I think that gliding performance in calm air is probably closer to its zenith than the more practically relevant performance mentioned earlier, which determines whether two very good pilots can fly through the thermals accelerating by 2 km/h schneller in real-life conditions. If it succeeds in having this 2 km/h schneller full-gas glider also climb very well in weak conditions, then at this level, it's something very good pilots might call a quantum leap.
Podz-Glidz, the Lu paraglider podcast. Stories from the cosmos of paragliding. Today with … Philipp Medicus. And I am Lucian Haas.
There was a time when paraglider construction wasn't possible. A glider was primarily a craft. Profiles were still cut out of cardboard, which were then used to wrap the fabric strips to ultimately arrive at the cutting patterns. And if things went well, a glider wouldn't just fall out of the sky at the end with a glide ratio of 1.
In the modern paraglider, the computer has become perhaps the most important tool for designers. More and more, it's not just CAD software that plays a role, but also more complex simulations of fluid dynamics. Philipp Medicus from Nova even goes a step further. He uses programs that can calculate the dynamic deformation of a paraglider when aerodynamic forces interact with dozens of other technical parameters that define a paraglider. Profile shape, cell count, line layout, cross-bracing, diagonal ribs, 3D shaping, mini-rips, etc., etc. In this episode 170 of Podz-Glidz, Philipp Medicus explains how this approach helps him build paragliders that remain as stable and high-performing as possible even in moving, turbulent air.
The conversation also covers questions like: When is the paraglider concept fully engineered? How is a specification sheet actually created for a new model? Or what role does AI already play in the development of paragliders today?
Speaking of AI. Behind this podcast, it's still 100% manual work—hand and mouth labor and human intelligence. If you know how to appreciate that, then become a supporter of Podz-Glidz. How to do that is explained in the Gleitschirm-Blog Lu-Glidz, specifically on the Support page.
Philipp, if you could design a glider just for yourself personally, what kind of glider would it be, in terms of type?
Well, there's a case study for that, and I'd say it's very close to the Bantam I. The Bantam I came about because I basically developed a glider for myself with a bit of a guilty conscience, because I didn't believe in the huge market potential of such a concept, and I presented it to the other owner in a somewhat ambivalent way—why we need such a glider. And to my surprise, it was significantly more successful than expected, or rather, the market potential was significantly larger than I thought.
Were you, in a way, perhaps ahead of your time with your idea or your approach to flying, where you say, I want a glider for this—so, hike and fly, going up mountains, having as little weight as possible, being able to jump back down again, and so on. Were you perhaps ahead of your time?
I wouldn't go that far. I think maybe other designers just don't share my passion for hike and fly. And the Bantam was really developed to be tailored to my style of hike and fly flying. I wanted a glider with which—you could maybe put the specifications like this, or describe my hike and fly flying like this: I really enjoy going to the mountains a lot. And I also go to the mountains without a glider when the weather is bad. And I wanted a glider that, simply, if I'm left on some peak in random weather, would get me down as often as possible, as safely as possible, and maybe even in a fun way.
That spoke against a singleskin, for example. It spoke for the very short lines, for instance. It was important to me that it was safe to land despite the small size. That's why the flare behavior was important. So, this specialty product probably—or apparently—didn't interest any other designer or development team as much as it did me personally. But I think that's more of a coincidence than being ahead of my time.
Are there any other gliders where you'd say you really put a part of yourself into it? Sure, there's something of you in every glider you design. But where would you say something of your flying philosophy is really visible, palpable?
included, alongside the Bantam? Yes, definitely. I mean, it would be a lie if I said it's distributed the same way across all gliders. I'm not an agro-pilot, for example. But this Glitch project, there's a lot of my passion in there too. Because even if it doesn't overlap with my own flying at all, I'm incredibly interested in it from a technical perspective. And maybe that's more of a technical passion in there, and the product overlaps with that. Because I'm interested in understanding the maneuvers as a "desk-top" agro-pilot and understanding the technical requirements. The Glitch is a completely different example than the Bantam.
And there are similar connections with many products. For instance, with the two-liner, I'm incredibly interested in what makes it possible to achieve such high stability. What makes it possible to set the cheat so that a very, very good pilot—who obviously flies much better than I do—finds a high potential. And so I'd say that aligns. Now, it doesn't necessarily have to align with my private flying that passion is involved. The hundred percent fit, where pretty much everything of mine is involved, including my own flying, is the Bantam.
You just mentioned
Desk-bound -Agroflieger spoken. So you then have to design gliders for the discipline. You say you don't fly them yourself, maybe you don't even understand them at first or something like that. How does a designer approach a project like that? So, did you sit down or did you sit down with Theo de Blick and say, what do you need for a glider, what does it have to be able to do? And how do you ultimately translate that into the construction? I mean, how do you go about it?
Yes, so the whole thing actually started with me sitting down with Theo. And he then formulated roughly what is important to him regarding the glider. If you want to sum that up in one sentence, it's that it has to shoot.
And I believe, well, of course, everything you can do additionally helps you, and it would certainly be better, it would help me, if I flew all these Stolto -Infinit -maneuvers myself. But I believe that my technical understanding of what enables this gliding of the glider still works quite well from the desk. And in that regard, the technical understanding is certainly better than that of a world-class acro pilot who can fly it but doesn't know what a lift coefficient of a profile is. In that sense, I believe that it's not a huge handicap for the basic design. Provided that you have test pilots, like in this case Theo de Blick, who makes it his life's work.
And then it just works through very intensive exchange with Theo. So sometimes he has an idea, sometimes I have an idea, and three out of four are a step backward and one out of four is a step forward. That's how we've fumbled our way there, prototype by prototype, line by line, and trim by trim over the years, approaching what he wanted until he was finally satisfied.
