Enyuan Hu, a chemist at Brookhaven National Laboratory explains the importance, and limitations, of intercalation in battery chemistry. “The materials normally used in lithium-ion batteries are based on intercalation chemistry. This type of chemical reaction is very efficient; however, it only transfers a single electron, so the cathode capacity is limited. Some compounds like FeF3 are capable of transferring multiple electrons through a more complex reaction mechanism, called a conversion reaction.”
Iron trifluoride (FeF3) is composed of “cost-effective and environmentally benign elements — iron and fluorine. Researchers have been interested in using chemical compounds like FeF3 in lithium-ion batteries because they offer inherently higher capacities than traditional cathode materials,” according to Brookhaven.
Substituting the cathode material with oxygen and cobalt prevents lithium from breaking chemical bonds and preserves the material’s structure
Scientists at the University of Maryland (which led the research), Brookhaven and the U.S. Army Research Lab developed and studied the FeF3 cathode. Xiulin Fan, a scientist at UMD and one of the lead authors of a paper appearing in Nature Communications, explains,” Cathode materials are always the bottleneck for further improving the energy density of lithium-ion batteries.”
Materials used in most battery cathodes allow the transfer of only one electron at a time, according to the researchers. UMD’s FeF3 enables tripling that transfer capability. It also helps overcome problems that handicapped earlier version of the material: “poor energy efficiency (hysteresis), a slow reaction rate, and side reactions that can cause poor cycling life.”
According to Brookhaven, “To overcome these challenges, the scientists added cobalt and oxygen atoms to FeF3 nanorods through a process called chemical substitution. This allowed the scientists to manipulate the reaction pathway and make it more ‘reversible.’”
Sooyeon Hwang, a co-author of the paper and a scientist at Brookhaven’s Center for Functional Nanomaterials (CFN), explained further. “When lithium ions are inserted into FeF3, the material is converted to iron and lithium fluoride. However, the reaction is not fully reversible. After substituting with cobalt and oxygen, the main framework of the cathode material is better maintained and the reaction becomes more reversible.”
Working at such nano levels requires high-powered equipment. Brookhaven has exotic research tools at the Center for Functional Nanomaterials (CFN), which explores the unique properties of materials and processes at the nanoscale. Brookhaven also features the National Synchrotron Light Source II (NSLS-II), a resource with “ultra-bright X-ray” equipment.
Brookhaven scientists Enyuan Hu and Sooyeon Hwang are pictured at the Center for Functional Nanomaterial’s TEM facility where the researchers viewed the cathode material at a resolution of 0.1 nanometers.
Researchers used transmission electron microscopy (TEM) at CFN to look at FeF3 nanorods at a resolution of 0.1 nanometers. This enabled them, “To determine the exact size of the nanoparticles in the cathode structure and analyze how the structure changed between different phases of the charge-discharge process.” They saw a faster reaction speed for the substituted materials.
Using NSLS-II’s X-ray Powder Diffraction (XPD) beamline, and directing ultra-bright x-rays through the cathode material, researchers were able to analyze light scattering to “see” additional information about the cathode’s structure.
Jianming Bai, a co-author of the paper and a scientist at NSLS-II explained, “The PDF analysis on the discharged cathodes clearly revealed that the chemical substitution promotes electrochemical reversibility.”
Xiao Ji, a scientist at UMD and co-author of the paper concluded, “Scientists at UMD say this research strategy could be applied to other high energy conversion materials, and future studies may use the approach to improve other battery systems.”
Investments in large-scale and undoubtedly expensive equipment will probably pay off in improved research techniques and much improved future batteries.
Boeing just announced the ten winners of Phase I in its GoFly competition, in which entrants design, build and fly a “personal flying device.” As Boeing explains, contest rules are designed to enable entrants “To foster the development of safe, quiet, ultra-compact, near-VTOL personal flying devices capable of flying twenty miles while carrying a single person.” The list of partners and co-sponsors is impressive and includes virtually all major American aviation advocacy groups.
As the Green Flight Challenge demonstrated seven years ago, prize money encourages a grand series of investments by individuals in hopes of winning a prize. In this case, 3,000 entries by 725 teams from 95 countries presented drawings and documents describing their proposed PFD, with a select 10 advancing to Phase II, which will require a demonstration of the proposed machine’s ability to perform as promised.
“To be able to engage so many individuals from leading universities, major corporations and startups, and connect them through our community of innovators enables us to impact the industry in an unprecedented way,” said GoFly CEO Gwen Lighter. “We know that the road to personal flight is long and difficult, but we are incredibly encouraged and inspired by the volume of strong submissions that we have received in Phase I. This is only the beginning.”
More pessimistically, “’The GoFly prize is impossible,’ said Michael Hirschberg, executive director of the Vertical Flight Society, a technical society for people working on vertical takeoff and landing flight. ‘There is no way — based on conventional thinking — that someone can make a device that can meet the low noise, small size and long endurance requirements that it requires.’”
“Hirschberg is hoping to be proved wrong. He hadn’t yet seen the winning GoFly designs, and at this stage, it remains difficult to tell whether anyone can achieve the minimum contest requirements.”
