While in Oshkosh – EAS 2019

The CAFE Foundation’s 13th annual Electric Aircraft Symposium will take place Saturday and Sunday, July 20 and 21, at the .Culver Family Welcome Center, close to Wittman Airport (OSH).

Speakers will cover the technology, infrastructure, regulation, and future of electric vertical takeoff and landing vehicles and conventional electric aircraft.  The  speakers have great expertise in both areas – and everything in between.

Register and see the schedule for the event here.

Speakers will include:

  • Yolanka Wullf, Executive Director of the CAFE Foundation
  • Gilles Rosenberger, CEO of Faraday Aerospace
  • George Bye, CEO of Bye Aerospace
  • Lior Zivan, CTO of Eviation
  • Todd Hodges, Retired Engineer from NASA’s Langley Research Center
  • Tom Gunnarson, Lead of Regulatory Affairs with Kitty Hawk
  • Boris Popov, Founder of BRS Aerospace, Inc.
  • David Ullman, Emeritus Professor of Mechanical Design, Oregon State University
  • Willi Tacke, Founder and Organizer of the e-flight-expo and CEO of Flying Pages GmbH
  • Kenneth L. Swartz, Board Member of the Vertical Flight Society and President of Aeromedia Communications
  • Mike Hirschberg, Executive Director of the Vertical Flight Society
  • Ryan Naru, Vehicle Standards Lead for Uber Elevate
  • Bruno Mombrinie, Founder and CEO of Metro Hop
  • Rob Bulago, President of Trek Aerospace
  • Keven Noertker, Co-founder and CEO of Ampaire, Inc.
  • Gregory Bowles, Head of Government Affairs for Joby Aviation
  • Earl Lawrrence, Executive Director for Aircraft Certification for the FAA
  • Edgar Mendes Rodrigues, Business Intelligence, Embraer X
  • Kevin Rustagi, Director of Business Operations for LIFT
  • Jim Murphy, NASA UAM Grand Challenge Technical Lead
  • Mark DeAngelo, Aerospace Standards Engineer for SAE International

Taking place in close proximity to AirVenture, this combination of technical, managerial and regulatory experts will provide deep insight into where electric flight is headed.

Registration is $175, including meals, and available until the beginning of the Symposium.

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Open PPG Rev. 4

An Open Source Project

Powered paragliders (ppg) have been a relatively inexpensive and fairly reliable method of getting off the ground for several decades.  The OpenPPG organization enables one to be part of a group effort to improve a simple, light framework and power systems as part of a group effort.

The group’s web site proclaims, “The OpenPPG project is the solution to easy, convenient, and affordable powered paragliding. With its simple user-friendly, maintenance free, and lightweight design it has never been safer and easier to experience the thrill of flight.”

Here we see the first flight of the rev. 3 model.  The body-cam is a bit distracting, but does give a view of the steps required to ready the machine for flight.

A second video shows two paramotors in flight, demonstrating great control (on a probably very calm day), and almost vibration free images because of the craft’s small electric motors.

How well will one of these things climb?  A pilot starting at a 4,400 altitude location climbed nearly 3,000 feet within the 50-minute maximum battery endurance for the OpenPPG.

Glydrfreak (Braedin Butler) explained details.  “Medium Tequila 4 (canopy) loaded at 242 lb (max end of soaring weight range).

5.6-pound Bonka battery pack. Most OpenPPG flights use four to six of these

“Between two flights on the same 6 Bonka batteries, climbing at 65 amps on each ESC, total height gain was 3400 ft. Launched at 4400ft MSL.”

Assembly and costs

The OpenPPG consists of a frame, pilot harness, motors and power system, and the all-important batteries.  The organization sells an array of parts, including the all-important battery packs and parachute canopy.  Prices seem reasonable and a builder can configure the machine to suit individual sizes, weights and general preferences.

It’s interesting to see what people are producing with Arduino and Pi circuit boards.  These budget items are remarkable for their versatility and seem to be well used in this application.  Several “open source” attempts have been made to bring low cost to flying.  Success remains elusive for most such projects, but seems to have come to OpenPPG.

