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Ilkay Özkisaoglu

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#239 Inside Austro Engine: Jürgen Schwarz on Aviation Engines, SAF & the Future of Flight

10.07.2026 34 min Staffel 5 Episode 197

Zusammenfassung & Show Notes

What does it take to build and certify modern aircraft engines in Europe?

How efficient are today's diesel aviation engines? And what role will Sustainable Aviation Fuel (SAF) and hydrogen play in the future of flight?

In this exclusive #Composites360onTour and JET-Circle interview, Ilkay Özkisaoglu (Composites Lounge) and Norbert Werle (JET-Circle) visit Austro Engine in Wiener Neustadt, Austria, and speak with Managing Director Jürgen Schwarz about aviation propulsion, production, certification, sustainability, and future technologies.

During the interview, Jürgen Schwarz provides insights into:

✈️ Austro Engine's role within the Diamond Aircraft Group
✈️ The company's inline four-cylinder Jet A-1 diesel engines and rotary engine technology
✈️ Why Austro Engine relies on a European supply chain with suppliers in Austria, Germany and Italy
✈️ Aviation certification processes and cooperation with EASA and Austrian authorities
✈️ Modern diesel aircraft engines versus traditional AVGAS-powered engines
✈️ Production capacity, engineering expertise and engine testing procedures
✈️ The recently addressed piston replacement program and continuous airworthiness practices
✈️ Sustainable Aviation Fuel (SAF) adoption and current certification limits
✈️ Hydrogen-powered aviation research projects with leading universities
✈️ Why piston engines are expected to remain relevant for decades to come
✈️ The manufacturing process behind approximately 900 aircraft engines per year at Austro Engine

The conversation also includes an exclusive factory tour showing how Austro Engine assembles, tests and certifies its engines before shipment to customers worldwide, including Diamond Aircraft facilities in Austria, Canada and China.

Featured Guests
• Jürgen Schwarz, Managing Director, Austro Engine
• Norbert Werle, Founder, JET-Circle
• Ilkay Özkisaoglu, Co-Founder, Composites Lounge

About Austro Engine: Austro Engine develops and manufactures certified aircraft engines for general aviation applications and is a key technology partner within the Diamond Aircraft ecosystem.

🔔 Subscribe for more aviation, composites, advanced manufacturing and sustainability interviews from industry leaders across Europe.

Interview conducted by: Ilkay Özkisaoglu (Composites Lounge) and Norbert Werle (JET-Circle)

Original interview recorded during the Composites Lounge and JET-Circle visit to Austro Engine in Wiener Neustadt, Austria.

