The engineers: Flying at the edge

23:22So basically we were out testing something, flight control issues. So we spent, the good thing was we had a lot of time and fuel and everything and because it was a test mission we have a whole control room which they're calling everybody in and working through it and we had to go through some pretty non-standard procedures of like circuit breakers. I mean you talk about the software and the automation and all of that. Of course this is developmental tests and so you do expect some things to go wrong. But that would be one for a while where we're all like, we may actually be in a scenario where we're not sure if we're going to be able to control this down to the runway.

23:52So that would be up there. Gosh. But in the end, we had all the engineer support and everything. And they basically had us run through some things, reset some computers. And then as soon as we were good, we're like, landing.

24:03Caroline Steel:We're coming down now. And we came down. But to the question before, but what that brings up is our software in the loop testing for software changes and stuff got a lot more vigorous after that. I'm amazed you got back in a plane again, to be honest. If that happened to me, I'd be like, I'm staying on the ground. Thank you so much for your question. We now need to take a short pause, and we'll be back very soon to find out more about pioneering aviation. Thank you.

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26:15Caroline Steel:You're listening to the BBC World Service. I'm Caroline Steele and this is The Engineers Flying at the Edge. I'm with three world leaders in the field of aviation engineering. Daniel Mochi DeLover is president and CEO of the aircraft innovators Embraer X. Rob Miller is a sustainable flight pioneer and director of the Whittle Laboratory at the University of Cambridge. And Kelly Latimer has been an experimental test pilot for NASA, Boeing and Virgin Galactic. And she's now president of the Society for Experimental Test Pilots. Everyone, please welcome back your engineers.

27:00Caroline Steel:So we're going to look ahead now. Rob, let's talk a bit more about your cryogenic engine. So the tech is there you've got the patents what next I'm thinking what infrastructural changes will we need to see so it really was brought home to me about 10 years ago I was actually in the pub in Cambridge with a friend of mine who worked at Red Bull Formula One and he asked me what we were working on and I talked about a new technology for a blade and he said to me when will it make engine when would it fly and i said oh four to six years and i said what were you doing today tony and they'd seen an adaption on the ferrari rear wing and they tested 20 rear wings that day and they fitted a computer surface you're talking about car motor racing here yeah car motor racing formula one they'd seen the ferrari rear wing and they'd seen an adaption and red bull had tested 20 wings that day and they fitted a curve through the results they predicted the best they tested it built it tested it it was the best and they then sent that to track and it was on the car the next day the adaption now formula one is easier than aerospace yes two dimensions rather than three but but not that much easier and it took us nine months to get tony out of red bull and everything changed in the Whittle app.

28:26And by using AI and augmented design, sort of running lots of computer simulations with the human interacting in a more sort of organic way, we managed to cut the design system, the design time down from about 100 days to one day.

28:41Caroline Steel:And this is with the help of Tony, who you took from Formula One. Yeah, that's right. Good work. And we can now take a technology. We did a formal trial, actually, with the UK government in about 2018. And the aim was to take four technologies around this loop. And in 2005, it had taken two years to take two technologies around this loop. And we did it in around a week. And basically, the new Whittle Laboratory is scaling that capability. We have a big new four-megawatt facility. It's going to create a Formula One-type capability, which will be at least 100x quicker than anywhere else in the world.

29:19Caroline Steel:And if you think about rolling out planes with cryogenic engines in airports like, say, Heathrow in London, how would Heathrow need to change? Because you've got to be able to get this fuel down to an incredibly low temperature. What kind of changes would you need to make? So the really important thing here is a decision about what is practical in infrastructure change for a cost in the minimum amount of time. And there are a few solutions here. So what is amazing about aviation is the 20 largest hub airports in the world are responsible for half of aviation's fuel burn. Now, changing 20 structures in the world compared to changing all the airports in the world is doable.

30:07So you could decide if you took strategic hubs and you converted those to cryogenic systems, I think that's probably the fastest way of making that conversion happen. I think the second thing to think about is political, because you have to have one political entity that would enforce the rules to force people, because as Daniel's been saying beforehand, the first time you build these, they will be more expensive. And so unless you politically restrict the operation, and probably the EU and the UK together is a good zone in which you could start to maybe not the long haul, but you could take the medium haul flights across Europe and you could tax effectively the jet fuel flights to make this more economic.

