From Ganged Motors to Wright’s Two MegaWatts

Twelve years ago, your editor gave his first talk at an electric aircraft symposium.  Dr. Brien Seeley asked that he include all motors up to 100 kilowatts in his talk – at that time a rarity.  Designers often had to “gang” small motors to drive a single propeller to obtain the necessary power.  Now, Wright Electric has announced its plans to develop motors (and associated equipment) in the 500 kilowatt to 20 megawatt range.  Motors of those sizes are still under development, but Wright claims to have tested and demonstrated “a megawatt-class, high performance inverter,” according to Green Car Congress.

Jeff Engler is getting recognized for his vision.  Here he give his virtual elevator speech at the Davos, World Economic Forum.

His positive and yet measured approach seems to gain acceptance for that vision.

Demonstrated Performance?

Aiming for some audacious levels of performance, Wright’s inverter could hit these metrics:

  • “99.5% efficiency –a 6x improvement in heat loss over current in-production aviation inverters resulting in significantly lower thermal management loads.
  • “30 kw/kg power density –in contrast, today’s technology delivers 10-20 kw/kg. On a standard single-aisle aircraft, this would result in a weight savings equivalent to adding an extra 5-10 passengers per flight.”

Working at high frequencies, the Wright inverter has a 300 kHz high-frequency output, compared to standard inverters which have 50 kHz to 100 kHz frequencies.  A “novel switching technology… reduces total losses for a factor of two over similarly rated systems.”

Wright will next integrate the inverter with “an in-house developed 2 MW motor,” and proceed to high altitude chamber testing, and qualification for flight readiness.  According to AIN online, Wright hopes to test the combined inverter and motor in an airplane at 40,000 feet within the next two years.  Jeff Engler, Wright’s founder and CEO explains, “We’re right now having those discussions about who’s going to do the manufacturing and things like that.  I think we’re heads down on proving out that the motors and inverters work on the ground and then at 40,000 feet.  And I would say everything else is a future decision.”  Wright’s two Megawatt system would eclipse anything currently available.

Wright shows this simplified sketch of their inverter, not willing yet to share the secrets to their claims

Wright’s motor would operate at “up to six times the voltage of existing motors, running at 1,000 Volts.  Partly because of the high operating frequencies and Voltages, the motor can be 75-percent lighter, 50-percent smaller, experience 40-percent less heat loss and offer twice the torque density of other motors.

These characteristics help reduce the weight of the overall system, thus maximizing payload and range.  AIN Online reports the combined power density of the propulsion system could be as high as 30 kilowatts per kilogram.  The company claims, “Given that currently, available technology delivers only between 10 and 20 kW/kg, such an increase would result in a weight savings equivalent to carrying an extra five to 10 passengers on each flight in a standard single-aisle airplane.”

From a Shoestring to ARPA-E and Beyond

Starting on the proverbial shoestring in 2016, Wright is currently part of ARPA-E’s ASCEND (Advanced Research Projects Agency-Energy, Aviation-class Synergistically Cooled Electric-motors with iNtegrated Drives) program.

Inverters seem to wrap around motor on simplified system sketch

Besides ARPA-E’s ASCEND program, Wright is funded by venture capital firms and the US government, receiving $7 million in motor/inverter-related government contracts in 2020.

ARPA-E defines its mission on its web site.  “The Advanced Research Projects Agency-Energy (ARPA-E) advances high-potential, high-impact energy technologies that are too early for private-sector investment. ARPA-E awardees are unique because they are developing entirely new ways to generate, store, and use energy.”  Wright Electric would certainly seem to fit that definition.

Wright’s 186-passenger airliner would have 800-mile range

Its 186-passenger, multi-electric-motor airliner will, according to Wright, be 20 percent quieter and use only 20 percent of the energy to fly its 800-mile trips.  This has made it an interesting partner for easyJet and VivaAerobus, and a recipient of not only ARPA-E funds, but those from Y Combinator and the Clean Energy Trust, as well as from various venture capital groups and private investors.  Wright’s goals are outsized compared to others, which seems to be focusing on 300-miles trips with 19-passenger regional commuter liners.  Good luck to them all.  A green future depends on multiple successes across a spectrum of requirements.


That’s the eSpirit!

We reported in the blog four years ago that Embry Riddle Aeronautical University not only displayed their eSpirit of St. Louis at AirVenture that year, but ran the motor for the crowd.  The crowd included Federal Aviation Administrator Michael Huerta, who sat in the cockpit during the runup.

The eSpirit of St. Louis

A product of Embry-Riddle, eSpirit is finally making its presence on the taxiway known.  Kelly Pratt, writing in the Embry Riddle Aeronautical News, reports, “After nearly four years of perseverance, the Eagle Flight Research Center (EFRC) team at Embry-Riddle is celebrating a milestone in its electric propulsion research: its Diamond HK-36 completed a successful taxi test exclusively on electrical power at the Daytona Beach International Airport.”

Erik Lindbergh, grandson of Charles, has been a guiding factor in eSpirit’s development, and the airplane reflects his grandfather’s “notion of balance between aviation and the environment.”

The quarter-mile on the taxiway may seem like a short trip, but student Sanay Satam sees it as a prelude to bigger things.  An Aerospace Engineering Master’s candidate, he explains, “I am ecstatic that we achieved this taxi milestone and look forward to our next milestone – flight – an arduous task, but not an impossible one.  We know the challenges that stand before us and are motivated to overcome them. It is all about the high fives at the end of the day, knowing that we were able to achieve our goals, thus fueling, or should I say, electrifying our ambition to succeed in the flight phase.”

Dr. Richard “Pat” Anderson, Department of Aerospace Engineering professor and director of the EFRC, performed the taxi event.  Joseph Thiemer, a student completing his bachelor’s degree, rode shotgun, programming and monitoring parameters in the motor controller and the battery management system (BMS).

