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Ilkay Özkisaoglu

Since 04/2021 169 Episoden

#154 The eVTOL Show Composites Lounge Enduser Panel powered by JEC on Composites Requirements

27.02.2025 47 min Staffel 5 Episode 112

Zusammenfassung & Show Notes

Join our restream of our Composites Lounge Enduser Panel powered by JEC Group on The EVTOL Show in Stuttgart.

This is the recorded and edited panel, which we turned into a special edition of an Composites Lounge Engineering Talk No 4: eVTOL Special Edition.

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The Composites Lounge Enduser Panel powered by JEC is on materials designed for the advanced air mobility (AAM).

We will review the process of selecting, testing and validating modern lightweight materials, like carbon and other composites with material and system suppliers as well as an AI company involved in process optimization.
We will bring you the big picture on "the requirements for fiber-reinforced composites in eVTOLs."

***

Our panel guests are:

Christian Heller, Owner of CH Aerospace
Simon Bendrey, Head of Design at Dufour Aerospace
Víctor Jiménez, BDM of Biesterfeld Group
Nicholas Ecke, Application Engineer at sensXPERT - Optimizing Plastics Manufacturing
Steffen Kress, BDM of Mubea Aviation

***

The Panel is divided into three sections and covers the following questions:

1️⃣. Development

Where do we start from prototype to serial production of eVTOLs?
What are the key benefits of carbon in eVTOL?
What challenges do eVTOL producers face?
AI needs data sets: How do you rate the amount of eVTOL production data?
During development, do eVTOLs evolve more like cars or aircraft?

2️⃣. Material

Which material to choose in which developmental phase?
Why is the interaction between the different materials so crucial?
How to increase passenger comfort while maintaining safety of the eVTOL?
Cutting cycle times: how can AI assist in this?
Besides the classical composites matrices thermoplast and thermosets, what about elastomers?
Are thermoplastic composites the go-to material for eVTOLs?

3️⃣. Process Optimization

How do you reduce downtime as an eVTOL (aerospace) OEM?
How to bring eVTOL start-up cost down in terms of composites' use?
What factors should be considered when adapting automotive process technologies for eVTOL manufacturing?

Your Panel Host: Ilkay Özkisaoglu, Co-Founder Composites Lounge
Your Relationship Manager and Co-Pilot: Yannick Willemin - The Composites Catalyst, Catalysium

Composites Lounge conducts with its format Hashtag#Composites360onTour
in partnership with the JEC Group during JEC World 2025 further interviews on Innovation, Technology & Sustainability

Please visit the JEC World 2025 exhibitors on their stand:

sensXPERT JEC World 2025 Hall 6, Booth Q24
Biesterfeld SE JEC World 2025 Hall 6, Booth K16
Mubea Aviation JEC World 2025 Hall 6, Booth P24
Composites Lounge JEC World 2025, Hall 6 Mezzanine, PRESS CLUB

Moreover, Composites Lounge is covering the entire show and we have a few slots left for your spotlight with a video podcast interview. Contact us!

