Электроавиация

Materials Science
Free of Heavy Metals, New Battery Design Could Alleviate Environmental Concerns
December 18, 2019 | Written by: Young-hye Na
Categorized: Chemistry | IBM Research-Almaden | Materials Science
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Today, IBM Research is building on a long history of materials science innovation to unveil a new battery discovery. This new research could help eliminate the need for heavy metals in battery production and transform the long-term sustainability of many elements of our energy infrastructure.
As battery-powered alternatives for everything from vehicles to smart energy grids are explored, there remain significant concerns around the sustainability of available battery technologies.
Many battery materials, including heavy metals such as nickel and cobalt, pose tremendous environmental and humanitarian risks. Cobalt in particular, which is largely available in central Africa, has come under fire for careless and exploitative extraction practices.1
Using three new and different proprietary materials, which have never before been recorded as being combined in a battery, our team at IBM Research has discovered a chemistry for a new battery which does not use heavy metals or other substances with sourcing concerns.
The materials for this battery are able to be extracted from seawater, laying the groundwork for less invasive sourcing techniques than current material mining methods.
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IBM researchers work in the IBM Research Battery Lab to combine and test unique materials and formulations for more sustainable battery technologies.
Just as promising as this new battery’s composition is its performance potential. In initial tests, it proved it can be optimized to surpass the capabilities of lithium-ion batteries in a number of individual categories including lower costs, faster charging time, higher power and energy density, strong energy efficiency and low flammability.
New battery design could outperform lithium-ion across several sustainable technologies
Discovered in IBM Research’s Battery Lab, this design uses a cobalt and nickel-free cathode material, as well as a safe liquid electrolyte with a high flash point. This unique combination of the cathode and electrolyte demonstrated an ability to suppress lithium metal dendrites during charging, thereby reducing flammability, which is widely considered a significant drawback for the use of lithium metal as an anode material.
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A Differential Electrochemical Mass Spectroscopy (DEMS) System in the IBM Research Battery Lab, which measures the amount of gas that has evolved from a battery cell during charging and discharging cycles.
This discovery holds significant potential for electric vehicle batteries, for example, where concerns such as flammability, cost and charging time come into play. Current tests show that less than five minutes are required for the battery – configured for high power – to reach an 80 percent state of charge. Combined with the relatively low cost of sourcing the materials, the goal of a fast-charging, low-cost electric vehicle could become a reality.
In the quickly evolving arena of flying vehicles and electric aircrafts, having access to batteries with very high-power density, which can scale a power load quickly, is critical. When optimized for this factor, this new battery design exceeds more than 10,000 W/L, outperforming the most powerful lithium-ion batteries available. Additionally, our tests have shown this battery can be designed for a long-life cycle, making it an option for smart power grid applications and new energy infrastructures where longevity and stability is key.
Overall, this battery has shown the capacity to outperform existing lithium-ion batteries not only in the previously listed applications, but can also be optimized for a range of specific benefits, including:
  • Lower cost: The active cathode materials tend to cost less because they are free of cobalt, nickel, and other heavy metals. These materials are typically very resource-intensive to source, and also have raised concerns over their sustainability.
  • Faster charging: Less than five minutes required to reach an 80 percent state of charge (SOC), without compromising specific discharge capacity.
  • High power density: More than 10,000 W/L. (exceeding the power level that lithium-ion battery technology can achieve).
  • High energy density: More than 800 Wh/L, comparable to the state-of-art lithium-ion battery.
  • Excellent energy efficiency: More than 90 percent (calculated from the ratio of the energy to discharge the battery over the energy to charge the battery).
  • Low flammability of electrolytes
From lab to industry with automotive, electrolyte and battery manufacturers
To move this new battery from early stage exploratory research into commercial development, IBM Research has joined with Mercedes-Benz Research and Development North America, Central Glass, one of the top battery electrolyte suppliers in the world, and Sidus, a battery manufacturer, to create a new next-generation battery development ecosystem. While plans for the larger development of this battery are still in the exploratory phase, our hope is that this budding ecosystem will help to bring these batteries into reality.
Accelerating materials discovery with AI
Moving forward, the team has also implemented an artificial intelligence (AI) technique called semantic enrichment to further improve battery performance by identifying safer and higher performance materials. Using machine learning techniques to give human researchers access to insights from millions of data points to inform their hypothesis and next steps, researchers can speed up the pace of innovation in this important field of study.
Building on a history of exploration and innovation in materials science
Using a multidisciplinary approach combining materials science, molecular chemistry, electrical engineering, advanced battery lab equipment, and computer simulation, the Battery Lab at IBM Research draws on IBM Research’s history of advancing materials science.
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Maccor Coin Cell Test Equipment in the IBM Research Battery Lab, which evaluates the electrochemical performance of the coin cells fabricated in-house in the lab.
IBM Research’s invention of chemical amplification, for example, helped propel the growth and advancement of Moore’s Law – ushering in an era of faster and cheaper semiconductor development that now is the backbone of electronic devices.
When we set out to explore solutions to the challenges associated with batteries today – and thus certain obstacles to renewable energy as a whole — we drew on IBM Research’s strong infrastructure that allows us to study how things work on a molecular and atomic level. This foundation is what has propelled our leadership in a number of areas.
Atomic force microscopy, for example, was pioneered and invented by IBM researchers. This method has allowed countless scientists, including our team building new battery technology, to study the forces and movements between materials at incredibly precise levels.
Combining this materials innovation and expertise in catalysis for applications ranging from plastics recycling to semiconductor fabrication – coupled with a deep understanding of chemical mechanisms – enabled the team within the Battery Lab at IBM Research to bring this exciting new battery technology to bear.
 