Other Embry Riddle Electrics

The Diamond HK-36 test vehicle was donated by Lockheed Martin Skunk Works, and is part of an ongoing series of hybrid and electric aircraft developments by faculty and students.  In 2011, for instance, ERAU managed to field a hybrid adaptation of the Eco-Eagle S10 Stemme motorglider in the 2011 NASA Green Flight Challenge sponsored by Google.

Despite being fourth out of four competitors that managed to make it to the starting line, ERAU’s team acquitted itself well.  Because liability considerations allowed only the pilot in the cockpit, the Eco-Eagle had a low score because the final results were based on passenger miles per gallon.  The fact that they managed to get an airplane to California from Florida and still fly in the competition was something nine other entrants, mostly professional, did not.  That’s how high the bar was at that time.

Since then, Embry Riddle has been busy with serial and parallel hybrid configurations.  One result is their Heurobotics electric Vertical Take Off and Landing (eVTOL) machine.  The carbon fiber flying wing can lift up to 115 pounds.

Battery Configuration

From the Green Flight Challenge on, EFRC lists at least five electric projects:

  • Design, build, and testing of a 100 kW serial hybrid electric powerplant.
  • Design, build, and testing of an 8-rotor eVTOL handling qualities research prototype.
  • Design and modification of a Diamond HK-36 motor-glider from gas to electric propulsion.  (The eSpirit)
  • Design, build, and flight testing of a twin rotor tail-sitter UAV.
  • Design, modification, and flight of the “World’s First Parallel Direct-Drive Hybrid Aircraft” for the NASA/Google-sponsored Green Flight Challenge.

Professor of Aerospace Engineering Dr. Richard P. Anderson, stands with the past and future of flight: the WACO, Heurobotics Mark 2 UAV, and the Eco-Eagle eSpirit of St. Louis at Embry-Riddle Aeronautical University in Daytona Beach, March 29, 2017. (Embry-Riddle/David Massey)

Embry Riddle notes, “The technology employed for the eSpirit’s electric motor and inverter is currently used in the automotive industry, [but] the EFRC designed its own battery packs for the aircraft.   These are configured to allow the packs, “To conform to irregular and small spaces.”

Dr. Kyle Collins, a research assistant professor at the EFRC, explains other factors in play.  “Battery weight is the critical factor when it comes to designing electric aircraft battery packs. To achieve this, the batteries operate near maximum performance and, as a result, generate heat. Care must be taken to design battery packs that can be cooled.”

Generation 1 eSpirit battery packs contain 84 cells, weighs 12.33 pounds. 30 are needed to fly eSpirit 1.5 hours. Gen 2 packs should be lighter, conformable to aircraft nooks and crannies

First generation packs used in the taxi test will be replaced by a bonded cell, liquid-cooled pack, the product of new equipment and research.

Theimer noted, “As advancements are made with battery energy density, the application of using electric motors for aircraft propulsion becomes more practical. Carbon emissions, noise pollution, and alternate forms of urban mobility will all benefit,.  Gaining experience with this equipment and in this field is very beneficial at the undergraduate level, to be able to take that experience to the industry and apply it towards something that will eventually be used worldwide.”  These new packs will power the fully-electric eSpirit in the future.


RavenSR: Hydrogen from Waste

Green hydrogen is getting a lot of press lately, at least partly because of the possibilities it allows in transportation design.  Raven SR, headquartered in Pinedale, Wyoming, has as its mission, “Providing revolutionary, clean technology to convert waste into renewable fuels and energy.”

Clean Technica took notice of the company’s interesting location, deep in “an epicenter of the US coal,” the Powder River coal basin.  Their article notes some of the politics involved.  “The United Mine Workers of America, for one, came through with a statement in support of President Biden’s climate-friendly American Jobs Plan, contingent on its members getting a share of those new green jobs.

“In the same statement, UMWA also lobbied for saving the remaining few remaining coal jobs, partly through policies that ramp up demand for the metallurgical coal used in steel making and other industries.”  Note that Wyoming’s coal is not metallurgical, though, and would never be used for smelting steel.

Diminishing Landfills?

America hauls a lot of its municipal wastes long distances to get rid of it.  Portland, Oregon, for instance lugs its garbage by truck or train to Arlington, Oregon – 140 miles up the Columbia Gorge.  There, it’s dumped into a landfill.  Opening in 1990, the site has a “projected life remaining of 143 years.”  Even with huge amounts flowing in (2.74 million tons in 2017), Arlington has a remaining permitted capacity of 329 million tons.  It accepts things like treated medical waste, animal carcasses, and used abrasive blast media (such as sand from sandblasting).  That creates some waste of its own – most landfills give off methane – a significant greenhouse gas.  Anything that reduces the need for transporting waste and heaping it in a toxic landfill is to be encouraged.  Waste-to-hydrogen plants are one hope.

As noted in their YouTube explanation, In 2018, Raven SR acquired Intellergy Inc.’s waste processing technology.  Intellergy’s technology is essentially unchanged today.

RavenSR manages its waste-to-H2 conversion through a “patented Steam CO2 technology” that, “transforms biomass, municipal solid waste, bio-solids, industrial, sewage, medical waste, and natural gas into renewable energy products including hydrogen, sulfur and nitrogen-free Fischer-Tropsch liquid fuels (diesel, Jet A, mil-spec JP-8), additives and solvents (acetone, butanol, naphtha, etc.) and electricity (via fuel cells or turbines and/or CAT syngas engines).”  The company claims the “significant difference between” them and their competitors is “no combustion.”

Somewhat like pyrolysis, Raven’s “technology does not admit any oxygen into its process.”  The firm claims this provides a cleaner process to convert all feedstock into fuel instead of burning.  It also converts more of the feedstock into synthetic gas (syngas), according to RavenSR.  Because there is no combustion, there are no hotspots or tar buildup in its gasifier.  This reduces maintenance and downtime.

