Despite weather conditions that made hoped-for speeds impossible, the Ohio State University Venturi Buckeye Bullet team set a so-far unofficial one-mile record of 240.320 mile per hour (386.757 kilometers per hour) in their Venturi VBB-3 streamliner.  The aptly named Bullet suffered damage from the rough track because of recent rains on the 12-mile stretch.  Normally, the Bonneville Salt Flats are smooth enough to allow re-use of the vehicle.

Bleeding an unidentified fluid on the salt flat, Buckeye VBB-3 did manage a mile record regardless

Bleeding an unidentified fluid on the salt flat, Buckeye VBB-3 did manage a mile record regardless

The Columbus Dispatch reported on the home team.  “’We went faster than we have ever gone with this vehicle, but it was a very difficult week on a very bumpy track and we have done some damage to the vehicle from extreme vibrations,’ said David Cooke, a mechanical engineering graduate student at Ohio State and a leader of the team, in a statement provided by the school.”

The Dispatch adds, “The record, which still needs to be certified by an international governing body, is for a specific vehicle type: Category A Group VIII Class 8.”

The 240 mph run is great considering the conditions (weather was bad enough to keep the team from building even a temporary shelter for over a week), but the team has done better – in 2010 hitting 307 mph in their VBB-2.5 streamliner.  The Ohio State team’s cars have come from Venturi, a Monaco-based maker of unique vehicles.

Siamesed motors, 2,000 batteries make a powerful machine

Siamesed motors, 2,000 batteries make a powerful machine

Three generations of VBB vehicles have taken diverse approaches to record setting.  The 2009 VBB-2 was powered by 2,000 fuel cells, driving a 740 horsepower motor cranking out 550 Newton meters (369 foot-pounds) of torque.   That was enough to push the 2.63 ton (5,260 pound) vehicle to a record-setting 487 kilometers per hour (303 mph).  The next year’s VBB-2.5 was lighter at 1.95 tons (3,900 pounds) and marginally more powerful at 800 hp.  Running on 1,500 cylindrical lithium iron phosphate batteries, it hit 495 kilometers per hour (307 mph).

Venturi VBB-3 with Buckeye team during a break in the weather

Venturi VBB-3 with Buckeye team during a break in the weather.  Team hopes for much higher speeds on future runs

Because VBB-3 has 3,000 horsepower and 2,800 Newton-meters (2,065 foot-pounds) of torque at its command, the constraints on speed this year had to be disappointing to the team.  While the original cars had front-wheel drive, the latest version has four-wheel drive to handle the four times greater power from the 2,000 lithium iron phosphate pouch cells.

Ohio State must have a strong engineering department, since they also fielded the Buckeye Current team with their electric motorcycle that did well in the Isle of Man TT, and continued three years of outstanding performance at the Pikes Peak International Hill Climb.  The Current team had its own problems, its champion cyclist, Rob Barber, having crashed during practice.

Both the bike and Barber needed rebuilding.  Joe Prussiano took over the ride and did the team proud with a “second [place finish] in its class and 16th overall out of 52 motorcycles with a time of 11:12.756. This feat is 46 seconds faster than the leading electric motorcycle of the 2014 Hill Climb.”  The fact that a group of students held their own against well-capitalized and supported professionals speaks volumes for their abilities and their advisers.  The fact that electric bikes are competing at nearly equal levels with fossil-fueled machines shows the impressive gains made in the last few years.

Ohio State calls this their “hype” video.  It’s only hype if it’s hyperbole – otherwise it’s accurate reporting – done well here by Lauren Alman, Marketing Coordinator for the team.

Racing does improve the breed, and CAFE has an understanding that much of what goes into our electric airplanes will come out of cars, and increasingly, motorcycles.  Economies of scale will bring prices down and competition will help hone the quality of products to a fine degree.  Congratulations to Ohio State for their continuing leadership in development and competition.

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We’ve seen several videos like this, a setup resembling a stomach distress remedy fizzing away and giving off bubbles of hydrogen and oxygen.  Dr. Daniel Nocera first created the idea of an artificial leaf, and several others have followed his lead and refined the process, which mimics nature’s leaves in converting sunlight to energy.

The U. S. Department of energy’s (DOE’s) Energy Innovation Hub, established at Caltech (California Institute of Technology) and its partnering institutions, has a main goal of creating “a cost-effective method of producing fuels using only sunlight, water, and carbon dioxide.”  Artificial photosynthesis has been tried in several variants, but researchers at Caltech and its Joint Center for Artificial Photosynthesis (JCAP) now claim to have developed “the first complete, efficient, safe, integrated solar-driven system for splitting water to create hydrogen fuels.”

Nate Lewis, the George L. Argyros Professor, professor of chemistry, and the JCAP scientific director, takes pride in his group’s accomplishment.  “This result was a stretch project milestone for the entire five years of JCAP as a whole, and not only have we achieved this goal, we also achieved it on time and on budget.”

Components for the water splitter seem simple enough, and are common among similar projects.  A photoanode uses sunlight to oxidize water molecules, generating photons and electrons as well as oxygen gas. A plastic membrane keeps the oxygen and hydrogen gases separate, thus preventing an explosion that might occur if the two gases mixed.  The membrane “lets the hydrogen fuel be separately collected under pressure and safely pushed into a pipeline.”