One of the promising features of this phase is contestants’ access to an international group of experts in aircraft design, structure, power, safety and other fields. Boeing explains, “Experts engage with innovators and share their insights in two different ways, as Mentors or Masters. Mentors work directly with innovators in their respective areas of expertise, providing tailored advice on projects and progress. Masters host monthly online lectures, offering teams around the world opportunities for learning and discussion.
The following Master Lecture provides a detailed overview of the rules, showing that contest officials have considered all or most of the aspects of the design phase.
Check out YouTube’s GoFly Master Lecture list. It’s an impressive range of experts presenting talks on all aspects of the competition.
But Wait! There’s Still Time to Jump In!
For those of you who are throwing in the towel because you missed out on Phase I, you can enter in Phase II, a ruling that helps increase someone’s chance of winning and ensures a good number of potential finalists.
Looking very much like a café racer motorcycle with now less than 16 rotors on four flying surfaces, this Latvian entry combines VTOL capabilities with fixed-wing speed. At least all propellers are not in direct line with frangible body parts. The single-page website shouts, “Yes, it’s like a motorbike, but one doesn’t need roads with it.”
Jack Langelaan, Associate Professor of Aeronautical Engineering at Penn State, explains the team’s entry. “We entered the competition because this was a very interesting and unique aircraft design project, but also because academically, it would be a great opportunity for the students in our aircraft design class and for our graduate students. We’ve reached a point where improvements in batteries, electric motors and electronic speed controllers have enabled new aircraft configurations. We’re excited to begin Phase II.” (Incidentally, Langelaan led the winning team in 2011’s Green Flight Challenge.
Another motorcycle-like vehicle, Hummingbuzz features a fully electric, ducted coaxial rotor configuration, with the fuselage on top. This configuration makes one hope that adequate protection for the rider is part of the design. Georgia Tech’s press release notes, “[Alistair] Sequeriahad to quickly learn new and advanced noise software to successfully conduct the preliminary computational fluid dynamics (CFD) and noise simulations, which ultimately lead the team to execute on the winning design.”
Vantage by Leap from the United Kingdom
“Vantage is a five-rotor airbike,” pretty much sums up what most publications managed to say for this entry. Reading Boeing’s more detailed material shows that the team is composed of aerospace professionals who’ve worked on projects such as the B2 bomber, serial hybrid power systems, “ballistic and heat-resistant materials for operation in extreme conditions,” and “a fuel cell UAV project at Boeing Phantom Works.”
Mamba by Mamba from the United States
Mamba’s design emphasizes safety, certifiability, and performance. According to the Kansas City Star, “’The KU team’s Mamba… six-engine hexcopter has a roll cage and is expected to have a training mode for new pilots. Originally the team envisioned a flying motorcycle and a name like ‘Sky Hog,’” said Lauren Schumacher, the team’s leader and a Ph.D. student studying guided munitions.”
Pegasus 1 by Scoop from the United States
The Pegasus us a Y6 tilt rotor with a wing and a hybrid powertrain with a cruise speed of 70 knots (80mph), according to Boeing. The team seems to consist only of the team captain: “Alex Smolen is a self-taught programmer who has experience creating and running a company. Smolen has built a full stack application and has in-depth experience with the design process. He has a bachelor’s in accounting, and experience in flying and building multicopters.”
A canard configuration with a motorcycle-like position for the rider, the S1 is powered by two electric motors with ducted rotors. The aircraft makes a 90 degree transition from vertical take-off to horizontal cruise flight. Not to join the chorus of doubters and hecklers, your editor is bothered by the proximity of the rider’s hindquarters to the rotor blades – especially when one considers this will take off and land with the rider facing straight up.
teTra 3 by Tetra from Japan
Tetra’s description, as that of Vantage, is terse. “The teTra 3 is not only efficient enough, but also stylish enough to meet commercial requirement.” The team, though, has a certified project manager and members from Honda, a software company and a major robotics firm.
Harmony by Texas A&M University from the United States
Harmony is a high-TRL [technology readiness level] compact rotorcraft designed to minimize noise and maximize efficiency, safety, reliability, and flight experience. Comments abound about the pilot’s exposed position and vulnerability if the machine turns into a giant Yard Dart. The contra-rotating propellers are large enough to reduce noise, perhaps, depending on rotational speed. As with most teams, Harmony relies on a multi-discipline group to make it a viable candidate.
FlyKart 2 by Trek Aerospace from the United States
FlyKart 2 is a single-seat, open-cockpit, 10-rotor, ducted fan, electrically-powered, VTOL aircraft. Trek has flown FlyKart 1, and number 2 is described by its designers as. “A new and improved version of our revolutionary FK1, it has ten of our ducted propellers and is custom designed to meet the challenges’ specifications.” It’s 9.6 kilowatt-hour battery will allow FK2 to cruise at 45 knots (51.75 mph) for 30 plus minutes. Its screened propellers will help protect pilots and passersby.