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Crossover Preparing for Market Re-Entry

Teofilo Leite introduced his Crossover, a touring motorglider powered by two Emrax motors, several years ago.  This video from six years ago shows how it was configured then.  Crossover has gone through several changes in its mode of propulsion since then and has become the svelte form that expresses a need to fly.

In its original configuration, Crossover’s flaps, landing gear and motors extended and retracted, a neat bit of packaging in the slender fuselage.  The airplane went through several changes, including one variant, shown at Aero 2014, that had a Rotax engine driving a long carbon-fiber shaft that drove a series of belts to a tail-mounted propeller.  On the other side, a hybrid version with Rotax engine driving a generator charged the electric motor on the tail.  It was a stunning display.

Eurosport Crossover showing Rotax-powered shaft drive…

And showing hybrid side with electric motor on tail, at Friedrichshafen Aero 2014

Under its beautiful canopy, which opens via Bluetooth command, the low-slung seating is accessible even from a wheelchair.  Carbon molded bucket seats “are shaped for long journeys and comfort with great adjustable cockpit ventilation for both pilot and passenger.” That would be highly desirable for the long distances Crossover is intended to traverse.  The 116-centimeter (45.66-inch) wide cockpit matches the overwhelming wide view.

Now the airplane has made a return, with a simpler setup of fixed engines on a center section still features the unique fuselage/wing junction, still similar to Munchen Akaflieg’s MU-31.  Apparently, the original plan to provide 12-meter (39.37-feet), 15-meter (49.2-feet), and 18-meter (59.06-feet) prevails.  The ability to select wings that match a desired performance or use shows a design versatility underlying the Crossover name.

Currently-configured Crossover on trailer shows motors on fixed center section

Linking the technology and engineering centers of northern Portugal, which supplied materials and fabrication with Brazil, which supplied design and aerodynamics from Professor Paulo Iscold (Universidade Federal de Minas Gerais), Crossover is a Portuguese project.

Sliding the outer wing panels onto the center section. Wing can be 12, 15, or 18 meters

Established in 2009, with first Crossover flights in 2013, Flight Dynamics and Eurosport Aircraft are scanning the horizon for new ways to fly.  Teofilo Leite introduced a sleek little two-seat Speedster at the 2014 Aero Expo at Friedrichshafen and this may follow the renewed Crossover.  Even more exciting, if that’s possible, “a Crossover-related remotely piloted platform with impressive range, which benefits from fantastic glider capabilities and low consumption of the hybrid mode,” may be in the wings.

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Total Operating Costs – Batteries Included

Gilles Rosenberger, co-founder of Faraday Aerospace with Michael Friend, former Technology Director for Boeing, commented on a recent entry on H55’s Energic two-seat trainer.  He expanded on the idea of total operating costs for electric aircraft, including the battery replacement.

He congratulated the H55 team and added a point about which your editor will attempt greater diligence.  “But why keeping talking about operating cost and not total cost of ownership?  No pilot, no student is going to pay only few dollars per hours based on the energy cost.  Who do you believe is going to pay for other cost including the battery amortization?”

Comparative battery prices over the last decade. Note the suddend drop for GM batteries because of shift to pouch nickle metal cobalt composition. Note also Tesla’s ability to remain less expensive than Chinese BYD cells

Practicing the best public relations and salesmanship gambits, most aircraft sales operations don’t mention the eventual cost of battery replacement.  Gilles, who can speak from experience because of his work on the Airbus E-Fan project, says, “Best industry standards seem to be today 1.000 € (or $1,125) per kWh for a 1,000 cycles non-certified battery pack.”

What Do Replacement Batteries Cost, Anyway?

Checking this against both automotive and small aircraft numbers, and assuming that aircraft certification will invariably raise prices, we present a few real-price examples.

A Nissan Leaf battery pack – a bit pricey, depending on its life time

Nissan Leafs have a smaller-than-Tesla pack, with 24 kilowatt-hour capacity for earlier models and 40 kWh for newer cars.  BatteryMan.com says new prices for the 24 kWh units now run $6,200 and $7,800 for the 40 kWh units. At $258 and $195 per kWh respectively, these prices undercut Gilles’s numbers considerably.  Unfortunately, they only apply to Japanese customers with a core battery for exchange.