Raven claims their system, “Is simply better for the environment.  We actually reduce greenhouse gas emissions at multiple levels.”  For that reason, “The technology has been approved by the Berkeley (California) Air Quality Department, which is among the most stringent in the country.”

Besides being a non-combustion system, Raven says its technology has four other advantages.

  1. There is no steam methane reforming (SMR), reacting methane and other higher hydrocarbons with steam in the presence of a catalyst to form carbon oxides and hydrogen.
  2. There is no auto-thermal reforming (ATR), which partially oxidizes a hydrocarbon feed with oxygen and steam and subsequent catalytic reforming.
  3. It is water neutral, recycling and “even manufacturing” any needed water, and can be completely water neutral.
  4. It meets the highest safety standards, using “sophisticated AlertPlus sensors to detect leaks and automatically shut down plant operations.

Raven claims their system produces more hydrogen or Fischer-Tropsch fuels (which can be converted to other liquid fuels).  Since their system are mobile and compact, they can be installed at sites next to methane flaring stations, taking a major greenhouse gas out of the air and producing clean-burning hydrogen or other carbon-neutral fuels from it.  Likewise, feedstock can include the previously mentioned municipal waste – with many of the same benefits.

Hyzon Takes an Interest

Compactness and flexibility led Hyzon, “a global supplier of hydrogen fuel cell-powered commercial vehicles,” to form a joint venture to build up to 100 “hydrogen hubs” across the U. S. and globally.  Hyzon will acquire a minority interest in Raven SR.

Moving quickly, the partners will build and commission the first hubs in the San Francisco Bay Area in 2022, “Then expand into the rest of the US and globally.”  Hubs will be built at or near landfills and convert “multiple organic wastes”…”into locally-produced, renewable hydrogen for Hyzon’s fleet of zero-emission commercial vehicles.”

Each hub, about the size of two semi-truck trailers (or cargo containers) are expected to take in 50 tons of solid waste per day and produce 4.5 tons of renewable green H2, “enough to power 100 heavy-duty commercial vehicles.”

Compact nature of plant belies its high productivity of green fuels

Craig Knight, CEO and Co-Founder of Hyzon Motors, sees future expansion leading to enhanced efficiency of operation.  “Hyzon aims to be one of the first companies to supply our customers with a hydrogen fuel cell truck, including our own garbage trucks, at total cost of ownership (TCO) parity with diesel-powered commercial vehicles. With our leading fuel cell technology, we are working closely with partners to scale up hydrogen production in the US and globally. In Raven, we see a technology that is highly efficient in waste conversion, scalable and mobile, enjoying a low cost of hydrogen and most importantly, capable of producing the quantity of green hydrogen that our vehicles will need. One hundred hydrogen hubs could convert over 5,000 tons of waste per day and power over 10,000 trucks.

More and larger sites will allow, “Hyzon [to] provide their customers with a complete zero-emission mobility solution—from hydrogen-powered vehicles to on-site or locally produced low cost clean-hydrogen.”


ZeroAvia’s Malibu in Off-Airport Incident

We share this press release from ZeroAvia to allay any rumors or misinterpretations as to what happened May 1 on a test flight of ZeroAvia’s Piper Malibu.  The aircraft was damaged in an off-airport landing, but everyone on board managed to exit the craft safely and carried out safety protocols.  The incident will doubtless be thoroughly investigated by ZeroAvia’s team and by the United Kingdom’s own Civil Aviation Authority.

ZeroAvia Off-Airport Landing Review

1 May, 2021, 08:00 BST

On April 29th, 2021, ZeroAvia’s R&D aircraft made an off-airport landing just outside Cranfield airport perimeter during a routine pattern test flight (logged as ZeroAvia Test 86, and the 6th flight in this flight testing segment). The aircraft landed normally on its wheels in a flat grass field and almost came to a stop, but was damaged as it caught the left main gear and wing in the uneven terrain at the end of the field at low speed. Everybody involved is safe, and without injury. The incident was immediately reported to the Air Accidents Investigation Branch (AAIB), and the Fire Service attended on the ground, as is the standard procedure.

The facts as they stand now are as follows: the flight conformed to the approved test route over the airport; the structural integrity of ZeroAvia systems was maintained throughout the incident sequence and there were no unintended hydrogen or electrical releases and no fire; after the landing, the crew were able to safeguard the battery and safely release hydrogen from the onboard tanks, following ZeroAvia safety protocol; no fluid leaks were observed at the time; and full data logs were preserved and will be used in our investigation.

Overhead view from Bedford Fire and Rescue shows detached left wing

Following the flight test incident, ZeroAvia appointed a team of experts to conduct the internal investigation. These individuals, led by Dominic Cheater, ZeroAvia’s Head of Airworthiness, are independent from the design and operation of the HyFlyer I program. Dominic holds extensive expertise in airworthiness, flight test engineering and air safety. He has past experience with major industry names such as Babcock International as Chief of the Office of Airworthiness.

Additionally, the team includes:

Christine Ourmieres-Widener, a senior advisor and member of ZeroAvia’s Board of Directors. Christine formerly served as a CEO of a number of airlines and a member of the International Air Transport Association’s Board of Governors.

  • Richard King, Global Policy Lead for ZeroAvia, a certified pilot who has held senior roles in aviation sector organisations, the UK’s Ministry of Defence and in the Royal Navy.

  • Dr. Yousef Abdelli, ZeroAvia’s CTO of Propulsion, and formerly Chief Engineer for Liebherr Group and magniX.

  • James Yapp, a flight test engineer with extensive experience of leading flight testing activities.

The investigation team will deliver a full review of the incident in collaboration with the UK’s AAIB, in-line with industry best practices and procedures. It will investigate the technical and operational events of the incident, identify its root causes, and ensure we learn from them. The process is already underway and we will share more once it is complete.