So, I'm very interested in the technical side of it, and for me, this enthusiasm and professionalism are really captivating. Plus, knowing that there's probably no one better for this project right now. So, if it doesn't work, I can only blame myself, because my partner in this case is incredibly good. That's additionally motivating and strengthens my interest. If you
If you have to construct a new glider type from scratch like this, how long does it take for you to say, "Okay, I've drawn a first prototype? Designed it on the computer and all that. It can be built now"? How long does something like that take? Is it a week's work? Is it a day? Is it four weeks that you sit at a desk on a computer to draw all that, have it calculated, and whatnot? How are you supposed to imagine that?
That has a pretty wide range. And you're just talking about a product that has no predecessor to build upon. That thing
glitches now, for example, where you say it's like a glider. Nova hadn't built any agro-gliders until then. Now a new task comes up and it means, I've been talking to the COD lead for a long time now. I think I've understood what he wants and now I'm building a glider like that. How long does it take then to say, okay, I have to define all of this on the computer now? It's not about how long it takes until you've tested all the x prototypes, but rather saying, I have a first one now. Just these steps that you as a designer then do in a sense. And in a sense, you're doing the preliminary work for this project. I would
I'd say it's about ten days of net working time for me. In reality, it's probably three or four weeks, and a huge part of that is very, very many simulations. By the time you get the impression that it's reasonably optimized—that you've identified the weaknesses visible in the simulation and have a general understanding of what it's about—that's the ballpark, but I think that can vary quite a bit, especially upwards.
You said it, simulations. At Nova, you have programs, you run a lot of calculations through them now. How has this way of working changed over the last ten years? I mean, were you already running simulations ten years ago, or would you say that back then you would have constructed a glider completely differently in terms of the process than you do today?
So, the simulations—since I started doing them as my main job a bit over ten years ago—have always been an essential component. The simulation capabilities have become much better and more diverse, and in some cases, it's reached the point where I'd say an initial prototype looks fundamentally different today than it would have ten years ago, because I can simply see aspects in the simulation that weren't visible ten years ago. For example?
For example, a major advancement in simulation is what's called fluid-structure interaction. I'll try to explain that in 30 seconds. There's this CFD simulation that simulates the flow around a rigid body. That's basically a virtual wind tunnel. And the result is the aerodynamic pressure and suction forces. In practice, this naturally leads to the glider deforming, depending on which pressure forces are acting on it. This deformation, in turn, influences the flow again, which then leads to other pressure forces that deform the glider even further.
And that's exactly the kind of feedback loop that we absolutely couldn't model in simulations ten years ago. And three years ago we could do it somewhat, and in the last one or two years very well. Or maybe in two years I'll be saying that we couldn't do it very well two years ago and only can do it very well now. But we've made great progress there over the last three or four years. And for certain applications, this feedback is naturally essential. If I want to know how a glider stabilizes from high speed and a low angle of attack, for example, I need this feedback.
So, to model any kind of dynamics or damping, it's essential. And that can even lead to a profile that I would have used ten years ago being rejected in one of the very first simulation steps today.
Because you can just see directly, okay, forces are occurring at certain angles of attack or whatever at places where you don't want them. And you see that immediately?
Exactly, I see that. Or I see that my brake pressure is way too high. My pressure on the B-line of the two-liner is too high. The glider has too little pitch moment at a very low angle of attack and doesn't stabilize at the speed it wants to. And these are relatively new achievements.
Are these things where you'd say that this form of simulation mainly serves to actually increase the stability of the gliders? In the end, I mean, you're not looking so much at what performance it provides now, but really, it should fly as stably as possible and also have a somewhat bearable braking pressure. So, that you have a few parameters and you can mainly define them with that.
Yeah, I'd put it that way. So, the pure straight-line glide performance does benefit somewhat from this feedback, because it can model this steady-state case more accurately. But the main effect is these dynamic or more dynamic states, where it's about a slight braking, a slight pitching. And that leads directly to a different profile choice, for example. And indirectly, it also expands my understanding. If I'm simply able to test out 20, 50, 100 things in the simulation, I eventually see patterns myself that I probably would never have noticed in practice, because on the one hand, you can't build 50 prototypes, and on the other hand, it's impossible in practice to cleanly compare the brake pressure between 50 prototypes.
And in the simulation, you, yeah, you compare 50. And
these comparisons you're making, or rather the changes you're making, are those mainly changes to the profile? First of all, in this feedback loop where you say, I want to find the ideal profile for this glider type? That
I wouldn't say that. The profile was more of my example for things I would have done differently ten years ago without today's capabilities. Basically, the profile isn't the most important thing about the paraglider. It's perhaps the most prominent, the easiest to grasp.
And on top of that, with a paraglider, the profile isn't as trivial to define as it is on a glider now, because we have the profile on the profile ribs and everywhere else on the glider—or rather on the cell—the profile is overlaid and influenced by the ballooning, and so my ballooning and my ballooning progression affect the average profile, i.e., the average aerodynamically effective profile. And that's another factor to consider. So I wouldn't say that these newer simulation possibilities primarily affect the profile, basically, but rather very, very, very many parameters.
That means, where do you place which things? Which diagonal ribs, which cross-bridles do you pull in, and stuff like that?
Exactly, exactly. Or what curvature does the glider need? What—and this is an exciting topic that I don't think is easy to convey in all its complexity—is what is often referred to as tension distribution. It's simply about where the glider has tension, and the more tension it has, the lower the stress. And there are incredibly many possibilities for how that happens at the front, at the back, at the upper sail, at the lower sail, at the center wing, at the outer wing. And there is a lot of optimization potential in that. And many of these parameters interact with each other.
That means if I increase the curvature, my optimal ballooning changes. If I change the washout—the variation of the angle of attack across the span—my optimal ballooning changes. If I change the line geometry, my optimal ballooning changes. And you can say the same in reverse. And this doesn't just affect these two, but many other parameters. And the more the simulation can model these, the better this optimization process works. And the better—and this might not be so obvious—the better my understanding of these correlations becomes. Sometimes there's also this trial and error, but sometimes, not so rarely, a pattern emerges from that trial and error.
And that ultimately sharpens my understanding and allows me to gain some insights that I probably wouldn't have achieved without these simulation capabilities.