Possibly Sean Captain, writing for Fast Company, did not pen the headline, editors often tackling that clickbait-luring task. His writing seems more thoughtful, including this hopeful note from GoFly’s co-founder. “There’s been a convergence of all of these breakthrough technologies that make this the first moment in time where we have the ability to make people fly,’ says Gwen Lighter, who dreamed up the GoFly prize, recruited Boeing to bankroll it, and now serves as CEO. Many of the advances come from the world of drones–high-efficiency motors, high-capacity batteries, and cheap navigation and stabilizing technologies that keep even newbies on course and out of danger.”
Captain includes some rational voices less enthusiastic than Ms. Lighter. “’Batteries have much less energy density than liquid fuel,’ says Mike Hirschberg, executive director of the Vertical Flight Society, one of GoFly’s partner organizations. Depending on the technologies, fuel could pack on the order of 50 times more energy per unit of weight, he reckons.”
Captain returns to the Mad Scientist name calling with this description of Larry Page and Sebastian Thrun, not even entrants in the competition. “Google co-founder and aviation fanatic Larry Page recruited members of AeroVelo for his stealthy electric plane startup, Kitty Hawk. The company’s CEO, Sebastian Thrun, founded Google’s mad-scientist innovation division and also led Stanford’s 2005 DARPA Grand Challenge-winning autonomous car team. Kitty Hawk is one of many recent examples of competitions propelling cash-strapped innovators into big-business opportunities.”
Engadget stopped at the headline, giving a short, but restrained bit of copy to the news.
“Boeing asked for quiet jet packs but got a bunch of air motorcycles”
The Los Angeles Times took aim at Boeing’s supposed intent and seems to premise an ostensibly disappointing outcome.
Engadget looks at the various hurdles still to be leaped. “But there could still be social hurdles, like noise. Prize criteria specify that loudness, from 50 feet away, not exceed 85 decibels. That’s about as loud as a diesel truck going by at the same distance and similar speed. Lauren Schumacher estimates that Mamba will put out only 67 dB, about the sound of a noisy dishwasher. Would that satisfy neighbors?
“‘However, the FAA regulates aircraft a lot more strictly than cities can regulate scooters,’ says Hirschberg. And it’s still not clear if the age of personal flight will even come to pass, at least at prices that make it more than a rare curiosity. ‘This GoFly prize intends to prove that it’s technologically possible,’ he says. “And whether this is something that society wants is a whole other question.'”
Professor John Andrews (center) with the RMIT team that conducted the latest proton battery experiments: Dr Shahin Heidari (left) and Saeed Seif Mohammadi (PhD researcher, right). Not pictured: Dr Amandeep Singh Oberoi (now at Thapar University Patiala, India)
The first rechargeable battery of its type, it is, as reported in Green Car Congress, “Environmentally friendly, and has the potential, with further development, to store more energy than currently-available lithium ion batteries.”
When charging, electricity applied to a catalyst breaks down water into hydrogen ions (protons) and oxygen. The protons pass through a membrane and are stored in the hydrogen storage electrode. In discharge mode, the hydrogen ions are released from storage, pass back through the membrane and join with oxygen from the atmosphere to form electricity and water vapor, as in a standard fuel cell. (Image source: RMIT University)
Interestingly, the battery uses no lithium, but relies on the building blocks of life, carbon and water, for its operation. In their paper in the International Journal of Hydrogen Energy, Andrews and his fellow researchers explain, “Essentially a proton battery is a reversible PEM [Proton Exchange Membrane, or Polymer Electrolyte Membrane] fuel cell with an integrated solid-state electrode for storing hydrogen in atomic form, rather than as molecular gaseous hydrogen in an external cylinder. It is thus a hybrid between a hydrogen-fuel-cell and battery-based system, combining advantages of both system types.”
Exploded view of proton battery shows simple construction
Unlike a fuel cell, RMIT’s battery does not form hydrogen gas during charging. Hydrogen bonds directly to the hydrogen storage electrode. During discharge (electricity supply mode), hydrogen atoms are released and lose an electron to become protons again. The protons pass through the cell membrane, combine with oxygen and electrons from the external circuit to re-form water.
Makers claim “much higher energy efficiency” from their proton battery than from conventional hydrogen systems, comparable to lithium-ion batteries. Losses from producing hydrogen gas and splitting it into protons as in conventional fuel cells are eliminated.
Future proton batteries will doubtless be larger, and generate more than 1.2 Volts
The prototype can generate 1.2 Volts, and researchers hope to scale this small cell to automotive or grid storage sizes. The use of easily recycled materials offers hope for the cell’s future development.
Lithium-ion and lithium-polymer batteries of various brands provide energy for Teslas, Leafs, and Bolts, but continue to disappoint by stalled energy density, power density, and safety concerns. Two relative newcomers to the field might have answers to these concerns. Unlike many other newcomers, production might be less than five years away.
Ken Rentmeester, a good friend and retired chemical engineer, volunteers in the local TeenFlight program run by Dick VanGrunsven. He shared his copy of the IEEE Spectrum containing an article about a new battery company that may have some answers to problems common to lithium batteries.
Stacked Deck: This cutaway view of an Enovix 3D Silicon lithium-ion rechargeable battery prototype has three stacked 1-millimeter-thick cells.