Motley Fools, in 2016, said Chevy’s Bolt battery cells would cost $145 per kWh at the cell level, with an estimated $210 per kWh at the pack level.  This was better than the Fool’s estimate of $260 per kWh for Tesla’s pack price, although Tesla claimed $190 packs – a controversial number.

Comparing Auto and Airplane Prices

Pipistrel’s January prices for its battery packs, as used on their Taurus electric self-launching sailplane, are 10,200 euros ($11,480) for the 30 kWh unit and 13,600 euros ($15,310) for the 40 kWh size.  This works out to $382.70 and $382.75 per kWh, respectively.  One wonders why the smaller pack works out to be five cents per kWh cheaper.

Pipistrel’s so-called “plug-and-play” electric propulsion system. Batteries are largest, heaviest and most expensive part of setup

Gilles points out, “With the assumption of 400 flight hours per year, the battery life should be in the 3 years range (not every flight will fully discharge the battery), and 50 kWh battery amortization will [require] about 46 €/$51.79 more per hour (50 kWh x 1.000 €/$1.13 per kWh / 400 hrs x 3 years).”  He adds, “Of course these figures will be discussed but nobody can say it will be nothing.”

Regardless of whether Gilles’ higher number or the examples shown above prevail, there is a “balloon payment” that lurks at the end of the battery pack’s life.  Your editor watches automobile auctions on TV occasionally, and notes the sometimes extraordinarily low price a gleaming classic fetches.  Announcers explain that the BMW or Bentley that rolled off the block is hampered by the fact that buyers know the previous owner got the initial mileage out of the vehicle, while second and third owners will face replacement parts bills and high-priced maintenance.  What will these similar considerations mean for the secondary electric aircraft market?

We will endeavor, in this blog, to come up with an average battery replacement cost where a more exact number is not available, to help determine a total operating cost for each aircraft we write about.

1934 patent drawing shows details of Dzuz fastener, or “Dzuz Key” named for its inventor. These held cowling doors and inspection flaps in place.  Whether by design or happy accident, a dime could turn the screw, so instructors would advice their students to always being one flying. Note the small pieces comprising the fastener and its nut-plate mount. Vibration cracks these and requires expensive labor to replace.

We might consider several other miscellaneous factors, such as lower vibration levels for electric craft, in formulating total operating costs.  Those who’ve flown in small, four-cylinder trainers know that cowlings and fairings often show wear and tear on fasteners, brackets, nut plates and other light-weight components.  Electric craft should have lower miscellaneous maintenance costs in this area.

Overall, electric aircraft should have lower total operating costs.  The simplicity and promised longevity of electric motors and controllers compared to the 1,000- to 2,000-hour time between overhaul periods for certified fuel-burning engines should bring about substantially lower numbers for future flight.

Thanks to Gilles Rosenberger for this consideration.

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Contrails and Climate Change

Contrails are the trails of condensed water vapor that follow an airplane at a high enough and cold enough altitude.  They became a visible presence in World War II and were part of newsreels of allied bombers hitting Germany and dog fights over the English countryside.  There was more than just an aesthetic side to the new, high clouds in the sky, though.

WWII saw the introduction of massive waves of high-altitude fighters and bombers, as depicted in this 1965 British postage stamp

Post-9/11

During the attacks on September 11, 2001, FAA controllers, “Did the only thing they could think of to try to control the situation: ordering every aircraft in U.S. airspace, about 4,000 of them, to land somewhere, anywhere, immediately.”

“Canadian officials followed. Airports in Atlantic Canada quickly filled with thousands of bewildered people who had been flying west across the Atlantic from Europe, but found themselves stranded in Goose Bay, Labrador or Stephenville, [Newfoundland].”

Following this mass grounding, an observable cooling took place.  Andrew Carleton, a geographer at Pennsylvania State University recalled his observations at the time.   “I remember walking to and from my office (in the days after the attacks) and thinking how incredibly clear the skies were.”

