A dual-use aircraft conceived by JetZero could serve as a military tanker while ushering Northrop Grumman into the airliner business. Richard Aboulafia of AeroDynamic Advisory joins Aviation Week editors as they discuss the merits and drawbacks of the blended-wing-body aircraft concept.

Don't miss a single episode of Check 6. Subscribe in Apple Podcasts, Google Podcasts, Amazon, Audible and Spotify.

Discover all of Aviation Week Network's podcasts on our Apple Podcasts channel or aviationweek.com/podcasts.

---

Rush Transcript

Joe Anselmo:

Welcome to this week's Check 6 Podcast. I'm Joe Anselmo, Aviation Week's Editorial Director.

He's done it again. Aviation Week Senior Editor, Guy Norris has rolled out another scoop, this one the latest cover story in the April 24th edition of Aviation Week magazine. Guy's story reveals how a California startup named JetZero is aiming to develop a blended wing body aircraft that could serve the US Air Force's desire for a new tanker transport. But it's more than that. This aircraft also could be repurposed as a commercial mid-market airliner, putting JetZero up squarely against the seemingly impenetrable Airbus-Boeing duopoly.

Audacious? For sure. But the fact that JetZero is partnering with Northrop Grumman shows that this project is more than a pipe dream.

Joining us today to discuss all of this are: Guy Norris; Aviation Week columnist Richard Aboulafia of Aerodynamic Advisory, who has visited JetZero and met with its founders. And rounding us out is Aviation Week Military Editor Steve Trimble, who has written for decades on blended wing bodied concepts.

Guy, let's kickoff with you. Really quickly, could you tell our listeners, first of all what a blended wing body aircraft is and why JetZero thinks this is the way to go?

Guy Norris:       

Hi, Joe. The blended wing body concept for those that don't know is essentially where an airframe structure and the aerodynamics are blended. So, when you imagine normally you have a distinct fuselage with wings attached to the outside. This time it's a seamless transition between the two. And this enables the fuselage to actually contribute to the lift. That's the huge part of the blended wing body secret, really. It's also known generically as a hybrid wing body. But the configuration is usually tailless and it's more efficient because obviously, you've got a reduced wetted area, there's less friction and lower form drag.

So, the additional benefit of this is not only do you get all this extra lift for free, but that's another debate. But you also get the fact that the engines have to be above the body, so therefore they're shielded from the ground. So it's a lot quieter too. So it ticks the boxes in an awful lot of ways as far as the nice aircraft to have for the future, both from a sustainability and a noise and environmental perspective.

And JetZero, just to quickly follow on from that, has been operating in stealth for a couple of years and it's emerged just now because it has found this moment in time when it's able to address a military and commercial market simultaneously. And because this military market will basically reveal its existence, it has decided the time is right to come out into the open. So, it's an exciting project. And I think it's well worth paying attention to.

Joe Anselmo: 

And the way it works is they would develop it as a tanker for an Air Force program and then also it would be repurposed as a mid-market airliner, correct?

Guy Norris:

Exactly. So this is the point of why this serendipity really is quite valuable to look at now. They've seen the fact that the Air Force is interested finally in adapting this concept for a future tanker transport. And at the same time, it just so happens, that that would make a pretty darn good 250, 220-seat type commercial aircraft, which oh, just happens to fill the mid-market sector, which Boeing and Airbus are really not addressing directly at the moment with any of their products or in the foreseeable future.

So, a bit like Boeing in the mid-'1950s when it developed the Dash 80, the D367-80 model, which ultimately became the Boeing 707 and the KC-135. They see a similar window of opportunity here to rewrite the landscape or redraw it, I should say, for commercial aviation.

Joe Anselmo:  

Richard, you and your colleague, Kevin Michaels, have been out to JetZero and talked with them. What did you guys see and what do you think of it?

Richard Aboulafia: 

It was pretty remarkable. A terrific team of folks. Their facilities are modest. Obviously, this is one of those typical startup ‘just-add-capital’ stories. But there's no denying the passion and the intriguing idea pretty much exactly what Guy, I think, was talking about before. It's hard to not be attracted to a promising new technology. It's been around.

And a couple themes that really appeal to me, one, people view technology as something that just happens and reinvents everything rather than the historical model of technology, which is that very often it's around for many decades and suddenly finds relevance. There are many other examples of that in history, and this certainly fits that pattern. David Edgerton wrote a great book called The Shock of the Old that talks about the historical parallels in technology development. And BWB of course, has been around for a great many decades and it suddenly seems to have this tremendous relevance.