Thermal Runaway: The construction of a conventional Li-ion cell, adapted from magnetic-audio-recording tape production techniques, makes it susceptible to thermal runaway, which can result in catastrophic damage from explosions or fires. llustration: Erik Vrielink
Making thermal runaway go away would make the Enovix battery a much desired energy source, especially for electric aircraft. A recent fatal collision of a Tesla Model X with two other cars near Mountain View, California ignited a major battery fire, which after being extinguished at the scene, reignited repeatedly in the salvage yard to which the X was towed. Mountain View Fire Chief Juan Diaz told reporters that “During a thermal runaway event, temperatures can exceed over 900 degrees Fahrenheit.”’
“The battery reignited twice in the storage yard within a day of the accident and again six days later on March 29. Two weeks later, in an effort to avoid more fires, the NTSB and Tesla performed a battery draw down to fully de-energize it, Diaz wrote in [a] memo.” This is not to denigrate Tesla’s battery technology, certainly among the finest in the world, but to show that current battery technology has some problems to resolve.
Enovix’s construction is unique, and makes thermal runaway highly unlikely. Based on microelectromechanical systems (MEMS) fabricated in three dimensions with photolithography, the battery can be made using existing systems and techniques. This should lower costs significantly.
Densely Packed: The 3D cell architecture orients and interlaces a cathode, 100 percent silicon anode, and ceramic separator in a thin (1 millimeter) flat plane, which significantly improves energy density and safety. Illustration: Jean-Luc Fortier
Material selection plays a part in how the battery works. “Instead of graphite, we use silicon for the anode material. Silicon is attractive because it forms a Li22Si5 alloy. That very high ratio of lithium-to-silicon bonding allows silicon to store about 4,200 mAh/g, an extraordinary amount. But silicon’s increased absorption of lithium ions can cause it to swell by up to 400 percent.”
Enovix avoids problems with such swelling – something that has long been a deterrent to the use of silicon in batteries – with careful sizing and selection of cathode materials. “Right now, we are using an NCA cathode, sized to match the capacity of the silicon anode. However, we can use any of the conventional Li-ion cathode materials, and that flexibility should allow us to meet the requirements of specific applications.” The firm also makes the silicon porous, “So that expansion pushes its tiny internal cavities together rather than swelling the entire anode.”
On the basis of volume, Enovix claims its cells can pack 1.5 to 3 the energy of conventional lithium cells. Considering the relative safety of the battery and its potential for low-cost mass production, this will be an attractive alternative for future development.
Perhaps even more intriguing, NAWA Technologies makes their ultracapacitors in two flavors, NAWACAP Energy and NAWACAP Power.
The firm makes big claims for its NAWACAPs: “A new generation of high power and high energy density ultracapacitor (their bolding).” The company predicts that “NAWACAP Energy will make it possible to store three to five times more energy than current ultracapacitors (15 Wh/kg today and expected to achieve 25 Wh/kg) while retaining the same power characteristics. (again, their bolding).”
Nanotubes comprise a great deal of NAWA’s ultracapacitor internal structure
NAWA says, “NAWACAP Power achieves power densities more than five times higher than existing ultracapacitors (100,000 W/Kg today and expected to achieve 500,000 W/kg).”
NAWA looks forward to developing hybrid ultracapacitor cells “With performance levels approaching those of lithium-ion batteries or even advanced lithium batteries that will surpass current lithium batteries in terms of fast charging and life cycle.”
Their nanotechnology is safe and recyclable, according to NAWA, because their ultracapacitors are made from carbon. “There is a significant difference in the way the batteries store electricity too. In a regular ultracapacitor, there is a purely electrostatic reaction, while with a lithium-ion battery there is a purely chemical reaction. NAWA Technologies’ combination of vertically aligned carbon nanotubes, a unique coating and a chemical electrolyte, allows its Ultra-Fast Carbon Batteries to sit between regular ultracapacitors and lithium-ion batteries, offering huge potential. That means higher-energy density and higher-power than regular ultracapacitors. They are also cleaner, safer, more reliable and kinder to the environment than current storage systems.”
Although even ultracapacitors have lower energy density than conventional batteries, the concept of combining ultracapacitors with batteries, and then using them in a structural form, might lead to lightweight, energy-dense automotive or aircraft structures. Certainly, the large surface area of wings, tails, fuselages and their internal components would allow using this energy storage in a way that would be lighter overall than a separate structure and energy storage system. That such systems can provide over a million operational cycles would ensure a long life for the aircraft structure.
NAWA’s video of CEO Ulrick Grape presenting at Ecosummit London last November does show that the company is still looking for funding, a common plight among such firms. It does remind us how dicey new developments are, however, and we might mellow our enthusiasm with a dose of economic reality. New ideas always face this kind of resistance to progress, and we still hope for a good future for NAWA and Enovix.
Kitty Hawk Flyer, the Larry Page-backed “sky taxi,” seems like a great summer escape machine. One can learn to fly it in about an hour, but it will remain low and slow enough to give the thrill of flight without inordinate dangers. That’s the marketing pitch from Kitty Hawk, and it’s not a bad one. Imagine going to a beach or lake with dozens of these fluttering about over the water’s surface. It’s the same kind of lure driving go-karts on a miniature race course has for vacationers.