About a year after the attacks, Carleton, David Travis, and another colleague argued in a paper that thin clouds created by contrails reduce the range of temperatures. Adding to cloud cover during the day, they reflect solar energy that would otherwise reach the earth’s surface. At night, they trap warmth that would otherwise escape.  Not surprisingly, temperatures change most in areas where the most flights take place.

In this video, Carleton explains the effects contrails have on heating and cooling the earth.

In a reversal of 9/11 effects, an air raid involving over 1,400 aircraft over England in May, 1944 measurably lowered daytime temperatures. This was in a time when only a few airliners departed London each day and private aviation was the province of the well-to-do.

In 2004, NASA scientist Patrick Minnis wrote that “increased cirrus coverage, attributable to air traffic, could account for nearly all of the warming observed over the United States for nearly 20 years starting in 1975.”  He attributed a one-percent per decade increase in cloud cover came from increased air travel, greater in more populated areas and in winter, “when contrails are bigger.”

A 2005 paper by physicist Robert Noland of Imperial College London suggested, “restricting airliners to 31,000 feet, and 24,000 feet in winter, could reduce the formation of contrails. Though lower-flying planes would be less fuel-efficient.”  NASA pursued that line of thought at around the same time.

Flying a lower altitudes prevents contrail formation, but would probably cut into airlines’ profit margins without new designs for aircraft

Minnis found, “The warming effect happened because the high-altitude clouds that contrails created tended to trap warm air. On balance, though contrails can both warm and cool, there is more of a warming effect.”

A 2015 Penn State study expanded the 2001 finding by comparing regions of the United States where contrails tended to form more strongly with areas where they didn’t. The more contrail-heavy the area, the less the variation between daytime highs and nighttime lows tended to be.

Higher Fuel Efficiency, More Flights

Maddie Stone, a science writer for Gizmodo, explains in a recent article that, “The climate impact of flying isn’t just about carbon emissions. The contrails that airplanes create also influence the temperature of our atmosphere—and a new study finds that impact is set to grow in a big way.  She explains, “Globally, the atmospheric warming associated with these clouds is estimated to be larger than that caused by aviation’s carbon emissions. That surprising fact has some scientists curious about whether the effect will grow as the skies continue to get more trafficked into the future.

Stone references researchers at the German Aerospace Center (DLR) and their findings published in Atmospheric Chemistry and Physics, “show that by 2050, contrail-induced warming could be three times higher than it was in 2006. In fact, this type of warming will likely outpace warming from rising carbon dioxide emissions, thanks to concurrent improvements in fuel efficiency.”

Stone adds, “The authors’ models indicate cirrus clouds will contribute some 160 milliwatts of additional ‘radiative forcing’—extra energy flowing back toward the Earth’s surface— by mid-century. Ethan Coffel, an atmospheric scientist at Dartmouth College who wasn’t involved with the paper, noted that for comparison, under the climate change scenario the authors use, heating from greenhouse gas emissions will be around 6,000 milliwatts per square meter by the end of the century.”

As contrails persist at altitude, they shield the earth from the sun’s radiation, but also trap heated air beneath

“’So while the contrail forcing is certainly significant, it’s a relatively small contributor to overall warming,’ Coffel told Earther via email.”

It will be a net cooling effect for jet engines to become more efficient and a net warming effect as flights become more frequent. Some are urging flying less or not at all.  That will demand more rail, bus and private car traffic, though, with possibly great effects on warming.

Geoengineering?

Some want us to turn to geoengineering to solve this crisis.  Again, the unintended consequences might be worse than the problem.  Should we create high, reflective clouds to radiate solar warmth back into space?  Should we work to get rid of all clouds? Either route seems to have a disaster-movie scenario attached.  Your editor just finished reading Richard Rhodes’ Energy: a Human History.  The book  relates the many changes in energy production through time, with each promising much, but having sometimes tragic effects on those who accepted the new “technology” with open arms.  With so much riding on our newly-forced choices, we must be as informed as we can be while practicing the highest levels of due diligence.

