Aviation Industry and Academia aredeveloping Innovative concepts and technologies for future commercial Aircrafts. The aircraft industry is expecting a seven-fold increase in air traffic by 2050, and a four-fold increase in greenhouse gas emissions unless fundamental changes are made. Biofuel offers carbon emissions reductions of between 36-85%, with the variability depending on the type of land used to grow the fuel crops.
The crucial next step towards ensuring the aircraft industry becomes greener is the full electrification of commercial aircraft. That’s zero CO2 and NOx emissions, with energy sourced from power stations that are themselves sustainably fuelled. The main technological barrier that must be overcome is the energy density of batteries, a measure of how much power can be generated from a battery of a certain weight. Tesla CEO Elon Musk has said that once batteries are capable of producing 400 Watt-hours per kilogram, with a ratio of power cell to overall mass of between 0.7-0.8, an electrical transcontinental aircraft becomes “compelling”.
Another goal is fully autonomous flight. Even at modern commercial airliners have automated systems that can augment or even replace pilots’ performance, managing engine power, controlling and navigating the aircraft, and in some cases even completing landings.
Several companies are developing fully autonomous aircraft, including Amazon and UPS, which want to use them for deliveries. Boeing and Airbus are designing self-flying air taxis, which would be used for flights of about 30 minutes and carry between two and four passengers, and have tested prototypes. A company called Volocopter has been testing autonomous air taxis in Germany since 2016 and plans to conduct test flights in downtown Singapore this year. Ridesharing giant Uber, helicopter maker Bell, and many other companies are also expressing interest in similar vehicles.
Airlines and manufacturers say they would save money and alleviate the current shortage of qualified pilots if they could reduce–or even eliminate–the number of pilots in the cockpit. Redesigning the front of the aircraft to be more aerodynamic could save even more money, if it didn’t need room for pilots, or could move them to another part of the aircraft. Large commercial airplanes will likely go pilotless later than smaller private aircraft, because of the amount of time and money required to produce them. But smaller air taxis simply are not economically viable if they require a human pilot on board.
Future aircrafts may utilize technologies like ultramodern shape memory alloys, ceramic or fiber composites, carbon nanotube or fiber optic cabling, self-healing skin, hybrid electric engines, folding wings, double fuselages and virtual reality windows.
Future aircrafts may also alter their looks . Whether it’s a business jet, a regional turboprop or a long-haul jetliner, most airplanes feature the same design elements. Typically, there’s a tubular fuselage attached to a pair of swept-back wings and a T-shaped tail section. Engines are mounted either under the wings or aft-mounted onto the fuselage with pods.
Those age-old design elements could someday go the way of fabric-covered wings, open cockpits and radial engines. That’s because aerospace engineers are using new technology, such as additive manufacturing and generative design software, to push beyond traditional boundaries and create cutting-edge aircraft that operate quieter, burn less fuel and reduce emissions.
“For the past 50 years, most of our experience with aircraft has involved traveling between large airports with hundreds of fellow passengers,” says Juan Alonso, a professor of aeronautics and astronautics and head of the Aerospace Design Laboratory at Stanford University. “Recent technological revolutions, however, will make future aircraft more important to our lives in many ways.
“From silent, efficient global transportation to personal or on-demand flight that frees us from roads, to autonomous air vehicles for delivery of information and goods, the future of flight will look considerably different than it does today,” claims Alonso.
“We are at a tipping point in commercial aviation,” adds Jim Heidmann, manager of NASA’s Advanced Air Transport Technology Project. “We are exploring and developing game-changing technologies and concepts that can dramatically improve efficiency, reduce environmental impact and accelerate the introduction of new aircraft.
Hypersonic travel, the future of avaiation
Nowadays, there are plans underway to revive supersonic flight, and there are those who are looking even further ahead, towards the hypersonic plane: from Europe to Australia and back taking the length of just a workday. This is more than three times faster from the Concorde that used to fly at 2,180 km/h, approximately Mach 2, or twice the speed of sound— and hypersonic flights —Mach 5 and above. Companies such as Airbus, and national space agencies such as those of Japan and Germany, are also betting on hypersonic flight.
Airbus has been awarded patent of its new hypersonic aircraft dubbed ‘Concorde Two’ because it would be much faster and quieter than the retired supersonic jet. The patent describes how three different types of engine, powered by different forms of hydrogen, would work together to propel the vehicle at speeds of 3,425mph (5,500km/h). It describes a craft that climbs vertically in the air before breaking the sound barrier as it travels horizontally.