Silicon and gallium arsenide, used in solar panels because of their efficient absorption of light, oxidize (rust) in water, but putting a 62.5-nanometer-thick layer of titanium dioxide (TiO2) on Si and GaaS electrodes enables them to absorb light and remain stable.  Adding a two-nanometer layer of nickel to the TiO2 on the photoanode provided a low-cost, highly-active catalyst.  This treatment enabled the water splitter to operate 40 hours without operator intervention and maintain 10-percent light conversion efficiency.

Lewis explains the record-breaking nature of the new systems.  “This new system shatters all of the combined safety, performance, and stability records for artificial leaf technology by factors of 5 to 10 or more.”

“Our work shows that it is indeed possible to produce fuels from sunlight safely and efficiently in an integrated system with inexpensive components.  Of course, we still have work to do to extend the lifetime of the system and to develop methods for cost-effectively manufacturing full systems, both of which are in progress.”

Caltech's JCAP hydrogen generator

Caltech’s JCAP hydrogen generator, a fully-integrated photoelectrochemical device performing unassisted solar water splitting for the production of hydrogen fuel.  Courtesy: Erik Verlage and Chengxiang Xiang/Caltech

One of the co-authors of the paper on the findings, Harry Atwater, director of JCAP and Howard Hughes Professor of Applied Physics and Materials Science, adds an administrative note.  “This accomplishment drew on the knowledge, insights and capabilities of JCAP, which illustrates what can be achieved in a Hub-scale effort by an integrated team.  The device reported here grew out of a multi-year, large-scale effort to define the design and materials components needed for an integrated solar fuels generator.”

Another author, Chengxiang Xiang, co-leader of the JCAP prototyping and scale-up project, says, “JCAP’s research and development in device design, simulation, and materials discovery and integration all funneled into the demonstration of this new device.”

Their paper’s title, “A monolithically integrated, intrinsically safe, 10% efficient, solar-driven water-splitting system based on active, stable earth-abundant electrocatalysts in conjunction with tandem III-V light absorbers protected by amorphous TiO2 films,” almost gives the plot and surprise ending away.  The paper is available in several formats on the university web site.

Other Caltech coauthors include graduate student Erik Verlage, postdoctoral scholars Shu Hu and Ke Sun, material processing and integration research engineer Rui Liu, and JCAP mechanical engineer Ryan Jones. Funding was provided by the Office of Science at the U.S. Department of Energy, and the Gordon and Betty Moore Foundation.

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Making batteries smaller, lighter, and more powerful is an ongoing trend, supposedly climbing at eight percent per year in terms of energy density (energy stored per unit of weight).  Even this blog is guilty of sometimes unrequited enthusiasm for some new developments that appear to be an “answer” for aircraft use.

Getting a battery that double or quintuples energy density would be ideal for aircraft, but seems to be a labor worthy of Sisyphus (you could look it up).  As constantly noted here, batteries have three major components, the anode, or negative electrode; the cathode, or positive electrode; and the electrolyte, usually a liquid that allows the flow of ions between electrodes.  That electrolyte is subject to overheating and on rare occasions, bursting into flames.

Cubic structure of MIT/Samsung solid electrolyte allows easy passage of ions.

Cubic structure of MIT/Samsung solid electrolyte allows easy passage of ions.  Illustration shows lithium atoms in green, sulfur atoms in yellow, PS4 (phosphorus tetrasulfur) tetrahedra in purple, and GeS4 (germanium tetrasulfur) in blue.  Image: Yan Wang

That has led researchers at MIT, Samsung, and in California and Maryland to develop a solid-state electrolyte that might overcome the safety issue while providing more energy storage in a given space.

Yan Wang, an MIT post-doctoral student; Gerbrand Ceder, a visiting professor of materials science and engineering, and five others report their efforts and findings in the journal Nature Materials. MIT’s announcement explains that while others have attempted creation of solid replacements for liquid electrolytes (including perhaps Anne Marie Sastry of Sakti 3?) the group explains they are the first to make “a formulation that fully meets the needs of battery applications.”

Ceder makes some interesting claims, including the idea that solid-state electrolytes would make for, “almost a perfect battery, solving most of the remaining issues” in battery lifetime, safety, and cost.

“Ceder adds: ‘All of the fires you’ve seen, with Boeing, Tesla, and others, they are all electrolyte fires. The lithium itself is not flammable in the state it’s in in these batteries. [With a solid electrolyte] there’s no safety problem — you could throw it against the wall, drive a nail through it — there’s nothing there to burn.’”

As significant as the safety issue is, Ceder says, “’With a solid-state electrolyte, there’s virtually no degradation reactions left’ — meaning such batteries could last through ‘hundreds of thousands of cycles.’”

Common thinking was that solids could not conduct fast enough to be considered as electrolytes.  Ceder says, “That paradigm has been overthrown.”

Starting with a class of materials known as “superionic lithium-ion conductors,” compounds of lithium, germanium, phosphorus and sulfur, the team turned to an “ongoing partnership” with Samsung through the Samsung Advanced Institute of Technology, conveniently located near MIT is Cambridge, Massachusetts.  Ceder explains that the alliance, “has led to important advances in the use of quantum-dot materials to create highly efficient solar cells and sodium batteries.”

This solid-state can still function at those temperatures below -20°C, Ceder says.  It also gives a 20 to 30 percent improvement in power density.  While this may not be the 2X, 5X or even 10X breakthrough we would love to see, the benefits in safety and longevity are certainly desirable.