31:00Caroline Steel:Thank you, Rob. So, Daniel, if your eVTOLs get to the point where the tech is 100 % there, they're ready to go, cities aren't built for them at the moment, right? So you're also going to have to think about infrastructure changes. How will cities need to change to incorporate eVTOLs? Absolutely. The good news for the start of operations is that the eVitals can start operating from existing heliports, helipads, airports. It's going to be a limited operation, not as many routes, but that's a good way to get started. As we progress, what we will need is to convert more locations to vertiports, which means bring the electrical infrastructure, the fast charges.

31:50The other major challenge is related to the air traffic management. We're putting a lot of investment on that aspect because this will really make the difference to allow that ecosystem to scale in the big cities. One big advantage that we have is the knowledge of operating the current airspace on top of city of Sao Paulo. I'll mention Sao Paulo because it's the most tolerant city in the world to number of helicopters flying simultaneously. The traffic is so bad. Yeah. And it's a noisy city. It's a loud city. So people accept those four to five helicopters today is the most tolerant environment, which creates, I would dare to say, the most complex airspace to be managed around the globe today.

32:41Caroline Steel:Do you think it's likely eVTOLs will be used to, say, shuttle people from a city centre out to an airport? To an international airport. That's one of the very first use cases that we see. Other use cases are like air ambulances or taking care of medical emergencies where the time you will save may imply in saving lives as well. So we'll start with few cities, few routes, and we're talking three, four years from now. It's not a distant future. Great. Thank you, Daniel. So Kelly, back to you. You have been incredibly important in super high-speed suborbital flight, and we're now hearing conversations about hypersonic passenger flights where people might be able to go from London to Sydney in under two hours.

33:29Caroline Steel:I mean, that sounds almost impossible. What's the idea behind it? What's the engineering? Well, I mean, so one thing is you could do a suborbital flight, because Virgin Galactic had talked about that, where instead of the suborbital flight going straight up and down, you basically do it point to point. But if you think about it, the vehicles we have now, even hypersonic mechanic vehicles after they do a test or space vehicles when they come back in they're essentially projectile so when you come back in and re-enter there isn't an engine there's no holding pattern there's no waiting for the runway to clear i mean you're coming down and you're not going to stop so and so if it's vertical one challenge is you know i mean starship be capable of that right but you need to have the whole landing and the catching mechanism and that type stuff or if like we come back in like a glider it's not going to be at chicago o 'hare you're not going and like clear the runway, everybody stand by, we got to land.

34:18But you certainly could do it. You know, so we flew out of Spaceport America. So it's Las Cruces. So it's kind of out there. You know, so if you pick a spot that's in the middle of nowhere and then you combine it with eVTOL, you know, you can actually have those fast flights land someplace. But to have the technology to still have an engine that can go from the ground to hypersonic back down to subsonic and land again is really, really challenging.

34:41Caroline Steel:So hypersonic is moving at faster than the speed of sound. and subsonic is slower than the speed of sound. Yeah, yeah. The average passenger jet is... Hypersonic is very fast. Supersonic is, you know, up to about Mach 3 or so, and then hypersonic is when you're above Mach 3 and Mach 5. And Mach 3 is three times higher than the speed of sound. And an average passenger jet is like 0.8? 0.8, yeah, about 0.8, yeah. Of the speed of sound. Okay, so this is, you know, a hugely different way of traveling. But there's a world in which you could go up, go sort of do a quick suborbital flight, come down, land maybe in the middle of an Australian desert, jump on one of Daniel's EVTOLs, go to the center of Sydney, and maybe do that in four hours?

35:21Caroline Steel:Yeah, see that. And it actually is possible to do it with, and not have to be like a vertical where you could actually have a runway and do it where you come in as a glider, because there's other companies developing suborbital vehicles that take off from the runway, get up and come back in. So it's possible. It's just a matter of weaving it in with current traffic and having some places a little bit outside of where all the congestion is for air traffic. And I guess one of the key things that might make this possible is that at higher altitudes, the air is thinner, there's less resistance, you can travel faster, you can use less fuel.