The other thing that really hit me was this going in as a taker and then finding the commercial relevance that Guy talks about. Because right now, it does seem incredibly neglected as a very promising business opportunity. You've got the A321neo, which is not very good for this mission, but its what everyone has to buy because Boeing has said they're not doing anything. So. you come in with something disruptive, hey, there's something there. And not only that, you've got Northrop's involvement as a tanker, as you say. I think that's important.

 As we all know, the defense contractors became pure plays. How do we entice some of them to get back into the commercial world? And this might be exactly the way to do that.

Joe Anselmo:          

I want to get to Steve, but Guy, one follow-up to what Richard just said, what are the advertised benefits of this commercial aircraft in terms of fuel burn, and operating costs, and things like that? What's the advantage of going with a blended wing body?

Guy Norris:      

We mentioned the position of the engines and the quiet side of things and how it would address any concerns you have on airport environment noise. But essentially, the key parameter from an airline economics perspective is the fact that you could look at between 30% and 50% lower fuel burn from the lower drag that I mentioned as far as the form factor of this blended wing body design. So, that immediately changes the game, because as a modern structure, this would be built from composites, therefore you have the advantages of that lightweight structure. But you've also got the ability therefore, to lift this aircraft, which would be, we should say that the concept they're looking at is about the size of a wing span of about an A330, but shorter than a 767, so if you can picture that combination.

But yet that's obviously a widebody sized aircraft, but it would be powered by either Pratt & Whitney PW 1100 geared turbofan or the CFM LEAP. So you're talking about an aircraft that traditionally would be powered by 50-60,000 pound thrust engines being powered instead by something about 35,000 pounds. And of course, this is a generation of engines that we know and love that have been optimized to for lower fuel burn anyway. So, the combination of those two factors plus the low noise of the upper mounted engines means that this would really fulfill a lot of the demands and wishes, particularly for the mid-market, which as Richard mentioned, is significantly underserved right now.

Joe Anselmo:      

Steve Trimble, they've teed it up for you. You buying what you hear?

Steve Trimble:   

I tend to be the glass-half-empty perspective on the staff, and it's definitely true with blended wing body, which I've written about in mini surges of interest over the past 20 years, really since the concept really got going by Bob Liebeck at McDonnell Douglass in 1993, 1994, that timeframe. And he was really the pioneer of all this. And then Boeing of course, and McDonnell Douglas became the same company and he tried to get it going there. But there were always some challenges, which Liebeck has always acknowledged, and I'm sure Guy is very well aware of, and Richard. I think those challenges are still with us. So, I'd like to go over them, a few of them, and see what Guy and Richard think about it.

There is an efficiency improvement obviously when you go from basically that circular fuselage structure that is just along for the ride aerodynamically speaking, not really contributing to the lift. If anything, detracting significantly from it, versus a full flying wing where much more of the structure is involved in producing lift, so you do get that efficiency. But it does come at a price.

The first is that it's hard to beat the load efficiency of a circular structure like a fuselage. And that's really how the industry consolidated on that shape to begin with. When you start making that center body shape rectangular or some other non-circular shape, you lose a lot of that strength advantage. And so what that means is you just have to bulk it up more. You have to make it stronger than it would be compared to a circular structure. And therefore, some of the efficiency advantages of a blended wing body starts eroding.

 Now, that's less of an issue, say for a military application that the Air Force is studying it for, because their business model, as you might say, is not so tied on cost-effectiveness. They're about mission execution with some interest in making it as cost-effective as possible. Whereas airlines are much more about the cost-effectiveness.

And not only that, it's not just the outside, but internally it's also very difficult to pressurize a non-circular structure. So what you're going to have probably are circular pressure vessels within that blended wing body center body, which means that you're going to have a lot of space where you can put some things in the non-pressurized space, but there's just going to be a lot of inefficient use of space compared to a circular fuselage.

So ,those are some of the classic issues with it. We could talk about some other things. Those engines ingesting the boundary layer on the back, the trailing edge of the thing are great. From a maintenance perspective and access, it's a little less so. That's come up in a lot of these conversations.

 Passengers are going to have to adapt to this kind of cabin, which is going to be a lot different than what they're used to. Probably won't have windows. May have skylights in the case of JetZero, which would be interesting when we go back to that structural loading conversation and how they're able to manage that. And egress has also been an issue when you talk about passenger applications.