Does that go as far as, with simulation and optimization, that you now say, okay, where I might have used one or at most two profile shapes—say, the mid-wing and outer wing were slightly different—that I now say, okay, I have a glider with 51 cells, or let's say 50 cells, that's easier to calculate, 25 cells on half the wing. And there, I now build in 25 slightly changing profiles because, of course, it always gets narrower towards the outer wing and so on. Do I optimize it so far that I also calculate the individual profiles and still basically have many individual profiles? Or is it still the case that gliders today actually have a continuous profile across all ribs?
Well, what you're saying is certainly one aspect of this more diverse optimization. For one thing, at my start, it was more like I oriented myself very closely to the standards, because any deviation from them carried a very large risk of failure. That's not the case anymore. The chances of success have increased through simulation and the understanding gained from it. And regarding the profiles across the span, many of our gliders now have a significantly different profile on the wing compared to the center wing.
But it's less about me optimizing 50 or 25 different profiles, since the glider is symmetrical; it's not like I'm optimizing 25 different profiles, but rather it goes in the direction of the outer wing. That makes sense for something different than the center wing. And then there's a transition where the profiles morph from one to the other, and that's it. But there is no glider where I have five differently optimized profiles across the semi-span, meaning across half the wing. I'm not saying cell 1 is this optimal, and then cell 15 is something else.
Rather, it's more of a relatively morphing transition from the center to the outside. And as far as I know, that's also common in other aviation—that it's more about two profiles rather than more.
gives.
When do you think we'll reach a point in construction, and especially in this simulation, where we could eventually say, we can build gliders virtually and test them virtually so that when we finally have the prototype built, it could already be the final glider. So that it flies so well that you say, we can actually try all of that out in the computer already.
Well, it's only conceivable if you scale down your own demands significantly. Or, to put it another way, you can't imagine that the manufacturer, who continues to test the glider with very good test pilots, won't have any significant advantage left. From my current perspective, I consider that very unthinkable. But how often
does it still happen that a test pilot gives you feedback where you then gain a sort of surprising insight, where you say, all the simulations didn't show me this. Why does this glider have this property that my test pilot just told me about? I mean, it still happens...
...I build prototypes that are a step backward from the previous prototype. And that's a natural surprise, because that wasn't my plan.
Could it also be that
could it also be that, like, those prototypes just have a sewing error or something and you don't see it?
That would be the generous interpretation for me, that they sewed it wrong. No, that's not it. I mean, there are surprises regarding the handling, especially regarding the stability. And as for the flyability in turbulent conditions, there are surprises. And if you take this Xenon 2 project mentioned earlier as an example. That's the two-liner,
which wasn't flown at the X-Alps.
Exactly, that was the X-Alps two-liner that Aaron Trogati and Nicola Donini tested. These are two very, very good pilots who fly XC at a comparable level and can simply determine, in a reproducible way, that in turbulent air, one can just always fly one or two km/h faster, even if the performance in calm air is relatively or completely similar. At this level, of course, that is a huge performance difference, and one that I can only predict very unreliably at best.
Do you have to note that down under luck, just saying, yeah, in the end it turned out that the glider flies that well?
Definitely, definitely. So there are very many—I mean, that's decreased over the last ten years, but there are definitely many aspects where my knowledge, at least for the time being, doesn't go beyond the fact that one thing works and the other doesn't. In the stupider case, it stays that way, and in the better case, a hypothesis eventually forms that is then confirmed later. But that happens again and again with many gliders, so with the prototypes themselves and also with changes that are then made to the prototypes. The rule, of course, is that you have a hypothesis and you apply it, and that then brings the desired result if I make the outer wing faster, or increase the distance between the A and B planes, or increase the curvature.
But there are also cases where the exact opposite of what I predicted happens. And if that turns out for the better, then of course we take that with us. And that's nothing other than the luck you mentioned.
You said earlier that with all these simulations, you can eventually recognize patterns or trends where you say, "Ah, so this is connected to that." That would be something where you'd typically say, "Ah, actually, you could train an AI on that quite well." AI is particularly good at recognizing patterns and certain connections—you throw in a lot of data and stuff like that. Do you already use AI in construction today? No.
So the problem I see with that is that for this kind of pattern recognition, AI currently still needs orders of magnitude more data than a human does.
This feedback loop simulation I mentioned is relatively time-intensive. I mean, to simulate a glider that settles in like that, it takes several hours on hardware worth 2,000 or 3,000 euros. And I don't think you get anywhere near the scale of the number of cases required for an AI. Plus, the parameters you can change there are just so diverse that the search space is insanely large. And yeah, I think we're just not there yet. So, personally, I'm very interested in the topic of AI.
I'm a heavy ChatGPT user for all sorts of things. But now, regarding design tips, the problem itself might be similar. The instructions for paraglider design available on the internet are so rare that the AI can't make any sense of them.
AI is very multi-layered, from these language models that have triggered the current hype to simpler machine learning in general. And there are interesting approaches in fluid dynamics simulation, for example. You might know this from weather simulation. I believe you're quite knowledgeable about meteorology. I think there was a recent breakthrough by Google where they no longer do these weather simulations based on physics. That means it's no longer a model. It's no longer a model that knows and applies the laws of nature, like the conservation of mass or energy, and simply calculates it step by step, step by step; instead, it's AI that knows nothing about all those equations, but I think you could say it's something like an intuition based on a massive number of cases—an intuition for the development of the weather developed based on the initial state.
And something like that actually also works for—perhaps not surprisingly—what works for the weather, it also works for fluid dynamics simulations. And that enables...
Faster calculation probably in the end. Shorter calculation. Maybe in the future, if you currently need three hours for one run, you might only need three minutes soon.
Exactly. And that would then maybe—so maybe this one AI, which makes the simulation itself significantly faster, would then enable in another step for the number of simulations to become so high that another AI can take over this optimization and that it works in the future. But you
you're not afraid for your job.