Closeup from ground shows severe damage, but mostly intact fuselage

We will continue to work with the AAIB to ensure the delivery of a full and detailed investigation of the incident. As with any investigation, it will take some time. It is paramount we follow procedure and refrain from rushing the process. We will provide updates as we are able.

This incident and the ensuing investigation will undoubtedly disrupt our 6-seat HyFlyer demonstration program that was coming to an end in the following weeks. However, we do not expect any negative impact on our commercial-intent HyFlyer 2 program targeting 10-20 seat aircraft, or our large-engine development program targeting 50+ seat aircraft.


In our last blog entry, we discussed a three-partner enterprise with an American airframe propelled by a French motor powered by British batteries.  In this round, we have a Canadian airframe powered by an Australian/American motor driven by Swiss batteries.  These international collaborations may pay off in big ways.

Datelined Vancouver, B.C., Everett, WA, and Sion, Switzerland, the joint press release shows a strong and well-organized partnership in action.  “Harbour Air, North America’s largest seaplane airline; magniX the company powering the electric aviation revolution; and H55, the spin off from Solar Impulse, producing highly efficient certified battery packs, announced a partnership to certify the world’s first electric Beaver (eBeaver) commuter airplane through a supplemental type certificate (STC) program.”  H55 is a part, also, of the Solar Impulse Foundation, organized to promote “1000+ efficient and profitable solutions to protect the environment.”  Their collaboration with Harbour Air and magniX is one of those solutions.

Even though a small airline (40 aircraft) flying short missions may not seem all that newsworthy, Harbour Air’s eBeaver electric flights and demonstrations of magniX’s eCaravan captured headlines in publications from the Puget Sound Business Journal to the PBS News Hour.  The partners’ eBeaver heads off the segment on electric aviation – something the media is finally recognizing.

After years of development, flights took place over the last two years, and H55 powered a Bristell Light Sport Aircraft with what looks like an Emrax motor and their own modular battery packs.  The partners hope to use H55’s battery modules, “To expand the eBeaver’s balance to weight ratio and endurance. The company’s battery modules have one of the highest energy densities on the market and will provide the entire energy storage system and redundant battery monitoring at the cell level for the eBeaver.”

The partners share an enthusiasm for the project.  Andre’ Borschberg, H55’s Executive Chairman, sees “synergies” emerging from the collaboration.  “We have been attracted by Harbour Air and magniX’s vision, pioneering spirit and commitment to make aviation clean. The collaboration will leverage our synergies and complementarities. We all understand that the path to electric aviation is complicated. But at the same time by joining forces, our combined experience will lead to quicker certification. And this in turn will offer a fast and safe way to reach the market and popularize electric aviation.”

Greg McDougall, CEO of Harbour Air, shares the optimism.  “I believe that H55 is the leading company in aviation battery solutions,” says “Having them as partners in the ePlane development means that we will be able to lead the global push for electric aviation.”

With no hints of actual energy or power density on H55’s web site or in their press releases, one can surmise that H55’s batteries must be better than those currently flying in the eBeaver or eCaravan.

H55’s battery packs configured to fit in Bristell LSA

magniX motors have demonstrated their ability to fly large craft, and are a known factor.  Roei Ganzarski, CEO of magniX, reflects on those qualities. “This partnership is another step forward in our vision of making emission free, all-electric aircraft a reality. With Harbour Air leading the way to become an all-electric airline, H55’s battery technology and magniX’s flight-proven propulsion, we are looking at an electrifying future.”

Snug fit in Bristell wing, H55 battery packs will have more space inside eBeaver’s span

The eBeaver has continued performing flight tests, measuring and collecting data on:

  • Cruise performance
  • Take-off thrust efficiency
  • Electromagnetic interference (EMI)
  • Battery management software logic
  • Noise levels

The partners are striving to optimize the electric propulsion unit (EPU), energy storage system (ESS) and related aircraft systems.  Borschberg, impressed with Harbour Air’s “pioneer spirit and commitment to the environment, concludes, “We all understand that the path to electric aviation is complicated. But at the same time by joining forces, our combined experience will lead to quicker certification. And this in turn will offer a fast and safe way to reach the market and popularize electric aviation.”


Bye Aerospace, Oxis Energy and the Safran Group have introduced an, “Eight-seat all-electric twin turbo-prop class airplane, the eFlyer 800™.”  It’s a fascinating combination of new airframe, new batteries, and new motors.  An American airplane powered by English batteries and propelled by French motors will be an international accomplishment, to say the least.

The Airplane

Maybe not coincidentally with Earth Day, Forbes magazine ran the following introduction.  “Bye Aerospace has announced an eight-seat all-electric twin turbo-prop class airplane, the eFlyer 800™, in response to growing demands for regional all-electric airplanes with significantly reduced operating costs, plus increased capacity and utility.”

The craft, roughly equivalent to a Beechcraft King Air 260 in every respect except range, will be a fully-electric luxury machine capable of carrying one or two pilots and up to seven passengers.  Cruising at up to 320 knots (368 mph) at 35,000 feet would make quick business of its 500 nautical mile (575 statute mile) range.  It will have to slow down to 280 knots to meet that 500 miles and still have 45-minutes of instrument flying regulation (IFR) reserve, though.  eFlyer’s 3,400 feet per minute rate of climb will take it to cruising altitude quickly.

Bye Aerospace says, “Aerodynamic efficiency is twice that of a typical legacy turboprop aircraft of similar size.”  The 800’s high overall propulsive system efficiency results from its high motor efficiency and low cooling drag.

Packing a full-airplane recovery parachute adds a safety backup that should rarely be needed, thanks to dual redundant motor windings and quad-redundant battery packs.  Further safety elements include an emergency auto-land system, software with an “intelligent algorithm ensuring envelope protection, terrain avoidance and routing for [that] emergency auto-land.” Optional solar cells could supplement the aircraft’s range and in-wheel electric taxiing could enable main battery use for flight operations only.