Cubic, tetrahedonal arrangements of elements in solid-state electrolyte

Cubic, tetrahedral arrangements of elements tried in solid-state electrolyte

While some might be disappointed that a fire-proof, essentially life-time battery is not more powerful, perhaps the team can combine their findings with Samsung’s recent announcement that they have achieved a battery with double the energy density of previous lithium ion cells.  After all, what are partners for?

The team’s paper, “Design principles for solid-state lithium superionic conductors,” can be found here.  Other authors include William Davidson Richards, Shyue Ping Ong, Lincoln J. Miara, Jae Chul Kim, and Yifei Mo.

The abstract explains the cubic nature of the solid-state electrolyte central to the group’s success.  “Lithium solid electrolytes can potentially address two key limitations of the organic electrolytes used in today’s lithium-ion batteries, namely, their flammability and limited electrochemical stability. However, achieving a Li+ conductivity in the solid state comparable to existing liquid electrolytes (>1 mS cm−1) is particularly challenging. In this work, we reveal a fundamental relationship between anion packing and ionic transport in fast Li-conducting materials and expose the desirable structural attributes of good Li-ion conductors. We find that an underlying body-centred cubic-like anion framework, which allows direct Li hops between adjacent tetrahedral sites, is most desirable for achieving high ionic conductivity, and that indeed this anion arrangement is present in several known fast Li-conducting materials and other fast ion conductors. These findings provide important insight towards the understanding of ionic transport in Li-ion conductors and serve as design principles for future discovery and design of improved electrolytes for Li-ion batteries.”

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Carbon Fiber, Batteries and Clean Air from CO2

Creators of a one-step process called STEP (Solar Thermal Electrochemical Photo) claim a world of benefits, including pulling carbon dioxide from the air and turning it into useful things, such as fuels, cement, and cheap carbon fiber.  The process can also purify and desalinate water, according to many of the 300 peer-reviewed papers by Dr. Stuart Licht of George Washington University and his graduate students.

STEP process uses sunlight's wavelengths and heat to capture carbon, produce usable materials

STEP process uses sunlight’s wavelengths and heat to capture carbon, produce usable materials

The elevator speech regarding their research can be found on the home page for the group.   “A new fundamental solar process has been introduced.  STEP efficiently removes carbon from the atmosphere and generates the staples needed by society, ranging from fuels, to metals, bleach and construction materials, at high solar efficiency and without carbon dioxide generation. By using the full spectrum of sunlight, STEP captures more solar energy than the most efficient solar cell or photoelectrochemical processes.”

According to the British Broadcasting Company (BBC), the sample of nanofibers Dr. Licht showed participants at the Autumn Meeting of the American Chemical Society represents one hour’s output at the laboratory scale now producing the material using STEP.   If STEP can be scaled up to industrial levels, the promise that earth’s atmosphere can be returned to pre-industrial age CO2 levels might be plausible. The researchers look forward to “direct removal & utilization or storage of carbon dioxide from the atmosphere or smokestacks.”  But first, that scaling will need to take place.

10 gram sample pf carbon nanofibers shown by Dr. Stuart Licht at American Chemical Society meeting represents one-hour's output at current lab scale

10 gram sample pf carbon nanofibers shown by Dr. Stuart Licht at American Chemical Society meeting represents one-hour’s output at current lab scale

According to the abstract for the team’s paper, “One-pot synthesis of carbon nanofibers from CO2,” in the August 15 issue of Nano Letters, “The first experimental evidence of a new solar process, combining electronic and chemical pathways, to isolate CO2 (carbon capture) is presented. This solar thermal electrochemical photo (STEP) process is a synergy of solid-state and solar thermal processes, and is fundamentally capable of converting more solar energy than photovoltaic or solar thermal processes alone. Here, CO2 is captured using a 750−950 °C electrolysis cell powered by a full spectrum solar simulator in a single step. The process uses the full spectrum; solar thermal energy decreases the energy required for carbon capture, while visible sunlight generates electronic charge to drive the electrolysis. CO2 can be captured from 34% to over 50% solar energy efficiency (depending on the level of solar heat inclusion), as solid carbon and stored, or used as carbon monoxide to be available for a feedstock to synthesize (with STEP generated hydrogen) solar diesel fuel, synthetic jet fuel, or chemical production.”

Carbon formation on inexpensive steel or nickel electrodes uses low voltage process

Carbon formation on inexpensive steel or nickel electrodes uses low voltage process

Dr. Licht’s “one pot” method of pulling carbon nanofibers from the air can demonstrably produce small amounts of these fibers with low energy inputs, but hoped-for larger carbon capture might be “problematic,” according to Dr. Katy Armstrong, a chemical engineer at the University of Sheffield and quoted in the BBC article.

“’As they are capturing CO2 from the air, the process will need to deal with huge volumes of gas to collect the required amount of carbon, which could increase process costs when scaled up,’ she told the BBC.”

Dr. Licht stands by his premises.  “’There aren’t any catches; there’s a necessity to work together, to test this on a larger scale, to apply some societal resources to do that,’ he told BBC News.”

Bringing down costs for manufacturing nanofibers could have disruptive effects on structural materials (imagine carbon fiber as inexpensive as aluminum), or battery development.