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Transkript

We have now a composite panel. And therefore I ask to stage the moderator. Ilkay Özkisaoglu from the Composites Lounge. Then we have panelists, Christian Heller from CH Aerospace Steffen Kress from Mubea Aviation Nicholas Ecke from sensXPERT. Victor Jimenez and Simon Bendrey from Dufour aerospace. The topic is the requirements for fiber reinforced composites in eVTOLs. -So thanks for the introduction, ladies and gentlemen. So we are coming slowly to the close of the the day. But let me ask you one thing. Is the materials industry prepared to enable EV tools to fly? Is the materials industry prepared to enable EV tools to fly? Have you considered that already? I mean you are considering wind infrastructure hydrogen all the days, but let's now dive into the materials and in my conclusion I will tell you yes, they are so with me. With me we have Christian Heller. He's an expert in the aerospace industry and has his own company. Then we got Simon Bendrey. He's the head of design of Dufour Aerospace, then Victor Jimenez from Biesterfeld, German group of company, but he's obviously from Spain. Then we got Nicholas Ecke and Nicolas will bring in the AI part into the into the materials, into the science part, the data part. And finally we got Steffen Kress. He is at Mubea Aviation in the business development. But who are we? Composites Lounge? We are a group. A digital network on LinkedIn, purely on LinkedIn. So please go over there and follow us. Give us a like. And this panel will be also restreamed in February so that your colleagues can enjoy also our discussion. We do this together with the JEC Group. JEC is a media hub and well, the leader in composites when it comes to promoting composites as a non-profit organization. In two weeks time, they will have this festival, the JEC World 2025 in Paris, which we will invite you. And finally, today we will talk about the requirements on materials for the eVTOL flying. And I really enjoyed all your input there. And now we would like to go into the details of materials. As I said, please check out Christian, Simon, Victor Nicholas and Steffen on LinkedIn. We will dive directly into the matter, because time is scarce. Let's start with Christian. Christian, so where do we start from a prototype to serial production? We've seen a lot of different kinds of models are flying around. But let's walk through this developmental part. -We all know how a conventional airliner looks like and how a helicopter looks like. When you start building an eVTOL. You have no role models. You start from a blank sheet, you have no role models, and you have no regulations, or you had no regulations in the past, which means you won't start with a prototype. You will start with the technology demonstrator. And what is important about the technology demonstrator? You need to get material. It doesn't need to be certified. It doesn't need to be the lightest one. You just need something quick. You need lots of changes coming. So available material and the important thing is: it flies. -Absolutely. It must function. Right. Next step is then going to a prototype. A prototype means you're already looking at certification. Certainly in eVTOL business, a prototype is not a one prototype. It's a constant change. You will have lots of amendments, which means also that material wise you won't go into tooling. So not looking at low weight, not looking at low cost at the very beginning, but during the development phase of the prototypes heading nearer to a pre-serial aircraft one day you need to decide when do I go to this? But in this first phase, larger suppliers may not be the right partners, because they're not that quick. They have their processes, which is very logical. They are suppliers to the aerospace industry, to Airbus and the likes. You need small agile companies to go quick, and then you need to find the right point where to switch to something, which later on might be certified. Okay, wonderful. So let's dive into composites are often known as what, from which fibre? Guess: carbon. Have you heard about carbon fiber? Carbon fibers. So my question to Simon is why carbon fibers are the great facilitator or enabler for eVTOLs. Okay. So carbon fiber as a material has several important properties. One is its very high strength and high stiffness and impressive fatigue performance. And those are all the positives. But you have to temper that with that there are weaknesses in through fiber strength and in inter shear interlaminar shear. So it is a very good material. But I think Christian touched upon a good point just now that you with any eVTOL, you get to start a design from scratch, which means you can design it for composite and how to use carbon best. So one of the benefits with the with carbon with eVTOLs over aluminium, as I said, is the material properties. Another one is the manufacturing process. So aluminium tends to be made in lots of smaller parts and joined together. Bolted joints and white carbon structures can be made into quite large structures and use with bonded joints which are much lighter. So the fact that you can make things more intricate with carbon can give benefits for the aircraft itself, such as pilot visibility or the ability to make complex shapes within single components, which you can't do necessarily with aluminium bonded joints is preferable as well. Historically, on I worked on aircraft, where we've had sort of a black metal approach where we try to change something that was aluminium to make it into carbon, but by integrating it with the rest of the aircraft and on both joints, you have an interaction between bearing a bypass. And that actually degrades the the carbon strength, so you don't get as much out of it. Whereas if you use a bonded joint, you don't get that. So if you're able to use carbon in the way it's intended and design your aircraft from scratch, you can get very good results. We have patented manufacturing