Operators will appreciate the low operating cost of the eFlyer 800, about one-fifth that of “traditional twin turboprops.  The craft, intended for the air-taxi, air-cargo, regional and charter aircraft markets, “…Is the first all-electric propulsion technology airplane that achieves twin-turboprop performance and safety with no CO2and extremely low operating costs,” according to George E. Bye, Bye Aerospace CEO.  He adds, “This type of remarkable economy and performance is made possible by the electric propulsion system and advanced battery cell technology that results in significantly higher energy densities.”

The Batteries

Charles Alcock reports in Future Flight that Oxis Energy, associated with Bye Aerospace for the last five years, “expects to start delivering its solid-state lithium-sulfur (Li-S) batteries to customers for trial applications in the fall of 2021. The UK company says the technology will offer significantly improved performance for electric aircraft developers, compared with existing lithium-ion batteries.”

Lithium-sulfur cells have a higher energy density than lithium-ion cells.  The Perlan Project used lithium-sulfur batteries on Perlan 1 and early on in the Perlan 2 because of that factor and the reassurance that they are less likely to experience thermal runaway and subsequent fires.  Oxis Energy makes that point by shooting bullets and pounding nails through their pouch cells with no loss of current and no release of the magic smoke inside.

Oxis seems headed toward a solid-state lithium-sulfur battery.  They will introduce Quasi Solid-State Li-S cells (with an electrolyte combining liquid and solid components with a specific energy of 450 Watt-hours per kilogram and an energy density of 550 Watt-hours per Liter this fall.  They hope to increase those numbers to 550 Wh/kg and 700 Wh/L by the fall of 2023, and then to 600 Wh/kg and 900 Wh/L by 2026.

Oxis Energy recently announced achieving 500 charge/discharge cycles for its Li-S cells – formerly a weak point for the chemistry

Oxis Energy CEO Huw Hampson Jones reports, “Based on our existing U.S. client base, we know that aircraft manufacturers welcome the move from conventional to solid-state Li-S [batteries.”   The company is also offering the new Li-S batteries for various marine, defense, and ground vehicle applications. It has been developing the technology over the past four years and three years ago filed nine sets of patent applications.  That’s a small part of the company’s innovative drive.  With over 43 patent families, OXIS has been granted 204 patents for its Lithium Sulfur cell technology. There are 101 patents pending.

The Powerplants

Bye Aerospace and Safran are powering the eFlyer 2 and eFlyer 4 with ENGINeUS™ motors, which integrate the motor and its inverter into one tidy package.  They are working together to determine, “The most efficient electric powertrain for the eFlyer 800 (dual ENGINeUS electric motors and GENeUSGRID™ electric distribution and network protection system).”  Hervé Blanc, Executive Vice President and General Manager Power with Safran Electrical & Power, explains. “Safran product lines with the ENGINeUS™ motors, rated from 50kW to 500kW/1MW and GENeUSGRID™ systems, perfectly fit with the Bye Aerospace portfolio of e-aircraft.  Building upon our successful cooperation on eFlyer2 and eFlyer4, we are very proud to bring our best expertise to support Bye Aerospace in the design of the new eFlyer 800.”

eFlyer 2 and 4 will have similar but smaller Safran motors than those to be used on eFlyer 800

 Combining the motor and inverter gives a package that is 94-percent efficient overall.

Bye said eFlyer 800 customer deposit agreements are complete, and several being developed with U.S. and European air-taxi, air-cargo and air charter services, “Details about those agreements will be announced soon, and as they are finalized.”

Bye Aerospace has led in getting FAA Part-23 certification for the eFlyer 2 and its professional flight training mission and the four-seat eFlyer 4 for air taxi, cargo and advanced training uses.

Flight schools, charter operators and other users will benefit from five-fold lower operating costs compared to those for internal combustion aircraft, no CO2 emissions, and decreased noise. “Bye Aerospace estimates the eFlyer will eventually eliminate the release of millions of metric tons of COeach year as its deliveries begin and the general aviation fleet is replaced.”

Thanks to Diane Simard,  Executive Vice President for Bye Aerospace, and Mélodie Susini of the Safran Group for material in this blog entry.


BETA and Blade Cut Deal for 20 Alia’s

Business as Unusual

BETA Technologies made a big move from its highly complex Ava to a simpler Alia, and managed to snag an initial order for up to 150 of its new craft from United Parcel Service (UPS).  This was followed by the signing of a binding agreement with Blade for another 20 craft for passenger service.

Vermont Business Magazine reports that BETA Technologies started with its first customer and partner, United Therapeutics, which will rely on BETA’s aircraft to deliver organs for human transplantation.  High speed and reliability are obvious premiums in this endeavor.  Recently, United Parcel Service (UPS) announced it reserved the right to purchase 150 of BETA’s aircraft, with the first 10 to be delivered beginning in 2024. UPS also purchased BETA’s charging stations as part of an integrated solution.

BETA’s charging station is modular, functional and just right for its intended purpose

Gaining government backing, the United States Air Force Agility Prime program continues testing BETA’s machines.  The program, “Marshals government resources to accelerate commercialization of air mobility vehicles.”

Blade founder and CEO Rob Wiesenthal explains his company’s plans for Alia.  “Blade is focused on its transition from conventional rotorcraft to electric vertical aircraft [EVA].  Beta’s delivery commitment date in 2024 is ahead of our current projected deployment of EVA in 2025. The transaction, consistent with our asset-light operating model, allows Blade to leverage our significant flight volumes and third-party financing partners to support the purchase of Beta aircraft by our operator partners.”

A Short History of Ava

Ava was a complex derivation of a Lancair ES and RDD-developed LX-7 wing.  Its eight independently-powered rotors were controlled by an undoubtedly complex hardware and software network.