I would also add that, I don't know this for a fact, but I suspect it may be difficult to customize or tailor the size of the blended wing body for a specific applications. So everybody probably listening to this podcast is well aware that there's a 737-7. There's a 737-8, a 737-9, and A320 and A321. And it's very straightforward to do that with a circular fuselage structure. You put a structural plug ahead of the wing and a structural plug after the wing, or actually on either side or the center of gravity, and you've got a larger or smaller aircraft depending on what mission application you're trying to tailor it for. It's not quite as straightforward with the blended wing body. You probably have to do that change if you're going to do it laterally instead of lengthwise, which creates some issues for gate access and other things.

So, from a military standpoint, and there is definite military interest, in fact, I think I actually broke the story on that with the Air Force reviving their interest in blend wing body based on some comments made at actually Aviation Week's MRO Americas Conference by an Air Force official last year. They are definitely pursuing this as a possible option for a next generation tanker and airlifter that would enter service at some time in the mid to late 2030s. I think there's probably merit to all that depending on what the Air Force decides to do and what requirements they establish for themselves. But the conversion to an airliner application, there's always been some issues with that. And I'm not sure if they've been completely addressed yet with the JetZero application.

Joe Anselmo:   

 Richard, even if it did work, if you look at the history of the Airbus Boeing duopoly, Embraer looked at taking it on, decided against it. Bombardier did at the lower end with the C Series, developed a great airplane, and then they got crushed and ended up having to sell it for a dollar to Airbus and get out of the commercial aircraft business. Comac only exists because of the Chinese government and really isn't a threat. So what makes this different?

Richard Aboulafia:  

Obviously that's the issue, barriers to entry. And this is an industry based on scale. And of course, it's an industry based upon commodity pricing, which means you go in expecting to make money in say year three, and everyone crushes you, just like you say about Bombardier. What's different this time is that possible in ramp via the military side. The prospect of moving up the learning curve and finding someone who's behind you that is deeply capitalized and then going with you down the commercial road, that's completely different from Bombardier or Embraer and certainly Comac.

And this is a long shot, right? But once upon a time, Northrop Grumman had a sizable commercial unit. They built the barrel of the 747s, as a matter of fact. Lockheed of course, had a very large commercial side, L-1011 and whatever else, and other transports. Who's to say that Northrop Grumman gets into this, likes what they see, sees a better mousetrap on the commercial side and says, "All right, let's get back into the commercial world"? And that would be intriguing.

Because you look at the world of possible new entrants and something that would break the duopoly. Two things are needed, one is for one of the duopolists to fall asleep at the switch and God knows it sure seems to be the case with Boeing right now, unless they decide to reverse their no-new-product this decade mantra. And the other thing that's needed is somebody with really deep pockets. And that of course, could be Northrop Grumman. So, I think this could be different, but it's far from a slam dunk.

Guy Norris:     

 And to Richard's point, I think the other thing that seems to be relevant in this regard is the fact that the supplier base as well seemed very keen on there being a third player in this market. So, if we believe what JetZero is saying, they say the reaction they've had across the industry has been remarkably positive. So we could be looking at a large base of industrial and supply base, which would be part of this process. It's not just a long shot in that regard. It seems that there are keen participants out there potentially looking at the duopoly and maybe changing the game here a little bit.

And of course, we mustn't forget, we've mentioned it before, but this middle market sector is crying out for a response and it's simply not being met. Airbus and Boeing have both decided for their various reasons, they just can't afford to or do not want to upset the apple cart right now. And neither is willing to push that way into the market. So, there is an opportunity, a genuine need.

And can I just say quickly about some of the criticisms, Steve, rightly so mentioned 'cause he's right. The blended wing body has been around a long time and why hasn't it happened before? It's a legitimate set of questions.

Egress for example, the design details that JetZero shared with us show that bizarrely there are actually as many exits available, say for a wheels-up landing for egress as there are on tube and wing airliner. And in fact, the access, the speed and distance from even a center aisle position in the center section of seats to the nearest exit is actually quicker or as quick as it is with any regular tube and wing. The loading effect on the circular fuselage argument, JetZero thinks it has basically enough composite knowledge now to overcome those earlier issues with squared off cabin sections. They looked at the design interior of this.

And the interesting thing about it is, yes, there is volume in there, but they think they can use it all. Even for example, if it evolves to a hydrogen economy in the future, there's plenty of room in there for liquid hydrogen tanks in the future. And scaling, that's maybe not something you'd have to worry about if they were aiming initially at this mid-market sector. But you're right, everybody has to consider what to do with the family. And Mark Page, who was principal designer at JetZero and one of the people who worked with Bob Liebeck for years, who came up with this T section way of being able to, you basically put an inverted T which forms the core of each of these models, and you can scale up around it, shrink it, or stretch it without affecting the overall configuration.