processes for the use of carbon. So we started very much with an idea to make a whole carbon aircraft. And we've designed the aircraft and the manufacturing processes and all the analysis processes to support the design. (Advertising) The hard work of composites teams should be shouted from the rooftops. We're on a mission to give your solutions better visibility and reach, to make them more widely known in the market and gain the appreciation they deserve. To make lightweight construction and specialized technologies available to end users, as well as attract projects, customers, and talent. Join our Composites Lounge community. The Composites Lounge community is open to entrepreneurs, C-levels, specialists, and managers who want to create a better world with their innovative composites and play a key role in the success of their company. So if you're a hidden champion who isn't sure how to best promote your work, join a supportive and innovative community, which is focused on making composites achievements visible to end users. The Composites Lounge community celebrates and promotes the best innovations, lightweight construction technologies and sustainable solutions in the automotive, aviation, renewable energy, oil and gas industries and many more. Get involved at Composites lounge.com (End of Advertising) So Simon, this means there's a lot of knowledge available within your company. Now, let me talk to Victor. Victor Jimenez from Spain. Victor, let's do not kid ourselves, but knowledge about materials. You know, you need the experts in your company. What are the difficulties and the challenges there? Well, there are a lot of challenges right now. We have seen a lot of technical challenges this morning here from the different presentations and their associated services that are on the table. We haven't solved them yet, and I will put in a word for this knowledge. So because we are doing something that is completely new, has it been done before? There is no knowledge in the market. The people who knows how to do the job. So we are seeing a trend for the company to learn what is knowledge internally. But this takes a lot of time. This takes money. And for the startups, money and time. This is killer. So what we are receiving as Biesterfeld, as different materials distributor, raw material distributor is let's say the request from the companies to be part of the design, to check to fill those gaps in the knowledge, specifically in the raw material aspect and I think we have, we can tell a lot of successful stories about this, and we have obviously a very technical expertise in the company. We have probably more than 100 years experience. And in designing for Airbus for the vehicle will be different contractors and composites with software experience. So we can really help those companies to develop from the beginning, from the design phase, to give them the knowledge about the material, how it performs and the up to the shop floor, how to laminate and how to put the material, the carbon fiber. I think the learning from this for the eVTOL companies is just about having just suppliers for the raw material type to bring it on the table. Partners were able to provide this technical expertise. They have been willing to go and work with you, with your challenges to the material, because this is quite a big cost saving. So fortunately skill development you say takes time and takes a lot of human resources, but fortunately now we have AI (Artificial Intelligence). So, Nicholas, AI does need a lot of data, but can we then work with that data in eVTOLs? Now, the development cycles are there. The people aren't here. How can AI help us? -I mean, this is a very common concern, right? As soon as people learn that whatever solution you offer includes machine learning, AI methods. One of the first question is how much data? How many data sets do you need to to, you know, get a good start? People have this submission area that you need thousands, tens of thousands of data sets. And for some applications, that's true. For us at sensXPERT that sounds like what what we bring to the table is domain knowledge, right? So we don't just take some data and apply a method to it blindly. But there's the domain knowledge. We know what the material is doing. We know how certain factors affect composite materials affect polymer and we can bring that to the table, so that really shortens down the time. So we have a first working model. Another thing that we bring to the table is our own measurement technology. So we look into what material does on molecular level inside during manufacturing, inside of the mold. All of that combined allows us to work with as few as, let's say, 50 production cycles. Once we've seen those, we are typically able to at least have the first working model. This might not be the end of the discussion. So as we see more data over time, we might still tweak and grow better, but 50 production cycles in some cases even 20 is, enough to at least make a make a first step. Steffen, you come from a company that produces not only for the automotive but also for the Aerospace industry. So now you hear 50 data sets, which in the automotive industry is nothing to be honest. But in an eVTOL context it may be changing the world. So how do we approach eVTOL? More like a car industry or more like an aerospace specialized, may be like Sonder Maschinenbau? I mean, in the end we're looking into the development work on how you approach it. But you have to factor it is obviously the volume, first of all, that you're looking into and also the certification that Christian, also was referring to. So what we're seeing is of course the strong trend and towards the aviation industry, for that, and also because of the production volume that you're looking into, because even with those 50 or whatever. Yes, we do work for Bugatti. That's the annual production volume. But when we're looking into the automotive business that we are considering, this is already