‘In the case of civil applications, the market envisaged is principally that of business travel and VIP passengers, who require transcontinental return journeys within one day,’ the patent states. The aircraft manufacturer says the hypersonic jet could also be used for military applications, working to transport soldiers at rapid speeds.
In the last 20 years several experimental hypersonic propulsion projects have been successfully developed, including NASA’s X-43 unmanned aircraft and its successor, the USAF Boeing X-51A. However the successful hypersonic commercial flight involves solving many challenges from propulsion technology, ultra high temeperature materials and structures and challenges in manoeuvrability and flight controls of the aircraft.
The wings we are already designing are near their peak in terms of aerodynamic efficiency, but they still vastly inferior in comparison of what nature has achieved in birds. Aircraft design templates are a century old, constrained by the limitations of the earlier day technologies, for example rigid structures with discrete control surfaces, but now researchers are turning to the natural world for inspiration.
Research work on peregrine falcons inspires future aircraft technologies
Scientists at BAE Systems and City, University of London have revealed how research work on how falcons fly is inspiring new technologies for aircraft that could contribute to their safety in the air, aerodynamics and fuel efficiency. The technologies could be applied within the next 20 years
The scientists have developed several concepts following research into how the peregrine falcon – the world’s fastest bird – is able to stay in control and airborne at speeds of up to 200mph, even in high winds. The technologies being developed include ‘sensory feathers’ – 3D-printed polymer ‘hair’ filaments which would act like sensors on the body of an aircraft, providing an early warning system if it began to stall. Similarly, more densely packed passive polymer filaments may also be capable of changing the airflow very close to the surface of the aircraft which could reduce ‘drag’ on the aircraft wing-skin. Aerodynamic drag ultimately slows aircraft in flight.
A further technology has been inspired by the falcon’s ability to stabilise itself after swooping or landing by ruffling its feathers. Small flexible or hinged flaps on an aircraft could allow the wing to manoeuvre quickly and land more safely at lower speeds. The added safety margin gained using this approach could allow future aircraft of a more compact design or to carry more fuel. In addition, the research so far has shown that the flaps could potentially lower aircraft noise pollution.
Professor Christoph Bruecker from City’s Aeronautical Engineering department, said: “The peregrine falcon is the world’s fastest bird, able to dive for prey at incredibly steep angles and high velocities. The research work has been truly fascinating and I am sure it will deliver some real innovation and benefits for the aerospace sector.
Additive Layer Manufacturing (ALM) or 3D printing process is used in numerous projects across Airbus. The aircraft such as their A350 XWB boasted over 1,000 3D printed parts. Autodesk and Airbus have unveiled the world’s largest 3D printed airplane cabin component: a ‘bionic partition’ to separate the passenger cabin from the galley. The result of the project creates sounded expectations: a partition that is structurally very strong but also lightweight, weighing 45% (30 kg) less than current designs. The component was created with custom algorithms that generated a design that mimics cellular structure and bone growth and then produced using 3D printing techniques.
Airbus also has pioneered the use of composites and other advanced materials in aircraft design and manufacturing. Known to be more reliable than traditional metallic materials, composites maximise weight reduction, as well as reduce the number of inspections required during service.
Airbus has fabricated the first 3D printed plane – a 13-foot flying drone. Thor, which stands for Test of High-tech Objectives in Reality (THOR), consist of 50 3D printed parts and two electric motors will most likely be employed for riskier endeavors and aerodynamic investigations.
Airbus also is advancing a wide range of technologies that have significant environmental benefits – including the use of fuel cells to power an airliner’s cabin and systems. Such fuel cells produce electricity in a cleaner, more efficient way than combustion engines. In addition, water – one of only three by-products, along with heat and oxygen-depleted air – can be used for the aircraft’s water and waste system, saving weight and therefore reducing fuel consumption and emissions. In May 2014, Airbus performed its longest flight using sustainable jet fuel with a KLM A330-200 to support the ITAKA European programme for the use of biofuel.
Electric and electric-hybrid flight
Airbus Group and Siemens have signed a collaboration agreement in the field of hybrid electric propulsion with the goal of demonstrating the technical feasibility of various hybrid/electric propulsion systems by 2020.
