The Flying Wing Part Two – The Blended Wing Body

The BWB is Born

As J W Dunne was conducting his early flying wing tests, there were  developments happening across the Atlantic in Europe. For the very first time, engineers were thinking of using the insides of the wings. A design philosophy was born.

The Pioneers

In 1910 Hugo Junkers of Germany patented a cantilever tailless wing design. It was an all metal construction (almost all aircraft until then were fabric and wood construction). Such a design & construction would be without any external wires or braces. Furthermore the wings could be hollow and the space used to house passengers, cargo and fuel. His designs were used by the Germans in WW1 and later in WW2 (he was ousted from his company in 1933 by the Nazis). 

The G-38 of 1929 was a major innovation of his blended wing concept and was for a time the largest landbased aircraft in the World. The passengers were seated in the wings which were 5 feet 7 inches thick at the root. The leading edges of the wings had sculpted windows giving passengers a panoramic view as they flew. There were three 11 seat cabins,in addition to smoking & wash rooms. The wings had a gangway through them that allowed mechanics to work on engines while inflight, a first. There were two operating aircraft and flew through to 1941(both flew until 1936)  before the final one crashed.

The Mitsubishi Ki-20 was based on the Junkers G-38. Six were built as heavy bombers between 1931-35. During WW2 they saw active combat. These aircraft were considered secret and their existence only made public in 1940.

Nicolas Woyevodsky was a Russian Aerodynamicist who filed a 1911 patent called ‘Aircraft’. Here’s where the patent gets interesting. It was filed in the United States in 1911 and granted in 1921 ( how and why did a Russian file for a patent in the USA and why did it take so long?). Not much else is known about this path breaking scientist other than his name, country of origin and patent.

The patent spoke of a continuous airfoil section integrating the fuselage and wings, what we now call the BWB. The patent further described a triangular shaped body with pterygoid (triangular) aerofoil sections that enclosed the engines and passengers. Such a construction would reduce drag and weight enhancing lift. This was considered revolutionary as most aircraft were biplanes with separate fuselage and wings.

Woyevodsky’s 1921 patent led to wind tunnel tests (probably in Russia & Britain) and validated his theory which led to designer GTR Hill of Westland designing and building the dreadnought. GTR Hill was already experimenting with the Westland Pterodactyl. The Pterodactyl was a revolutionary flying wing and flew through the 1920s & 30s in the hunt for a safer aircraft. The Dreadnought unfortunately crashed on its very first flight. After an initial stable take off and stable flight the Dreadnought stalled at 100 feet altitude and crashed, seriously injuring the pilot. The design was abandoned at the time, however It is recognized and appreciated by history.

The British further tried to pursue the BWB airliner design in the late 1930s & 40s through the Miles M.26 & M.30. The data was useful, however a full scale prototype was never constructed.

The BWF (Blended Wing Fuselage)

The timeline between the 1940s & 1990s is a BWB gap (very similar to the flying wings but longer, aviation development had moved rapidly in the direction of conventional aircraft ),except for the military applications between the 1950s – 1980s when the BWF was used. The A-12 Oxcart and its successor the  SR-71 pioneered the BWF design. The BWF integrates the fuselage and wings in a smooth aerodynamic transition, however the fuselage continues to be a distinct structure. 

Such a design used the fuselage as a lifting body, and the chines around the body contribute between 15-30% of total lift generated. The design used Area ruling and mitigated parasitic & wave drag through smooth transitions.

In the 1970s the Rockwell B-1 introduced variable geometry to the BWF. The wings pivoted on 6 ton hinges which are buried inside a wide fuselage. The BWF of the B-1B contributes approx 15-20% of the total required lift. 

The Tu-160 which has a very similar design to the B-1 has an even larger BWF. The BWF contributed approx 18-25% of the total lift in supersonic flight.

All the aircraft mentioned had variable geometry inlets of various types (spikes / ramps).

The BWB Evolution

The Generation 1 BWB’s commenced in the 1990s and ran through to the 2010s. They represented the ‘ High Risk High Reward’ approach to BWBs where they envisioned extra large 800 seat BWBs with maximum aerodynamic efficiency. This meant Boundary Layer Ingestion (BLI) of the engines and integrating them inside the airframe. This proved to be difficult to accomplish & certify.

The NASA/McDonnell Douglas Studies were funded by NASA between 1993-96. The studies included wind tunnel tests of tailless BWB concepts at 1-6% scale. Models tested had the centre body contributing between 31-43% of total lift and exhibited between 6-8% fuel savings. 

