Opinion: Why It Is Time For The Blended Wing Body
The protests at last month’s European Business Aviation Convention and Exhibition in Geneva remind us of the need for aviation to accelerate its decarbonization progress (page 30). Sustainable aviation fuel is the only realistic near-term option for long-range jetliners but will be lucky to reach 15% penetration by the mid-2030s. Hydrogen has significant promise but is decades away as a potential solution. Aviation needs a game changer. Paradoxically, that could be a design concept that has been around for 100 years: the blended wing body.
The BWB’s key advantage is fuel efficiency. Its airfoil-shaped body allows the entire aircraft to generate lift, reducing fuel consumption at least 30-40%. When coupled with sustainable aviation fuel (SAF), carbon emissions could fall more than 80%. There are other advantages. The empennage is eliminated, and top-mounted engines reduce aircraft noise by 15 dB or more. BWBs offer improved survivability with lower radar and infrared signatures in military applications. And there is ample space for cylindrical hydrogen fuel tanks, which are not particularly compatible with tube-and-wing aircraft designs.
The BWB does have downsides. Moving away from the load-efficient cylindrical fuselage can add weight and complexity to the structure. Passengers would need to adapt to a dearth of windows and a new cabin format. Then there is inertia: The aerospace ecosystem has utilized tube-and-wing designs since the beginning. How would the industry transition? How would BWBs be certified?
Three notable BWB concepts were introduced in recent years. The first, a 200-passenger design powered by hybrid-hydrogen turbofan engines, was introduced by Airbus in 2020 as part of its ZEROe initiative. Airbus also flew a small-scale demonstrator aircraft.
The second recent BWB concept, revealed last year, is the Bombardier EcoJet. After flying a small-scale demonstrator, the OEM believes it could reduce aircraft emissions by up to 50% through a combination of aerodynamic and propulsion enhancements. It also sees the potential for an enhanced passenger experience.
The most intriguing design was unveiled recently by California startup JetZero. Its Z5 (see image) is designed to carry up to 250 passengers over a range of more than 5,000 nm. JetZero says the aircraft’s structure is lighter per passenger than comparable conventional aircraft. The Z5 is aimed squarely at the New Midmarket Airplane (NMA) category, and rather than 50,000-60,000-lb.-thrust engines required for tube-and-wing aircraft, JetZero expects to be able to use conventional CFM International Leap or Pratt & Whitney geared turbofan engines with perhaps 35,000 lb. thrust. The result is an estimated 50% reduction in emissions.
Why could JetZero succeed in entering the jetliner business with an unconventional design when every new entrant has failed over the last 50 years except for Embraer? There are several reasons.
First, the Pentagon is interested in leveraging BWB advantages for a tanker or transport aircraft. The design could expand fuel-carrying capacity, increase range and offer improved survivability—all critical for emerging mission requirements in the Asia-Pacific region. JetZero is in a down-select phase for a public-private, full-scale U.S. Air Force BWB demonstrator program.
JetZero has impressive partners, including Northrop Grumman and Scaled Composites. Among its leaders are Tom O’Leary, a former Tesla and Beta Technologies executive; Mark Page, a McDonnell Douglas BWB veteran; and John Vassberg, Boeing’s former chief aerodynamicist. The company’s advisory board is a who’s who of aerospace.
Another reason for optimism is that the pressure for tangible emissions reductions will only increase. The BWB offers a step-function improvement with the ability to use SAF and transition to green hydrogen.
JetZero also benefits from timing. The Z5 offers the potential of a rare “troika” of enhanced national security, sustainability and economic benefit—all priorities in Washington. With interest from both civil and military customers, the Z5 could follow the path of the Boeing KC-135 and 707, where the Pentagon funded much of the aircraft’s development costs before commercializing.
Finally, the target NMA market segment is wide open. Boeing does not plan a new aircraft until the mid-2030s, and the strong sales of the A321neo demonstrate the magnitude of the opportunity.
It remains to be seen if JetZero can challenge the Airbus-Boeing duopoly, but its entry could spur incumbents to innovate much like Tesla and SpaceX did in their respective industries.
Former Airbus Americas President and CEO Barry Eccleston is on JetZero’s board of advisors. When asked why he’s a supporter, he stated: “The industry deserves it and doesn’t do well when it stops innovating.”