Like probably every other profession, I believe mine isn't threatened by AI. I think the developments over the next five years are so hard to predict and the possibilities are so diverse that I don't want to be drawn into making any kind of prediction.
What would you say is still the biggest challenge today as a paraglider designer or in paraglider construction? Especially challenges that an average pilot might not even imagine, given the level of subtleties, specialized knowledge, and everything else that is necessary nowadays.
Interestingly, there are many different approaches among paraglider designers, and among the good paraglider designers, there are a surprisingly large number of ways of doing things. That's why I wouldn't necessarily want to say that a technical basic education is essential, because there are simply examples that would immediately disprove that for me. It is difficult, for instance, to interpret the feedback from different test pilots. Very good pilots who might then, with completely different approaches and different backgrounds, translate it into a similar language, and where I ideally also manage to filter that out,
thanks to my broader technical understanding, maybe to filter out what I classify as reliable feedback or what might not be entirely accurate. That's an aspect that some people might not think of. What do I do with it when Aaron Turokati and Nick Tonini say they have no chance against Proto B with Proto A during fast gliding, and I have no way of understanding that at this flying level? And if I find that completely implausible, what do I do with their statement and to what extent do I question my own ideas?
How often does it happen?
how often does it happen that you have professional tests that contradict each other and you have to say, "Oh man, you're saying it turns well around the corner or something, but it doesn't do that," or in a performance comparison, you say it does, but you don't know that one person sits so much more loosely in the harness that it already makes a difference and it actually performs much better, while the other sits stiffer or has slightly different settings and then the glider just doesn't work as well. So how do you deal with such contradictory statements?
Yeah,
that actually happens, and luckily it always happens with real world-class pilots; they make three comparisons with two gliders and even these comparisons don't just contradict each other, they sometimes even contradict themselves. So we had that during the Xenon-2 development, where we eventually told them for fun that we have to swap you out for people who can actually fly, because what you're saying makes no sense, and there's no option with the X-Alps winner to go find a better one, you just have to deal with this,
I try my best, they try their best. I think what's very important, and what I also encourage the test pilots to do, is that if they find three different things, they should tell me straight up. And if they find something terribly bad that they liked the day before, they should tell me straight up. Not because there's already some loss of information because they want to look good or want to praise my product. But that is actually difficult, even for very, very, very good pilots.
A lot of it probably depends on the weather conditions and stuff like that. Absolutely, absolutely. In your development work, whether it was Xenon or whatever it was, have you ever experienced a situation where you'd say, "Actually, we have a glider that works brilliantly, let's say in 80 percent of the weather conditions, but there's 20 percent where it fails." For whatever reason. So, where you see it becomes problematic or something doesn't happen, and because of that, we have to decide against it, even though it's actually an excellent glider otherwise. Or how do you deal with those kinds of difficulties at all? There are gliders that are excellent in calm conditions and they might be more demanding than the other in slightly more turbulent conditions, but they are clearly at an advantage in those calmer conditions.
So how does a manufacturer decide? I mean, which concept...
which one do you go for? I think you have to distinguish or decide based on the target group, in terms of the weighting of the target group or the perceived weighting of the target group.
An X-Alps two-liner that loses those 2-3 km/h in accelerated flight in turbulent conditions, for example, because it becomes too unstable and you simply can't fly as fast, is a no-go. If a Low-B glider accelerates, it turns out that, in my opinion, there's some competitor product that can fly 2 km/h faster in turbulent air, and for that, our product is [fine] in the majority of all other situations, but the weighting is completely different. So I think that's very product-specific. With an Acro glider, you can accept that the...
Shoots. You have to accept that it shoots, but we also accepted for a long time during the prototype phases that it was a glider very prone to collapse and dangerous to fly, because those competition runs that Theode Blick needed as the only pilot on the glider at the time simply worked well enough. And that would be a no-go for the production glider, of course. I think it's a target group definition that decides what's more important and how these strengths and weaknesses are balanced. As a...
Do you have a designer's preference for certain classes, where you say, "I actually prefer designing this"? Or is it like you say, "EN-A is boring and EN-D is where the music is, like a two-liner, that's way more fun"? Or is it specifically these Low-Bs, where you say, "this really has to fit perfectly"? There's so much there where you as a designer really have to put in the brainpower to squeeze out even more—whatever that may be, safety, performance, whatever.
So, honestly, I think there is a certain correlation between classes. In an X-half glider, there's a bit more,
Optimization potential might not even be the right term; there's a bit more prestige in an X-Half glider than in a training glider. That might be what's resonating there. And in a glider where performance and stability are so important, I can maybe contribute more with my work than in a training glider, where I'd say the main part of the success lies in the testing. Yeah, maybe that's actually the real correlation. Where I can contribute the most, my motivation is probably at its highest.
Because you're being asked as a technician. How many different gliders have you actually built in your career as a paraglider designer? Prototypes or production gliders?
Production gliders first. I never really kept count or maybe stopped counting at some point. So, if there were only three, I could answer you now. I'd have to do the math. I mean, of course I know the ION3 was my first glider design. And now, four generations later, I'm just guessing off the top of my head, somewhere between 20 and 30. Maybe it's 20.
Were there any among them that, looking back now, you would say weren't actually that successful? Of course.
So of course there are gliders I'm prouder of and some I'm less proud of. And of course, the sales figures don't just measure my performance, but there is a correlation to my performance. And yeah, so definitely. What has been your most successful model in terms of sales so far? I think the ION4 was the most successful model in NOVA's history.
That's maybe a good example, because the level of innovation compared to the ION3 was actually relatively modest. So, what went into it from my side compared to the ION3, compared to the predecessor, was nothing. You didn't have much
reconstructed, but the test pilots basically trimmed it better.
Yeah, well, I've changed things, but they weren't things I'd be particularly proud of looking back. No strokes of genius that made the ION4 design possible compared to the ION3. So, what my personal successes correlate with—which, of course, doesn't perfectly align with the commercial success.