Safety is obviously a factor for a machine meant for amateur use. John Lyon explains this in the Robb Report: “The zero-emissions Flyer is completely powered by electricity, and its propellers all operate independently, meaning that if there is a problem with one or more propellers, the entire vehicle won’t come crashing down. That said, even if it did, the aircraft is only meant for flying over water and only flies between three and ten feet off of the surface, so even a worst-case scenario would only involve a short plop into the water.”
CNN’s Rachel Crane traveled to a secret lake-side enclave in the desert near Las Vegas to train in and float in the Flyer. Colleague Matt McFarland watched, interviewed Kitty Hawk CEO Sebastian Thrun, and made the seemingly inescapable link to the Jetsons.
One troubling aspect was the dunking practice. “The hardest part of the day was definitely the ball pit,’ recalled Rachel.
“During her training session, she was strapped into Flyer and turned upside down in a ball pit. The drill is a way to practice unbuckling one’s seat belt and escaping Flyer if it were to crash upside down on water.” That possibility might give potential flyers pause.
Covey of Kitty Hawk Flyers indicates production goals for future
Kitty Hawk’s website offers a light once-over on technical aspects of the design, letting us know the craft’s “All-electric motors [are] powered by lithium polymer batteries,” and “Innovative software… utilizes data from multiple sensors to make flying intuitive and easy.” The “Revolutionary Design [is] expertly crafted using highly durable composite material that is lightweight, aerodynamic and waterproof.” The last point is necessary because the Flyer will only be authorized, like its first iteration, for operation over water. This version, looking like an open kayak with outriggers, will do well on water, large open bodies of which provide safe places to practice one’s skills.
Kitty Hawk will be “Significantly quieter than any fossil fuel based equivalent” – whatever that might be. Rachel Crane’s flight was software-limited to six mph and a lake-skimming altitude. As Flyers achieve more hours in the air, these limits will expand to enable commuter-like flights at altitudes where they might interfere with Amazon and Dominos’ deliveries. Everything is FAR Part 103, avoiding licenses, medicals and other impediments to personal flight.
Todd Reichert leads the engineering effort. He and his team from Aerovelo built and flew the first human-powered ornithopter, won the Sikorsky Prize for human-powered helicopters, designed, built and ran Eta, the fastest human-powered vehicle on earth (89.59 mph). This is an aerodynamic achievement as well as an athletic one, and is a huge contrast to the Flyer.
Kitty Hawk offers several opportunities to partner with the firm. One might want to operate a fleet of flyers, or stage an event involving several craft. One might decide to purchase a Flyer (price unknown yet) for personal use. These options require you to fill out an application and await an invitation from the firm. One can connect with the company and receive current news updates, and for those with the necessary skills, join the Kitty Hawk team.
Aeroelastic deformation, the reshaping of wings, tails, and even fuselages on aircraft subjected to the forces surrounding passage through the air, can be destructive, twisting and shaking aircraft surfaces. UAVOS, a company specializing in flight controls for drones of all sizes, has created a tandem-wing, tri-tailed High-Altitude Psuedo Satellite (HAPS) called ApusDuo.
https://en.wikipedia.org/wiki/Aeroelasticity Wikipedia gives a long and involved discourse on aeroelasticity, but UAVOS gives a lighter, more graphic approach that shows the dangers involved, and UAVOS’ approach to conquering those perils.
The firm makes three autopilots for varying sizes of aerial vehicles from those weighing less than 15 kilograms (33 pounds) to up to 1,500 kilograms (3,300 pounds). UAVOS craft include rotary-wing vertical takeoff and landing (VTOL) machines capable of carrying from one kilogram (2.2 pounds) to 90 kg.(198 pounds), and conventional aircraft that include an autonomous version of the Pipistrel Sinus.
Albatross 2-2 is UAVOS’ autonomous version of Pipistrel Sinus
Their ApusDuo has two wings, with the main wing spanning 15-meters (49.2 feet), equal to that of a standard-class sailplane. Much lighter, though, with a 23-kilogram (50.6 pound) maximum takeoff weight, span loading is a little over half a pound per foot (divided between two wings of equal area). The airplane would be incredibly fragile except for AUVOS’ method of actively managing flight loads. UAVOS explains this in two terse sentences. “Innovative solution in control of extended aspect-ratio flexible wing analyzes the spanwise deformation and adjusts lift force at a required section. This type of control allows [us] to distribute the load all over the wing, reduce the structure weight and effectively control the aircraft in all flight modes.”
At its 15,000-meter (49,200 foot) operating altitude, the drone can cruise at 27 meters-per-second (60.4 mph). That altitude enables surveillance of large areas at much closer distances than extra-terrestrial satellites. The machine’s two-kilogram (4.4-pound) payload should enable high-resolution imaging, or intelligence gathering through a large number of lightweight sensors.
Endurance should be close to perpetual, with 21-percent efficient solar cells spread across both wings able to collect enough sunlight for operation at 20 degrees latitude 365 days a year.
