From hydrogen to nuclear fusion, Aviation Week's Graham Warwick and Guy Norris report on the bleeding-edge aerospace technologies that were discussed at the recent AIAA SciTech forum.

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Transcript

Guy Norris:

Hello. Welcome to Aviation Week's Check Six podcast. We're coming to you from the AIAA Scitech conference down here in Orlando, Florida. I'm Guy Norris, senior editor, and with me to discuss what we both agree is the busiest Scitech we've ever been to is Graham Warwick. What are you Graham? Senior ...

Graham Warwick:

Executive editor for technology.

Guy Norris:

That's it. Sorry. Executive editor for technology. So Graham, yeah, what are your top line thoughts? Because it has been crazy with over 6,000 attendees, which is a record I think for Scitech.

Graham Warwick:

Yeah, it feels that many of the rooms are really stacked out to the limit. So this is organized by AIAA, right? The American Institute of Aeronautics and Astronautics. And it's always been a kind of an international event because the attendees are quite international and there's always been people giving presentations from other countries, Korea, Japan, all that sort of thing. But the last couple of years, the European industry has used it really to showcase European research, particularly the Clean Sky and now Clean Aviation program. So, I spent the week in pretty much every morning and every afternoon long sessions looking at Clean Sky and Clean Aviation and as a research and everything like that.

So Clean Sky, which has been going for about 10 years, actually finishes at the end of March. And so all of these demonstrators that they've been doing over the last 10 years, really they're supposed to come to an end in March and then deliver the results. And those results are really what are going to go into the next generation of airplanes that take shape over the next few years.

Clean Aviation is going to take some of those technologies a bit further forward, but really if you're looking at what's the next generation airplane going to have, you kind of look at Clean Sky, Clean Sky Two. So, what I've been doing is obviously we now know that Airbus is, they've got it public and said they've started to work on the success of the A 320. And so, you're sitting in this room and they're detailing all of these demonstrators they've been doing, and you can't stop yourself again going, "Okay, right. Is that technology ready? Is that technology ready? Is that technology ready?"

So, some of the big ones, so Sue Partridge, who's the head of Airbus's Wing of Tomorrow program, she did a great presentation today, which the room was completely packed out and she really just brought that program up to date. And that's developing not just the design of the wing for the next single aisle, but how you manufacture that at high rate from day one. So manufacturing is as important as the design of the wing. And the key thing to that wing is it's got a much longer span than the current A320 wing. So they're having to fold the wing tip on the ground, so they're like 777X’s.

So, they've got these demonstrators in Broughton and Filton in the UK where they've got a wing fold demonstrator. They're finalizing the assembly of the full-scale wing demonstrators. They're going to do a static test, then they're going to do a full, what they call a run at rate test, which is where they'll show they can build this wing at this high rate that they want to do. So that's one, and you look at it and say, "Okay, we know where that's going."

With a demonstrator like that, they've actually tested alternative technologies. Each of the demonstrators has got several ways of doing the same thing. So if you're going to go do a product, you'll pick one of those technologies. But you can look at that design and say, "Okay, we kind of know where that's going. It's a long-span wing folding wing tips. Guess where we're going to use that." Big drag reduction, fuel saving, emission saving.

The other one is they're a big demonstrator of a thermoplastic fuselage, complete fuselage section, eight meters long, same cross section as an A320, totally made of thermoplastic composites, and very highly automated robotic assembly and everything like that. Really, really cool to see the videos of these robots putting this welding. It's all welded thermoplastic welding. And the guy admitted right at the end, somebody asked him a question, he said, "We pushed too far in many ways," IE. that a lot of these technologies, they worked on the demonstrator, but they're not mature enough, but several of the technologies are ready.

So for thermoplastics, he said on the A350 they use thermoplastic clips, which are the small pieces of carbon fiber that you use to attach the bigger pieces of structure. So he said, "We use thermoplastic clips on the A350. From when we go to the next airplane, we could probably do the frames and the stringers with thermoplastics and connect that to the more conventional thermoset skins, because they're not ready to go to thermoplastic for the skins, even though they demonstrated it on this demonstrator. It's just a bit pushed different.

So then there was a whole bunch of laminarity, hybrid laminar flow control, lots of other, gust load alleviation for big long wings. And so there was lots of these technologies and you are pushing to say, "What maturity have you got to? Are you ready? Is that ready to go for the next airplane?"

Guy Norris:

Well, and of course talking about maturity, I sat through a lot of the clean propulsion studies. And this time, the third round really of the clean initiative is really dominated by propulsion studies. Much of which of course is targeted at least adjacently in some cases that hydrogen combustion. And I don't know about you, but I picked up the distinct feeling that, of course Airbus launched its Zero-E initiative with much fanfare a couple of years ago now, and really targeting the possibility of introducing a hydrogen fueled airliner by the mid-'30s, 2030s. I'm definitely getting the feeling that the reality of all that is starting to kick in and they're talking less and less about, at least in a meaningful way.