“Electric and electric-hybrid flight represent some of the biggest industrial challenges of our time, aiming at zero-emissions aviation. The progress we have achieved in this arena, together with our industrial and governmental partners, in only a few years is breath-taking, culminating in last year’s channel crossing of our all-electric E-Fan aircraft, said Tom Enders, CEO of Airbus Group. “We believe that by 2030 passenger aircraft below 100 seats could be propelled by hybrid propulsion systems and we are determined to explore this possibility together with world-class partners like Siemens.”
Airbus Group and Siemens plan to jointly develop prototypes for various propulsion systems with power classes ranging from a few 100 kilowatts up to 10 and more megawatts, i.e. for short, local trips with aircraft below 100 seats, helicopters or UAVs up to classic short and medium-range journeys. “Through innovation and out-of-the-box thinking, Airbus will continue to meet its eco-efficiency goals, and ensure that air travel continues to be one of the safest, and most eco-efficient, means of transportation,” says Airbus.
Airbus’s “Vision 2050” for ‘Smarter Skies’
Unveiled at the 2010 Farnborough International Airshow, the Airbus Concept Plane illustrates what air transport could look like in 2050 if advances in existing technologies continue apace. The experts at Airbus presented its vision for sustainable aviation in 2050 and beyond that looks beyond aircraft design to how the aircraft is operated both on the ground and in the air in order to meet the expected growth in air travel in a sustainable way. Their Smarter Skies vision consists of five concepts which could be implemented across all the stages of an aircraft’s operation to reduce waste in the system (waste in time, waste in fuel, reduction of CO2).
- The bionic cabin structure of future shall mimic bird bones which are light and strong because of their porous interior. This shall reduce the aircraft’s weight and fuel burn, as well as allowing features like oversized doors for easier boarding and panoramic windows.
- Aircraft will take-off through assisted ‘eco-climb’ system, a renewably powered, ground-based device provides the propelled acceleration that shall allow steeper climb from airports to minimize noise and also take-off from shorter runways,
- Highly intelligent aircraft would be able to select the most efficient and environmentally friendly routes (“free flight”), making the optimum use of the prevailing weather and atmospheric conditions. High frequency routes would also allow the aircraft to benefit from flying in formation like birds during the cruise, bringing fuel efficiency improvements due to drag reduction. Advanced automated aircraft navigation systems shall allow passenger planes to fly within 20 wingspans of each other much less than the four nautical miles which separates civil aircraft today.
- Low-noise, free-glide approaches into airports shall reduce emissions during the overall decent and reduce noise during the steeper approach as there is no need for engine thrust. These approaches would also reduce the landing speed early which would make shorter landing distances achievable (less runway needed). Technology could optimize an aircraft’s landing position with enough accuracy for an autonomous renewably powered taxiing carriage to be ready, so the aircraft could be transported away from runways quicker, which would optimize terminal space, and remove runway and gate limitations.
- Powering future aircraft and infrastructure through sustainable biofuels and other potential alternative energy sources such as electricity, biofuels, hydrogen, solar and energy harvesting shall further reduce aviation’s environmental footprint in the long term. The company’s research suggests that every flight in the world could on average be around 13 minutes shorter. This would save around 9 million tonnes of excess fuel annually, which equates to over 28 million tonnes of avoidable CO2 emissions and a saving for passengers of over 500 million hours of excess flight time on board an aircraft
Airbus has been testing many Innovative concepts and technologies towards its future Vision for ‘Smarter Skies’ through highly intelligent aircrafts and Eco innovation. Future-gazing by Airbus shows blueprints for radical aircraft interiors. Airbus engineers talk of morphing seats made from ecological, self-cleaning materials that change shape for a snug fit; walls that become transparent at the touch of a button, affording 360-degree views of the world below; and holographic projections of virtual decors, allowing travellers to transform their private cabin into an office, bedroom or even a “zen garden.”
“Imagine an aircraft made of a single structure instead of components. The engine, cockpit, power storage, transmitters, sensors, and more are part of a seamless airframe. There are no wires to pass information through, no fuel containers, or large electronics,” according to Lockheed Martin’s Applied NanoStructured Solutions (ANS) division.
To reduce a plane’s turn-time, Airbus proposed “a removable cabin module. it’s a detachable cabin passengers board while its at the gate. Once everyone is seated, the pod is lowered onto the plane. When you arrive at your destination, the cabin is removed, another is added, and the plane takes off.