way above any of the production levels that we also see in the foreseeable future on the eVTOL side. And therefore, yes, we are looking into processes and also material certification wise, this is closer towards aviation industry. Whatsoever goods that we have with the interaction, you see the customers being more in the discussion together with you. As you know, with from the automotive industry. So you can really work together on design for manufacturing. So this is where you bring in some of the automotive approach here. -By the way, we have three rounds here. So that was the first round that was around the developmental cycle. So we've discussed more from the developmental aspect. And now we are diving deeper into the materials. And what I want to know from Christian is, Christian, on which material do we rely in which developmental phase? Can you walk us through those developmental phases from a materials point of view? -As previously said as an answer to the first question. It's at the very beginning and you do not care about it as long as it takes it in the air. At the end for eVTOL, all those OMC and all that weight is crucial, but also cost. So not the same thing. And then of course certifyability, which means you may go to additive manufacturing which gives you low weight, rather expensive for metal. For plastic it's not structurally. Carbon fiber you need molds. It takes time to build molds and then to change them is expensive again. Same for glass fiber. You can think about thermoplastic. So it's very much depending on the aircraft, on the application, on the load on those parts. And you cannot give a general answer which is the right thing for which aircraft. It also depends very much on the quantities referred Ian this morning thousands of aircraft. Thinking about other 50 the Bugatti number. And where do we go? We do not know yet. -So when we don't know where to go yet. Simon, let's dive into this material. Still with the material part. You've mentioned that the materials interplay is also very crucial. We have maybe on the one side, metal. On the other side, we have carbon. But how do they interlink? How do these connections work? And do we have in an eVTOL special challenges here? -I think we do. As I said earlier, a lot of the companies took a black metal approach originally. And certainly as the day passed, we say it's a growing skill and make it a carbon instead of aluminium. But then we bolted it to a low availability of structure, and we had a number of problems at those joints. I mentioned being bypassed quickly. But you've also got thermal strain interaction, carbon strains that are very different to aluminium. It's much stronger. So what happens if you have a large strip of aluminum bolted to a large piece of carbon? You see aluminum just breaks up into lots of small strips. Relatively quickly. You've also got galvanic issues. Effectively you could create your own little battery with a bracket bolted through steel to a carbon structure. So you have to be very careful to add zinc or glass protective coating to protect structures. So there's a lot of processes you need to follow and you need to be aware of. The carbon is also conductive when you don't want it to be. And it's not conductive when you do want it to be. So with an electric aircraft, the risk of shorts through the structure if the electrical systems are not properly grounded is also something. So these are unique features of the eVTOL aircraft. But as I said earlier, you're starting from a blank piece of paper. So if you are able to design your structure to be modestly linked and something that we've turned to for research to look at, as Christian said, you start, first of all, something that works. So I started with laminated carbon structures using aluminium brackets, which we bolted or bonded to those structures. What we've gradually gone through is a process of then developing 3D printed and forged carbon brackets to replace the aluminium brackets. That means that they integrate completely with the carbon structure, and then you remove the bolts issues around bolt joints, issues around thermal and incompatibility and galvanic correction and stuff like that. So it can be done. You do have to know what you're doing and design the aircraft for that standard and in a way that you can be certified. -Excellent. So we've talked about the material features like Lightweighting non corrosive. And one of the presentations this afternoon were about the comfort. Is this gentleman still here about the comfort? Who does consider passenger comfort with that feature. And this is something that I would like to discuss with with Victor, because we have a proposal for you, because we are thinking of comfort. And what do you have how to reduce, for example, noise with the materials construction? That's true. We have been looking at the noise of the aircraft outwards. So what is the noise that the aircraft creates? This morning we will have the project from vertical, which was very interesting. Although what happened to me, the noise inside the cabin. If you think of a helicopter, for example, the noise is quite low. So you need to wear special protection. And the it will not be the same because you have a turbine to replace the choking by a motor. I think there are a lot of other noises that you will hear inside the cabin. For example, the vibrations from the propellers, if we properly quickly through the carbon fiber because it's very stiff and you will it will create noise in the cabin. So how to tackle this? It is something that we have been trying to investigate with our suppliers of material at Biesterfeld and they are working on multi-functional materials that can not only do, let's say, a structural part, but also noise damping by damping. And they have a very, I think, very promising material that is from Kraiburg company. It's an elastic adhesive. And you can the nice thing about it is that you can put it in the inside the laminate so you can put