35:51Caroline Steel:Is that right? Yeah, because once you have enough, it's all about getting the energy to get you out of the atmosphere. Then once you're out, it's pretty much a free ride, you know, but how far you're going dictates how much energy and how much thrust you need to get there. So it all comes down to whether you're taken off from the ground, whether you're being air launched, and then how far you want to go. So it might be a good option for London to Sydney, but would be totally pointless for like London to Berlin, for example. Yes, yes. It'd be fun. It'd be really fun. Probably not economical. Not efficient, yeah.

36:22Caroline Steel:So, Rob, your lab defines itself as a global centre for net zero aviation and energy. Cryogenic engines, super exciting. We're not quite there yet. They haven't been rolled out yet. Is there anything that airlines or passengers could do right now to reduce the environmental impact of flying? Yes, I think what a lot of people don't understand is that half the climate impact of aviation is not the burning of the fuel. It's the clouds, the contrails that form. So basically, one in 25, the white lines behind planes don't do any damage. but one in 20 flights travels through an area of airspace called ice supersaturated, about to grow a cloud.

37:09That cloud grows. It lasts for sort of six, nine hours. And we know, you know that at night, if it's cloudy, it feels warmer. And if it's a clear sky, it feels colder. And that's because the cloud's like a blanket keeping in the heat to the earth. and those clouds, that one in 20 flight, the cloud over six to nine hours does the same warming of the planet we think, though the uncertainty is relatively high, as the CO2 from all 20 flights do over 100 years.

37:43Caroline Steel:What? Okay, wait, so in that very short time period you're having the same effect as all of those flights over 100 years? Yeah. But now, this is a real benefit because the areas that form those clouds are like thin pancakes. And therefore, if you knew you were in one and you changed the altitude of the plane, you could switch off that cloud formation. And so this is something that we think you could tackle relatively simply. We think that maneuver is probably a 1 % to 2 % extra fuel burn, but the savings are huge. Hopefully, you will see in the next year or so the first large-scale trials going off, and hopefully the UK will be leading those trials.

38:28But this is a real opportunity over the next five to ten years to have a big impact.

38:34Caroline Steel:Because am I right in thinking that the impact on climate change from clouds formed through planes is higher than from the fuel burnt? Which is wild. It's amazing. So I think what's really interesting about it is there's only two ways to cool the planet. One way is to capture CO2 from the atmosphere and store it underground. the other way is to stop making the clouds from planes tomorrow right sounds slightly more doable well and by 2050 we estimate that this cloud formation will be worth 0.1 degrees of world warming now with the climate agreement of 1.52 degrees 0.1 degree is a large amount chunk yeah my final question which is for all of you so we've talked about suborbital flight evtols cryogenic jet engines all really exciting but can we just be realistic for a moment so if if you think about the future of flight in the next 30 or 40 years what do you realistically think it will look like what changes do you think we will actually see so yeah let's start with you rob okay so the big challenge over 30 to 40 years is that at the moment the way we're decarbonizing flight is we're talking about sustainable aviation fuel.

39:50And sustainable aviation fuel is making a replacement from jet fuel out of effectively waste biomass. Now, if you scale that up to 2050-60, you're pretty much using half of the world's waste biomass for aviation. It just becomes an unsustainable problem. And therefore, if we're going to decarbonize aviation, not thinking about the difficulty in the shorter term, if you're thinking about 2050 to 2060, you have to get carbon out of the cycle. And really, hydrogen is one way of doing that. There are other ways of doing that. But you cannot imagine a world of aviation in 2060 plus where carbon is still in the system.

40:36There just isn't enough biomass on the planet, and the collecting of it will become too extreme. The demands on the planet will become too extreme. So sustainable aviation fuel is a good transition, but the end state has to be different.