More to Read and Ponder

A final note: This link provides a good overview of post-9/11 research on aircraft contrails and their effect on climate.  Obviously, an electric alternative would be a great one – but we’re still short on the necessary battery technology.

The site warns, “If any of the links above do not work, copy the URL and paste it into the form below to check the Wayback Machine for an archived version of that webpage.”

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Volt Aero Cassio Hybrid – From France

You may have noticed an ongoing divide in electric aircraft philosophies, that of designing from a blank sheet, or that of converting an existing airplane from fossil fuel to electric power.  French company VoltAero has chosen the second path with its Cassio. A conversion of a Cessna 337 Skymaster, it shares similarities to Ampaire’s 337 conversion, with significant differences in its power configuration.

What has Five (Three?) Motors and Three Propellers?

Ampaire’s 337 conversion retains the “push-pull” arrangement of the original, with the “pusher” an electric power unit behind the cabin and between the twin tail booms.  VoltAero’s replaces the front engine with a faired, engineless nose and one REX 60-kilowatt (80.4 horsepower) electric motor on the nose of each boom.

According to Flyer magazine, Cassio 1 now has a single electric motor coupled to an internal-combustion engine bringing up the rear.  “The prototype Cessna-based Cassio has two 60kW motors driving two forward facing propellers on the wing. A hybrid power unit comprising a 170kW piston engine and 150kW electric motor drives a pusher prop at the rear. That’s a total of 440kW, giving the aircraft the ability to fly fuel, batteries and nine people for 1200km, according to [Jean] Botti.”  Botti was Chief Technology Officer for Airbus when they developed the e-Fan, which was flown by Didier Esteyne, co-founder of Volt Aero.

Volt Aero’s original rear power system with three REX motors and one Nissan six-cylinder engine

Shifting Strategies

If the “puller” electric motors encounter a problem during a takeoff, for example, the pusher power system will turn on immediately.  Other configurations are planned, but since the current first flight article doesn’t seem to match what had been reportedly planned, we will wait until further developments ensue. When the aircraft reaches its final stage with twin puller motors and a hybrid rear power sytem Botti predicts, “This configuration will help us go to EASA (European Aviation Safety Administration)  and then we’ll go quickly to the FAA.”

Volt Aero cutaway showing battery locations, initial engine/motor composition

Paul Lemoire, electrical engineer with VoltAero, said the 10-kg battery racks include the BMS (battery management system) with five sub-packs per motor and can be changed out in two hours. The “electrical range” is 30 minutes including takeoff and climb, and 40 minutes if only used for cruise. There are five battery racks on each side of the aircraft, with 15 in the nose, together driving the aircraft’s five electric motors (three in the tail in the original design and one on each wing).

Volt Aero principals with e-Fan when Esteyne (left) and Botti worked for Airbus

Cassio 2 will have a composite airframe and further revisions to the power systems. The 25 battery packs will provide for 30 minutes of pure battery flight.  The initial prototype carries 37 liters of fuel for the hybrid’s engine.  A projected range of three-plus hours seems a bit speculative in the 4,400 pound, 200 mph airplane.  We’ll wait to see how the final version scales out.

Like the Ampaire, the airplane has flown.  Orders are piling up for the American and French hybrids, and one wonders whether enough Cessna 337’s exist to satisfy the demand.  In any case, once development work is completed for the American airplane’s power system, construction will start on the Ampaire Tailwind, a far sleeker craft.

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EcoPulse™, a collaboration by Airbus, Daher, and Safran is a fixed-wing distributed hybrid propulsion aircraft whose power system emulates many of the Urban Air Mobility vehicles that use an electric Vertical Take Off and Landing configuration.  Safran, notable for its gas turbines, will supply the propulsion system (excluding batteries).  The system consists of a turbogenerator (combined turbine and power generator), an electric power management system, and integrated electric thrusters (or e-Propellers) including electric motors and propellers faired neatly into the wings.

EcoPulse partners claim the six small electric motors spread along the leading edge, while providing propulsion thrust, lead to a reduction of wing surface area – much of the wing gaining lift from the blown areas, lowered wingtip marginal vortices from the thrusters on the wing tips, and therefore lowered drag.