NASA BWB-17 was tested between 1997-2000. With a 17 foot wingspan, the 6% scale RC model was built by Stanford University for NASA. The model demonstrated low drag and had centrebody lift of between 30-40%. The model proved BWB flight handling with a tailless design. The BWB-17 had stability issues and needed artificial stabilization to correct. The model further highlighted scaling & control issues on larger aircraft.

Boeing Phantom Works BWB studies ran between 2000-2007. Post the McDonnell Douglas acquisition of 1997, Boeing continued to build on the earlier program that ran between 1993-96. 

Part of the program was to construct the 35 foot wingspan X-48A demonstrator in 2004, however the program was cancelled before construction began. In 2005 a 12 foot wingspan BWB model was constructed to study transonic aerodynamics in a wind tunnel. This model exhibited a 15-20% drag reduction and lift to drag ratio of 20-23. As the project was for 450 seat passenger airliners it highlighted manufacturing complexity & airport compatibility issues.

The Boeing X-48B program ran between 2007-2010. It was a 8.5% scale 21 foot wingspan model that was powered by three jet engines and flew between Mach 0.3-0.7. The centrebody contributed 35% of the lift and had L/D improvements of approx 20% over conventional designs. The X-48B continued to have challenges with yaw handling and full size scaling. Furthermore engine out control and stall characteristics were tested and needed improvement. The aircraft needed artificial stability management.

The Generation 2 BWBs run from approx 2010 to date. Gen 2 highlights a safety first approach to design and has podded engines mounted above the airframe. The realistic path sacrificed potential efficiencies for safety with the approach. The Gen 2 BWBs also explored different propulsion types.

NASA N2A/B/C BWB concepts ran between 2010-2015. The concept was for a 300-450 passenger aircraft. Conducted in partnership with Boeing the N2A had two podded engines mounted on top of the upper surface of the aircraft. Wind tunnel testing was done to study its aerodynamic and acoustic performance at low speeds. The N2B used BLI and had embedded engines. While the N2B showed improvements over the performance of the N2A, the embedded engines increased manufacturing complexity. The N2C was a supersonic concept. The data gleaned from these concepts was to inform the future aviation industry on future design areas.

The Boeing X-48C first flew in 2012. With a wingspan of 21 feet it was a 8.5% scale of a large transporter. The C was focussed on noise reduction and featured vertical surfaces adjacent to the engines.The Modified X-48B had an extended aft fuselage on which the engines were mounted. It completed its 30th and final flight in 2013.

 

NASA N3-X Hybrid Wing Body that ran between 2013-2018 is a concept design. NASA tests such concepts through computer simulations and & wind tunnels. The research was on advanced technologies and propulsion. Some of the concepts explored included Turbo Electric Distributed Propulsion where instead of large engines, smaller electric fans distributed propulsion across the aircraft. Another concept explored was the Superconducting Power System, where superconducting technology allows for high power density with minimum energy loss. Others included wingtip generators and liquid hydrogen cooling. 

The N3-X can achieve a 70% reduction in fuel burn, significantly lower emissions and noise levels while maintaining performance at the same time.

The Airbus Maverick began development in 2017. With a wingspan of 10.6 feet and a length of 6.7 feet, the Maverick had two engines to the rear with each having a vertical fin on it. The model explored aerodynamic and technical specifications and results were encouraging .

Airbus has further built on its BWB program by targeting 2035 as the first year for a zero emission aircraft. Such an aircraft would use hydrogen combustion or cells for propulsion. Storing Hydrogen is a big challenge in aviation and the BWB is considered an excellent test design. Airbus is further  studying conventional aircraft for its zero emission program. 

JetZero 

JetZero is founded by Mark Page a BWB pioneer. He was part of the seminal NASA / McDonnell Douglas collaboration on the BWB program as technical program manager. NASA concieved the program as a challenge to rethink aircraft design for greater efficiency. The program (although Mark was not part of it after 1996) culminated in the BWB-17(spoken of earlier) the very first BWB of the modern era. It was inspired By Northrop’s flying wings of the 1940s but was a completely fresh approach to aircraft design. The BWB design was co-created with Robert Liebeck & Blaine Rawdon and offered 20-30% better L/D ratios than conventional aircraft. The three of them authored ‘Beyond Tube and Wing’ in 2020 in which they charted the path to the BWB design.

The philosophy was Multidiciplanry Optimization (MDO) integrationg aerodynamics, engines, stability and internal structures to minimize drag and maximize efficiency. Page virewed the BWB as the fundamental reimagining of an aircraft blending wing and body into a seamless flowing structure. In one presentation Page mentioned imagine a Boeing 777 fuselage cut up into three parts and placed side by side. You then stick wings on the first and last sections, the middle one being the longest (with the cockpit) and place the engines on top of the stacked side by side fuselage, and lastly smooth them all together into one fused structure.