What would you describe as the most successful glider for yourself personally, for whatever reason? Hm,
that's difficult. Well, what I actually have is a very strong bias toward current gliders. As soon as a glider is introduced into the series, thermals don't really interest me as much anymore, and my sense of success regarding them fades immediately. So I feel, yeah, the ION6 and even the ION7 or the Mentos 7, from my point of view, are so old that I've almost forgotten them. Because of this bias, I would mention something very recent, and that's perhaps the XENON2, where with a lot of time pressure and a few setbacks and a lot, lot of enthusiasm and weekend work from the test pilots,
...from Aaron and Nick, I believe, have put together a very, very good product under a lot of time pressure, with a few setbacks, and a lot, lot of enthusiasm and weekend work from the test pilots.
Do you actually just sit at the computer for something like this, or are you also one of those people who sits down at the sewing machine and says, "I need to re-sew something, I need to put another webbing in there," and stuff like that? So, do you actually do that work too?
I'd say that among all the components you could count as part of the designer's scope, or paraglider development, sewing would be my blind spot. I can sew in a tension band if I have to and no one else is around, and I can sew lines, but unlike all the other aspects of development, it's not something where I... Not your strength. Not my strength, exactly. I never spent my evenings teaching myself that, like I did for many other areas.
Let's jump back a bit in your life. Where did this interest in aviation actually come from for you, or when did it start?
It was really in my early childhood. There's a funny, almost kitschy anecdote—it's hanging in my room—my mother dug out a picture from the attic a few years ago from when she was eleven. It's one where I drew a paraglider with a Nova logo on it. I'm not a superstitious person, otherwise there would certainly be a very special interpretation of that. But what you can take from it, and what I remember, is that aviation has occupied me since my childhood.
My classmates were confused by the many paper planes I built and that it could still be funny after 100 of them. Were you also basically optimizing them and did you always...
looked for ways to improve this plane.
And thought about it? Definitely, I wanted them to fly far, for example. So I didn't build 100 identical ones, but I wanted them to fly far, I wanted them to fly in loops, whatever. And as a kid, I rode my bike to the Innsbruck airport, the glider port, quite often; I just watched from over the fence how the gliders took off, and then at some point I started with RC flying, where I mainly built, flew, and actually mainly repaired gliders, I have to say, because the crashes were quite numerous. So flying has captivated me since my childhood for some reason, without there being any explanation for it in my family environment or anything like that.
At 15, at the earliest possible moment after a summer job or two summer jobs, I think, in a printing house, I had saved up the money for the glider license, because you can start training in Austria at 15, and by 16 I was the holder of the glider license. And that was my aviation home for a few years. Then, by chance, I got into a cheap paraglider course. It was like a job deal: building a launch site in exchange for help with a paraglider license. Yeah, somehow that interested me and I thought, let's check it out.
And the sailplane pilots, at least in my club, always had a rather dismissive view of paragliders. And after being socialized there, I felt that way at first too, and then I was surprised by how the simplicity of paragliding fascinated me rather than repelling me. And I think I did both in parallel for a very short time and then converted to paragliding. That means you gave up sailplane flying completely? Yes, yes.
Back then, giving it up was certainly a financial necessity. Nowadays, it would be a matter of time. So yes, I gave it up completely.
How did you end up at Nova then? If you already drew this paraglider as a child, that's very nice, but how did it happen?
I had forgotten about this drawing. That was until my mother found it. That was another coincidence. And ultimately, I think it was through the DHV forum or by email. I started as a student and a paragliding beginner, exchanging emails with Hannes Pappesch about some technical topic that I can't remember anymore. What I do remember is that I thought at the time that Nova was a German manufacturer. So, even though I lived just 15 minutes outside of Innsbruck back then, I didn't know that Nova was in Innsbruck, and I certainly didn't know that Hannes Pappesch, with whom I was exchanging these emails, lived maybe a kilometer and a half away in the neighboring village.
And that somehow got cleared up after a few, yeah, after a few emails—that the physical distance is so small. And that's how my contact with Nova came about. And during my studies, which was mechanical engineering in Graz, I did all sorts of jobs for Nova. It was doing checks during the holidays, writing some remote texts for the website. They were all different, different student jobs. And that then gradually tipped more and more into development, first into testing and then into design,
without me being able to define a clear starting point for the development work or for the design, because it happened somewhat gradually.
How did it come about that it said, okay, ION3, your first glider, and then how did the decision come that said, come on Philipp, you're building us the next one, our next Lobby?
That they put it together chronologically correctly—I mean, Hannes did decide to switch from Nova to Advans, but if I remember correctly, the beginning of the ION3 development wasn't shaped by that decision yet. Instead, I think it was my concern, and the concern of the other owners, that they simply involve me more and more in this design work. And I grew into it gradually, starting with some loose exchange of ideas and then an introduction to the design and simulation software, until it eventually became appropriate for both sides to say,
this is your glider, which of course isn't created by me in isolation as the first glider, but I took primary responsibility for at least all the simulation steps, all the prototype steps and so on. That's why I'd say that was my first glider. How important was Hannes Papisch as
design mentor for you?
So, for these beginnings, it was obviously crucial.
Without this chance encounter, starting with this initial contact, the connection to Nova probably wouldn't have happened. And without his introductions to the basics, or to his world of paraglider design...
my chances of getting started would have been massively hindered, at least that's how I'd put it. Would you say,
In the end, was it actually just a coincidence that you became a paraglider designer?
Yes. Yes, well, I really think—I suspect that without this funny email incident, I wouldn't have ended up at a paraglider company, but maybe in something more classic, technical. So, up until that point, I didn't have the idea of becoming a paraglider designer. I'd guess that was due to coincidence, and at the time, I had no idea at all about paraglider development. From what I still know, besides the fact of being surprised that Nova is based in Innsbruck, I was also surprised by how small the paraglider world is. So, as a pilot back then, I somehow...
without thinking about it for long, I think I rather assumed it was an industry like mountain biking or something in that direction, which from my place of residence looks somewhat similar, but it wasn't clear to me in some way that I was sitting at the absolute hotspot of the paraglider world. In that sense, I had a completely wrong idea of the paraglider world and certainly no accurate one of paraglider design, and if I hadn't stumbled into it, I would never have seen it as an option or a possibility at all because I knew nothing about it. Now we have
looking back. Let's look a bit into the future. When is the paraglider designed?