Airbus will oversee aerodynamic optimization of the distributed propulsion system, installation of “high-energy density” batteries and their use to power the six electric motors.  Daher will oversee component and systems installation, perform flight tests, and assist with regulatory compliance.

The aircraft has received assistance from CORAC (the French Civil Aviation Research Council) and DGAC (the French Civil Aviation Authority) with the goal of improving the environmental efficiency of aircraft.

According to Green Car Congress, the project aims to, “Validate technologies designed to reduce CO2 emissions, noise pollution, and create new uses for air transportation.”

Ecopulse is yet another example of adapting an existing airframe to electric or hybrid power.  In this case, the Daher TBM accepts the same basic hybrid system produced by Safran and used in Bell’s Nexus UAM vehicle and Zunum’s regional airliner, among others.  Safran tests its system on a large stationary platform

Stéphane Cueille, Head of R&T and Innovation at Safran, explains his firm’s interest in the project: “Safran has developed a technology roadmap for the installation of electric thrusters on aircraft. EcoPulse offers us an excellent opportunity to evaluate and identify the specific features expected by this market, particularly in terms of new hybrid propulsion aircraft projects. Safran intends to position itself as the market leader in this type of propulsion system by 2025.”

(L to R) Nicolas Orance, Stéphane Cueille and Jean-Brice Dumont show off model of Ecopulse at press conference

Nicolas Orance, SVP Aerospace and Defense BU at Daher added: “Reducing the environmental impact of aircraft is a priority for the industry as a whole. So it is with enthusiasm and determination that we welcome the opportunity to be part of this unique partnership alongside Airbus and Safran to succeed in the ambitious challenge set by CORAC. We are determined to make it a distinctive feature of the French aviation industry and are certain that all stakeholders will unite around it.”

Airbus will be involved in the aerodynamic modeling of the demonstrator, both to support configuration choices and to enable the development of flight control laws. All these considerations should make it possible to demonstrate the benefits of distributed propulsion, and provide the baselines for the design of optimized distributed propulsion aircraft in terms of methods, tools and outcomes.

Jean-Brice Dumont, Executive Vice President Engineering at Airbus, sees future possibilities stemming from this initial effort.  “This distributed hybrid propulsion demonstrator is a very important step towards preparing the certification standards for a more electric aircraft. It also gives us the opportunity to improve our simulation models and consider their use on larger aircraft.”

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Borschberg, H55 Introduce BRM Energic

Leadership is about empowering people to make them owner of their world, and constantly challenging them to make them extend their known territory.”

Andre’ Borschberg

Andre’ Borschberg’s current challenge, shared with Bertrand Piccard, involves their Solar Impulse Foundation, whose goal is to foster 1,000 solutions “that protect the environment in a profitable way.”  “Profitable” helps produce results, and with Piccard being a psychiatrist, ensures the self-interest that drives many also drives a certain level of altruism in saving the environment.

Borschberg and two other Solar Impulse leaders, Sébastien Demont and Gregory Blatt, founded H55 and produced a modification of the Silence Twister, a single-seat aircraft with a Siemens motor.  Their latest conversion, following their philosophy of, “Building up experience by flying existing airplanes with electric propulsion,” uses what looks like an Emrax motor in a Bristell Energic two-seat training craft.

“Single Engine Dual Battery Pack System”

Energic is an electric variant of a Czech Republic Light Sport Aircraft, with an electric power setup replacing the conventional Rotax engine.

Motor, batteries and cooling system all fit neatly under tight cowling

At the heart of the Energic, a modular 50 kilowatt-hour battery pack drives a 90-kilowatt (120.6 horsepower peak output), 65 kW (87 horsepower) continuous output motor for up to 90 minutes.  According to H55, the battery can be recharged in one hour. The battery system embedded in the wings, is controlled by a dual analog/digital battery management system (BMS).  Batteries include both 18650 and 21700 (18 millimeter diameter x 65 mm long and 21 mm diameter x 70 mm long) cells.  H55, working with authorities, hopes to certify the system CS23, Europe’s equivalent to FAR Part 23.  The European Union Aviation Safety Agency (EASA) oversees CS 23.