YouTube Episode: https://www.youtube.com/watch?v=Ro5IruEQJYI

Transkript

Wonderful, good afternoon, dear LinkedIn Community and Composites Lounge members. This is now day two with Diamond Aircraft. And now we have completed our Diamond Aircraft Composites production. And we did our test flight with the Chief pilot. And now we are back on the ground with Austro Engines. And this is basically the supplier of the nice engines to Diamond Aircraft. And together with me, I have the honor to see the managing director, Jürgen Schwarz. Jürgen, thank you for being part of our show. Welcome to our nice facility. -This is the first time I'm actually talking to a engine manufacturer who is supplying the aircraft industry. How long do you do that? If I may start with a personal question, -I personally, I'm in the business since around about 15 years. I started my aviation career with Continental Aerospace Technologies, a short time at Red Aircraft Engines doing a big V-12. And since 1st of January 25, I'm here. Wow. That's a brilliant aviation history. And I may ask you, do you have a passion for flying? I have passion for flying. I don't have a pilot license myself, but I have the opportunity to fly also the Diamond aircrafts whenever I'm interested in. You have also a nice scenery here. So let's dive into the company, Austro Engines. Tell me about your company and the product portfolio. And yeah, the strategy would be very much interesting. -Austro Engine is located here in Wiener Neustadt (Austria). Very next or very close to our friends of Diamond. Our mother company. We have round about 130 employees. The main departments obviously is the engine development. So the so-called DOA, design organization and as well the production organization. And then obviously, surrounded by supporting functions like HR, finance. So, so we have everything we need. What we are not doing. We are not machining any parts. So we are not manufacturing engine components. We only assemble the engine here in our facility. This sounds only like this is a simple task, a simple job, but of course it's not. So you have a supply chain a complete value chain set up. Tell us about how you manage this value chain. And where is this value chain for. Supply chain obviously is the challenging part. Yes. So our supply chain is mainly located here in Europe. All core components are produced let's say in Germany, Italy and Austria. So we are very focused that we, we we purchase as low as possible. For us it does not make a lot of sense to to purchase anything overseas. It's just too complex for our small volumes. So that's why we try to get everything in a distance, let's say 1000km, 500km. This is perfect environment for us. -And also this makes it flexible to, you know, respond to anything that may be going out of control, supply chain issues and things like that. Having the local sourcing makes total sense. So tell me about, for example, the aerospace industry of course is the major certification industry. Everything has to be certified. So do you get grey hairs when certification people come to you and audit you? Not really. -Oh, really? No no no no. We have quite a very good working relationship with our authorities. Let's say EASA is the major authority and ACG the Austrian authority, mainly for production. So this is kind of like day to day business. We keep a very close relationship. Typically we can do a lot simply by phone calls, keeping the authorities in the loop from day one, we are planning to do any changes or if we have any problems. And this is typically the key keeping a good relationship to the authorities. Let's say if it comes to a full new development of an engine, the process is so described. So how to certify an engine. Also, this normally is not creating any grey hairs for us. It's obviously it's a lot of work to do, a lot of documentation, a lot of preparation, but the process is very well known. It's completely different if we would enter new areas of certification, for example, certifying an H2 engine, because there is no rulemaking yet done for such an engine, and this is obviously much more challenging because then you have to discuss rulemaking with the authorities. And rulemaking obviously needs to fit everyone in the industry, not only us. And then it becomes really complex and time consuming. -My colleague Norbert will dive with you into hydrogen a little longer or a little later also. So now you've been let me grab the chance. So you are quite a few years in this aviation industry. So if you compare aviation 15 years ago or maybe even prior to that, what has changed recently? Yeah, this is in my terms, let's say not. It's not really a problem of aviation, but the innovations is fairly slow. If you really look, uh, kind of like, as I grew up, aviation at continental, we had both gasoline engine as well, the jet powered engines. And if you look at the gasoline engines, I would say there was no innovation in the last 40 years. Okay. Mainly, yeah. You barely see engines with a full engine controller. Still, you see very simple injection or even a carbureted engine. I think the biggest innovation, not only Austro also all other companies, kind of like invented the jet powered piston engines again, because all these engines are controlled so ECU controlled. And I think this really brought a big portion of in one area safety to the additional safety to the market, I have to say, but also some innovations, because now you have a modern engine. We don't need to care about mixture control and starting the engine. So this is all like. Like we are nowadays used from cars. But I definitely would not say that the engine manufacturers in aviation are innovative compared to the automotive industry or even to motorsports. So we are decades behind us. -So it's an honest, statement from you, but you see, community, I have this, I'm from a textile industry. Not now, from mechanical engineering, but for textiles. The seating in an aerospace. In an airplane, for example. These are specs from 1982. The textile industry has evolved much further than that. New fire resistant textiles are available, but they are not spec'ed in. So there cannot be used. But what it is, of course they have been proven, they have been tested and there has been no issue with it. So they carry on using these textiles. -Correct. And this is a problem most probably with engines Yes, a many times more even. All right, Jürgen, thank you so much for this introduction. And