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While plans for the larger development of this battery are still in the exploratory phase, our hope is that this budding ecosystem will help to bring these batteries into reality.
Несомненно, это ключевая фраза сего опуса. :)

Moving forward, the team has also implemented an artificial intelligence (AI)...
Ну, теперь победа точно обеспечена. :)

При этом ни слова о конструкции батареи и применяемых материалах. Видимо, чтобы идею не украли. :)
Ну, и на хрен сюда такие "пустышки" вешать? Ведь информации нет совсем, сплошное биение пяткой себя в грудь.
 
Rolls-Royce построил самый быстрый в мире электросамолет
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Концерн Rolls-Royce представил самый скоростной в мире самолет с электрической силовой установкой - одноместный моноплан с одним воздушным винтом.
Машина, названная ionBird, является тестовым прототипом проекта разработки высокоскоростного воздушного судна с нулевым выбросом углекислого газа.
Кульминацию проекта ознаменует запланированный на май будущего года перелет из Лондона в Париж при достижении рекордной скорости для электросамолета в 480 км/ч.
ionBird построен по классической аэродинамической схеме с низким расположением крыльев. Трехлопастной воздушный винт спереди приводится от трех электромоторов суммарной мощностью 500 л.с. Винт вращается с меньшей скоростью, чем на самолетах с двигателем внутреннего сгорания, что дает меньше шума и вибраций.
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Между силовой установкой и кабиной пилота располагается батарея из 6000 элементов питания, снабженная высокоэффективной системой охлаждения. Запас энергии полностью заряженной батареи достаточен для снабжения 250 домохозяйств (за какой срок не сказано). КПД силовой установки превышает 90%.
Прототип предназначен для испытаний силовой установки, в том числе в режиме максимальной мощности.
Партнерами Rolls-Royce в разработке электроустановки для высокоскоростных полетов с нулевым выбросом СО2 являются производитель электрооборудования YASA и стартап Electroflight. Половину бюджета проекта покрыл правительственный грант на научные исследования.
Промышленный концерн Rolls-Royce сегодня специализируется на производстве продукции для оборонного и энергетического комплексов, авиакосмической отрасли и судостроения. Производство прославленных автомобилей выведено в отдельную компанию в 1973 году. Автомобильная компания Rolls-Royce Motor Cars с 1998 года входит в состав концерна BMW.
 