Complexity of structure and operation of Ava’s pivoting rotors is apparent in this view

The 4,000 pound eVTOL (electric Vertical Take Off and Landing) aircraft stood atop long, spindly legs to help its eight large rotors clear the runway and its power plants pivoted on stalks long enough to help those rotors run clear of the fuselage.

A Simplified Alia

Alia’s rotors are are oriented horizontally to provide vertical thrust only.  Its single pusher propeller provides thrust for forward flight.  This configuration is greatly simplified from Ava’s, since no motors or cabling have to move to create the desired motion.  Beta’s web site promotes Alia as “The Future of Flight,” and explains, “The ALIA electric vertical aircraft is just simple enough to be revolutionary.”

Back in the 1920’s William Bushnell Stout, designer of the Ford Trimotor among other things, famously said, “Simplicate and add more lightness.”  This challenge seems to have inspired Beta’s designers.  Although the aircraft is heavier than the Ava, it is much simpler.  In keeping with Stout’s dictum, “BETA Team Members achieve[d] their goals by removing every unnecessary element.”

Alia can carry up to 1,400 pounds or up to 200 cubic feet of cargo as far as 250 miles and recharge in 50 minutes.  It utility factor should be high.

An In-House Design

BETA’s power system is an in-house design and creation, “The cornerstone of our ability to fly long distances economically and in an environmentally friendly way.”  Air cooled and redundant, Alia’s motors are controlled by dual inverters.  BETA assures us, “With safety as priority, our inverters are designed with 3 lines of communication with the system and built with redundancy in case of failure.”  All independent power systems are fed by a set of “environmentally sealed” battery blocks under Alia’s cabin floor.

Networking is Important

Since delivering organs, packages and complete people requires infrastructure, BETA has designed, “A thoughtfully constructed network of charging systems to recharge the aircraft, pilots, and crew enables electric flight.”  Their Rapid Charging Charging systems are a bit like Tesla’s Superchargers, and can be deployed on- or off-airport.  Hooked up to a 480 Volt AC, three-phase, 60 Hertz line, the charger can deliver up to 450 Amps and a boost charge current of 500 Amps.  The charger can connect to a vehicle through CCS or CHAdeMO plugs on an ADR 2.0 Demand Response Interface.  Users can pay through credit cards, phone apps, or an RFID tag.

Multi-Featured Charging Pad

BETA Technologies explains their highly functional modular charging station and landing pad.  “With thoughtful consideration to the needs of pilots and crews, multi-featured charging systems include workshop and maintenance space, lounge area and short-term lodging.”

Highly modular and using nicely modified shipping containers to accommodate equipment and personnel, each station includes the following:

  • Battery energy storage
  • Generator
  • Elevated landing deck
  • Pilot Lounge
  • Sleeping Accommodations
  • Maintenance & repair workshop

The elevated landing deck is a secure landing zone with light systems and deicing for all weather operations.

With orders from United Therapeutics, UPS, Blade and ongoing interest from the Air Force, BETA Technologies and their dedicated crew has many avenues to success.  The fact that they clearly define the problems they need to solve shows a promise for the way forward.


A Decade of Development

A modified version of Elektra One, flying since 2011 and certified in the German ultralight  class, Calin Gologan’s Elektra Trainer could provide affordable flight training with lower operating costs.  Calin displayed Elektra One at the 2012 AirVenture show in Oshkosh, Wisconsin, flying daily on the power of its solar-charged batteries.

Elektra Trainer in retractable gear version

The company details its background.  ” Elektra Solar GmbH is a spin-off from the German Aerospace Center (DLR), Institute for Robotics and Mechatronics.  The roots of the company go back to 2011. This year PC-Aero GmbH was founded in 2011 by Calin Gologan.  Elektra One electric aircraft was the first product flying in March 2011.

“In the same year, we [received] the Lindbergh Prize for Electric Aircraft Vision. Elektra UAS GmbH was founded in 2012 for unmanned systems and application. Both companies merged in 2016 under the new name Elektra Solar GmbH.

“In 2015 we flew with the Elektra One Solar for the first time over the Alps. The first flight of the larger Elektra Two Solar took place in 2017. In 2019 we flew with the Elektra Two Solar UAS (unmanned version) up to 10 km (32,800 feet) altitude completely autonomously, including start and touch down. Our aircraft systems for control and operation were already used for many hundreds of flight hours as UAS (Unmanned Aerial Systems) or OPS (Optionally-Piloted Systems).”

Elektra Trainer has a wider and longer fuselage than Elektra One, with reinforced, 13.5-meter (44.3-foot) wings.  These enable a glide ratio of about 28:1 and a cruise speed of 120 kilometers per hour (74.5 mph).  A 14.5-meter (47.5-feet) span version is available.  The Trainer can stay aloft on only 11 kilowatts (14.75 horsepower), less than a third of its Eck-Geiger HPD-40’s rated power, and only a fifth of its short-duration maximum output of 60 kW (80.5 hp).  A 35 kilowatt-hour battery ensures at least two hours in flight with a healthy reserve.  An 18 kW charger can “top off” the battery in under two hours, giving the airplane a high usability factor.  With a normal training flight of 50 minutes and training cycle of 35 minutes, the Trainer can accommodate two training flight before required charging.

A Thoroughly Modern Trainer

Calin is a master at lightweight structures, his Elektra One having parsed its 300 kilograms (660 pounds) into roughly 100 kilos for structure, including landing gear, motor and controller, 100 kilos for batteries (remember these were a decade-old technology) and 100 kilos for payload.

Elektra Trainer may be even more of a svelte creation, its empty weight of 400 kg (881.85 pounds) including the complete power system – batteries and all.  It stays within ultralight rules (Light Sport Aircraft in America) with a maximum takeoff weight of 600 kg (1322.8 pounds).

