China reportedly adds an 800-passenger jet with a ‘flying wing’ body to its big aircraft plan. A futuristic plane model has a wingspan 1.6 times that of a B-2 Spirit stealth bomber and seats more than the world’s largest commercial aircraft. Earlier, back in 2022, India’s DRDO flew the GHATAK Flying-Wing UCAV Demonstrator.
The US Air Force (USAF) B-21 Raider “flying wing” bomber made its first flight back on 10th November 2023, and it has rekindled thoughts of an airframe design that has been evolving for nearly a century but perhaps needs more exploitation. Like its predecessor, the Northrop Grumman B-2 Spirit, the B-21 Raider will be able to deliver both conventional and nuclear weapons around the world using long-range and mid-air refuelling capabilities. At nearly $750 million apiece, it is a costly beast. The USAF plans to buy 100 of these stealthy planes, which Northrop Grumman calls sixth-generation aircraft. The flying wing appears to have secured its place in the USAF bomber fleet well into the 21st century. Among the other flying wings produced in significant numbers was the Lockheed Martin RQ-170 Sentinel. In the prototype stage, aircraft and unmanned aerial systems (UAS) include the BAE Systems Taranis, Boeing Phantom Ray, Sukhoi S-70 Okhotnik-B, Dassault nEUROn, and the technology demonstrator DRDO Ghatak. The prototype flew on 1st July 2022.
The Flying-V is a proposed flying-wing airliner being studied by researchers at Delft University of Technology in the Netherlands.
Because a deep wing is needed in practice, the flying wing concept is mostly adopted for subsonic aircraft. There has been continual interest in using it in the large transport role, where the wing is deep enough to hold cargo or passengers. Several companies, including Boeing, McDonnell Douglas, and Armstrong Whitworth, have undertaken design studies on flying wing airliners to date, but no such airliners have yet been built.
Flying Wing Concept
A flying wing is a tailless fixed-wing aircraft that has no definite fuselage, with its cockpit, fuel, payload, and equipment accommodated inside the main wing structure. In some cases, a flying wing may have vertical stabilisers. A pure flying wing is theoretically the lowest-drag design configuration for a fixed-wing aircraft. However, because it lacks conventional stabilising surfaces and the associated control surfaces, the flying wing remains unstable and requires a specially designed control system.
Possibly the first true flying wing, which was shaped like an elliptical seed, was designed and flown by Czechoslovakian designer Igo Etrich in 1909. He finally abandoned the true wing concept and added a tail for stability.
More formal flying wing configuration studies began in the 1920s. Over a dozen flying-wing experimental aircraft were developed in the 1930s and 40s, including the German Horten Ho 229 jet. Many were planned as gliders.
But there were serious stability issues on both the pitch and yaw axes. Finally, ailerons and elevators were combined into one unit, called elevons. Rudder control for yaw was provided by wing tip-mounted split-clamshell flaps that opened to create drag on the desired side. If the wing tips were placed farther aft of the centre of gravity, they tended to act like a tail for a stabilising effect.
Military interest in the flying wing waned during the 1950s with the development of supersonic aircraft. It was renewed in the 1980s due to its potential for stealth technology and the military’s increasing need to penetrate areas heavily defended by radar; the flying wing was reborn. It finally led to the B-2 stealth bomber. In early 1988, Northrop Corporation received a $2 billion contract to build the B-2. The USAF contracted for the procurement of 132 aircraft. With the demise of the Soviet Union, the number was reduced to 20 operational aircraft plus one test aircraft.
Adopting a thick wing that accommodated the crew and equipment directly conflicted with the optimal thin wing for supersonic flight. No supersonic flying wing has ever been built.
Advantages and Limitations of Flying Wing
Aerodynamically, the pure flying wing is not a very good design. Also, it is unstable. Only after modern computer-controlled fly-by-wire systems evolved was it possible to compensate for the aerodynamic drawbacks. Remaining subsonic is another drawback in the hypersonic age. Because the flying-wing aircraft used the whole aeroplane to provide lifting force, it would allow carrying a heavier load. The big advantage is the huge onboard real estate for fuel (range and endurance) and integral weapon bays.
Flying Wing Bombers
The Northrop YB-35 was an experimental flying-wing, pusher-propeller-powered heavy-bomber aircraft developed shortly after World War II. Only prototypes and pre-production aircraft were built. Two of the unfinished airframes were converted to use eight Allison J35 jet engines and designated YB-49. Seven incomplete airframes began conversion to jet power as YB-49B but were never finished.
The B-2 has a worldwide reach through aerial refuelling. It is powered by four General Electric F-118-GE-100 engines with 17,300 pounds of thrust per engine. The B-2 has a wingspan of 172 feet and a length of 69 feet. It is a high-subsonic-speed aircraft with a ceiling of approximately 50,000 feet. Its unrefuelled range is approximately 6,000 nautical miles, with a 40,000-pound payload. The B-2‘s composite materials, special coatings, and flying-wing design all contribute to stealth.