As reported in Aero-News Network, “’By its very nature, this solution replaces the low-orbital space grouping and can provide services not available for conventional satellite systems,’ comments Vadim Tarasov, UAVOS investor and Board member. ‘Such aircraft can carry out long missions, for years barraging in the air currents over the expanses of the World Ocean, over territories with no airfield infrastructure, sparsely populated areas, sea borders, taking and relaying information for both civilian and military facilities.’”
An active control system that overcomes deformation of such a light structure will almost certainly have applications in larger aircraft, and may make turbulence endurable even for the sensitive flyer.
George Bye has been enjoying a year filled with great expectations (and accomplishments). With 121 deposits on the Bye Aerospace Sun Flyer 2 from seven countries, the training aircraft needs only two things to make dreams come true for a large number of people – a motor and FAA certification.
Siemens Steps In
In a joint press release, Bye, CEO of Bye Aerospace, announced a partnership with Siemens that will see the German firm “collaborate on future development of Bye Aerospace’s Sun Flyer 2.”
L-to-R: Olaf Otto, Siemens Head of eAircraft Sales and Business Development; and George Bye, Bye-Aerospace CEO. flanked by Siemens small aircraft motors
Bye explained, “We are pleased to announce an agreement with Siemens to provide the electric propulsion motor and inverter for the Sun Flyer program. They will be an active partner through the FAA certification and production phase for the Sun Flyer 2.”
Siemens will supply the two-seater with its SP70D motor with a peak output of 90 kilowatts (115 hp.) and a continuous rating of 70 kW (90 hp.). Bye explained the nice “fit” with the Sun Flyer 2. “Given its performance and form factor, the SP70D motor is perfect for Sun Flyer. Members of the Siemens team have already been participating in development and certification meetings with the FAA, and we will be making future announcements about progress with the Sun Flyer 2’s flight test program.”
Dr. Frank Anton, Executive Vice President and Head of eAircraft for Siemens, added, “The Siemens SP70D motor has been specifically designed for the needs of 2-seater flight trainers. We know that safety, performance and cost of electric propulsion in the flight training market will be game changing and we are proud to partner on the Sun Flyer family of aircraft.”
Bye Aerospace claims that their trainer will have a total operating cost of $14.00 per hour (compared to $88.31/hour for a Cessna 172). Even better, the coming four-seat Sun Flyer 4 will feature $19.80 total operating costs per hour (Compared to $122/hour for a Cessna 182). These low operating costs and minimal maintenance costs, compared to piston-engine alternatives, might breathe new life into a moribund pilot training market.
Siemens is a huge international business with $92 billion in revenues last year. This level of backing will be a welcome change in the usually cash-strapped world of private aviation. Siemens has grand plans for its electric aircraft motors, though, including powering Uber’s sky taxis and large-scale regional airliners. See this presentation for an overview of Siemens’ far-ranging efforts in electric aviation.
A Sad Note
As a counterpoint to this encouraging news, a Siemens-powered Magnus eFusion crashed in its native Hungary, killing its two occupants. One report indicated a fire had occurred before the craft crashed and burned.
JetSuite’s current offerings include aircraft, “Ranging from the four-passenger Embraer Phenom 100s to the large-cabin, 13-passenger Legacy 650 to our JetSuiteX edition, 30-seat Embraer 135s, the JetSuite fleet offers our clients a variety of options for their aviation needs.”
Members and customers can find scheduled flights within JetSuiteX’s California and Arizona operating range. Prices are similar to business class accommodations on Southwest or Alaska airlines. It will be interesting to see if lower operating costs for Zunum’s regional hybrids pencil out in customer’s favor. For example, Zunum says, ”A Seattle-to-Whistler flight could cost $79 and take only an hour and a half in door-to-door travel time. For comparison, the one-train-per-day Amtrak train voyage would cost just over $90 and take nine hours, 15 minutes(!).
Seattle-to-Portland could take a couple of hours door-to-door, based on the use of regional airports.” Looking up drive times for similar road trips means at least a four-hour run to Whistler and a three-hour drive to Portland, not counting frequent traffic jams and impediments like bridge closings or border crossings.
The joint press release shows a market ready for exploitation. “Zunum aircraft are well-positioned to refresh the roughly $1 trillion stock of aircraft currently serving regional routes. Notably, Zunum has disclosed that its range-optimized aircraft features a maximum cruise speed of 340 mph, and with a low runway requirement of 2,200 feet for takeoff.”
Zunum’s hybrid-electric technology could provide low operating costs. Basic design allows use of smaller regional airports
JetSuite seems to be serious about adding these craft to its fleet, announcing plans to buy 100 of Zunum’s planes. Given JetSuite’s business model of providing exclusive transportation to a nation-wide network of airports for its members, private charters can transport executives and their staffs.
The two companies explain the utility and public acceptance possible for their new electric vehicles. “The Zunum Aero aircraft are optimized for distances up to 1,000 miles, where efficient travel options are limited, with low numbers of regional flights, high costs and cumbersome door-to-door travel times, making it a perfect fit for the short-haul private and semi-private travel offered by both JetSuite and JetSuiteX. By reducing noise and emissions by 80 percent, these aircraft are positioned to fly near residential communities, accessing over 5,000 underutilized airports in the U.S., reducing door-to-door travel times and costs.”