carbon, carbon, carbon, the adhesive and then again carbon. And you do get a very interesting advantage in terms of noise propagation, vibrations propagation and structure. It has some other applications like I think for the eVTOLs this could be a key point. It's already used to not working in Aerospace. So yeah, I think it has to be taken into account from the first stage of the design, because you have to be saying, you know, to break the propagation of the noise in the structure. But it's very interesting. -Just to avoid a misunderstanding, because carbon and Kraibon sound very similar to different products as we know. And let me come to Nicholas. Now Nicholas, our materials in composites, they are either thermoplastic or duromers thermoset materials classically of course they are then elastomers and ceramics. But let's focus on thermoplast and thermoset. So one of the concerns in the industry is always that cycle times in composites are way too long or considered with a press, body in white parts, body in black parts are often very long cycle types. So how can AI help us to reduce these cycle times? -So of course, I'm mainly going to explain our approach here. And that is looking at what the material is doing on molecular level. So we are really determining a degree of cure, for example, or TGA in situ. That's the part is curing. Then see, if we can dynamically control, because we have deviations in the material, especially in thermosets. You're going to see deviations from batch to batch often even from cycle to cycle. And so that gives you the potential to optimize. In a highly regulated environment, of course, that's always a fairly predictable thing to do, right? Once you have a certified process, you're going to want to meet that at all. So key there for my perspective is to come in as early as possible, because this approach is also applicable of course, during development. And so that's the time where you can still make adjustments with, you know, reasonable effort. Another thing that I like to point out is that you can of course, also there's room for improvement beyond cycle times. Even just in monitoring alone, being able to not only say, okay, this the temperature at this point was within a certain envelope, but really saying the molecular state of the material is according to the requirements. That's a very strong statement. And that's something that goes beyond traditional process management. -So in materials we assume always to increase productivity to reduce scrap. And this is what we are actually doing. And now Steffen, thermoset or thermoplastic what's the way to go? -So it depends on what you're looking for. Then in the end I mean thermoplastic I mean there's an ample discussion around it for I mean, you mentioned the process time where on the one side, it could look promising. Recycling, are a lot of companies are looking into that one as well. Specifically when we are talking about the application and for eVTOLs and Christian was relating to as well. We have to look into the development cycle in where we are the tooling costs around it design changes and, well, the capital available. Therefore what we have seen everywhere that to start off with we always talk about thermoset solutions initially. Then also considering the tool cost design changes which they are might still occur or which often not occur. Then when talking about then that higher scale production, is it thermoplastic. Is that the answer? A lot of the cycle time we're looking into is also when it comes to the preforming of the carbon fiber, which is actually eating up a lot of the time as well. So it's more of the away from the black metal design and to a real composite design, which is often enough then more helpful than just thinking plainly about the material system itself. In the end, to say yes, every material will have its unique application for the specific volume for the cost and for the weight benefits that its offering. We do see a number of different propulsion systems and obviously every kilogram has a different price with each of the system and profiles that the aircraft is being used for. And based on that, then the decision will be taken. (Advertising) So we did now a short break here. Let me then move on to process optimization. As I said, materials always assumes reduced cost, reduced scrap or increased output. Now let's go into how-to increase the output. And one of the ways to increase output and also the flying time and everything is to get also the downtime of an eVTOL down. Now let's imagine your eVTOL is 24/7 on the fly. But now it needs maintenance. It needs repair, right. So how to reduce downtime similarly? -So yeah, traditionally MRO, that's maintenance, repair and overhaul has been the biggest cost to an operator, followed by fuel. And so with the eVTOL we now have electric powered aircraft with very few moving parts. So the system should require a lot less maintenance than a traditional, certainly a helicopter with K boxes and drive shafts. So we need to look at the structure and make sure that we are designing and building a structure that has a similar level of reduced downtime. And this is where composite and carbon specifically comes into it. So as I mentioned earlier, the fatigue properties of carbon are significantly better than aluminium. An example of this: the A350 that Airbus recently released to has a design life that's 4 to 5 times higher than the original A330 that it effectively replaces. And that was achieved through the use of carbon. The way having millions of fibres within the structure means that you have lots of miniature level paths within the structure, not one big piece of metal cracks don't propagate through it in the same way. Therefore you're able to significantly increase the time between your inspections. So you don't need to ground the aircraft and look for cracks. You don't need to catch a crack before it's gone critical, and therefore your scheduled maintenance time are lower. eVTOLs