Некоторые технические подробности по ionBird.

Машина предназначена для установления нового рекорда скорости для электрических самолетов, который в настоящее время принадлежит самолёту Extra 330LE с двигателем Siemens (210 миль/ч).
В самолете используется блок батарей из 6000 ячеек, который, по словам компании RR, является «самым энергоемким блоком, когда-либо собранным для самолета; он содержит столько энергии, что можно пролететь 200 миль (от Лондона до Парижа) на одной зарядке».
Воздушный винт вращают три осевых электродвигателя. Их максимальная суммарная мощность - 500 л.с.

Полный (т.е. с рекламными взвизгами) текст - вот здесь.
 
Причём делал это с двигателем в 350 л.с. А здесь с пятисоткой надеются получить 480 км/ч.
Из этого делаем вывод, что потребное количество бензина легче чем аккумуляторы. Вот такая экология, лишний вес возить.
 
Из этого делаем вывод, что потребное количество бензина легче чем аккумуляторы. Вот такая экология, лишний вес возить.
достаточно представить себе ситуацию, когда продукты сгорания бензина/ керосина необходимо возить с собой, и всё с электричеством станет предельно ясно. ;)
 
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вот я точно не уверен, но вроде для быстрохода ставили какой-то форсированный вариант. мерещится мне что он что-то около 500 сил и давал.
Где-то пишут про форсированный двигатель, а где-то говорят, что движок был штатным, и всё сводилось к его точным регулировкам.
В любом случае понятно, что "электричка" от R-R имеет куда большую нагрузку на крыло, и потому угол атаки приходится увеличивать, что высокой скорости не способствует.
 
Bell’s eVTOL vision changes as it eliminates two rotors and goes all electric
Bell’s eVTOL vision changes as it eliminates two rotors and goes all electric
By Garrett Reim, Amarillo, Texas6 January 2020

Bell changed the design of its proposed electric vertical take-off and landing (eVTOL) aircraft, removing two rotor ducts and adding a purely electric propulsion option, after hearing from potential customers that shorter inner city travel would likely come before longer-range trips between metropolitan areas.
The new demonstrator aircraft is called the Bell Nexus 4EX. The “E” stands for electric and the “X” stands for experimental.
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Nexus4EX-Image_PressRelease

Source: Bell
Bell Nexus 4EX eVTOL concept rendering
The Nexus 4EX will have four rotor ducts instead of the six rotor ducts proposed for the original Nexus eVTOL, which was unveiled a year ago at the 2019 CES in Las Vegas. By removing two ducts Bell says it can build an aircraft that has less drag and thus is more efficient in cruise mode .
Efficiency is critically important as battery energy density remains one of the chief limiting factors for electric aircraft, says Scott Drennan, vice-president of innovation with Bell.
Bell expects that its 4EX would be capable of flying up to 52nm (97km) while carrying four to five passengers, plus a pilot.
“The battery energy power densities right now are right on the edge for a mission like this,” says Drennan. He believes battery energy density could improve 10% to 15% by the mid-2020s, when Bell hopes for the eVTOL industry to take off.
For longer flights, Bell is working on a hybrid-electric variant of the 4EX, which will use a turbo-generator to charge batteries, which will power electric motors. That aircraft would have a range of 130nm. The hybrid-electric aircraft would be developed after the all-electric aircraft.
With its change to all-electric power, Bell dropped its former propulsion supplier Safran. A replacement electric motor supplier is to be named in early 2020. Bell says it is still considering Safran for hybrid propulsion.
The company says the Nexus 4EX demonstrator will likely closely resemble the eVTOL aircraft it eventually puts forward for commercial certification; a regulatory hurdle it expects to clear in the latter half of the 2020s.
“You’re not going to see it have an electrical system, or a duct, or a rotor system that is markedly different than what you’ll see down the road in the certification plan,” says Drennan.