Others working on pulling in CO2 and bringing out products include Joule, reported in this blog for solar-powered brews of ethanol and diesel fuel using engineered bacteria; and Audi, working not only with Joule, but with several other European firms to produce fuels for its automobiles.

It’s most exciting to see progress in even the remote possibility that the “insolent chariots,” as once described by critic John Keats, could become a socially responsible means of cleaning up our profligate act and possibly use fuels or run on batteries from their one-time waste.

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2015 British Human Powered Flying Club Rally

Human-powered flight is about as green as it gets, although the pilot/powerplant does emit CO2 and some methane during the exercise.  A human pilot can put out only about 0.25 to 0.5 horsepower for reasonable periods, with the record holders like Brian Allen flying The 70-lb Gossamer Albatross in its 26-mile cross-channel flight in 2 hours, 49 minutes,.and Olympic cyclist Kanellos Kanellopoulos of Greece flying 71.5 miles between Crete and Santorini in 3 hours, 54 minutes on April 23, 1988.  The flight holds the official FAI world records for total distance, straight-line distance, and duration for human-powered aircraft.

Airglow glowing in the early twilight

Airglow glowing in the early twilight at 2015 BHPFC Rally

The British Human Powered Flying Club holds a gathering of the hopeful every year, this year at Lasham Airfield, between London and Winchester.  Depending on how one looks at it, only six competitors showed up this year – or amazingly, six competitors who had designed, built, and test flown their craft, showed up this year.

Building even a simple airplane is a relatively complex task: dealing with the ultra-lightweight materials used in creating a featherweight machine that will survive being assembled, disassembled and flown for a week – often be several different pilots – is a definite challenge.

Past years have focused on getting airborne and seeing if a pilot can pedal and control the airplane for as long a distance as possible.  The BHPFC introduced new tasks this year, including taking off from grass, rather than a tarmac runway.  An added challenge, taking from grass and managing a 220-yard flight proved doable for three aircraft.  This is significant, since the extra power required to take off from grass can be a challenge even for a low-powered airplane.

Jupiter under construction, showing the extreme difference between the complex structures of early human-powered airplanes and today's simpler variants.  Jupiter took10,000 man (person) hours to build

Jupiter under construction, showing the extreme difference between the complex structures of early human-powered airplanes and today’s simpler variants. Jupiter took10,000 man (person) hours to build

According to Man-Powered Flight (the title reflecting its first being published in the pre-PC era), by Keith Sherwin, the rolling resistance of short grass is 2.5 times that of a typical tarmac runway.  One advantage the HPA has is that its landing gear is also powered, helping with initial acceleration and attaining take-off speed.  Chris Roper reports, “It was significant that three aircraft all managed this.”  Chris, more than incidentally, is the designer of Jupiter, among the most successful of all pre-MacCready HPAs, having traveled 1171 yards in 1072 when piloted by Flight Lieutenant Potter.

The whiteboard shows the week's standings.  There are no big prizes, but the fun and honor are worth everything

The whiteboard shows the week’s standings. There are no big prizes, but the fun and honor are worth everything

Chris explains the scores for the event.   “Note that the Scores, both for each pilot and for each team are the best-for-each-task during the week that each achieved. To win, you’ve got to be an all-rounder and score well for each task.”  Your editor found the rules fairly straightforward, but the scoring seems somewhat more difficult than cricket.

Voltaire came to an untimely end early in the week.  Luckily, there were no injuries other than to pride.

Aerocycle 3 had the winning ways this year, being flown by Bill Brooks, here, and by Mike Truelove, in alternate flights.  The plane is a design by John Edgley, of Edgley Optica fame.

Here, Aerocycle 3 is flown by Mike Truelove.  This craft and Betterfly were the endurance champions for the week.  Airglow, flown by Robin Kraike, had the top score with 7,715 points.

Paul Wales had the second highest score, 6,595 points, guiding Betterfly.

The first French entry, Bordeaux University’s Millesime 1, did not place, but showed a simple structure and good proportions.  This was the first French entry in the event, and Chris Roper would like to see an American entry next year, too.

Aside from the video by Bordeaux University, all moving images are by Fred To, who flew the first man-carrying solar-powered airplane in 1978.  Which brings us to another consideration.   These may not be the fastest or most practical aircraft in the world, but they do show what we can do with simple, light structures.  Your editor would love to see an expansion of this sport in which small, model aircraft or pedelec motors would augment the human powerplant, making a human/electric hybrid that might provide a relatively low-cost sporting craft with unique potential.  The electric motor, though not for purists, would enable those of us who are not champion cyclists to at least think realistically about low-powered flight and to explore a realm of flight where we could share the sky with real birds.

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Keeping Battery Fires at Bay

Fires on or in aircraft are anathema, leaving a pilot and passengers with few options. Even a laptop starting to smoke in the cabin will cause an emergency descent and a diversion to the nearest airport. As designers incorporate larger lithium batteries into new aircraft (and they are essential to motor-driven planes), the need to keep things from self-igniting becomes imperative.

Researchers at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory, working with funding from the Joint Center for Energy Storage Research (JCESR) discovered, “That adding two chemicals to the electrolyte of a lithium metal battery prevents the formation of dendrites – ‘fingers’ of lithium that pierce the barrier between the battery’s halves, causing it to short out, overheat and sometimes burst into flame.”