Airbus has called this the “aircraft pod concept,” saying “passengers could be pre-seated in cabin pods before the plane actually arrives, ready for integration on the aircraft, saving time and making processing much simpler.” The time it spends on the ground is drastically reduced.
NASA’s vision of Flight in 2025
In October 2008, NASA asked industry and academia to imagine what the future might bring and develop advanced concepts for aircraft that can satisfy anticipated commercial air transportation needs while meeting specific energy efficiency, environmental and operational goals in 2030 and beyond.
The proposed aircraft will also have to operate safely in a more modernized air traffic management system. And each design has to fly up to 85 percent of the speed of sound; cover a range of approximately 7,000 miles; and carry between 50,000 and 100,000 pounds of payload, either passengers or cargo.
In late 2010, NASA awarded contracts to three teams — Lockheed Martin, Northrop Grumman, The Boeing Company — to study advanced concept designs for aircraft that could take to the skies in the year 2025. The teams recommended a variety of improvements in lightweight composite structures, heat- and stress-tolerant engine materials, and aerodynamic modeling that can help bring their ideas to reality.
The GE Aviation team conceptualizes a 20-passenger aircraft that could reduce congestion at major metropolitan hubs by using community airports for point-to-point travel. The aircraft has an oval-shaped fuselage that seats four across in full-sized seats. Other features include an aircraft shape that smoothes the flow of air over all surfaces, and electricity-generating fuel cells to power advanced electrical systems. The aircraft’s advanced turboprop engines sport low-noise propellers and further mitigate noise by providing thrust sufficient for short takeoffs and quick climbs.
With its 180-passenger D8 “double bubble” configuration, the Massachusetts Institute of Technology team strays farthest from the familiar, fusing two aircraft bodies together lengthwise and mounting three turbofan jet engines on the tail. Important components of the MIT concept are the use of composite materials for lower weight and turbofan engines with an ultra high bypass ratio (meaning air flow through the core of the engine is even smaller, while air flow through the duct surrounding the core is substantially larger, than in a conventional engine) for more efficient thrust. In a reversal of current design trends the MIT concept increases the bypass ratio by minimizing expansion of the overall diameter of the engine and shrinking the diameter of the jet exhaust instead. The team said it designed the D8 to do the same work as a Boeing 737-800. The D8’s unusual shape gives it a roomier coach cabin than the 737.
The Northrop Grumman team foresees the greatest need for a smaller 120-passenger aircraft that is tailored for shorter runways in order to help expand capacity and reduce delays. The team describes its Silent Efficient Low Emissions Commercial Transport, or SELECT, concept as “revolutionary in its performance, if not in its appearance.” Ceramic composites, nanotechnology and shape memory alloys figure prominently in the airframe and ultra high bypass ratio propulsion system construction. The aircraft delivers on environmental and operational goals in large part by using smaller airports, with runways as short as 5,000 feet, for a wider geographic distribution of air traffic.
The Boeing Company’s Subsonic Ultra Green Aircraft Research, or SUGAR, team examined five concepts. The team’s preferred concept, the SUGAR Volt, is a twin-engine aircraft with hybrid propulsion technology, a tube-shaped body and a truss-braced wing mounted to the top. Compared to the typical wing used today, the SUGAR Volt wing is longer from tip to tip, shorter from leading edge to trailing edge, and has less sweep. It also may include hinges to fold the wings while parked close together at airport gates. Projected advances in battery technology enable a unique, hybrid turbo-electric propulsion system. The aircraft’s engines could use both fuel to burn in the engine’s core, and electricity to turn the turbofan when the core is powered down.
NASA’s goals for a 2030-era aircraft, compared with an aircraft entering service today, are:
- A 71-decibel reduction below current Federal Aviation Administration noise standards, which aim to contain objectionable noise within airport boundaries.
- A greater than 75 percent reduction on the International Civil Aviation Organization’s Committee on Aviation Environmental Protection Sixth Meeting, or CAEP/6, standard for nitrogen oxide emissions, which aims to improve air quality around airports.
- A greater than 70 percent reduction in fuel burn performance, which could reduce greenhouse gas emissions and the cost of air travel.
- The ability to exploit metroplex concepts that enable optimal use of runways at multiple airports within metropolitan areas, as a means of reducing air traffic congestion and delays.