Logan Jones, managing director at Boeing HorizonX, is optimistic. “In short order, Zunum and JetSuite will prove out a model that is incredibly innovative.”
XTI TriFan 600 Finds Favor
Perhaps even more exclusive, but offering even greater flexibility and similar economy of operation, XTI’s TriFan 600 can dispense with the ride to the airport. Thomas Walker, Business Development and Sales Consultant for XTI Aircraft, recently gave your editor a brochure extolling the virtues of this hybrid electric VTOL business aircraft. The 3,500 pound empty weight, single-pilot, five passenger machine can fly from existing helipads, or at a heavier gross weight, from conventional runways.
Planned future development for XTI’s TriFan
The $6.5 million machine, with a relatively low claimed operating cost of $350 per hour, can save its owners $1 million per year if the owner flies the TriFan 1,000 hours, according to the company. One hour could take the passengers 340 miles at an operating cost per passenger of $70.
XTI compares these costs to those for other VTOL aircraft with comparable range – 660 miles with an 1,800-pound payload and cruising at 270 knots (310 mph). Using its conventional takeoff and landing (CTOL) capabilities, the airplane is projected to carry a payload of 2,800 pounds 1,200 miles. The craft can reach its maximum cruise altitude of 29,000 feet in only 11 minutes.
Robert LaBelle, XTI’s CEO, explains the capabilities of this unique aircraft.
A product of eXtended Technology and Innovation (hence the company’s name) the TriFan has three ducted fans powered by two 260 kilowatt motors each. These are motivated by a single 750-kilowatt (1,000 horsepower) turbine driving three generators. XTI is looking at engines such as the Honeywell HTS900.
Reported in AIN online, Chief Engineer George Bye explains the control and power systems that will make the TriFan a safe business machine. Besides “’a triple-redundant fly-by-wire system with a very high refresh rate to accommodate gust loading, …The electric propulsion system in the ducted fans will allow for very rapid adjustments to gusts in the critical phase of flight as you are lifting up and away.’
“The turboshaft engines will be connected to three generators powering six electric motors, two for each of the Trifan’s three ducted fans. Takeoff power will come from onboard battery packs. Bye said the batteries can handle the task as the takeoff phase is brief before the two wing-mounted ducted fans rotate forward to cruise flight position and turboshaft power takes over for cruise flight.
“Batteries would be supplemented by solar cells in the wings. In the event of main engine failure, the electric motors can be reengaged to provide limited duration power for landing and the Trifan will also be equipped with a whole aircraft ballistic parachute system.”
Potential customers for the XTI TriFan 600 are probably otherwise successful
XTI reports sales of 60 TriFans, with a significant number sold at the Ft. Lauderdale International Boat Show last November.
With low operating costs, charter services may consider TriFan’s as next-level commuters, hauling more passengers over longer distances than they urban equivalents. Quiet operation and redundant safety protocols will make these more than acceptable transportation devices in a range of urban environments.
We can tell things are heating up in the electric aircraft marketplace. Established aircraft companies are investing (Boeing and Airbus for starters), growing numbers are planning for electrified and autonomous future flight (Uber Elevate Summit), and an absolute plethora of new designs are tumbling forth from an aeronautical cornucopia. Their video of an Uber sky taxi ride illustrates the charm of the idea.
A Common Reference
Uber provided two common reference eVTOL (electric vertical takeoff and landing) reference models for partners to emulate. Both seem to share a common passenger pod with an unusually long tail boom.
Perhaps taking the 2011 Green Flight Challenge as his reference point, Mark Moore explained how Uber inspires others to give their best efforts to create several plausible vehicles. The American Institute of Aeronautics and Astronautics (AIAA) reports, “’We will never build a vehicle, but we want to make sure that our partners who are building vehicles are successful and that these aircraft are as community-friendly as possible,’ Moore said, explaining Uber Elevate’s partnership with manufacturers and regulatory agencies to clear the way for Uber to provide on-demand flight through a mobile app. Some of the companies partnering with Uber have not publicly released their aircraft concepts, so Moore unveiled a ‘common reference model’ that illustrates some of the challenges these electric aircraft will face, including battery energy density and noise pollution.”
Karem’s Uber Entry
Uber’s reference model seems to have inspired five similar efforts including one from Karem (otherwise known for development of the Predator UAV and heavy-lift machines). The company’s web site describes their effort in only general terms. “Electric Vertical Takeoff and Landing (eVTOL) Aircraft: Karem is applying its decades of innovative aircraft design and proprietary VTOL technology to the eVTOL market in partnership with Uber. In the future, it will offer riders a 10x improved transport experience by flying above traffic, point-to-point, at speeds up to 200 mph – all at the cost of an UberX ride today.”
“Our large rotors let us draw less power from the batteries than vehicles with smaller rotors, enabling immediate economic viability without waiting for future batteries,” Ben Tigner, Karem Aircraft’s chief exectuive, said
This may be due, in part, from “Karem’s patented Optimum Speed Tiltrotor (OSTR) technology [which] combines the fast, inexpensive, safe operation of efficient fixed-wing airplanes with the robust hover capability of helicopters.