were also looking, because their new aircraft as ways of health monitoring. And again, those aspects can be taken into traditionally with aircraft you ground them for inspections. You might not find anything. You've grounded the aircraft in flying. You're not setting a seat, but then you find cracks. So then you have to repair and you have to replace items. So two things I firstly, carbon doesn't crack in the same way, which means we're not really looking for cracks. If we help gauge up the aircraft and are doing health monitoring, we can then do preventative maintenance. And if you're designing your aircraft to be modular, as we tend to do for, we can then look to replace the cell units or tower units or a wing and therefore that's modually available. You can swap that out very quickly onto the aircraft, and you get the aircraft back in the air as quickly as possible. You can then do your lower level inspections on the structures back at base and refurb things and get them back in. So both in the design of the aircraft and the use of carbon, you can significantly improve and reduce downtime. -So reducing downtime during the operation is a nice thing to have and must have for everyone. But until those materials that we heard at several times today are certified, a lot of cost, energy and time evolves. Victor, how can a startup reduce the certification of these materials? Does every startup has to do their own certification of their materials, or are there ways to reduce those? There is a cost associated with the certification materials. In general, in our case, there is nothing cheap. Everything is expensive. But as far as you are flying and you are flying with passengers, you have to certify and everything that must be put into the aircraft has to be certified as well. So you have to go through a qualification of the materials. In terms of composites typically for an aircraft structural materials you would need to certify four, six materials, imagine. So you will need to spend easily a couple of millions, 3 millions and spend probably one year or even more until this qualification is completed. So it's very expensive. And for a startup it's again time and money. So it's a killer. I'm glad to tell you a story that repeats very, very frequently when we go to customers and we go through the material selection, because customers typically want the best material, super adapted to their application. And before we start the meeting, we just tell them something that surprises them. So just to put a bit of background, you kind of take a qualification of what's here that has been done by anyone else, because obviously it's expensive. So the specification and the design, of course, they are their property. So the customers will come to the meeting afraid of what is coming, the cost and so on. And we say, you guys, I don't know if you know, but there is a database publicly be available with specifications and design along models of a wide range of materials or composite materials that you can access. You can run it, if you buy the material and you can use it for your aircraft, because those data, they are trusted. They are backed by FAA and EASA so you can use it in your aircraft. They laugh and think it is too good to be true. It's not. It's actually it is. With the state University Wichita in US they have made kind of a wide range of material qualifications. They call it the NCAMP. It's a national composite material for high performance. And then you have about 20 to 25 materials. And the biggest contributor of this is a SYENSQO, former Cytec, the biggest manufacturer of composite materials and you can find epoxy formulations, thermoplastic and any type of fiber from standard use high containment modules and fabric glass, district glass even. So, I think it's a very good start for startups. And you save a lot of money. You don't save 2 to 3 million after you spend maybe 10%. -A significant amount. Let me come back to Christian one more time. On the material side, we were talking about thermoplastic thermoset, but I understand also elastomeric matrices. Elastomers are also an important contributor in eVTOLSs. Where are elastomers used and are they already certified like we process? Elastomers and mainly high performance elastomers are used in conventional aircraft for the combustion engines or the wings, movable surfaces, and for the interior. Combustion engines at least if it's not a hybrid aircraft, no. Moving surfaces, less, there is no speed. Remains the material for cabin, which is mainly comfort, prevent the passenger from air current and giving more comfort. And again we have here weight versus payload. And every kilo I put into comfort will go away from my payload. And payload is a big issue. So I think to my mind there's a few applications for this one. And as long as the battery ranges are not high, you will go to a very poor interior. And as we heard this morning from Manta aircraft, integrating a climate control in the aircraft is not typical today. Going to Dubai and you may not have a conditioning air conditioning. So I think this is something which comes at the mid-term. But for the moment being there's not a big market. Nicholas, now the colleagues say, okay, we have downtime reduction during the operation. That is what Simon says. Victor brought us a few features how we can select some categorized materials, which have already some basic certifications. Now, let me ask you, because you have a deep understanding of process technologies. Do eVTOL producers or anyone who is in the plastics or composites industry, do they need to change their processes just to have a new certification on their process? Or is there a way around now with AI? Of course, if you I mean, there are established, established routes that you can go. This is what you just just mentioned. If you have a material that is pre-qualified, you follow the prescribed processing. Then you are on the safe side. I think the discussion becomes a little bit