to Austria engines. My colleague Norbert Werle will take over now, and he will dive with you a bit into the technology of engines. So thanks, Mr. Schwarz, for being also with the JET-Circle here today and giving us a little bit of insight into Austrio Engine and airplane engines that we just experienced in our flights now with the DA62. So to give us a bit of background, maybe what are you producing here? What are you assembling here in Austro Engine. -We have one major type of engine we are producing. It's our inline four cylinder diesel engine. So it's an internal combustion engine. Very similar technology what is used in the automotive industry. So it's a high pressure common rail diesel injection type. So injection pressure is up to 1,650 bars. This is a state of the art I would say. We have a smaller engine, a rotary engine, which is mainly used for, let's say, our main applications for glider, powerful for gliders. These are the two engine types we are producing here. The inline four cylinder engine is produced in four different variants, which is mainly driven by in which aircraft it goes in and which most power output the engine has to produce. -So why four that of course the DA42 and DA62. But where are the additional ones? The 40, 42, 62 on the very end of the 40. So we have I think two variants on the 40s. -So and both of them are here. Right. These are only demo engines. So this is mainly for people coming in. This is for planes a little bit too generous of the engine. So we do Because from the outside, the engine, they look so similar. There's no need to put four lookalike engines in one row. Okay. And you said it's coming from the automotive industry. So I think in the past I heard it was always the Mercedes C-Class or so. The two litre engine was pretty much similar. Or which class was it, which engine was it? I think it was an A-Class engine. Correct. The point was the the core engine was the original automotive engine and Diamond and Austro Engine decided to convert this engine in an aviation engine. There's one one big advantage to go this path. You build your engine on a proven technology already instead of drawing everything from scratch. So this speeds up the development process typically quite a bit. We are now in the phase where we do not source any components anymore from the original manufacturer. So from Mercedes. So we have our own sourcing supply chain. So each and every component is fully under our control in terms of design drawings and supply chain. -And that means also where are those components mainly coming from? -Most of the components on nearly all components are produced and sourced within Europe. So we have nothing from overseas. And this is all around let's say in an environment 1000km around Wien or Wiener Neustadt. Tell us a little bit, like you said, 150 people are here. That's partially production, partially then the design organization. How is that? How many engines do you manufacture? How many? How is the distribution between production and engineering there? Our run rate is roundabout. So at the moment we are at a run rate of, let's say 900 engines a year, -900? Obviously in this production environment, we let's say in one shift we could go up to 1,200 engines a year if we need more. Then obviously we had to introduce maybe a second shift or half a second shift or whatever. We are not using Saturdays, Sundays. So it's a normal working day for all our employees. The split between engineering and operations is about 40 to 60%. So 40% engineering, 60% more production related. So you can see we are quite heavily engineering loaded, but this is also driven by the demand of the authorities. So that means you could scale the production here still quite flexibly up and down from the 900 as you needed. Absolutely. Typically we can scale up and down as needed. So let's say if you would look at our week to week production, it's quite flexing a bit. -But what is then the main constraint in this like the sourcing of material. Because everybody hears now that all the manufacturers of engines have either computer parts like chips for the control mechanism is missing or certain parts are missing. Is that an issue for you with the supply chain? No. First, let's say in terms of volume, the supply chain is not the problem because we would not go from 900 engines to 9,000 engines. This is unrealistic. So for us a higher demand would already be going from 900 to 950 or 1,000. So the supply chain can cover very well. Obviously it needs a little bit pre preparation. But internally for example the engine testing would be a bottleneck. So as we only operate three dinos for serial production. So this would become one of the first bottlenecks that maybe we need to have higher capacity in engine testing. -So how is it now if somebody has a broken engine. Is he having a quick then delivery time from your site or does he need need to wait long time or from Diamond's side, whoever needs to deliver the engine? No. Normally we try to keep at least from each of our engine models, one engine here on stock, we call this AOG engines, which then, in an ideal world, can be shipped within 24 hours. Okay. Now there was some discussions on the market that there were also some issues there where engines needed to be changed. Can you explain a little bit what happened there, what was there happening in the past, and where are we going in the future? Yeah, we had one, let's say one lately, major, major issue with, uh, with the piston. So we had a crack in the piston, which let's we call it an MSP mandatory service bulletin, uh, which requires all affected engines that the piston needs to be replaced. So to explain that it really is affecting all flying airplanes outside the that were having this engine on it. -The piston. We can, because of the tracking we have to do, we can clearly say which engines are affected. So every customer who is affected is aware of the situation. And so, they get an information from our site or officially from the authorities as well that they have to replace the pistons. And there are some times where they have to do it or they have to do some special inspection. This is currently ongoing. So from a technical perspective, this problem for us from an engineering perspective is resolved around about one third of the field replaced already the pistons. And they're flying now with any with any issues anymore. And the other ones are in the in the face of replacing. And obviously all