That's a difficult question.
A very good indicator might be that many people ask themselves this about many, not just technical sports equipment, but technical products in general. I think that 20 years ago, people might have asked themselves about mountain bikes or skis, what else can you do with these two boards or these two wheels, and there is an insane amount of potential in there. People still ask themselves that about computers, and I don't know if Moore, who founded Moore's Law, really believed in it, but somehow this development continues. And I think, with gliders,
my approach would be similar. What's added to that—and we've already touched on this—is that performance, well, I think if you say "engineered," you're probably thinking of performance first and foremost. But performance is very multi-layered. So, I think that glide performance in calm air is probably closer to its zenith than the more practically relevant performance mentioned earlier, which determines whether very good pilots can actually fly faster through thermals in real-life conditions. And performance is so multi-layered that you could also derive from that that there's still quite a bit of potential left.
And if it succeeds in making this glider, which is 2 km/h schneller, also climb very well in weak conditions, then at this level, it's something that very good pilots might call a quantum leap, even if these two gliders glide exactly the same in calm air. And I think, because of this multi-layered nature of performance and all these different aspects of performance, I suspect there is still a lot of potential left. But as a designer, I certainly have a bias. And it would be hard for me to say. I can't imagine that I'll be able to do anything about that in two years.
When you look at the trends over the last few years, I find that—at least with the gliders I test—you can notice they're becoming increasingly pitch-stable. More and more manufacturers are saying so and highlighting it too. But you can also feel it; nowadays, you often have to fly much, much less actively in the big stuff, you have to make far fewer large braking movements because the glider does more and more on its own. Have we already reached a plateau there, or will there eventually be hyper-pitch-stable gliders that still provide decent performance?
have? Well, I'd think that we haven't reached a plateau yet. But what you're mentioning is, for example, a development that sailplanes went through several decades earlier.
I'm not completely up to date on that, but the most modern gliders from 20 years ago weren't better or more successful because their pure glide performance was significantly superior; rather, they were much easier to fly. You could bank them very slowly at the limit without having to risk an aggressive stall. In total, you could fly them for over eight hours without fatigue, unlike the aircraft from the 80s. That's all shifted far into the past for gliders. But the fundamental development is very similar, and it's probably already an indication that we are at least closer to the plateau in terms of pure glide performance.
...as with this multi-layered performance with all its aspects. And predicting a plateau like that, I think it's like reading a crystal ball. I mean, for my own sake, I tend not to see a plateau. I don't actually believe a plateau has been reached. Is there a downside to this pitch stability?
You could say that, but I don't really believe that such a stable glider lulls the pilot into a false sense of security. You could say that the pilot feels the air less and then flies in conditions that they would identify as dangerous with a different glider, but not with a pitch-stable one. I think that might be true in individual cases, but I believe that overall, the safety advantage of the higher pitch stability and the higher club stability prevails.
With pitch
-Stability also always brings up the word reflex profile. Does that always mean that a pitch-stable profile has to have a reflex in it? Or can you also build pitch-stable profiles where you'd say, there's no reflex in there?
I mean, both of those are a continuum—both pitch stability and reflex.
My definition of a reflex profile—and I'm not entirely sure if that aligns with the aerodynamics literature—would be that at its zero-lift angle, meaning when it has reduced the angle of attack so much that it's producing no lift, it still has a tendency to pitch up. That would be my definition of a reflex profile. That when it's just about to stall, it doesn't tend to reduce the angle of attack, nor is it indifferent, which would be the case for a symmetric profile for example, but rather that it pitches up. And there are colossal differences between what could be called a soft reflex and the type of reflex profiles you find in parakeets.
So, you can technically call both of them reflex profiles, but if you say they're the same, you're making a mistake because there's naturally a non-reflex profile out there that is much more similar to this soft-reflex profile than the soft-reflex profile is to this extreme reflex profile. I think you have to be aware of this continuum.
...be. I once read somewhere where it always said, "Yes, power wings already build such great reflex profiles, they're so stable and all that, why isn't that used in paragliding, in classic paragliding?" Then it always said, "Yes, they're good, they're stable, but they don't actually offer the performance." Yes, so they simply have worse performance. But now you see that even in the END, CCC, and other classes, they have very stable, pitch-stable profiles in there, probably with a certain reflex component. How did they manage to get the performance into these reflex profiles?
So I don't think it was some new discovery regarding airfoil design that was the prerequisite, but rather these airfoils—well, on the one hand, it's true that a reflex airfoil reduces performance. Essentially, the reflex airfoil generates a bit of drag at the very back so that it can generate its switch-up moment. And that's impractical, at least from a performance perspective, if part of the airfoil generates drag just to generate that pitch moment again. But these performance wings, these END two-liners for example with a reflex airfoil, they are at the lower end of this mentioned continuum of reflex airfoils and their performance, and the performance losses you have to accept because of them, are simply very small.
And that might have more to do with this trend reversal, where it's been said that this glide performance in calm air or on the computer shouldn't be prioritized over everything else, but it might be smarter to sacrifice a theoretical tenth somewhere so that it can fly those 2 km/h in turbulent air more relaxed and faster. I think that's more of a small trend reversal, a shift in philosophy, rather than people now seeing that if the profile shape is like this and that, you can balance pitch moment and performance.
To what extent do you still test your paragliders yourself today? Or what class are you? Are you still out there as a test pilot, for example? So I...
I fly all the prototypes except for the akro gliders, and I'm saying at different levels. So my input on the X-Alps 2 Liner is very low for this actual application, measured against what Aaron and Nick do, which is why the question of whether it makes sense to adjust the development size towards my slightly higher weight never even came up. In that case, it's more about me always getting a rough impression.