40:50Caroline Steel:And Kelly, what do you think? What do you think we're going to see in our skies in 30 to 40 years? So I think in the near future, we're going to see the return of supersonic commercial flights. I think there's a big push for that now. NASA has a program with the Quiet Boom X-59. So they're demonstrating Quiet Boom technology FAA due to this is going back and kind of look at those changes so I think that's one thing that we're going to see as far as getting faster we're going to see that jump back into supersonic plates so commercial passenger jets being able to go faster than the speed of sound like the Concorde yeah used to yeah and I think we'll see that and it used to be just over water but I think we'll actually see that change and be over land as well which is a huge opening to the market there's other technologies out there like flying wing has been there for a long time and there's actually companies that are involved in doing that NASA's looking at a potential x-plane for that but that sort of looks like it's just a giant wing and people sit inside the wings there's no kind of tube with wings it's just a big flying triangle yep exactly and it's about about 30 percent more efficient than you know with the fuselage wing so new interior though so you're gonna have some like you know little cameras that are just showing a picture of stuff and not actually looking out the window and daniel what about you what do you think 30 to 40 years what are we realistically going to see in our skies?

42:03You know, when we launched EVE Air Mobility, which is the spin-off company working with the eVTOL, one of the things that I think really got us excited is that we see it as challenging as it is as a first step in the long journey. The eVTOL has been teaching us how to deal with high voltage systems on both the aircraft, battery systems, battery management systems. It's a whole new world that is opening up, but still is a first step. What we see in the timeframe that you described is for shorter haul, I mean, the eVTOL will cover a very short distance inside the city, but maybe connecting cities that are not that far from each other, we'll start seeing hybrid electric solutions or hydrogen fuel cell will eventually get to hydrogen being burned in the turbine.

42:57We'll have to see sustainable aviation fuel as a transition. We agree with that. Brazil, for example, has a very successful biofuel programs for decades. We can run our entire automobile fleet 100 % ethanol. If we electrify that fleet, maybe we'll have a lot of ethanol available to go to a route that we call ATJ, alcohol to jet. So we can...

43:28Caroline Steel:Rob looks like he wants to jump in. Very briefly. Yeah, go for it. So I think one certainty over the next 20, 30 years is it's going to be an incredibly exciting domain to work in. And I wish I was younger. Well said. Extremely well said. And the configurations that Kelly mentioned, the blended wing body and other examples, for very, very long time. We've been used to think of an airplane as the tube and the wings. Yes, it's hard to picture a flying triangle. It's hard to picture something different, right? Yeah. The eVTOL is already something very different. Pretty different, yeah. The blended wing body is another example.

44:03What other examples of configurations, novel configurations may come up from the brilliant minds of the young engineers who are still about to join our industry and that are probably more welcome to do so right now than in any other time. in the last decade. So it will be indeed a very exciting time.

44:22Caroline Steel:Thank you. This is the engineers flying at the edge from the BBC World Service. It's the turn of our audience again. Who has a question for our panellists? If we go to, I think, the person who's directly in front of you there, and then if we come to the person here. Thank you. Hello, my name's Sandy Millen. You mentioned quite a few different fuel sources, but nobody said anything about solar. Will solar have any role in the future of aviation at all? Good question. Rob, do you want to take this one? Yeah, I'm happy to take that. So the power density involved in solar is just not sufficient to do anything more.

45:00You will see solar coming in in what are called HAPs, high-altitude vehicles. So you might well get communication systems that can be put up at high altitude or monitoring of ground for environmental reasons, but there isn't just the power density, I'm afraid. And batteries will take you a certain distance, but ultimately some form of fuel, chemical fuel. And really just the one choice in chemical fuel you have to make is jet fuel at the moment, or we know it as dinosaur juice, is an incredibly complex molecule. and making complex molecules is hard. Really, you want a way of making a simple molecule, CH4, methane or H2.

45:54They're the ways we're going to scale fuel production. Scaling making dinosaur juice is just really expensive and hardware heavy.

46:04Caroline Steel:Great, thank you, Rob. And so we had a question over here. First of all, thank you all very much. It's fascinating. I began in the aviation industry in 1969 with BOAC, so I've watched aviation change considerably. The key thing about aviation is that it runs for profit, allowing for government, war and emergency. It's got to be profitable. This is where the divide between science and technology and socioeconomics comes in. How are you going to ensure that your technology meets, actually goes into service sustainably. I think maybe there's one for you, Daniel. You said that you're hoping for the eVTOLs to be a similar price to a sort of premium taxi.