Aurora Becomes Boeing, Elevates Its eVTOL
Recently purchased by Boeing, Aurora Flight Sciences fields its multi-rotor design. Like many others, it features eight vertical lift rotors and a propeller and wing to provide forward motion. Aurora and Boeing predict test flights in 2020, and some statements in a recent Bloomberg article suggest things may happen quickly. Dennis Mullenberg, Boeing’s CEO, says, “I think it will happen faster than any of us understand. Real prototype vehicles are being built right now. So the technology is very doable.” Bloomberg explains that sales will take place in the next decade, although without sharing when in the decade that might be.
Bell Helicopter Has Been Showing off a Cabin
Showing the cabin from their Uber-related sky taxi, Bell has shared their vision with audiences at the Consumer Electronics Show (CES) and South by SouthWest (SXSW). The Fort Worth Star Telegram reports that Uber and Bell will be flying a full-tilt version of what is described as a “tilt-rotor” machine much like a V-22 Osprey by 1923 over the north Texas skies. Bell’s long history in vertical flight development bodes well for their project.
Bell’s cabin/simulator shown at CES, SXSW, other venues. Flight configuration is still somewhat mysterious
Pipistrel’s Unique Configuration
As to be expected with Pipistrel, their offering is highly aerodynamic, with a swept wing and fighter-like cockpit enclosure – and no visuals on how the vertical lift system will work. Given Ivo Boscarol and Tine Tomazic’s history of innovative and sometimes revolutionary work, we expect some surprises. According to Clean Technica, Ivo explained, “Pipistrel is not trying to reinvent the helicopter by giving the vehicle many rotors, but is rather embracing dedicated propulsion solutions for cruise and vertical lift with built-in scaling capability.”
Embraer Combines Helicopter with Multi-Rotor
Embraer X is based in Melbourne, Florida with innovation teams in Silicon Valley and Boston. It revealed a four-seat “DreamMaker” at Uber Elevate. Powered by eight electric motor-driven rotors and a tailfan, the cabin will provide a great view for its four passengers. CEO Paulo Cesar de Souza e Silva predicts, “We are relentless in our quest for constant growth, and through Embraer X we will drive disruptive innovation and accelerate the creation of new businesses with the potential for exponential growth. Urban mobility is ripe for transformation and we are committed to having a major role in this key market.”
Uber plans to invest 20 million euros ($23.4 million) with France’s École Polytechnique over the next five years to develop sky taxis. According to The Verge, “The company announced Thursday that it will build a new Advanced Technologies Center in Paris focused on its ambitious Uber Elevate project, the ride-hail company’s first research and development hub located outside North America.”
France may be an interesting choice for an academic partnership, considering violent protests by Parisian cabbies when the service attempted to start a few years ago.
Uber is just one of many organizations garnering attention and largesse in financing electric aircraft. Others not following either Common Reference, or striking out in new directions known only to them at this point, are bringing other waves of creativity and surprise with them.
A new motor from Australia, the MagniX Magni5, promises 300 kilowatts (402 horsepower) from a 53-kilogram (116.6-pound) package, or about five kW per kilogram. This is competitive with other power-dense permanent magnet motors.
Torque Line is flat from zero to 2,500 rpm top speed of Magni5 motor, with impressive 1,000 Nm output
The Magni5 claims an absolutely flat torque curve (more a line, really) from zero to 2,500 rpm, producing 1,000 Newton-meters (737.5 foot-pounds) throughout its revolution range. This is a great deal like steam locomotive performance. Its 444 millimeter (17.5 inches) diameter and 275 mm (10.8 inches) size is perfect to hide behind a propeller spinner. The torque should guarantee a good rate of climb, and might be a worthy candidate for powering a Pikes Peak International Hill Climb contender.
The company certainly seems to be on track for designing around aircraft use, promoting their expertise and that of partners with a “Strong background in [the] FAA certification process.”
MagniX claims, “The magni5 uses a combination of advanced electromagnetic designs and materials, optimized motor topology, and a proprietary cooling system to deliver exceptional power and torque density with great efficiency.”
Even more promising, MagniX’s technology is apparently on the verge of creating a superconducting MagniAlpha motor that could product 25kW per kilogram. That would power an ultralight with a 2.2-pound motor, or a Light Sport Aircraft from a mere eight or nine pound powerplant, leaving extra poundage for batteries. MagniX is not without experience in superconductivity, explaining, “We build superconducting generators for energy-intensive industries such as smelting and hydrogen fuel production. Our superconducting generators are the most advanced and efficient in the world.”
Magni5 performance is already impressive, and superconducting MagniAlpha would provide five times that
To maintain safe operation and predictive maintenance, MagniX’s Xbrain is an intelligent control unit with artificial intelligence (AI) algorithms enabling a “military grade” safety system. Xbrain enables an advanced heat management system for the liquid-cooled motor, and multiple layers of redundancy. If the motor has the same relative torque density as the Magni5, it would be, in the words of its creators, “a transformational advancement.”
The company provides design and implementation services to those interested in its products. Its personnel programs seem to encourage a culture of creativity and accomplishment we hope will be reflected in future products.