What are they talking about regarding the B-pressure? What do they mean by the fold in the gas? I mean, sure, there are photos and videos of that now. But how do they rate the rolling? For me, it's more about getting a rough idea of their feedback. And with other gliders, it's correspondingly more. But as I said, I fly everything except the Akro gliders. I think my input there would simply be completely useless.
Do you also test gliders from other brands in between to get a feel for things and then say, what do they do differently than I do? Is there something you like that you'd say, "I want to achieve that with Nova gliders in the future" or something like that?
Definitely, yes. I think it's called benchmarking,
this looking at competitors' products. Yes, we do that. Because we're bringing the Xenon -2 development now, we started the Xenon -2 development by buying the most successful competitor model—I think you can probably imagine what kind of glider that was. And then we did all the comparisons, had Aaron and Nick fly it. Otherwise, I consider that essential. And I fly these gliders too.
To what extent do you, as a designer, get into a different construction and look at internal details and such, or is it more about the feeling during flight, where you say, okay, what makes this glider what it is?
It's both. The main reason we acquire or sometimes borrow these competitor gliders is for practical testing; you just don't want to waste time celebrating some internal progress. Proto 3 flies much better than Proto 2, but if you actually compare it to the competitor's product, I'd say Proto 3 flies like total shit. And it's simply—above all, it's about this reference in practical flying regarding handling, stability, and performance. And of course, as a designer, I also take a closer look at the competitor products if I suspect there's something interesting in them.
Well, there are the
test pilots you have, like from Nova, who give you a lot of feedback. Then at some point you have the product finished, it goes out, and then you probably get a lot of feedback from the outside too, including from testers like me, who then somehow test a glider and then write down that they liked this, didn't like that, and so on. To what extent do such external opinions influence your work? Ultimately, to say, maybe for the next glider my specifications, now the thermals have written this and that or Lu-Glidz has said this and that, it doesn't turn the corner quite as nicely as the old one or whatever. Okay, I'll put that into the specifications, the next one has to do that again, I want to please Lucian too or whatever. Is that even decisive?
So the sum of this external feedback is, of course, definitely decisive.
You can't please everyone, but the goal, of course, has to be to please the majority, and that naturally influences the specifications as well. So we try—whether it's external testers, team pilots, or partner flight schools—we try to gather opinions before a new product, and that doesn't just include the flight behavior, it also includes the
...transmission case and all sorts of other details. So, as a rule, we start with a specification where these external opinions are actually very central.
Now you're just launching the AONIC 2—what's included in the specifications for that, for example?
Exactly, that's a good example. We've gathered a lot of feedback from partner flight schools and also from team pilots. Now, I have to put this diplomatically so as not to dwell too much on the weaknesses of the AONIC 1. Although, it might be a grateful example because the AONIC 1 was very well received all around, and there was detailed criticism, for example, regarding the takeoff and landing behavior. So, there were pilots who felt that the glider could glide away more beautifully or more easily with more tolerance toward timing errors.
That was listed there as feedback, for example. That actually is...
We never identified that internally during the AONIC 1 development, but we did hear it from external sources every now and then. And if you hear it more than just once, but a bit more often, then it naturally makes its way into the specifications. And alongside this external feedback, there are also target weights and, ultimately, target production prices, and all those details that you probably have in a mountain bike development as well.
If you look at the AONIC 2 now, you see, okay, it has a few more cells, I think slightly more stretch, it has mini-rips in the back and stuff like that. Are those things where you'd say, okay, for flairing, so that it flairs better, I just need to put mini-rips in the back, then it will probably work a bit better?
So the flair behavior is influenced more by the braking geometry. The mini-rips help a bit with the performance and the handling. So maybe it's related indirectly, but I wouldn't say that if you sew mini-rips into the glider, it will then flair better.
The main reason for the mini-rips was the performance advantage they provide. And on top of that, the slight handling advantage they offer.
Why more cells? So, do decisions like that sometimes have a marketing background? Like, you say, okay, I need to show this to the outside world, it has to look even more like progress. The one before had 49 cells and now I'm building one with 51, and then you can say it now has more cells.
It's actually the other way around, I'd say. So these two cells together, in addition to the Aronic 2, that's—I'd say from a technical point of view, it's a relatively small change, but then you pick it up in marketing because it would be stupid to build in more complexity and hide it from the customer. Usually, it happens that we do it out of technical necessity, like with the Mini-Rips for example. And in the end, we look at what can be communicated sensibly, what is easy to understand.
Of course, too. What sounds good in marketing out of all these things that have been changed. Some new voltage transition or something—there can be an incredible amount of brainpower and a huge benefit behind it. But it's very difficult to communicate that in a way that doesn't sound completely hackneyed. At least from my point of view, because everyone says it anyway, and it somehow says everything and nothing, and you can't explain it in the necessary depth, so you just pull out the things that can be quickly traced on the glider or in the technical data, and in this case, that was the Mini-Rips and these additional cells as extra effort.
Does it ever happen that you say, okay, I have this marketing requirement, I have to offer something to the outside world so that it looks better, where you actually say, okay, I'm going to build this in as a designer, basically for the marketing?
Let me think for a second if I can come up with an example and then if I want to mention it.
There might be weight limits, for example—I wouldn't say, as he might have told marketing, that we need 80 cells and that's the minimum, or that we need a certain amount of extension. With weight, there might be cases where you say we want to be under three kilos and we're only missing 80 grams that we want to get rid of, and basically you could say those 80 grams are irrelevant from a technical point of view, but it sounds particularly good in marketing.
So, maybe in that direction, if that's what you meant. Otherwise, I think as a company, we feel more obligated to the technology than to the marketing.
To take the example of the AONIC again. With the AONIC, you had a normal glider and a light glider. And now I've seen that you're basically building the AONIC 2 as a light one, or what's considered semi-light and light today, where you say you have a fabric mix of decent fabric—decent in quotation marks—a heavier fabric at the leading edge and then the rest is a 27g fabric in the back and stuff like that. But then we only have this one glider. So is that actually the trend, that people say you don't need normal and light anymore, but all new gliders are actually becoming more light?