new engines are already since the beginning of last year, equipped with the right configuration of pistons. -So that from beginning of 2025, everything that was shipped was not having any issues anymore. So all the new airplanes that are now coming out are with a new nice engine. Let's go also more into the future because often the engines are now talking about okay, we have not anymore the latitude fuel here. We have now already kerosene jet A-1 engines. But the future is also going to hydrogen or more electric aviation. Where is Austro Engines standing there or what do you do there? Obviously we are not that deeply involved into electric aviation. In terms of powertrain, we support Diamond where needed, but it's currently not in our focus to produce electrical motors. So that's not in the scope, but we are a strong believer that the piston engines will survive maybe another 40 years in aviation. So I'm not very concerned about this near-term future. Definitely sustainable aviation fuels. So this is where we are mainly concentrating. So we are part of different committees. Also the ASTM meaning also in the rulemaking for sustainable fuels to make sure that not only turbines are under the radar, that also piston engines are under the radar because compared to turbines, we have two major factors. We need to be sure we need a certain theta number so that the engines do themselves ignite. This is a very important characteristics of the fuel and also the lubrication factor as we have. Like I mentioned, the components carrying the fuel with very high pressure. So we also need lubrication in the fuel. This is our main focus so far all future sustainable fuels or I would say the fuels which are available and can be produced, they will fulfill the spec we need now. But anyway, we need to track this a little bit. That's what I wanted to ask now. So on today's production slots of sustainable aviation fuels like OMV is here in Vienna, for example, producing. Would the engine cope with 100% of this fuel, if it would be possible in aviation to do 100% in the tank of this SAF? At the moment, let's say approved jet fuels is only blends with 50:50. And all the blends which are certified, we can use them without any question at the moment. It's more really looking into the fuse future when it gets 100% SAF, then we need to make sure that the fuel characteristic fits to a piston engine. -So that's still questionable. If 100% SAF would be fully okay with the engine. Yes. From an engine perspective, I think the risk is fairly low, because the demand of jet A-fuel is so high that maybe in the foreseeable future, it's very questionable if we can produce all the amounts which are needed. Absolutely. But like we had also a client just two weeks ago that was really demanding us to fly on 100% SAF, of course not in the tank, but at least backed by 100% SAF. So our operator purchased with OMV the amount that was appropriate to the overall CO2 emissions that this whole flight would have done. And so that's why some clients would be also happy to have 100% SAF in the tank in the actual tank of the airplane, but that would be at the moment need to be a plan because of certification. -It depends a little bit if it's let's say one specific customer who is operating, let's say out of one location or one operator who can say, I can guarantee that I always get the same sustainable fuel. We would be able kind of like to do kind of like a special application for him, or check the fuel for him so that that he can get a special permit, for example. Also to fly already now with 100% of SAF. -50:50 is no problem at all. If it's a certified jet A-fuel. So it needs to be certified jet A-fuel based on ASTM standards. -Okay. Anything in the hydrogen area that you are doing? -We are looking in hydrogen not not by ourselves. So these are we have several programs, joint programs with universities as they are much better equipped for hydrogen than we are. We have close relationship with the University Technical University of Vienna. So they run a single cylinder and a four cylinder hydrogen engine based on the Austro engine as well the University of Dresden. They are entering into a project using a DA62, which should be converted then to a hydrogen airplane. Obviously this is a long term ongoing project. It will take a while also on the aircraft side, but this is definitely something we are looking into. We are maybe a little bit special because our concept is to offer a dual fuel engine, not only hydrogen, so we still would carry kerosene on board. And for us this is more like for the customer to be able, if he would say if the project materializes and the customer is flying a hydrogen engine and he has to land somewhere where he only can get jet fuel, he would be able still to operate his aircraft. -It would be both possible, like a hybrid. We heard from Martin Scherer, the Chief Pilot, during our test flight that the airplane engines are extremely efficient, with really low fuel consumption and extremely good power output. What is making it so efficient. What is the reason for that? Give us a background. This is really based on the automotive technology. Due to the case that we are using a common rail injection system. So we are able to vaporize the fuel, very efficient to the combustion chamber, and we are able to burn like every single drop of the fuel due to this high pressure, we inject the fuel and then we can create a very high thermal efficiency. And in the engine business we typically we talk about grams per kilowatts or specific performance. And our engines typically are about 210g/kW hour output. And if you compare to turbine there are for example more like on 400g. So two times more. And also here we have to put this in a perspective as bigger turbine is getting as more efficient the turbine is. This has to do with some turbodynamics of a turbine. But a turbine in a 400 horsepower class is quite inefficient, for example. And how is it with comparing this to like normal piston engine from continental Lycoming and so on? -If you compare it against an older avgas engine, obviously we are more efficient. Let's say our jet A powered piston engine is the same like the Continental or like the Red, because we are all using the same principles. So maybe here we talk about 1 or 2% of differences, maybe in specific points. But that's not the point. The big difference is compared to the older avgas engine. And if someone would take the money nowadays and