Focused flight envelope
Whereas traditional helicopters are designed as utility vehicles, with broad abilities that vary from emergency medical service, police, or passenger transportation work, Bell envisions its eVTOL aircraft having a much narrower performance envelope, purely focused on moving passengers as efficiently as possible from point A to point B.
The Nexus 4EX is to have a max gross takeoff weight of about 3,200kg (7,000lb). It would have a cruise speed of 130kt (241km/h).
Nexus4EX-Image_Cover

Source: Bell
Bell Nexus 4EX eVTOL concept rendering
Based on conversations and surveys of potential customers and stakeholders, such as ride-share companies, as well as city, state and national governments, the company estimates flights on average would be 13nm to 22nm in length.
Each aircraft is likely to operate 2,000h per year, the company says.
Bell believes hundreds to thousands of eVTOLs would be needed within a city to significantly change traffic patterns on the roads. The company declines to say how many aircraft would be required to reach profitability, noting its analysis is ongoing.
The manufacturer anticipates that eVTOLs would be primarily used for faster ride-share, public transportation and cost-sensitive traditional helicopter applications.
At least in the beginning, Bell doesn’t anticipate eVTOLs creating new travel demand – trips people would not take if they didn’t have access to the speed and range of the aircraft. Rather, early users will likely fly out of curiosity or experience seeking. Gradually, the company expects the aircraft to become routine part of business and personal travel, says Drennan.
Bell says it is forecasting demand using traffic, mobility and cellphone databases, examining how different factors such as passenger load, weather, digital infrastructure, and eVTOL airport loading patterns, might affect usage.
Predicting aircraft usage will be key to managing the battery charge levels and lifecycles of a fleet of eVTOLs, says Drennan.
“State of charge at any given moment in the life – and really the operating day – effects the next flight available because of time of recharge required and the life of the battery,” he says. “Therefore, it is imperative to smartly manage fleet operations and battery system operations by mixing flight distances to optimise operational cadence and battery life for our customers.”
The Bell Nexus 4EX’s batteries are to be supplied by Electric Power Systems. Algorithms within that company’s battery management system will be used to monitor battery temperature, current, voltage, discharge and charge rates.
The stringent performance requirements of eVTOL aircraft means degraded batteries could likely be resold and recycled into other industries, such as the automobile, boat or smart power grid sectors, which have less demanding power needs, says Drennan.

Automated flight controls
Bell is aiming to build an eVTOL that has fully autonomous flight controls. However, to initially gain public trust and US Federal Aviation Administration (FAA) certification the aircraft will have a pilot or “mission manager” onboard as backup.
Indeed, because eVTOL aircraft are so novel Bell is taking the liberty to rethink many aspects of the aircraft’s flight controls, including removing the helicopter’s traditional collective, cyclic and foot pedals.
“When you’re talking about fly-by-wire it just doesn’t make sense anymore to make people move their feet, move their hands and wiggle their ears all in unison to make this thing fly,” says Drennan. “A fly-by-wire aircraft can have control laws that can take into account intention [and] mission. And, if we integrate that in the right way we will take a great step right through the piloted piece to the autonomous.”
In its Future Flight Controls simulator Bell says it has studied how more than 6,000 participants, including professional helicopter pilots, but also a wide variety of amateurs, interact with different arrangements of digital flight controls.
For cost and safety reasons Bell is aiming to ultimately make its eVTOLs fully autonomous. In light of two recent Boeing 737 Max crashes caused by that airliner’s automated flight controls – the Maneuvering Characteristics Augmentation System – Bell is quick to explain its belief that designing an automated eVTOL from scratch is safer than adding automation to an aircraft not initially designed to be automated.
“By starting with the understanding that it’s going to be fully autonomous from the beginning you have a different mental starting point than when you iterate to something over time,” says Michael Thacker, Bell’s executive vice-president for technology and innovation.
The FAA has not formalised regulations for certificating eVTOL aircraft or rules for inner city autonomous flights. To help flush out operating procedures and flight rules, Bell was contracted last year by NASA to conduct flights using its Autonomous Pod Transport 70 cargo drone. The company is to conduct demonstrations in the Dallas-Fort Worth, Texas airspace in the summer of 2020.
The company also says it is ready to volunteer information to the FAA such as a detailed architecture of the Nexus 4EX’s propulsion and flight control systems, as well as its related safety analysis.
In addition to public and regulatory confidence in safety, Bell believes reducing the amount of noise produced by its eVTOLs will be crucial in getting people to accept hundreds or thousands of aircraft buzzing overhead. The company thinks that a decibel level in the high 70s or low 80s, about 15 decibels quieter than a traditional helicopter, should be its noise goal for the Nexus 4EX.
“Bell will strive for the lowest holistic noise considering not only loudness (decibels), but also tone, ambient noise and community noise tolerance,” says Drennan, noting that people in some cities may accept less sound than those in other regions. “Noise is too critically linked to performance and cost to set an arbitrary loudness level that doesn’t take all of these factors into account.”