Single motor, dual battery system in H55’s Energic

The Energic flies at a maximum weight of 850 kilograms (1,870 pounds) while carrying a payload of up to 200 kilograms (440 pounds) – enough for two substantial passengers and luggage.  Energic seems plenty energetic, with a climb rate of 900 feet per minute.  Operating costs are low, with a recharge, in Europe, costing a mere $7.00.  In the Portland, Oregon area, PGE would charge about $5.50 at normal rates.  Being able to do an hour of touch-and-goes for a total operating cost under $10 an hour would do a great deal to entice new students into learning a new skill.

Energic’s batteries nest in each wing, are split between 18650 and 21700 sizes

Building is Relatively Easy, Certification is Harder

H55 explains, “The biggest challenge is not building and flying a prototype, rather certification. The gap between a first and a certified aircraft is considerable and that’s where H55 brings its expertise, experience and solutions.”  Again, that’s why the firm chose an established trainer as a test bed and eventual marketable choice for operators.

One of several trainers coming on the market and offering potential operating cost savings for flight schools, the Energic will find completion from Pipistel’s Alpha Electro and Bye Aerospace’s eFlyer 2.  Competition will improve the breed quickly and customer acceptance will increase competition.

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A Huge Battery with an Airplane Painted On It

Eviation, an Israeli company developing Alice, a high-speed, intermediate-distance commuter airplane, brought its prototype to the Paris Air Show this week.  Eviation co-founder and CEO Omer Bar-Yohay gave journalists a 27-minute overview of the aircraft, the philosophy behind it, and projections on its immediate future.

“It’s basically a huge battery with some plane painted on it,” he told reporters.

The 6,350 kilogram (13,970 pound) airplane carries 900 kilowatt-hours of batteries, equivalent to the cells in nine Tesla S P100D automobiles or one Tesla semi-truck.  Even that, according to rough figuring by yours truly and polished calculations by a smarter reader, seems to provide for only half the necessary energy to provide the range Eviation claims.  Will flight tests prove us misguided?

Fuel Burn vs. kWh

Carrying capacity and performance are similar to the Beechcraft King Air.  The King Air burns 100 gallons per hour at a fuel cost around $550.  The Alice consumes about 400 kilowatt hours at a cost of $44 (based on the PGE rate of 11 cents per kW-hour).  Its sleek shape provides Alice with a better lift-to-drag ratio, but maybe not enough to account for its total efficiency.

Cape Air Airlines Buys Some

The Martha’s Vineyard Times reports that Cape Air Airlines will be the first to purchase at least 10 Alices.  “At the Paris Air Show, the chief executive officer for Eviation, Omer Bar-Yohay, announced that Cape Air would be the first customer to implement the new efficient aircraft technology, with ‘double-digit’ order numbers.”

Alice drew a crowd to hear an address by Eviation’s CEO, Omer Bar-Yohay

The Times adds, “Although the plane is still in its developmental stages, two different versions of the Alice are planned. The initial model will be used for air-taxi operations, and will use energy stored in a lithium-ion battery. The following version will be an extended-range executive aircraft with a larger, more powerful aluminum-air battery.”  That battery will probably come from Phinergy, which has been developing such a battery for the last several years.

Phinergy claims an energy density of eight kilowatt hours per kilogram of aluminum, an excellent number compared, for example, to the 260 Watt-hours per kilogram in Bye Aerospace’s eFlyer 2 or 4.  That’s a demonstrated number by Kokam, an established lithium-ion provider.  Note, though, that the Phinergy number is for the aluminum only – not the total battery weight or its control or charging mechanisms as is the Kokam number.

Phinergy CEO Aviv Tzidon shows off the basic battery design of the company’s Alunergy technology

Still, Phinergy has demonstrated 1,000-kilometer (620-mile) range with its batteries in a Renault Zoe (similar to a Nissan Leaf.  Only 112.5 kilograms (247.5 pounds) of aluminum would be required to match the energy in Alice’s current cells.  We can only speculate at this point on the total weight of the complete energy package.