The Northrop Grumman B-21 Raider is currently under development as part of the Long Range Strike Bomber (LRS-B) programme. It will be a long-range, stealth intercontinental strategic bomber capable of delivering conventional and thermonuclear weapons. It will replace the Rockwell B-1 Lancer and Northrop Grumman B-2 Spirit by 2040, and possibly the Boeing B-52 Stratofortress after that. It is expected to enter service by 2027. Details are still confidential.
The Russian Tupolev PAK DA is a next-generation, flying-wing design, subsonic stealth strategic bomber currently under development. The aircraft is expected to enter serial production in 2027. It is being designed for a 12,000-kilometre operational range and an endurance of 30 hours, and it will carry both conventional and nuclear payloads of up to 30 tons. The Xi’an H-20 is an under-development, flying-wing design, subsonic stealth Chinese strategic bomber. It was heavily anticipated to be ready by 2025, though its official fielding timeline remains tightly guarded.
Great for Unmanned Platforms and Drones
Most unmanned aircraft still fly subsonic. Once the technology proliferates and becomes easily accessible and cheaper, more UAS will be of flying wing design. Many drones are made in flying wing configuration. India test-flew the Autonomous Flying Wing Technology Demonstrator, a precursor to future combat drones.
The Lockheed Martin RQ-170 Sentinel, nicknamed Wraith, is an American flying-wing drone operated by the USAF for the CIA. The flying-wing X8 can fly autonomously from takeoff to landing. The user can plan, fly, and modify the UAV mission in real time. Flying up to a max speed of 100 Kmph, it can be used for surveillance. Skywalker is a long-range flying-wing design drone that can be used for mapping, surveillance, carrying a specialised payload, or even as a target drone.
The Northrop Grumman RQ-180 is an American stealth, flying-wing-design unmanned aerial vehicle (UAV) surveillance aircraft intended for contested airspace. The Hongdu GJ-11 Sharp Sword is a Chinese stealth flying-wing UCAV that can carry a 2,000 kg payload.
Turkish Aerospace Industries (TAI) flying-wing combat drone Anka-3 has already flown and is meant to enable low radar visibility, high-speed transfer capability, and a high payload. The Sukhoi S-70 Okhotnik-B is a Russian stealth heavy unmanned combat aerial vehicle (UCAV) with a flying-wing design being developed as a sixth-generation aircraft project. It will be part of manned-unmanned teaming with the Su-57 fifth-generation fighter.
Blended Wing-Body
Both Boeing and Lockheed Martin have been working on stealthy tactical cargo aircraft with a blended wing-body (BWB) design for more survivable airlifters and flight refuelers. These could be flying wings, with or without a vertical stabiliser. The Boeing-NASA X-48 is an uncrewed or pilot-optional subscale design for such experiments. The US Air Force is separately looking for a stealthier successor to the C-17 Globemaster III cargo aircraft. A BWB-type vehicle could be developed in the next 10 to 15 years as a subsonic transport and tanker, incorporating some degree of stealth.
Future Airliner Options
A wing that is made deep enough to contain the pilot, passengers, engines (optionally), fuel, undercarriage and other necessary equipment will have an increased frontal area, when compared with a conventional wing and long-thin fuselage. Boeing Commercial Airplane Company has been studying possible applications for civilian and military transports. Responding to the sharp increase in air travellers, Boeing and NASA have been developing a passenger aeroplane design that will be able to carry 800 passengers per flight (160 more than a 747). The new blended-wing body, or “flying wing,” design does away with the cigar-shaped fuselage and tail section that has been featured since the 1930s. The new sleek platform resembles a boomerang.
The double-deck cabin would be divided into five bays per deck. Most passengers won’t have a window, so the aircraft will have video screens that display window views. Each bay will have doors at the front and back to make emergency exits easier.
There are still several challenges before a production aircraft can be made. The much larger cabin would require a freshly designed pressurisation system. While current airliners fly around 950 Kmph, achieving the same in a flying wing with a thicker wing and much higher drag would mean higher engine power and fuel consumption. Aerodynamic stability and system redundancies would have to be built in. The passengers would have to be convinced of safety. Similarly, emergency evacuation systems would require redesign with adequately close exit doors.
The flying wing has the potential to be more than just a commercial passenger jet. It could also be used as a cargo aircraft and a very long-range military airlifter. With the airline industry bursting at the seams, the flying-wing design may help airlines meet the needs of an increasingly mobile society in the 21st century.
NASA has already prepared design criteria for a flying-wing cargo plane. Thus, cargo and passenger aeroplanes of the future could have a flying-wing design.
Future Designs
Aircraft designers and manufacturers are continually searching for ways to improve aircraft for speed, range, weight-carrying capacity, and many other characteristics. The bi-directional flying wing is a variable-geometry concept comprising a long-span subsonic wing and a short-span supersonic wing, joined in the form of an unequal cross. Evolving since 2011 under a NASA study, the low-speed wing would have a thick, rounded aerofoil to contain the payload and a long span for high aerodynamic efficiency, while the high-speed wing would have a thin, sharp-edged aerofoil and a shorter span for low drag at supersonic speed. The craft would take off and land with the low-speed wing across the airflow, then rotate so that the high-speed wing faces the airflow for supersonic travel. It will also reduce sonic booms.
Header Picture Credit: Representative Image Generated using AI
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