develop a brand new gasoline aviation engine, let's say based on modern automotive technology, they would be also very efficient. Just because the technology is available nowadays and which was not available maybe 40 or 50 years. Ago, even this engine is still a bit older technology even like what 90s, 90s or so A-Class was using. Okay. Very good. So I think we got a really nice wrap up of what you are doing here. And now we will see a bit more from the actual production here. And thanks Jürgen for this information. We start our tour through the through the company in the warehouse. So in the warehouse all the parts are stored, after incoming inspection and checking. So whenever a part is here, it's already released for production. So in our warehouse, it also takes place the commissioning for each engine. So you will see later on in the production. So one mechanic is building one engine and he gets all the part ready commissioned for his engine. So we don't have any Kanban system or so everything is commissioned based on a production order. -So did I understand that correctly, that one technician gets all the parts for all the engine, and then he starts doing the whole process through. So it's not like different stages where different people are then doing the engine. -We only have two main stages. We call it the core engine and then the final assembly of the engine. So it's mainly more or less two mechanics on one engine working. Core, and then later the assembly of all the additional material around it. And on these trolleys the parts are pre-picked from the the warehouse and just waiting for the mechanics. They pull the car, they pull the trolley and then they bring it to their workstation. -So one trolley is one engine full or what? Or several trolleys. -Several trolleys are getting to one engine. Correct. Then the mechanic typically starts with the crankcase. He puts the crankcase on his assembly tray and then he assembles a step by step the engine. Whenever there is a specific step where he needs a second control phase, he's calling an inspector, and an inspector will come to his place. And then they assemble. Let's say during this special assembly process with the four eyes principal. And then the inspector has to sign off that maybe a bolt was taught or a component was assembled to the engine. -How long does it take one mechanic to build one engine? -The whole round is about something roundabout 12 hours in total to build one engine, but not by one mechanic. Really total working hours. And so 12 hours of total working time. And one engine is going off and it starts from like a the crank. -Exactly like having the crankcase assembled. Here we have the crank already in the frame case. So that's already maybe fifth or sixth stage steps. That's an example. One of our colleagues is currently preparing turbochargers. So it's an assembly process. So once the turbocharger is completely assembled, it goes back to the storage room and then waiting for the production order. So in these stations here, the engines they got, let's say more individual, because here the big difference is for example, but you can see here the engine harness and the engine harness obviously is related to the aircraft. The engine needs to go in. So once an engine is here it's already clear in which aircraft type the engine will end up. Some hardware components are a little bit different. -But the block is the same, or? But the block is the same. Cylinder head is the same. So really the big core components are all the same. And then obviously it's the mapping is different. And then some little details on the engines also describing the horsepower. Once an engine is fully assembled we put it on a special dyno rig. It's fully installed, fully filled with all the liquids, cooling liquids, everything. We need to operate the engine. Then the engine is brought into the test cell, and then at first it becomes a running in procedure, which is run about 1.5 hours. Running in, starting with very low performance, going up to max performance. And then as the final approval a full performance curve. Performance curve in aviation is kind of like a must is described by the authorities or the authorities ask for it so that we can guarantee that the engine is in a certain limit. We are not allowed to have less performance, but we are also not allowed to have more performance. So we need to be in a specific bandwidth. -And that will be checked during the engine test. How long does the engine test take overall? -So roundabout in and out. I would say it's round about two and a half to three hours, including installing the engine on the dyno. And how long is the engine running then? -Really 1.5 hours for the kind of like running procedure, breaking procedure, how we say, and then maybe another ten minutes for the calibration curve. So once the engine is released from the dyno here, we do kind of like the final inspection of the engine. So it's check that all parts are there, all liquids are drained and all the accessories are also put into the boxes. And then the engine is signed off and then we cover the engine and it's ready for shipment. Okay. Well shipment is usually not that far. Well it depends if we if it needs to go to Canada, our production plant in Canada, obviously it's quite a distance or to China. Yes. We have production plants there as well. If it only goes to Diamond Austria. Obviously it's just around the corner. -Well, what's wonderful to see all the stages of the production of such an engine. Now we understand much more and see how you do the reliable Austro Engines here for the Diamond Aircraft. So thanks a lot, Mr. Schwarz. And hope to see you again. -Hope to fly with you again soon. Thank you. -How do we connect you with stories within the composites and sustainable materials industry? We are on the ground to find the facts. We examine big, innovative ideas. We led diverse perspectives on technology and sustainability, emerge and ignite conversations that matter most to bring you the composites and sustainable materials world. Stay informed. Stay connected. Stay inspired. From our online studios in Germany covering events and corporates from France, Italy, UK, Central Europe and many more European regions, join us for creating sustainable value with #Composites360onTour, Composites Lounge Engineering Talks and Composites Lounge Enduser Panels hosted by Ilkay Özkisaoglu weekly on LinkedIn, YouTube and your preferred audio podcast apps.