46:50Caroline Steel:Could you give me a quick answer to that question? Aviation is a very thin margin industry, as you certainly recall. So it's a big challenge when we talk about sustainable aviation fuels, when we talk about even liquefied hydrogen. Today, it seems like very hard to make them comparable on a price basis. But as a society, we need to be asking ourselves the question, how do we price the carbon-based fuels, the dinosaur juice, the externalities that are not considered when we make those price assumptions? how do we want to split or share that cost when we deploy new technology? They start at a higher point, and the learning curves and scale will typically bring that cost down.

47:42But you need to get started. So I think you've hit the big problem with transition of technology in aviation. No aircraft ever launched, which isn't at least a 10 % better value proposition than the incumbent aircraft has ever succeeded since the start of aviation. And many that are better than a 10 % value proposition have failed. Now, we've modelled, if you're interested, the Aviation Impact Accelerator global modelling capability led out of Cambridge has modelled the costs. and virtually all the routes to net zero are about 30 % more expensive. So you've got to tax in some way if you want to get that transition.

48:27There is one route which breaks that rule, and that is the route to green methane. So if you had an aircraft today that ran on liquid natural gas, it would be cheaper to operate in the United States by about 10 % than a current aircraft. Once you've done that, you've got a cryogenic system in operation, and then you would start to scale into green methane. And the green methane is going to be scaled because Musk is scaling green methane in California for the Mars missions. And the reason he's doing that is because CH4 is super easy to make. You know, it's not dinosaur juice, it's cow farts. It's the sabbatia process, and they're going to fly the plants to Mars and build the fuel to come back.

49:17So California will be awash with green methane. So there is a route there that is practical and cheaper, but it is the only one. The rest are all more expensive.

49:28Caroline Steel:Can I get hands up? Who's got a question for Kelly? The woman in the blue trousers in the middle, please, just there. Hi, my name is Kath, and I've got a question about when you're talking about the suborbital flights going up and coming down, does that introduce high Gs, and is that something the average community needs to get used to, or is that something that needs to get overcome before that's realistic? Yeah, so basically the pull to go up is on the order of 3.5 to 4 Gs, and then the reentry is 3.5 Gs. So, yeah, when we have our spaceflight participants come out, we actually give them a week of training.

50:08So it actually would be something, because that's a little bit past what you would normally see. And so we give them some training on how you combat the high Gs. It's actually for a short amount of time, but that's something where in designing the vehicle and the profile, if it's going to be a commercial flight you're not going to people come out for training so you would have to actually adjust the profile for that anything up to 2g's you can do because that's like a 60 degree bank turn but um yeah great point that the mission that the profile that we fly would probably not be suitable for just commercial anybody jump on or when you buy a ticket you

50:39Caroline Steel:might have to i don't know go do a day of training where you sit with an elephant on your chest to Get ready. OK, so we've got time for one more question. Hands up. Let's go for this person in the very front. Yeah. So we've seen driverless cars come onto our streets. Do you think in the future we will see flightless or pilotless aircraft? Sadly, yes.

51:09Kelly's like my job. much more excited way. Yes, yeah. I would say there's a huge, I mean, we're talking about the future. The future is, and there's a question about automation. The future is more automation, more autonomy. I mean, artificial intelligence, co-pilots. I mean, that's the future. So yes, I think you would never have a commercial flight with a lot of people without anybody who's monitoring, but it may just be one person. But absolutely, that's the future. For the e-veeatles, it's part of the design. So we pragmatically believe we'll start operating with the pilot on board. But again, in order to scale up that industry, pretty much all players are assuming it will be autonomous.

51:45Caroline Steel:Okay, so you need to get ready for flights without pilots. Sounds absolutely terrifying. And I will remind you, for those in this room who are about my age, elevators use it to have pilots. So it's a good point. There were elevator operators, that's true. We're not using them. Yeah. Thank you so much for your questions, everyone. I wish we could take more, but I'm afraid we're out of time. That's it for the engineers flying at the edge at the Royal Geographical Society in London. I'm Caroline Steele. On behalf of the BBC World Service, our partners, the Royal Commission 1851, and my producer, Charlie Taylor, please join me in giving a warm round of applause for our brilliant engineers, Rob Miller, Daniel Mochidlover, and Kelly Latimer.

52:32Caroline Steel:Thank you so much. Thank you. Goodbye.

52:41Thank you.