Green fingers of dendrites on untreated electrodes could poke through separator material, cause shorts and fires.  Treated electrolyte subdues dendrite fingers

Green fingers of dendrites on untreated electrodes could poke through separator material, cause shorts and fires. Treated electrolyte subdues dendrite fingers

Preventing these shorts will lead to the next-generation batteries being able to take advantage of lithium-sulfur and lithium-air technologies with up to 10 times the energy per weight of batteries now used in electric vehicles.

Yi Cui, who spoke at this year’s Electric Aircraft Symposium, explained the importance of the research. “Because these batteries would be much lighter than today’s rechargeable batteries, they have a lot of potential for extended-range electric vehicles. But one of the things that’s been holding them back is their tendency to form dendrites, which are also the culprit behind overheating and occasional fires in today’s lithium-ion batteries.” Dr. Cui, an associate professor at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory, worked with colleagues including Fiona (Weiyang) Li, a postdoctoral researcher in Cui’s lab, and Yet-Ming Chiang, a professor at the Massachusetts Institute of Technology.

Dendrite formation occurs when a battery electrode degrades, with metal ions deposited on the electrode surface. As they grow longer, the dendrites pierce the barrier (separator) between battery halves, causing shorts, overheating and fires.

The Stanford news release reports, “In a previous study published last October, Cui and his colleagues reported that they had developed a ‘smart’ lithium-ion battery that senses when dendrites start to puncture the barrier so the battery can be replaced before the situation becomes dangerous. This could offer a solution for millions of batteries now in use in cell phones, laptops and other devices, as well as in electric cars and airplanes.” That development is an early warning system for potential trouble. The newest breakthrough could theoretically make that warning system unnecessary.

Enlarged rendering of dendrites, smoothed

Enlarged rendering of dendrites: smoothing by addition of two chemicals to electrolyte promised longer life and more energy from batteries

Cui and company’s latest, different approach adds chemicals to the electrolyte to prevent dendrite formation. Lithium nitrate could also improve battery performance, while lithium polysulfide, formed when a sulfur electrode degrades, “has been considered a nuisance,” traveling to the lithium metal electrode and ruining it.

The team, while brainstorming, realized that the combination of one performance enhancer and one destructive chemical “could potentially react with lithium metal to form a stable, solid interface between the electrode and the electrolyte.”

The team made coin cell batteries like those in calculators and watches, and then added varying concentrations of the two chemicals to an ether-based electrolyte. After running the batteries through charge/discharge cycles, they performed autopsies on the cells, examining the electrodes with an electron microscope and an X-ray technique that reveals their structure, form and chemical makeup.

Adding both chemicals in just the right amounts stopped lithium dendrite formation; harmless pancake-like deposits grew instead. The lithium metal electrode acquired a stable coating that helped protect it from further degradation and actually improved the battery’s performance, with batteries operating at 99-percent efficiency after more than 300 charge/discharge cycles: those treated with only lithium nitrate showed lower efficiency after only 150 cycles.

Fiona (Weiyang) Li, first author of the team’s paper in Nature Communications, said, “This is a really exciting observation. We had been doing experiments all along with these two chemicals in there, but this was the first time we looked at the synergistic effect. This does not completely solve all the problems associated with lithium metal batteries, but it’s an important step.”

Yet-Ming Chiang helped the team interpret their results. He wants to study the next steps, including seeing if this approach will work in larger-scale cells that would be more practical, or with other metals for electrodes, such as magnesium, calcium or aluminum – all of which have the potential of producing even more energy. “Preventing dendrite formation is going to be key to their success,” Chiang said.

The team’s paper, “The Synergetic Effect of Lithium Polysulfide and Lithium Nitrate to Prevent Lithium Dendrite Growth,” was published in the June 17 issue of Nature Communications.

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Sunseeker Duo, Dynamic Duo Do the Alps

Irena Raymond shared the following about her and huband Eric’s flight across the Alps from northern Italy to Switzerland and return – a four-day tour of the mountainous country, and validation of the Sunseeker Duo’s performance.

Coming and going, the Raymonds topped the Matterhorn

Coming and going, the Raymonds topped the Matterhorn, its peak shrouded above

The latest of a series of accomplishments, the trip’s mission was to “stop and show the airplane at different airports,” according to Irena. Remember that Eric crossed the United States on solar power in Sunseeker I in 1990, 23 years before Solar Impulse managed the feat. Eric crossed the Alps on his way from Friedrichshafen, Germany to the World Air Games in 2009, guiding Sunseeker II over sometimes cloud-shadowed peaks. Now he and Irena have made a two-person Alps crossing and tour of the country in a practical solar-powered airplane. By comparison, Solar Impulse, wonderful as it is, does not qualify as “practical” aerial transport, being pursued around the world by a 60-member crew. Eric and Irena, usually the only pilots and crew of the Duo, are showing a hoped-for future that will allow all of us to fly in a fuel-free way.

Your editor assumes the couple started from their home field in Verghora and, as they describe, headed to Torino Aeritalia airport on August 2, flying in, “smooth air up high so the crew was able to cruise level with a slight climb on the solar panels. The distance flown due to restrictions of the airspace was 171 [kilometers].” (About double the straight-line distance.)

The next day was more difficult and longer, with the intrepid couple facing low clouds and a steep climb from the foothills of the Italian Alps, struggling with downdrafts on the Italian side of the Matterhorn, and confronting what Irena described as “an impassible wall of ice.”