Eck-Geiger’s Duplex motors share shaft, operate independent of one another

To enable a good cruising speed (120 kilometers per hour or 75 mph), quick takeoff (200 meters or 657 feet) and a three meters per second (590 feet per minute) rate of climb, Elektra Trainer has an electrically-actuated monowheel landing gear.  A fixed tricycle gear is an option.  Its 1.75-meter (5.74-feet or 69-inch), three-blade propeller turns slowly for maximum efficiency.  Electric flaps help the craft land in the same distance in which it took off.

Elektra Trainer’s excellent aerodynamics and light weight are complemented by the power system, an integrated dual motor, controller and bespoke batteries.  Eck-Geiger Engineering’s HPD40 Duplex motor is really two separate motors on a common shaft.  The firm describes its redundancy and safety.  “Two mechanically and electrically completely separate individual motors work without gears on a propeller shaft, so that if there is a fault in one powertrain, the aircraft can continue its flight as normal.”  For all that power and refinement, the motor weighs a mere 12 kilograms (26.5 pounds).

Described as “whisper silent,” the craft will generate a claimed “about 50 dB,” which would make it one of the quietest aircraft outside of a sailplane.  Completing the sailplane comparison, the craft can be transported in a “normal glider trailer” and assembled in 30 minutes.

Elektra Trainer with tricycle gear

Its large cabin, 1.2 meters (47.24 inches) wide, can accommodate pilots up to two meters (78 inches) in height.   Its quiet, emission free operation should find favor with instructors and trainees alike.  Its low operating cost, claimed to be 50 euros (about $60 US) per hour including depreciation, maintenance, charging, battery replacement costs, and insurance, are about half those for typical trainers, according to Elektra Solar, Calin’s firm.  Elektra Solar claims the craft will save operators about 500,000 euros (about $598,000 US) over its 10,000 hour lifetime – more than double its less than 200,000 euro ($239.000US) purchase price.  .

A Digital Option

DAP (Digital Aircraft Platform) is the basis for all control and monitoring elements of the aircraft.  DAP performs real-time monitoring and logging of all aircraft parameters, provides intelligent assistance to the pilot and activates protection algorithms automatically in critical situations.

DAP simplifies aircraft operation and maintenance.  The life of each essential part (like batteries, motor and propeller) is monitored in real time, analyzed  and documented continuously.  With special software, the flights can be visualized and analyzed.

One hopes this doesn’t lull pilots into falling asleep at the stick, emulating drivers who become too confident of the degree of assistance their “autopilot” will provide.  Two passengers were recently killed in a wreck of a popular electric car, neither in the driver’s seat while the car hurtled along.


Pipistrel’s triple alliance with SF Express, a Chinese package delivery enterprise, and Amazilia, a software/hardware firm in Germany, will help fulfill high-flying ambitions.  Pipistrel, a well-established company with its roots in Slovenia, already has affiliates in Italy, China, and the USA.  Now, its partnership with SF Express and  Amazilia has obvious links to the need to keep things on track in transporting people and cargo with the new eVTOLs (electric Vertical Take Off and Landing) vehicles Pipistrel is developing.  SF Express is a huge “logistics” firm, delivering packages throughout all of China.  “Amazilia Aerospace is a young engineering company in the heart of Munich, Germany, developing digital flight control, flight guidance, and vehicle management systems for civil manned and unmanned aircraft.”

Pipistrel is crafting a “heavy cargo hybrid VTOL drone” for SF Express, capable of taking products anywhere in China within 36 hours – a significant challenge in such a huge country.  It needs to be able to climb over mountains and traverse long distances in that quest.  It will carry over 300 kilograms (660 pounds) of cargo in a 2.3 cubic meter (81.2 cubic feet) space – equivalent to the space in a minivan.  Pipistrel’s cargo hauler has a range of 500km (310 miles) with cruising altitudes up to 6, 000 meters (19,685 feet) and VTOL capability up to 2500 meters (8,200 feet) above sea level.

For each of the 1,000 projected cargo hybrids, eight European Aviation Safety Agency (EASA)-certified Pipistel E-811 vertical lift packages will be required.  “Highly efficient and redundant battery packs [will] assure safe operation even if two rotors are inoperative.”  Building a thousand airframes and 8,000 motors will put Pipistrel in the front ranks of aircraft production in the next few years.

This makes Pipistrel Founder and CEO Ivo Boscarol proud and happy.  He points out “To be chosen by one of the largest logistics companies globally to design and produce a tailor-made line of vehicles for aerial cargo transportation is a solid recognition of Pipistrel’s capability built up on more than a decade of achievements in electric flight. We look forward to becoming even more involved in strategic business solutions on a global scale, where our vehicles will change how aerial logistics work and have further significant impacts to sustainability and quality of life.“

Pipistrel’s V300 cargo hauler will deliver payloads across China for SF Express. Amazilia avionics will control and guide autonomous craft

To help guide these cargo haulers on their way, “Amazilia Aerospace will deliver an advanced digital flight control and vehicle management system, their Automatic Flight Control System and Vehicle Management System (AFCS/VMS).  Both the avionics hardware and software are capable of automating the entire cargo mission. Designed for VTOL or conventional aircraft configurations, the system seems well-suited for Pipistrel’s design which combines both types of operation.  Designed specifically for large scale logistical operations by logistics companies such as SF Express, Amazilia’s systems seems almost melded to such needs.  The system partially results from, “Years of research at the Technical University of Munich (TUM) reinforced with aerospace industry experience.”

Pipistrel will flight test the eVTOL, “With the Amazilia Aerospace system in Europe followed by operational validation in China starting in 2022. By 2023, SF Express intends to deploy the HVTOL cargo drone fleet in their domestic and non-domestic business operations.”  This will be a connecting flight between large-scale operations with jet cargo planes and “last-mile” deliveries with smaller drones.

