By Bjorn Fehrm

March 13, 2026, ©. Leeham News: The flying wing has been researched for almost 100 years. During the Second World War, the Horten Brothers developed as flying wing military aircraft in Germany with mixed success. The Northrop company then flew several flying wing prototypes after the war, finding these to have severe stability issues at higher angles of attack.

With the advent of Fly-By-Wire, this could be mastered, and the flying wing’s inherent low radar cross-section is used in the B-2 and B-21 US Air Force bombers.

A flying wing is not suitable for use as an air transport passenger aircraft, as passengers would feel as if they were being transported in a coffin within the wing. An evolution of the flying wing is the Blended Wing Body (BWB, Figure 1), which moves the center section forward to form a blended fuselage that houses the payload.

Figure 1. The JetZero Z4 BWB in United’s colors. Source: JetZero.

As the search for lower fuel consumption and emissions intensified, the search for a more efficient way to transport passengers has led to increased interest in the BWB concept since the early 1990s, primarily from NASA and the US aircraft industry.

The proliferation of composite primary structures since 2000 has helped address the structural problems of a BWB. This has created a renewed interest in BWBs, both for military and commercial applications.

The fundamentals of Blended Wing Bodies, BWBs

In this Corner series, we will look into the fundamentals of the BWB as a commercial airliner and analyze its advantages and disadvantages. To do this, we need to cover some aircraft design fundamentals, as there are many misconceptions about why BWBs would be a more efficient way to transport passengers than our dominant Tube-and-Wing aircraft.

It’s not about more lift

Much of what is written about BWB says these are good because the entire aircraft now generates lift. An airliner that cruises does not need much lift. It only needs enough lift to compensate for the aircraft’s weight, Figure 2.

Figure 2. The fundamental forces on an aircraft at cruise. Source: Leeham Co.

The wings of Tube-and-Wing airliners do this just fine; in fact, they’re over-dimensioned for the required cruise lift. And that the fuselage of an aircraft shall generate lift is not a desired state. In fact, the advanced wings of the Boeing 787 and Airbus A350 are designed to allow the fuselages to fly with minimized lift, thereby increasing aircraft efficiency.

The micro-adjustable flaps ensure the wing curves more when the aircraft is heavy, generating the needed increase in wing lift, thereby allowing the fuselage to remain at a very low Angle of Attack to minimize detrimental lift.

To generate lift efficiently, we want a very wide structure to reduce the global circulation around it that generates induced drag (Figure 3).

Figure 3. The global circulation that causes induced drag. Source: Leeham Co.

A fuselage is narrow and long; therefore, it is a lousy lifting surface, which creates a lot of induced drag as the angle of attack increases.

It’s about lower drag

The principal advantage of the BWB is that it can generate less drag at the same transported payload than a tube and wing aircraft. To understand how, let’s examine the buildup of drag on a typical airliner, Figure 4.

Figure 4. The drag components of a single-aisle airliner at cruise. Source: Leeham Co.

The pie chart shows the different types of drag and their size of total drag for a single-aisle airliner at cruise. The pie chart will look slightly different for a BWB airliner, but it won’t change much. What’s interesting is whether the total drag, i.e., the total size of the pie chart, can be reduced.

We see that the dominant drag for an airliner is skin friction drag, which arises on the aircraft’s outer surface and results from the skin’s scrubbing friction against air molecules. The way to reduce this drag is to minimize the surface area of the aircraft, called the Wetted Area.

The second-largest drag is the induced drag, the one where we want the widest possible airplane to stop air molecules from passing from below the aircraft to above it (Figure 3).

This is not a local wigtip phenomenon (like some wingtip device designers think), it’s a global movement that is still recognizable several wing-widths out from the aircraft. The way to minimize Induced drag is to make a wide wing and to have an elliptical lift distribution from wingtip to wingtip.

The rest of the drag types in the chart are small contributors for a well-designed aircraft. We will focus less on these than on the dominant drags: air-friction drag and induced drag.

The BWB drag advantage

So to make a BWB be more efficient than the typical Tube-and-Wing airliner for the same transported payload, we need to reduce air friction drag or induced drag or both.

A lot of research using CFD (Computational Fluid Dynamics) modelling and scale tests in small and large wind tunnels (i.e., free-air) has quantified the drag advantages of the BWB. The results vary greatly as the BWB has some fundamental problems away from cruise that can sabotage the design of an efficient BWB.

We will start detailing all this in the next Corner, now that we have established the basics of how we can achieve BWB efficiency.