I definitely see that trend. And that would be another example of a sales move—maybe in this case less of a marketing-driven decision than a sales-driven one—resulting from our gathering of external feedback that the demand peak is simply very concentrated around this semi-light, and therefore almost completely light, glider. And I still see that trend persisting. So, a trend toward lighter equipment, in any case.
When you go out to fly for yourself, how much can you put the designer aside? I mean, can you just enjoy a flight, or are you the designer on every single flight, always looking at the glider and thinking, "What else could be done there?" Or, "Ah, the fabric is wrinkling a bit, one could have..." or something like that? Or can you really sometimes just go out and enjoy it?
I definitely can. So when I do my, what, hundredth flight with my current Vantam, there are many flights where I don't look up at the canopy a single time and don't even have any technical thoughts about the canopy above me, but just enjoy the flying. But then there are also the flights, the private flights, where I look up and think, either damn, or cool, that could be done better, that's really well done.
Have you ever had a real eureka moment while flying, where a solution to some problem suddenly occurred to you?
Most of these ideas come to me, especially during the hike and flies, but more during the hiking than the flying. Probably because that's just the more monotonous, mentally less challenging activity. It happens quite often that my thoughts revolve around the flying or the design, and I actually often get ideas that I either note down on my smartphone immediately or the,
without writing them down, they just stay in my memory. While flying itself, it happens too, but I have less of that where thoughts can just circle around a problem in peace until some solution emerges. What does flying give you?
A lot, to put it very vaguely—just this fulfillment of my childhood dream, which for some reason was always there.
And more specifically, with high-cant flying, it's simply the possibilities that a few square meters of nylon fabric provide. As I said, I love mountain sports, and this high-cant flying option has somehow turned the mountains from a comparatively arduous obstacle into a beautiful playground that I can explore in three dimensions.
Generally, I'd say I'm just fascinated by the simplicity of those few square meters of nylon that fit in a backpack and that, when deployed, offer so many incredible possibilities for thermals, for flights, or for some alpine adventures. And somehow, this fascination with flying itself. Maybe many children have that. I think many kids have this dream of sometimes flying. The dream of being able to fly without a craft. So, Doctor, did you ever have something like that? I had that a lot.
Yeah, I used to always... I lived in big cities, back then it was first Mexico City and then later Buenos Aires. So until I was twelve, I grew up abroad. And there were always these big subways. Mhm. And I dreamed of being in those subways, pushing off the pillars and stuff over people's heads, like gliding right over them and swimming through the air like that. That was my real idea of flying that I had as a kid.
My memories of my dreams back then are actually also in an urban setting. I didn't know about subways at the time. For me, it was some kind of... but the flying, flying through some kind of alleys. And yeah, I think part of that childhood fascination or that childhood dream still flies along with me.
Is there still something like a dream flight today that you'd like to make a reality?
No.
The thought just occurred to me—my best trip, which was also my best flight, was to Socotra almost 15 years ago. There's a film from the year after that. It's also on YouTube, right? Exactly, exactly. I'll put a link in the
the show notes, so people can check out the trip to Socotra.
That was the following year. The trip I'm referring to now was with a colleague the year before, when we had no information at all on whether paragliding was even possible there—I think we were the first ones to fly there. We explored this island by paraglider and it somehow exceeded all expectations and dreams. I think that's one of them, Theo, the look on his face was also there, and he's the one who knows the whole aviation world. Those are the coolest dunes that exist. And we had those back then, and I believe there was no one there in front of us, because it's quite difficult to get there and these
to explore the island and these dunes and this landscape by paraglider, yeah, that was a striking flying experience for me somehow. And how
did you actually ever come up with the idea of, like, an island that nobody knows about, we're flying to Yemen and then we're going to head out to the island, and you have to somehow... I mean, how do you come up with an idea like that? That was funny. I was there
at my colleague's house, he had a Geo magazine on the table with a portrait of this island, Socotra. So, Geo magazine. Geo magazine, exactly. Geo magazine, and this island is known for all kinds of endemic plants that don't exist anywhere else. And on some of the plants, on some of the pictures, these dunes were also shown, and we had never heard of this island before and thought, because we were both enthusiastic paragliders, that would be cool and who knows, maybe you can search these dunes, and then we searched unsuccessfully for information on paragliding, but then we did our own research on Voxabil,
back then without Windyty and all that, what the wind systems and this monsoon from the north and south look like, and then we realized that right now should actually be the best time for paragliding there. So we decided very quickly, booked a three or four-day trip there, took a few gliders with us, and arrived there to find this paradise of 200-meter-high white sand dunes in front of the cliff. Yeah, that's a special memory of mine, and maybe the island isn't quite the same as it was back then, but that's the first thing I thought of when you ask me about the dream, although that might not be repeatable.
That means you've had your dream
has sort of already realized it. Maybe you should look at it that way, yeah.
Philipp, it's actually a great story, if you can say that I've already had the dream and I can tell my grandchildren about it someday. Thanks also for all the other stories you've already shared here. I think some people have seen completely new insights into the subtleties and details of paraglider construction, where, yeah, how difficult it is to really optimize something down to the last detail, and that there's apparently still enormous potential for optimization in those details, even in the future. Thanks anyway for this story. It was fun, thanks, yeah.
That was Philipp Medicus, the designer of NOVA. I can well imagine that you learned just as much new information, or perhaps less-known details, about the paraglider in this episode as I did. If you want to hear more of these inspiring and perhaps educational stories from the cosmos of paragliding, I would be happy to have your support for my work. On my blog www.Lu-Glidz.blogspot.com, you can find all the necessary information and links under the "Support" section on how you can keep this project alive with a freely chosen financial contribution, large or small.
I want to thank all my supporters. See you soon. Fly high, fly long, fly far. Ciao. Yours, Lucian.