Eric, founder of Solar Flight and designer of the Sunseeker Duo, explained, “We needed to climb several thousand feet more, just to slip into Zermatt, but the batteries were low from all the motoring. We flew back south and soared in difficult conditions until the batteries were fully charged. We were looking at the wall of ice again from below, but I promised Irena another world just on the other side when we started the motor again, less than 10 miles from Zermatt. Using less than half the battery we crested the lowest point, crossing a few hundred feet over people skiing.”

While the skiers wonder how that airplane got there, we wonder the same about the skiers

While the skiers wonder how that airplane got there, we wonder the same about the skiers

Since their goal, Munster-Geschinen airfield, was now easily attainable, “Eric and Irena Raymond detoured to the Aletsch Glacier and high mountains behind it – the top of Switzerland, the Jungfrau, Eiger and Mönch.” At 4,090 meters (over 13,000 feet) they could have continued to Interlaken, Bern, Lucerne or Zürich, but kept to their original goal of landing in Münster. They may follow the route north on their next Swiss flight. They had traveled 384 kilometers (238 miles) and charged the Duo’s batteries after landing.

Chasing its shadow over the high peaks

Chasing its shadow over the high peaks

Eric’s mother was Swiss, and left him with “precious memories of the mountain hikes they did together.” On August 5th, Irena got to hike to the top of the Eggishorn with members of the Swiss ground crew, while Eric took his hang-gliding friend Stefan over the ice floes. Irena used a long telephoto lens to take magnificent photos of the Duo skimming over the glaciers.

Irena’s daughter Janja had a full day, accompanying her mom to the Eggishorn as part of the photo crew in the morning and getting a flight in the late afternoon around the Jungfrau, Eiger and Mönch, as well as the Rhône Glacier.

Brilliant alpine sun, ancient glacier, the future of flight all in one scene

Brilliant alpine sun, ancient glacier, the future of flight all in one scene

The Friday August 7th flight back to their home based was easier than the struggle up the Matterhorn on the trip into Switzerland, with perfect weather that made topping the cloud-cap peak for the spectacular view a photographer’s dream. Eric explained one difficulty. ”The maximum altitude we climbed was 4,545 meters (14,900 feet). We could easily go much higher, unfortunately we do not have a dual oxygen system yet.” This four-hour, 230 kilometer (143 mile) flight took them from the crystal-clear air of the Alps to the hot cloudiness of the Po Valley. Not many can boast of having spent five days flying over two countries and not having used the gasoline credit card.

A skilled couple enjoying the fruits of their labors

A skilled couple enjoying the fruits of their labors

You can see more stunning photos of the flight here . Did we mention that Eric and Irena are professional photographers?

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Chip Erwin is one of many who are trying to find less expensive ways for people to experience personal aviation.  His company, Aeromarine LSA, fields a range of small aircraft, but he has taken a turn toward the lighter end of the market with his latest offerings.

We wrote last month about his dinner presentation at the ninth annual Electric Aircraft Symposium and this month he’s followed up on several of the craft he discussed that night.

CAD rendition of motor mount for Chip's motor on E-Plane.  Don Lineback designed interesting powerplant

CAD rendition of motor mount for Chip’s motor on E-Plane. Don Lineback designed interesting powerplant

His web site explains the different rules and regulations that govern small aircraft.  Many rules are not yet established (electric motors in U. S. light sport aircraft, for instance).  The second segment of the “About Us” section of Aeromarine’s web site describes each of four different sets of regulations – a collection that must stress aircraft designers working on small, light aircraft.

Visualization realized on real airplane.  Chip says E-Plane is ready to paint

Visualization realized on real airplane. Chip says E-Plane is ready to paint

Four major rules guide how ultralight aircraft may be flown.  FAR Part 103, the guiding light for ultralight designers and pilots in America for the last 30 years, limits weight and performance.  Brits have the advantage of the new SSDR (Single-Seat Deregulated) rule, which allows a heftier airframe (or heftier pilot) with a 300 kilogram (660 pound) gross weight.  This rule allows a 35 knot (40.25 mph) stall speed and no maximum speed limit.  That makes a grass-strip capable single seater with a cruise of 100 mph a practical reality, and more practical than most ultralights.  Chip explains that he will be able to offer aircraft that meet that rule and will operate on electric, gasoline, or hybrid power.

Chip's unique battery tubes are neatly emulated by pool floats of the same diameter.  Weight and balance considerations limit how many battery cylinders can be fitted here

Chip’s unique battery tubes are neatly emulated by pool floats of the same diameter. Weight and balance considerations limit how many battery cylinders can be fitted here

The Experimental Amateur-Built (E-AB) rule, according to Chip, is widely accepted in many countries including the USA and in the European Union.  A customer must assemble or fabricate at least 51-percent of the aircraft, and the Zigolo ultralight has already been inspected and approved under this rule by the FAA.  The Stinger and E/G-Plane (Merlin in its native Czech Republic) will meet this and SSDR rules. E-AB provides a means to fly before any future certifications

To expand weight and balance options, six battery cylinders in each wing root spread stresses outward

To expand weight and balance options, six battery cylinders in each wing root spread stresses outward

The Zigolo has already been inspected and approved by the FAA for this category. The Stinger and E/G-Plane will also meet this rule. E-AB provides a path to the market immediately and prior to any future certifications.