- ну и куда Bell с копытом, туда и Hyundai с клешнёй:

Помешались они там все на eVTOL :rolleyes:
 
UAV Turbines unveils hybrid-electric 'microturbine' for drones
By Garrett Reim, Los Angeles 10 December 2019
UAV Turbines unveiled on 10 December a demonstrator hybrid-electric “microturbine” for small unmanned air vehicles (UAVs) that it says allows drones to harness the efficiency of a turbine and the quick power of an electric motor.
The Monarch Hybrid Range Extender is based on the company’s Monarch 5 turbine, a small turbine demonstrator the company unveiled in September in a Navmar Applied Sciences-made TigerShark, a small Group 3-size UAV usually powered by a piston engine. Group 3 UAVs are classified by the US Army as having a max gross takeoff weight of less than 600kg (1320lb).
UAV Turbines Monarch Hybrid Range Extender

Source: UAV Turbines
UAV Turbines Monarch Hybrid Range Extender on teststand
The use of electric-powered UAVs has increased dramatically in recent years by commercial and military operators as the cost of circuitry such as flight control equipment, electric motors and batteries has declined. In particular, quadcopters with electric propeller systems have proven simpler mechanically and easier to control than traditional piston or gas turbine helicopters.
However, electric-powered UAVs have limited flight duration due to the power output of batteries, which have less energy density than liquid fuel used by piston or turbine engines. UAV Turbines is promising the best of both worlds.
The company’s hybrid system uses a turbine to generate electricity, most of which is used to power electric motors that turn aircraft propellers, while the remaining electricity is siphoned off into a small battery. The system’s batteries serve as a reservoir of energy for flight manoeuvres that require extra power, such as vertical takeoff and landing.
“A common rule of thumb is that liquid fuel contains at least 50 [times] as much energy per weight as batteries,” the company says. “The battery is your sprinter, full of explosive power, while the turbogenerator is your marathoner, lean and efficient.”
The Monarch Hybrid Range Extender can provide UAVs with up to 33shp (25kW), says Fred Frigerio, senior vice-president of engineering with UAV Turbines. The engine weights around 27kg and the total hybrid system weighs closer to 54kg.
UAV Turbines Monarch Hybrid Range Extender - 3

Source: UAV Turbines
UAV Turbines Monarch Hybrid Range Extender on teststand
The hybrid system eliminates mechanical complexity and weight, says Frigerio.
“Instead of having a shaft doing power transmission, you have cables going into an electric motor,” he explains.
In addition to having fewer hefty mechanics, weight is saved by carrying smaller batteries and relying on liquid fuel, which burns off during flight, says Frigerio.
Much of UAV Turbine’s technology was developed as part of US Army programmes such as the service’s 2000s-era modernisation effort called Future Combat Systems and its Small Unmanned Aerial Vehicle Engine programme, says Frigerio.
The company does not have any customers for the hybrid turbine, emphasising it is a demonstrator that is not optimised to specific applications. Early interest in the system has predominately come from the US military, though the company is also pitching it as a powerplant for commercial UAV cargo applications, says Frigerio.
 