Page’s contributions influenced the X-48B/C programs as well. These programs validated the theory of BWBs with subscale models and wind tunnel testing. They sorted out  issues such as space by moving the main landing gear to the rear of the aircraft from the centre, saving space and increasing passenger numbers another example is sorting out pitch stability control issues with belly flaps, every thought had to be out of the box.

Later in 2012 Page co-founded DZYNE Technologies as chief scientist & VP and here he continued to focus on aircraft with high lifting efficiency , but the BWB bug was always there, first as a business jet and later as an airliner. In 2021 Page along with Tom O’Leary founded JetZero to take forward the BWB vision.

Page has mentioned that startups like JetZero are ideally placed to revolutionize the aircraft manufacturing space as they do not have massive legacy businesses that need to transition ex : Boeing & Airbus.

So far it has walked the talk with Alaska & United Airlines investing in JetZero through their investment arms. Delta Airlines is a strategic partner sharing expertize from a customer engagement perspective. In addition JetZero are talking to 14 other airlines and the USAF has awarded a $235 million contract to JetZero to build a full scale demonstrator, but we are getting ahead of ourselves.

The 12.5% scale JetZero pathfinder with its 21 foot wingspan first flew in 2023 and received FAA clearance in 2024. The USAF found the Pathfinder to exhibit similar characteristics to the X-48 program and has given the go ahead to JetZero to create a full scale demonstrator which is to be ready by the first quarter of 2027. The demonstrator is being constructed by Scaled Composites founded by the legendary Burt Rutan who has aircraft/spacecraft such as Spaceship One (won the Ansari X Prize) and Stratolaunch to his credit. Scaled Composites is now part of Northrop Grumman (its amazing the name Northrop is involved here, a doff of the hat to Jack Northrop).

The Z4 is a multirole platform and can be used for both passengers & military applications such as a sky tanker (the USAF is looking at the KC-Z4 as a replacement to its aging KC-135 tanker). To cut down the development & certification runway JetZero will be using Commercial off the shelf (COTS) parts where possible. 

The engine choice is Pratt & Whitney PW2040 each generating approx 43,000 pounds of thrust. These are the very engines that powered the Boeing 757 & the Boeing C-17 Globemaster. While the design of the engines might be almost 50 years old, they are tried and tested and have a solid track record. Delta have provided three engines for the demonstrator. These engines are more than capable of managing the Z4s 5,000 nm range and cruise altitude of 45,000 feet. They will obviously be modernized for the production models. In future the Z4 might be offered with newer engines. Mark Page did note they were not looking for perfect tech, but are more interested in proving the airframe.

The fuselage ( after the demonstrator)will be made of composites and be manufactured at their Greensboro facility. Some of the other innovations it will have are shorter landing gear to enhance low speed handling, cargo door matching the KC-10 size (USAF applications). The passenger experience stresses comfort & efficiency (the 3D renderings on the JetZero website look stunning).

The personal passenger experience aims to revolutionized by offering larger seats, flexible cabin layout and dedicated overhead bin space (have forgotten what this feels like!). Instead of physical windows JetZero plans on high definition exterior cameras that provide a live view on digital windows. There is a possibility of overhead windows as well in addition to mood lighting.

While the overall exterior design of the aircraft is very sculpted, Page and his colleagues came up with a ‘ T ‘ shaped plug solution to scaling up the aircraft to either smaller or larger capacities, this means the aircraft construction has to be modular in nature almost like ‘LEGO’ !! They did this back in the 90s and the 25 year limit on the patent has expired, in Page’s own words “ I am happy to have it back” !

Mark Page emphasizes pragmitism over perfection and this is achieved by delivering on the USAF contract, using milestones to attact fresh funding (the Z4 is expected to cost approx $5-7bn to develop as per Jon Ostrower of TAC) and target the largest market segment for aircraft the 200-250 passenger aircraft market worth over $2.5 Bn per annum. With projected savings of 50%, this will be a no-brainer for airlines future fleet decision making.

BWBs have promises to keep…..

Please be sure to read Part 1 of the two part series which details the evolution of the flying wing in detail at http://theaviationevangelist.com/2025/09/13/the-evolution-of-the-flying-wing-part-one/

End of Part 2

For more deep dive easy to read articles please go to https://theaviationevangelist.com do keep scrolling down, and do share

Follow me:

LinkedIn : https://www.linkedin.com/company/the-aviation-evangelist/

X : @ManiRayaprolu

Reddit : r/theaviationevangelist

Facebook : https://www.facebook.com/profile.php?id=61583497868441#

https://www.instagram.com/theaviationevangelist?igsh=ZjA5YXI3MWd3OGZs&utm_source=qr