Chip wants to fly an electric airplane with amphibious floats, second only to Dale Kramer and his e-Lazair

Chip wants to fly an electric airplane with amphibious floats, second only to Dale Kramer and his e-Lazair

A Special Light Sport Aircraft (SLSA) rule, “Offers an inexpensive path to certification which allows us to sell finished aircraft. There is a provision in the LSA rules for a single-seat aircraft. As the cost of the engine and airframe is much less we can offer a finished SLSA for only $35,000! “  A big impediment in the U. S. is the FAA’s exclusion of electric power, with a limitation to “reciprocating engines only” to preclude the use of turbine and jet propulsion in the LSA class.  This unfortunately precludes the use of electric motors, too.

How Chip Erwin and other developers work around limitations set by regulations will be interesting to see.  We already have the varying interpretations of whether batteries in a Part 103 ultralight constitute part of the aircraft’s empty weight.  Adoption of SSDR-type rules, or changes to the SLSA rules would help resolve that issue, and make way for many aircraft that don’t easily fit any existing category now.

All these rules, existing or potential, avoid entanglement in the always thorny thicket of FAA medical requirements, a happily-avoided problem for many.

In the meantime, Aeromarine LSA and Chip Erwin are forging ahead with some low-cost alternatives for personal aviation.   He promises his next newsletter will include either the first flights of his Zigolo ultralight with new electric power or testing of is amphibious floats.  That’s an embarrassment of riches which we hope to share soon.

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The Man Who Made This Blog Possible

Your editor received this sad announcement yesterday from Andy Kecskes, editor of the Sailplane Builder newsletter, forwarded from Murry Rozansky, President of the Experimental Soaring Association.

“Bruce Carmichael passed peacefully with his family by his side on Tues. I am glad that our and the other soaring organizations honored his contributions before this sad event. Bruce was 91+years old, an accomplishment in itself.  There will be a celebration of Bruce’s life on Sat. Aug. 15th at 10:30 am at Palisade’s Methodist Church, 27002 Camino de Estrella, Capistrano Beach, CA.  Reception to follow services.”  Please RSVP to; georgianatives@yahoo.com.”

Bruce Carmichael speaking at a meeting on flying wings

Bruce Carmichael speaking at a meeting on flying wings

Bruce was a pioneer in low-Reynolds number aerodynamics, and had been influential in the design of many record-breaking and visionary aircraft.  He is listed as part of the team on Solar-Flight’s web page, performed a detailed design analysis and drag breakdown on Mike Arnold’s record-breaking AR-5, and was inspiration for many designers to explore the new realm of microlift, a low-speed, high-lift concept that led to ultralight sailplanes such as Danny Howell’s Lighthawk, the Archaeopteryx, and Ilan Kroo’s Swift flying wing.

His work with Mississippi State’s Raspet Flight Research Laboratory and Dr. August Raspet on boundary layer control influenced a generation of designers, and coupled with his life-long research efforts, led to his being awarded the OSTIV (Organisation Scientifique et Technique Internationale du Vol `a Voile, or the International Scientific and Technical Organization for Gliding) Plaque with Klemperer Award in 2014, the soaring equivalent of the Nobel or Pulitzer Prize.  The Plaque was awarded, “For his many significant contributions to soaring technology in laminar flow research, scholarly papers, popular articles, books and seminars in recent years.”

The blocks on the left represent the very low Reynolds number areas in which Bruce Carmichael contributed his insight , and which led to the kinds of ultralight sailplanes shown

The blocks on the left represent the very low Reynolds number areas in which Bruce Carmichael contributed his insight, and which led to the kinds of light and ultralight sailplanes shown

“He has made information on laminar flow research, design and practical operation from more than forty years of industry and personal experience available to a wide audience through his many scholarly papers, popular magazine articles and books on ultralight gliders, sailplanes, motor gliders and personal aircraft drag reduction. In addition, he has planned, organized and conducted dozens of seminars and conferences on soaring technology which have introduced many interested people to the science and culture of soaring. He has inspired and motivated several generations of soaring enthusiasts.”

Bruce was a gentle and dignified gentleman who asked your editor to present at the Western Workshop of the Experimental Soaring Association ten years ago.  This led to a friendship and an invitation to present at the following year’s Workshop.  That year, your editor’s presentation on available model aircraft electric motors caught the eye of Dr. Brien Seeley, founder and President of the CAFE Foundation, who invited your editor to speak at the third annual Electric Aircraft Symposium.  After presenting at several more Symposiums and Workshops, your editor was approached again by Dr. Seeley who asked that he write the CAFE blog, an enormous honor considering the non-expert status of this English major ex-teacher and retired technical writer.  Incidentally, one surprising thing that helped cement our relationship was that Bruce wrote poetry about the scientific interests he pursued.

Any success this blog has had through the last five years and over 800 entries is a direct outgrowth of Bruce Carmichael’s invitation and continuing support. Your editor is deeply indebted and saddened by the loss of a great man and a great and true friend.

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Aluminum Yolks and Titanium Shells

A new “yolk-and-shell” nanoparticle could boost the capacity and power of lithium-ion batteries.