Перевод, конечно, внушаить: :)
...one of the four jet engines will be replaced by a 2MW electric motor, which is roughly equivalent to that of 10 medium-sized cars.
...один из четырех реактивных двигателей будет заменен электродвигателем мощностью 2 МВт, что эквивалентно порядка 10 авиационным двигателям среднего размера.

А по сути - очередная демо-игрушка, не имеющая никакой практической ценности.
И уж ни о каком "шаге вперёд" здесь говорить не приходится.
 
Компания Airbus Helicopters совместно с Автономным управлением парижского транспорта провели летные испытания аэротакси CityAirbus. Аэротакси способно доставлять по воздуху без страховочных канатов четырех человек и перемещаться со скоростью 120 км/ч. Двигатели работают на электричестве, а взлет и посадку аппарат совершает вертикально. Ожидается, что сервис запустят к Олимпийским играм 2024 года между Парижем и Диснейлендом. Стоимость полета на 1 км, предположительно, будет составлять €1–2.


 
 
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E-Fan X hybrid project edges towards system integration
E-Fan X hybrid project edges towards system integration
By Cirium 23 January 2020
Airbus has started preparing a BAE Systems Avro RJ100 for installation of an experimental hybrid-electric propulsion system later this year, as part of the joint E-Fan X technology project with Rolls-Royce.
The regional jet (G-WEFX) was in service with Swiss until 2017, Cirium fleets data shows. Airbus has stripped out the cabin interior and put in a flight-test engineer station, says the airframer’s E-Fan X programme director Olivier Maillard.
Airbus E-Fan X Demonstrator

