For decades, the blended-wing-body (BWB) aircraft concept has been the topic of many conversations in the aviation industry. A blended-wing-body is described by NASA as a “hybrid shape that resembles a flying wing, but also incorporates features from conventional transport aircraft,” such as a passenger cabin and cargo hold. It has been thoroughly researched by many different companies and organisations who have revealed the many benefits and advantages of the design.
These benefits include its range and payload capabilities, its aerodynamically superior design, its prevailing efficiency and improved passenger comfort. However, while having an abundance of advantages, the BWB concept does have some problematic flaws that are the reason it is not commonly seen in the skies today. This analysis will describe the benefits and downsides of the blended-wing-body aircraft while outlining the basic features of the concept that, although over 30 years old, could be the key to future success in aviation and air travel.
The BWB concept is a massive leap in aircraft and air transport standards. It is a thick hybrid flying wing that could carry up to 800 passengers over extremely long distances in a centre-body that smoothly transitions into the outboard wings and is an ingenious aircraft concept for high-speed subsonic flight that can be implemented on both civilian and military operations. The BWB design integrates the engines, wing and body into a single lift-producing aerofoil in which the passenger cabin and/or cargo holds are situated. The aircraft would have a high thickness body and low aspect ratio wing to create maximum lift with minimum drag (which will be covered in further detail later in the report).
To make the aircraft as aerodynamic as possible, slight adjustments are made to the basic frame. For example, large winglets are gradually blended at the ends of the wings to assist with wingtip vortices and control surfaces are located on the trailing edge of the structure rather than a conventional tail assembly for the rudder and elevators, in order to reduce interference drag. The spacious configuration opens up a very flexible design space, allowing manufacturers to possibly integrate various different types of propulsion systems.
Airbus Industrie describes the BWB concept as a “complete departure from traditional aircraft architecture” as it defies the conventional tube-and-wing design that is seen in the vast majority of today’s aircraft, and instead, is a “triangular tailless aircraft that effectively merges the vehicle’s wing and body” (Boeing). This game-changing concept is a renaissance in long-haul transport and will continue to grow closer to reality due to the increasing demand for efficient and environmentally friendly aircraft.
Compared to the conventional tube-and-wing aircraft, the blended-wing-body design provides a quantum leap in overall performance and efficiency. The aircraft’s aerodynamic and structural efficiency is due to its wingtip-to-wingtip lift distribution. This reduces the amount of form drag and enhances its ability to generate lift with minimal drag. Greater space above the wing allows for more efficient higher bypass engines or other propulsion systems.
BWB aircraft provides significantly improved fuel economy with almost 30% less fuel per seat-mile than a conventional airliner. This is due to the saving of structural weight which increases its economical efficiency, making it a greener aircraft. The reduction in fuel required to power the aircraft aids in reducing the operating cost per seat-mile, giving the design a superior payload-range performance. Noise levels and, hence, pollution can also be reduced by placing the engines or other propulsion systems on top of the aircraft. Not only is this better for the environment, it adds to the passenger comfort levels.
BWB aircraft will see a great increase in passenger comfort and airline service standards. Its greater internal volume will significantly improve the passenger experience due to an “exceptionally spacious cabin layout” (Airbus). This additional cabin space will allow for more legroom, baggage storage and larger aisles, all of which are constant issues with today’s conventional passenger aircraft. Airbus believes that passenger acceptance of the BWB concept could also be built with the use of technological concepts that involve virtual screens for situational awareness, such as virtual windows, similar to those currently used by Middle Eastern carrier Emirates in their new Boeing 777-300ER First Class suites. Without the acceptance of the BWB concept from passengers, it will be extremely difficult to implement the aircraft on regular public transport operations.
Although the blended-wing-body has many benefits, there are some challenges that are faced when designing such a unique aircraft. A major challenge is the integration of payload into the centre section volume. The smaller the aircraft, the bigger the challenge, however, the wing box needs to be tall enough for 95% of the world’s tallest people to be able to stand upright without their heads touching the ceiling. There also needs to be space above the ceiling and below the floor for ventilation and systems. Other challenges include the execution of an emergency evacuation, ground handling and airport compatibility due to the shape and wingspan of the aircraft and lack of passenger comfort and acceptance. The majority of test aircraft and prototypes therefore favoured freight operations over passenger operations due to these issues arising from safety concerns.
The short moment arm for control surfaces is another reason as to why the BWB is not extremely common, as rotating the aircraft about the lateral axis is a challenge, particularly on rotation. Most aircraft manufacturers would not develop a blended-wing-body aircraft as they prefer to design families of aircraft, rather than a single, fixed variant. The BWB is not like conventional tube-and-wing aircraft where a simple stretch or shrink of the base design will create another variant. Hence, the concept is not exactly a reality just yet.
Overall, the blended-wing-body is a ground-breaking concept that, while troublesome in some aspects, has benefits that outweigh the challenges, such as outstanding payload and range performance potential, superb aerodynamics and matchless fuel efficiency.