And my last point, sorry to go on, is that one of the initiatives that Mark's come up with is this pivot gear design. And this is really a key part of the concept. It enables the whole body to be tilted six degrees or thereabouts, so the body angle contributes to the lift, which means that you don't have a lot of the pitch control issues that a lot of these larger BWB concepts have had in the past. That's going to be an important design change in this.

Joe Anselmo:             

Steve, our listeners can't see your face, but I can, and you looked a little skeptical there.

Steve Trimble:          

Well, skeptical but impressed. I'm glad that they're addressing some of the... I'm sure they're aware of those issues and it sounds like they've got some pretty ingenious and clever ways of dealing with it. Like I said, I mean, I do think that there's definite interest and it's an easier path for them on the military side for a lot of reasons. But of course, the military itself may not actually have the financing in capitalized ability to pull this off on its own.

In fact, when they came out with their RFP for companies to submit to build this X-plane that they want to build in the next few years at this scale, they said that we want a company that can show us a business plan to make an airliner out of this so that they can defray and offset some of the costs so that the Air Force doesn't have to pay for the whole thing. So they will have to address these issues almost simultaneously, these efficiency issues and performance issues that they have to address in order to make it competitive in the airliner space.

And then of course, it's what Richard was talking about, just the financing and leverage advantage, the scale advantage that Airbus and Boeing can bring to the table if they so decide is hard for anybody to overcome, even with the backing of the Air Force, given that the Air Force order, it will only ever be 15 aircraft per year at the most. I mean. Well, maybe more, but it's hard to imagine that at this point.

 So that's what they're up against. I really wish them well. It'd be great to see it happen. I've covered this for many years. I was there when Boeing delivered the pultruded rod stitch efficient unitized structure or PRESEUS that they tried to solve a lot of these structural loading problems under a NASA contract back in 2012 or so. And I hope that they figured it out. But it is a big challenge.

Guy Norris:    

And just mentioning NASA, of course, I must point out that they were pretty keen on, they've got the Sustainable Flight Demonstrator Program, which they awarded to Boeing with the Transonic Truss-Braced Wing, which is another great efficient design that's been hatched for the future. But they were sufficiently keen on the JetZero concept to award them an initial subscale flight demonstrator contract. And that is being built as we speak. Or in fact, it's been built and it's about to go up to the desert to begin flying later this year. So, it's not to say that NASA themselves weren't encouraged by what they were seeing with this new concept, particularly the pivot gear that I was just mentioning.

And people will say, "Well, hang on a minute. Why is NASA, if it is that interested, why didn't it award JetZero the contract for the full up aircraft? Or why did it go to Transonic Truss-Braced Wing?" Well, of course, that is a different sector of the market. The TTBW will really address the replacement single aisle market for the future, whereas it doesn't at the moment anyway, scale up to anything much larger than a 75. So you're in that gray area, but essentially two different markets.

Joe Anselmo:        

And what's the timetable? When is the Air Force going to make this award for the tanker?

Steve Trimble:     

Well, so there's a process that they're still unfolding. Now the plan is to start with this X-plane, which they talked about being a full-scale X-plane and actually to have it fly by the end of 2026, or fiscal 2026, which I think seems very ambitious and aggressive even for an X-plane. But perhaps that they can make that work. A lot of it depends on how much funding they can get from Congress in fiscal 2024, assuming they can get any funding at all out of this Congress this year, because that could delay things as well.

Based on that, they want to be able to get this product, if this is the way they go for next generation tanker and airlifter, they want this to be the follow on to the KC-46 or whatever comes out of the bridge tanker concept. That's a whole other story about where that's going. So in the mid 2030s, late 2030s, they want to have this, whatever that is, be available to be that next tanker. And they want it to be more stealthy, which a flying wing can help them accomplish as well. So that's the general plan, but it depends on several factors that are not even all in the Air Force's control.

Joe Anselmo:    

We will continue to stay on top of this story, obviously. Steve Trimble, thanks for your insights. Guy, congratulations on your scoop. Always great to have you. And Richard, thanks for taking the time to join us. We always love having you on as well.

That is a wrap for this week's Check 6 Podcast. A special thanks to our podcast editor in London, Guy Ferneyhough. Don't miss the next episode by subscribing to Check 6 in your podcast app of choice. And one final request of our listeners, if you're listening to us in Apple podcast and want to support this podcast, please leave us a star rating or a review. Thank you for your time and have a great week.