Source: Airbus
The E-Fan X was launched as an innovation project in 2017 with flight testing of the aircraft set for 2021
Several test flights were completed in December 2019 to confirm the emptied aircraft’s nominal aerodynamic and engine performance. But now the four-engined aircraft is staying on the ground at Cranfield in the UK for installation of the hybrid-electric equipment, which Maillard says will take place toward year-end.
The Avro’s No 3 engine will be replaced with a 2MW electric fan, powered by a 2.5MW generator – in turn driven by a Rolls-Royce AE2100 turboshaft, which normally equips Lockheed Martin C-130 military transports – and 2t of lithium-ion batteries. All of the equipment will be placed in the aircraft’s cabin. The gas turbine is to be located at the aft end.
Programme illustrations indicate that an air intake and exhaust outlet for the power-generation system will be installed in the aft fuselage crown. A separate air intake will be fitted on the forward fuselage’s port side for equipment cooling. Flight testing of the converted aircraft is scheduled for 2021.
Airbus and Rolls-Royce are in the process of testing individual components of the hybrid-electric powertrain. In October 2019, the airframer opened a dedicated test centre for full- and hybrid-electric aircraft technology, named the “E-Aircraft Systems House”, in Munich. Here, Maillard says, trials of a system controller have begun and further components will be added until the demonstrator’s entire hybrid-electric powertrain can be tested later this year.
Ground testing and systems installation will run in parallel, as the ground tests “generate evidences” required for the Avro’s conversion and clearance for flight tests, says Maillard.
Rolls-Royce’s E-Fan X programme director Riona Armesmith notes that the aircraft is a demonstrator for potential future technology rather than a distinct product development, and says the two manufacturers still have “many lessons to learn… Every day we are learning something new.”
The objective is to understand the limitations and benefits of hybrid-electric propulsion in an airborne environment – rather than ground tests – and to build a business case for the technology’s potential deployment on future aircraft, she explains.
Rolls-Royce Systems Tests
In August, Rolls-Royce started tests of the 2.5MW generator in Norwegian city Trondheim, at a bespoke facility newly built for testing of high-voltage, multi-megawatt electrical equipment. Rolls-Royce notes that the project has benefited from the company’s marine-sector experience, specifically its work on permanent-magnet motors for electric propulsion systems on cruise ships.
The trials have included endurance tests to assess the generator’s long-term performance. “We are putting time on the equipment to really understand its operation,” Armesmith says.
The generator will deliver alternating current at “very high” frequency. This will then be converted to 3kV direct current in order to include batteries in the powertrain and to enable the use of more lightweight cables than would be required for AC. Prior to reaching the electric fan, the current will be converted back to AC.
Central to the safe and efficient operation of the electric equipment is a cooling system. Armesmith notes that “every time you touch [power], it generates loss” – in other words, heat.
In US city Indianapolis, Rolls-Royce has developed an “advanced” cooling system for the power-generation equipment. The UK engine maker is responsible for the gas turbine generator, related electronics, and the electric fan. Airbus, meanwhile, is developing a separate cooling system for the equipment under its responsibility: batteries, electrical distribution and control electronics.
In Indianapolis, Rolls-Royce has tested the cooling system on a full-scale, flight-representative thermal test rig. Armesmith describes the cooling of the electronics as “a pinch point” because the components are “quite sensitive” and their maximum allowable temperature is “quite low”. She highlights a key learning from the tests: the equipment can be sufficiently cooled to allow the manufacturer to “pool” the electronics in a “small area”.
Later this year, Rolls-Royce plans to test the entire power-generation system – turboshaft, generator, AC/DC conversion equipment, thermal management and control systems – in an integrated fashion at its facility in Bristol. The control system was previously tested, on its own, at the engine maker’s headquarters in Derby.
The electric fan equipment will meanwhile be tested on a separate test rig which is next to the power generation system and connected to it by cables.
Airbus System Tests
Airbus has, in Czech capital Prague, conducted short-circuit tests of the cabling network. Maillard says the high-voltage trials are continuing “very intensively”. He acknowledges that an increased likelihood of arcing round high-voltage conductors at altitude is a key challenge for the E-Fan X project.
Known as the corona effect, electrical discharge through air can naturally occur around high-voltage conductors on the ground. But the effect increases with reduced air density and poses a risk of short-circuits. Airbus and Rolls-Royce have previously that they are looking at new ways of insulating cables, reducing electric-magnetic fields around conductors, and managing electric loads.
Maillard confirms that the objective of the flight tests is to explore the Avro’s entire flight envelope, which has an operating ceiling at 35,000ft. “If we feel that we can reach this altitude safely and we are convinced we can do it, we will be keen to fly to this altitude,” he says. But he indicates that the flight tests will be conducted in a highly controlled fashion. He adds: “The exact altitude and exact flight operation is something we firm up in the course of our progress.”
Airbus has also commissioned a battery-testing laboratory. Maillard says that tests have concentrated on different safety cases for the batteries and increasing the number of battery cells to achieve the required performance. He says the manufacturer is “getting closer to” a solution for the batteries. In Bristol, the airframer is in the process of conducting windtunnel tests in Bristol with a 1:8 scale model of the modified Avro.
The electric propulsion unit will feature the fan of an AE3007 engine – employed on Embraer ERJ-family jets – and be enclosed in the same nacelle as the Avro’s original Honeywell LF 507 engine. The motor used in the electric propulsion unit will be the same hardware as the generator employed in the power-generation system, Rolls-Royce says.
The electric fan will produce slightly lower maximum thrust than the LF 507 engine it replaces. But Armesmith says: “At altitude you won’t see any difference.” Maillard expects the electric fan’s performance to be in the “in the same range” as the conventional turbofan’s. The electric propulsion system’s output will be “noticeable for the pilots and crew”, he says.
When the E-Fan X project was launched in 2017, Airbus and Rolls-Royce said they might replace a second gas turbine with an electric fan “once system maturity has been proven”. Maillard confirms that the proposal is still an option, but says the two manufacturers are not working on it “right now”.
The project’s “absolute priority”, he says, is to successfully operate the system and become “the first in the world to fly such a powerful hybrid system” on a transport-category aircraft. While the two manufacturers have “no clear picture right now” of what a hybrid-electric commercial aircraft might look like, Maillard says the technology must be available for a potential future application from around 2030 “at the latest”
This analysis was written by Michael Gubisch, a London based member of Cirium’s reporting team
 
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