Li Dongqi, SF Express Vice President and SF Unmanned Aircraft Systems Chairman, sees great promise in these plans. “Our efforts to achieve 36-hour countrywide delivery throughout China face significant challenges, such as natural barriers, underdeveloped logistics infrastructure, and more, especially in rural China. SF Express intends to adopt cargo VTOL drones to solve this bottleneck due to their flexibility and high speed, which is on par with helicopters, and has low costs which are competitive with truck delivery. The high-altitude capability allows us to extend our civil air cargo service coverage to even difficult to reach mountainous areas. We believe VTOL drones will become a major vehicle in China, and SF Express alone will need more than 1000 in the next 10 years.”


Two Wood Aircraft Leading to the Future

Two French manufacturers are reverting to bois et toile (wood and fabric) for ultra-modern aircraft.  Both of their aircraft will be electrically powered, and both will use non-traditional approaches to construction.  In the meantime, both have fairly traditional demonstration models.

The French have done wonders with wooden aircraft from the very beginning of aviation.  Santos Dumont built the petite Demoiselle with bamboo longerons, for instance, and Henri Mignet crafted his diminutive Pou du Ciel (flea of the sky, or flying flea) from available wood.  After World War Two, Messrs Joly and Delemontez fashioned a small single-seater, the Jodel D-9, from wood and ply and powered it with converted VW Kubelwagen engines, Jeep-like German vehicles which littered scrap yards and former battlefields.  Avions Mauboussin and Aura Aero use more modern power systems and vastly different approaches to bois and toile structures.

The Jodel D-9 was part of the rebirth of postwar French amateur aviation, being built by hundreds of enthusiasts.


Mauboussin goes back to prewar times with small aircraft that look as though they could have come from a home shop   Even their latest endeavors are aerobatic machines with wood and carbon fiber frames that combine traditional looks with modern aerodynamics.

A tres racy poster for Mauboussin fly-in highlights pretty woman, Porsche, and historic airplane.  Mauboussin went on to develop jet trainers

The company has two machines, one very much realized and the other on the virtual ramp.  They make a mission statement for both.  “Alérion M1h and Alcyon M3c are personal means of transport dedicated to interurban mobility.  Their performance allows them to cover a large distance and operate from a reduced infrastructure: small airfield, heliport, sports field, parking lot, public park or lawn of a residence.”  The company foresees reduced environmental impact from their machines through the use of natural materials, reduced fuel consumption, and minimum emissions “thanks to electricity and hydrogen.”  Although the video is in French only, the graphics convey the tidy surroundings in which the airplane is being developed.

The Alérion M1h is a modern interpretation of traditional two-seat touring aircraft, with a modern adaptation of the fuselage in wood, but wrapped in high-strength composite materials and “bio-sourced resins.”  Power will come from a single Zephyr hydrogen-hybrid engine system – not yet well defined or seeing the light of day.  Composites World reports the powerplant will produce a total power of 80 kilowatts (110 horsepower), for electrically-powered takeoffs and hydrogen fueled cruising speeds of 250 kilometers per hour (155 mph).  The company suggests trips like Belfort to Toulouse (around 390 air miles) would take two and a half hours.  By car, the shortest route is 795 kilometers (493 miles) and takes at least nine hours.

A press release from Mauboussin explains their schedule for the next seven years. “The creation of Zéphyr (hybrid hydrogen propulsion) will lead to the marketing of Alérion M1h (the first of the Mauboussin aircraft), in 2025 for the kerosene hybrid version and 2027 in the hydrogen hybrid version.

“Alcyon M3c will be launched in 2026 for the kerosene hybrid version and 2028 for the hydrogen hybrid version.”

In artist’s rendering Mauboussin Alcyon shows off its grass field abilities

The company promises, “Avions Mauboussin will offer the Zéphyr propulsion drive train to other aircraft manufacturers, helicopter manufacturers, manufacturers of VTOL flying taxis or drones, as well as other manufacturers in the maritime and automotive sectors.”  This would help build a customer base for the powerplant and help reduce manufacturing costs through economies of scal

Maurboussin’s Alcyon M3c makes no bows to tradition, exhibiting thoroughly modern, if not outright futuristic, lines.  It will carry five in probable luxury, lift off from an STOL (short takeoff and landing) airstrip and cruise at 370 kilometers per hour (229 mph) for up to 1,500 kilometers (932 miles).  It will share with the M1h HOTAS (Hands On Throttle and Stick) control, a heads-up display and Wi-Fi, satellite and 4G connectivity.

Aura Aero

French aerospace firm Aura Aero is a newcomer, as is its intended battery source.  Verkor, although new to the field, is already affiliated with established groups like digital software company Capgemini and Schneider Electric. It’s not necessarily an innovative firm, starting as a “fast follower,” using existing technology and manufacturing techniques to fill in gaps in needed production.

Aura Aero’s 19-seat commuter liner bears resemblance to AEG’s Bird of Prey, would provide swift regional transit

Its aerodynamic partner is starting with a series of two-seat aerobatic aircraft much like Mauboussin. Aura Aero has a slightly more ambitious follow-up, though, with its 19-passenger, six-motor regional airliner.  Aura’s enterprise will begin in an historic hangar at Toulouse Francazal, where the hangar’s rebirth as the center of a high-enterprise soon take place.  Like many other energy-efficient startups, Aura Aero is being supported by its local region, the Occitanie, known for its Pyrenees Mountains. reports, “Aura Aero plans to become a ‘key player’ in the low-carbon sector, it says, ambitiously aiming to carry out a maiden flight of the 19-seat transport in 2024 for service entry in 2026.”  Its partnership with Verkor highlights its use of their “specially-developed batteries.”  The company also proposes a freighter version of the larger craft.

Both companies show that wood aircraft are in no way outdated, and can suit modern needs quite well.