Cape Air, while pioneering electric power on its routes, will doubtless benefit from the publicity accruing from their forward outlook.  We need others to follow suit.

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Pipistrel Electrics in America and France

Celebrating its 30th anniversary, Pipistrel rolled out its new 801 at the UBER Elevate Summit in Washington, D. C. last week and is flying its Alpha Electro Trainer at the Paris Air Show all this week.

Launching the 801 at UBER Elevate

Dr. Tine Tomažič, Pipistrel’s Director of Research & Development, was a keynote speaker at the conference in Washington, D.C. on June 11, where he presented just enough to whet appetites for more on the coming 801 eVTOL design.  His final touch – presenting an ostensibly realistic recording of the 801’s sound, demonstrated how quiet the vehicle will be.

That’s accounted for by the eight fans being tuned to different frequencies, cancelling each other out like the dynamics in noise-cancelling headphones.  That’s just one of the design factors in a well-integrated design.  Its integrated lift system, embedded in the craft’s wings, help mitigate noise. The specially-shaped fans will operate at relatively low RPMs, another step in reducing noise.  Conceptual test vehicles of varying sizes helped refine the noise-control methodology.

Tine calls the new design “an aeroplane” because its fixed wing craft will rely on fairly conventional aerodynamics to cruise at 160 knots or more for its battery-powered 50-mile range – enough to cross Los Angeles in 20 minutes.  801’s flight profile will include a 45-second lift phase, transition to high-speed cruise, and a 45-second descent phase, making the most of its qualities as an aeroplane and shortening the battery-draining lift portions of the flight.  The transition between lift and cruise phases is the most difficult part of flight, but this has been factored into the interface between the aeroplane’s wings and lift units.

In his talk, Tine described the baggage, both physical and emotional, we all carry. Nobody should get emotional at having to leave anything behind on the 801

In a move to reach “the next level of battery safety,” those batteries will be divided into four different packs of differing types to avoid the same failure modes in all four packs.

Another safety factor, passenger safety, comes from energy-absorbing cabin frames and seats.   The high wing and overhead fans enable easy and safe access to the cabin.  A “brain” from Honeywell is certifiable and ready for autonomy.  That factor will ensure safe passage even on unpiloted trips

Tine says vehicle technology will be available sooner than regulatory approval, with technology ready to fly in commercial service by 2025 or earlier, and regulations following by 2030.  Tine added that the 801 will truly be ready when one’s family and friends want to fly on one.

Meanwhile at the Paris Air Show

Pipistrel shows off their Alpha Electro trainer at the DGAC (the French Civil Aviation Authority) stand every day, and makes demonstration flights every afternoon through the end of this week’s air show.

Ivo Boscarol (right) shows the Pipistrel trainer to Mrs. Violeta Bulc, the European Commisioner for Transport.

On Monday, Pipistrel’s stand was visited by the President of French Civil Aviation Authority (DGAC) Mr. Patrick Gandil and Mrs. Violeta Bulc, the European Commissioner for Transport.  Pipistrel’s General Manager  Ivo Boscarol  was happy to explain the fine points of the little trainer to such distinguished guests.

On Monday Mr. Jérome Coornaert wrung the little plane out, doing almost everything the Boeing’s and Airbus’s did, but ever so much more quietly.  Pipistrel highlights this on their web site: “Alpha Electro is totally quiet, the only sound it makes is the whisper of propeller moving through the air. Electricity makes no noise!

“It’s so quiet that even at full speed, people sometimes don’t even realize it is flying straight over their heads”

Pipistrel’s Alpha Electro was allowed to fly from its home field at Toussus le Noble across the City of Light to Le Bourget Field

French authorities showed une grande sign of trust in the Slovenian company and its electric trainer.  They allowed it to fly across the center of Paris on its way from Toulouse to Le Bourget Field.

Dr. Tine Tomažič will present his thoughts on Urban Air Mobility at the Sustainable Aviation Symposium, October 7 and 8 at the University of California at Berkeley.  Come and share a first look at a machine that may command urban skies in the next few years.

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