Graham Warwick:

Yeah, I think so. I mean, I'll just second your comments about propulsion. I think that's really the big theme from this conference. There used to be a whole conference that AIAA did that was just about propulsion, and that's got wrapped into another conference now. This was really a propulsion conference, and I think it's just how aerospace works. You only get a new airplane when you get a step change in propulsion. It's only worth doing a new airplane when you get a step change in propulsion. And that's what we're seeing here is this what's the next step change in propulsion? And therefore what's the airplane that comes out of that?

I totally agree with you on hydrogen. I'm still surprised at how much work is going on in hydrogen. Really, really, I mean, just enormous amounts of research. But I do think the timeframe, the timescale is completely unrealistic and therefore there is a bit of realism coming in. So what you're hearing is one of two things. Either that 2035 will slip later, or that the airplane they do is going to be a lot smaller than they talked ... They talked about 100 seats, but it could end up being a lot smaller, which means it's in the hydrogen electric, same as Zero Avia and Universal Hydrogen. That's doable in that timeframe. It's just not a step change that Airbus set out to do. So I think either you'll see it go later or you'll see it go smaller.

Guy Norris:

Yeah. Well, I'm glad you agree because, honestly listeners, we haven't rehearsed this in any way. That was pure spontaneity there. But I think that talking about propulsion, I think one of the other big themes at the event was really the updates on the nuclear thermal propulsion, which I sat through a lot of that.

Graham Warwick:

Not for single-aisle airliners, I promise.

Guy Norris:

Yes, yes. We should point out that was in space propulsion applications, which of course NASA's been driving at and hoping to get for 50, 60 years. And now finally something's happening thanks to this new arrangement, a joint program between DARPA and NASA on the Draco program, which really aims, and they've got a very firm target of getting into space to light the candle on this nuclear thermal rocket engine in March '27. And it's already January of '24 as we're recording this, so the clock's ticking.

But there was a good group here, it was a packed out three sessions through the week. So yeah, that was really encouraging. And of course, just like hydrogen down here in the terrestrial environment, they know they've really got their work cut out. One of the big problems, of course, is how on earth they're going to test this. They really can't at the moment test it anywhere on the ground for obvious reasons. The reactor will not even be activated until it's in orbit. So that at the moment, the first time they'll know if any of this works is when they try and activate the reactor in orbit from the Earth. So yeah, fascinating stuff to listen to.

Graham Warwick:

Yeah, I stayed away from the space propulsion stuff because it would've made my head explode if I'd actually gone into that. But I did oddly enough, end up in one presentation on future space flight propulsion. And the funny thing I think is that the guy who did the opening presentation, it's on the report that NASA's just done, basically what he was saying was, "We have studied this to death for the last 50 years." They've done every sort of Mars fast transit study you could think of with every possible combination of propulsion options: chemical, nuclear, electric, solar electric, you name it. But what the difference is, he said, as he said right at the end, he literally just went through a 50-year history of how this has been studied to death, how we would use these advanced propulsion. He said, the difference now is we have actual programs that are developing nuclear thermal, nuclear electric, and all of these things. He said for the first time in this 50-plus-years of studying this problem, there actually are programs developing the technology.

Guy Norris:

Yeah. And the thing that seems to have made the big difference is advances in particularly in material science, which just weren't there 50 or so years ago, which were real showstoppers essentially. And now also compared that with the imperatives of defense considerations for cis-lunar space, and of course the longer term ambitions to reduce exposure of astronauts to cosmic rays during transits to Mars. So it's all falling into pace at the same time, really.

Graham Warwick:

And there were even some papers here on nuclear fusion actually for aircraft propulsion, which I think is going to be that next frontier. But again, one of the guys I was talking to was saying that he's got interested, he's an aircraft designer who's started to look at nuclear fusion. And the reason is that a lot of startups have started to look at these compact nu ... Now we're not anywhere near there yet, but the interesting thing is that the work's being done, a lot of innovators are looking at it, so you never know, there might be some breakthrough somewhere. So maybe sitting here, if we're still around in 10 years' time, we still may be sitting in Orlando at AIAA Scitech talking about nuclear fusion for aircraft propulsion,

Guy Norris:

And of course, a little bit nearer term. We do see the progress with exhibits on stands on programs such as the X-66, which is the NASA Boeing sustainable flight demonstrator based on the transonic truss-braced wing. And there was a nice new model of that. But of course, while that's here, there's the actual work on the MD-90 that's going to form the basis for that conversion is beginning in Palmdale, California. So yeah, the PDFs are starting to turn into reality.

Graham Warwick:

That's just literally what I was going to point out is we started writing about truss-braced wing from Scitech, from being academic papers being presented at Scitech 10, 15 years ago or something like that. Boeing Sugar was 2010 and before that UVA was working on it. So the conceptual design with the academic community, and now they were presenting papers here and now it's on its way to being an actual flying vehicle. And so it's why we're here. It's why we come to Scitech.

Guy Norris:

Yeah, and as usual, we probably wish there was at least three of each of us because there's been some times when we wish we could be in at least three places at once.

But anyway, it's been another packed AIAA Scitech and we've thoroughly enjoyed ourselves. And as Graham says, our brains are basically fried at this point. But anyway, I guess that is a wrap for this week's Check Six. And thanks to our producer, Guy Ferneyhough, who we believe is in Korea at the moment. And thanks very much for listening. Take care.