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The gray sphere at center represents an aluminum nanoparticle, forming the “yolk.”  The outer light-blue layer represents a solid shell of titanium dioxide, and the space between the yolk and shell allows the yolk to expand and contract without damaging the shell.  The background image is an actual scanning electron microscope image of a collection of these yolk-shell nanoparticles.  Image: Christine Daniloff/MIT

MIT’s press release gives a graphic overview of what damages electrodes and shortens battery life.  “One big problem faced by electrodes in rechargeable batteries, as they go through repeated cycles of charging and discharging, is that they must expand and shrink during each cycle — sometimes doubling in volume, and then shrinking back. This can lead to repeated shedding and reformation of its “skin” layer that consumes lithium irreversibly, degrading the battery’s performance over time.”

Dr. Yi Cui and teams at  Stanford’s National Accelerator Laboratory (Formerly the Stanford Linear Accelerator Center), and the Environmental Molecular Sciences Laboratory (EMSL) at Pacific Northwest National Laboratory all published papers on a similar  joint accomplishment three years ago, as reported in this blog.  Dr. Cui had studied several alternative ways to reduce the effects of expansion and contraction on electrodes.

According to an MIT news release, “Now a team of researchers at MIT, led by Professor Ju Li, and Tsinghua University in China has found a novel way around that problem: creating an electrode made of nanoparticles with a solid shell, and a ‘yolk’ inside that can change size again and again without affecting the shell. The innovation could drastically improve cycle life, the team says, and provide a dramatic boost in the battery’s capacity and power.”

Dr. Cui and his teams used “commercially available single silicon nanoparticles in ‘conformal, thin, self-supporting carbon shells, with rationally-designed void space between the particles and the shell.’”  MIT and Tsinghua University use a titanium dioxide shell and an aluminum yolk, which they say has proven to be “the high-rate champion among high-capacity anodes.”

The MIT researchers explain that most lithium-ion batteries have graphite anodes with a storage capacity of 0.35 ampere-hours per gram (Ah/g).  Looking at alternatives, lithium metal can store about 10 times as much energy per gram, but, according to the researchers, is extremely dangerous, short-circuiting and catching fire on occasion.  Silicon and tin have very high capacity, which drops at high charging and discharging rates.

Aluminum is a low-cost option with theoretical capacity of 2 Ah/g, roughly six times that of carbon.  But Li found much the same thing Cui did with silicon, it expands considerably when charged to high capacity, and absorb lithium, then shrink when discharging and releasing lithium.

Repeated expansion/contraction cycles cause mechanical stress, and break down the electrodes.  Complicating things further, liquid electrolyte in contact with aluminum decomposes and forms a solid-electrolyte interphase (SEI) layer around the Al, which sheds particles when charged and discharged.  This has caused previous attempts to use aluminum in Li-ion batteries to fail.

Professor Li explains there is a “big difference between what are called ‘core-shell’ and ‘yolk-shell’ nanoparticles. The former have a shell that is bonded directly to the core, but yolk-shell particles feature a void between the two – equivalent to where the white of an egg would be. As a result, the ‘yolk’ material can expand and contract freely, with little effect on the dimensions and stability of the ‘shell.’”

MIT’s titanium oxide shell separates the aluminum from the liquid electrolyte, and does not expand or contract much, stabilizing the SEI layer and protecting the aluminum inside from direct contact with the electrolyte.  This was an unplanned outcome.

“We came up with the method serendipitously, it was a chance discovery,” Li says. The aluminum particles are about 50 nanometers in diameter, and naturally have an oxidized layer of alumina (Al2O3). “We needed to get rid of it, because it’s not good for electrical conductivity.”

Converting the alumina layer to a thin layer of titania (TiO2) gave a better conductor of electrons and lithium ions. Reacting Alumina with sulfuric acid released excess water which reacted with titanium oxysulfate to form a solid shell of titanium hydroxide with a thickness of 3 to 4 nanometers.

The team explains, “What is surprising is that while this solid shell forms nearly instantaneously, if the particles stay in the acid for a few more hours, the aluminum core continuously shrinks to become a 30-nanometer-across “yolk,” which shows that small ions can get through the shell.”

After further treatment, the particles are then tested through 500 charging-discharging cycles. Thickening the titania shell.    The inside of the electrode, though, remains clean with no buildup of SEIs, “proving the shell fully encloses the aluminum while allowing lithium ions and electrons to get in and out.” The resulting electrode gives more than three times the capacity of graphite (1.2 Ah/g) at a normal charging rate, Li says. At very fast charging rates (six minutes to full charge), the capacity is still 0.66 Ah/g after 500 cycles.

Performance charts for yolk-shell nanoparticles show stability after even 500 cycles, strong drops in performance at higher charge/discharge rates

Performance charts for yolk-shell nanoparticles show stability after even 500 cycles, strong drops in performance at higher charge/discharge rates

With inexpensive materials and a simple manufacturing process that could be easily scalable, Li says, “It’s probably the best anode material available” for applications that require a high power- and energy-density battery.  Full cell tests using lithium iron phosphate as cathode have been successful, indicating ATO is quite close to being ready for real applications.  That cathode would be a further protection against thermal runaways.

The research team included Sa Li, Yu Cheng Zhao, and Chang An Wang of Tsinghua University in Beijing and Junjie Niu, Kangpyo So, and Chao Wang of MIT. The work was supported by the National Science Foundation and the National Natural Science Foundation of China.

Li is Battelle Energy Alliance Professor in Nuclear Science and Engineering, who has a joint appointment in MIT’s Department of Materials Science and Engineering.

MIT’s and Tsinghua University’s work is published in Nature Communications.

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