more crunchy once talking about optimization. I want to be as efficient as possible. And then, of course, you're not gonna make any improvement without changing anything. That's kind of where I guess a mindset issue also comes in. You cannot just stay. This relates to what I mentioned earlier, stay within the fixed certified process and expect anything to change. For good or for worse. If you want to discover any hidden potential and optimize, obviously you're going to have to adjust. Ideally you do it early on. And that's the nice thing the eVTOL business. Many projects are still in a development phase where you can make adjustments before everything it is tried, tested and fixed for definitely. Ultimately I'm hoping for an approach where you also say at the end. As long as my temperature is consistent, I'm fine, I'm overexaggerating, but that kind of the approach. I'm fixing process parameters and then I'm trusting that the parts are going to be consistent. But there are intrinsic fluctuations and inconsistencies that you don't catch. And the mindset, in my opinion, should be I don't want the process to be consistent. I want the part to be consistent. And if the material has deviations, then my process needs to be adjusted dynamically. That really gives you the optimal outcome. Really reproducibility of the component, the part and not the process. Yes. And that means that documentation can help you. Right? So you produce documentation that ensures the certifier that the process is intact. So we are coming slowly to the end. Glad that we stay within our time limits, which is really unusual for my panels. Thank you for your discipline, gentlemen. Steffen, what factors should be considered when adopting automotive processes, technologies for eVTOL manufacturing? Now, we are not talking Bugatti. Now we are talking Volkswagen Golf, right? -Hopefully we reach that volume. But this is absolutely the third question or the one of the inputs to be considered. What volume are we actually talking about for what component. We do see that the automotive composite business that it's highly depending on the volume that we're doing into what level of automation, Into what level of invest you actually therefore going into. Therefore then together with the certifying authorities to say, okay, what is actually possible into what can you do? This is really one of the greater triggers together with the what mentioned before, what is the kind of euro per kilogram that you are willing to spend here, when you are following that route. -In conclusion, now, my conclusion is I've presented you a panel today on materials. And we as a material industry, we are ready for eVTOLs. So you're looking for skilled labor. We've discussed that. We are looking for downtime this reduction. We've talked about that. So these are all no issues. We have AI in the system and from the raw material to component manufacturing, all the developmental cycle, we've covered it, and we've seen that even the automotive numbers could be reached, if we are really successful. And there was a reason why I asked this Lufthansa Consulting gentleman, whether the eVTOL flying to the airport will be a first class experience or tourist class experience. I personally hope, because of the numbers, it will be available and affordable for everyone. This is how the eVTOL industry started promoting and giving us their marketing promise. And by that I'm concluding the materials science is ready. Materials are all available. We have proofed this today to you. And now, if you have any questions to our expert panel, please ask your questions. We have, I think, one more minute. Anyone on carbon? You are on carbon? I'm coming to you with the microphone. What is the state of the art in repair solution? So if you get a crack and you hear it and you cannot really detect it, how do you handle that? I think it was a big issue in the automotive and what's about in this topic here? I think Simon is the best to answer that. -It's actually relatively easy to repair. It's a very good process. So I started this 20 years ago with Airbus looking at how to repair composites, because the way that you create a laminate is a step by step process. You can effectively just reverse that to remove the damaged area and then repair it and bring it back up to spec. But as I said, you don't want to be doing that on the aircraft. You want to have a modular approach where you can take a damage part off, replace it with a brand new one, and then repair and refurb something and then make it back available for spares. I think again, if you can design your eVTOL to support that, then you can then offer the operator what they need, which is minimum downtime repairability. It may not be commercially viable to repair. That's something that the the industry can look at, but certainly the technical ability to do the repair is already there. -Any more questions? Okay. If not, then just a final reminder. Our expert panel, beginning with Nicholas, sensXPERT, you will see them at JEC World 2025 next week. Please come and see them. We got Biesterfeld at JEC World 2025, and we got Mubea at JEC World 2025, and I'm at JEC World 2025, too, so we could then deepen our discussions. And by that, I'm thanking also the eVTOL show organizers for this fantastic show. When I was approached by Andrew. Where's Andrew? -Outside. Outside. Okay, Andrew, thank you so much. Then you will listen to it later when they approached me. Can we have you know, discussion on these composite materials? I said immediately, yes. You know why? Because eVTOLs are through and through with composites. And if we don't influence this as a composites lobby, who will do that? So it's in our vast interest to get composites and eVTOLs up and running. And I'm very bullish after what I've heard today. I think we have still a few things to regulate and to certify, but I think it will be a great and successful industry in the future. Thank you so much. Thank you very much, Gentlemen.