifically over the last ten years—and really the last five or six, where the modern training glider has ultimately made its mark and arrived everywhere—there doesn't need to be a huge impulse anymore today. That means if I'm launching the glider right now, I can lead it up really comfortably and slowly. I can initiate a control phase, even if I'm pulling forward, without having to be fast. The gliders have become lighter. The airspeed, the way the glider stays right above us, is significantly lower than it was ten years ago. And there's so much more calm now. And then I can do an orderly launch, a conscious one—really self-controlled and not one that happened by chance because I tripped over the mountain.
That's something you could definitely say to older—well, not necessarily older, but to pilots who have been active in the paragliding sport for a long time and have been out there for a while, who still fly freely: yeah, take a look around. Try something new again and try out a new launch technique as well.
I saw that you're retiring next year. Yeah. Will you continue working as a flight instructor then? Or will you say, no, I've earned my pension, I'd rather fly myself now because I want to get my own flight hours too?
Yes, well, for me it's an early retirement with a partial retirement scheme that my current employer has made possible, based on the structural issues we're facing in the automotive sector and, of course, especially due to Corona. I'm happy about it because I really do want to continue training people as a flight instructor. I enjoy it, but this time I'll schedule it so that I also have time for myself. Since I'm now in the fortunate position of not having to work as a flight instructor to make a living, it's a nice side job. It's nice. It avoids discussions at home about why I'm buying new equipment again. I can use that very well for that. But I really want to go all out.
So, working half-time, continuing to train. Simply experiencing that sense of success from the training. I think that's a very important and truly rewarding part, not just for the flight student, but also for the flight instructor. And the other thing is, it's a way for me to get back into flying in various ways. Plus, after I got my family into flying—my daughters-in-law fly too—it's also the case that the grandchildren will soon be ready for model aviation. So that's the next project, which I'm also taking on accordingly. You
you're working on the Seeren flight dynasty. Yes.
That's one way to put it. Yes, that's true.
Alright, Paul, I wish you much success on this path. Thank you very much. Have many more great flights and many wonderful experiences with your grandchildren, who will then start following in your model aviation footsteps—uh, flight paths, footprints. Flight paths, that's good. Footprints and flight paths, or whatever you want to call them, then they'll follow in them. Yes, thank you for this very interesting conversation and all the best. Thank you very much.
That was Paul Seeren in conversation with Lucian Haas. For those who want to learn more about this topic, Paul has also given several interesting lectures on various areas of paraglider aerodynamics during the so-called pilot days at the Papillon flight school. Recordings of these can be found on YouTube. I have put together the relevant links in the show notes for this episode in the blog. There is also some interesting reading material from Paul; in the Papillon blog, there is the series Paul's Pilot Tips. Those are also linked, of course. It's worth taking a look.
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