January 19 marked the first flight by a Raptor UAS drone using pelletized hydrogen to power a fuel cell that generates electricity and makes the propeller turn.
Cella Energy, a Scottish-based enterprise, is now producing small quantities of their little green beads (just in time for Mardi Gras), filled with solid-state hydrogen. Claimed to have “two or three times” the energy per weight of the best of lithium-ion batteries, Cella’s pellets are designed to enable low-pressure transportation of hydrogen in a form that allows fueling to take place with a bit of magic sleight of hand. Looking like miniature green dumplings, Cella’s mix of plastic and encapsulated hydrogen has the advantage of using existing infrastructure, “with minimal alterations.” Think of the pellets as a dumpling with a hydrogen filling which can be repeatedly extracted and refilled. How many refillings is not stated at this time.
The pellets release their hydrogen into a fuel cell when they are heated to a “moderate” level. The “empty” pellets can be sucked from the fuel tank where they’ve done their magic and placed back in the fuel tank or truck in which they were stored. The depleted pellets are replaced by energy-laden ones. “One of the biggest challenges facing the roll-out of hydrogen cars is the investment in high-pressure filling stations.
Each pellet contains one liter of hydrogen. 100 loaded in the Raptor E1 would have kept the airplane up for two hours
Another magic trick regenerates the H2 in the pellets so they can once again be transferred to a waiting power plant or vehicle. Pellets are lyophilized, or freeze dried, to keep the stored hydrogen in place at room temperature.
Cella’s two stage hydrogen extraction uses a gas generator which turns the H2 gaseous, coupled to a fuel cell which burns the hydrogen and creates electrical power. The system is integrated by Arcola Energy, another partner in the project.
The Test Airplane
Raptor UAS’s Raptor E1 incorporated Cella’s power system and was flown by the Scottish Association for Marine Science (SAMS). Funded by a grant from Innovate UK, Trias Gkikopoulos of Raptor UAS teamed with Cella and Arcola to make a first-of-a-kind vehicle that points the way toward potentially longer missions and bigger craft.
According to UAS Vision, the airplane flew with 100 pellets, each capable of generating about a liter of hydrogen. The flight lasted 10 minutes, although it could have continued for two hours with the fuel on board. Cella points out that a larger system (which the partners are devising) could reach the goal of three times the energy density of lithium-ion batteries.
Cella claims its system is scalable, able to be increased in size to power larger aircraft, probably in the ultralight and personal aircraft range for now – but who knows where this development might lead?
NASA’s Glenn Research Center reviews the prevalence of fossil fuels in keeping us flying for over a century. “Since the beginning, commercial planes have been powered by carbon-based fuels such as gasoline or kerosene. While these provide the energy to lift large commercial jets into the world’s airspace, electric power is now seen as a new frontier for providing thrust and power for flight.”
Noting the use of hybrid and turboelectric power used to increase efficiency in cars, boats and trains, NASA has set a goal “to help the aircraft industry shift from relying solely on gas turbines to using hybrid electric and turboelectric propulsion in order to reduce energy consumption, emissions and noise.”
This would require a large shift in propulsion and overall aircraft design and Jim Heidmann, manager for NASA’s Advanced Air Transport Technology project reflects on those changes. “Moving toward alternative systems requires creating new aircraft designs as well as propulsion systems that integrate battery technologies and electromagnetic machines like motors and generators with more efficient engines.”
Prospective “looks” could be new and unusual to say the least. Using power systems that generate electricity in place of, or in addition to, thrust at the turbine engine, and using that electricity to produce thrust at other places on the aircraft. That seems to allow distributed thrust with theoretically more economical ways to produce that thrust – NASA’s suggesting a 30-percent fuel saving.
Amy Jankovsky, subproject lead engineer says distributing power throughout the aircraft could, “reduce drag for a given amount of fuel burned,” and adds, “Part of our research is developing the lightweight machinery and electrical systems that will be required to make these systems possible.” This includes work at the base material level right down to wires and insulation, magnetic materials and semi-conductors.
Cheryl Bowman, a technical lead on the project, sees the big picture of what can be saved. “Considering that the U.S. aviation industry carries over 700 million passengers every year, making each trip more fuel efficient (by up to 30 percent) can have a considerable impact on the nation’s total use of fossil fuels.”
ProAirSport’s GlowFly landing gear – an electric motor aiding acceleration on the ground. Once in flight, the microturbine takes over
At the lighter end of the scale, ProAirSports’ Project Glow uses a hybrid approach that negates the slow acceleration one might experience with a small turbine, applying a seven-kilowatt electric motor to drive the landing gear wheels for a high-torque kick-start to the takeoff run. The Titan puts out about 88 pounds of thrust, enough for climb and throttled-back searches for thermals, while the motor provides enough urge for takeoffs from farm strips, according to Light Aviation, the publication of the UK’s Light Aircraft Association. Their judgement, “the acceleration really should be outstanding, in fact wheel spin could be an issue if power is applied too quickly.”
NASA’s depictions of considerably larger airlines show a conventional-looking machine with hybrid turbines under the wing and on the tail, probably benefiting from the added thrust a larger ducted fan could provide. Cross-pollination of ideas for both large and small aircraft could lead to some interesting cross-over designs of different sizes.
Conceptual illustration of hybrid electric airliner, with electric motors augmenting power of jet engines
Modelers have been flying with microturbines for years, and even with micro turboprops, as shown by this “Ugly Stick” model from New Zealand. Think of this coupled with an equivalent electric motor that would enable lower fuel use and thrust distribution where it could do the most good on this “draggy” craft.
This is a “medium” sized aircraft in terms of how big models get these days, and some European flyers are piloting twin-engine scale models of turboprop commuter liners. Their engines come in a great range of sizes, leading to that cross-over point where models engines become full-scale aircraft powerplants, much as with electric motors. Combining the best elements of both might be an interesting direction for not only NASA and the “big boys,” but for homebuilt craft that will one day no longer have 100-octane low lead to take them skyward.
A significantly large and geographically diverse group of researchers has invested a large amount of time and intellectual capital investigating superoxides, an innovative way to keep lithium-air batteries refreshed and ready for more. Groups at Argonne National Laboratory, the University of Illinois at Chicago, Hanyang University in Seoul, South Korea; the University of Utah and the University of Kentucky all contributed to the ongoing project.
While still serving as U. S. Secretary of Energy, Steven Chu called on academia and industry to develop a battery five times as powerful as then available lithium cells, at one-fifth the cost of then current batteries. We may not have arrived at that ambitious goal yet, but Argonne and UIC see a possible breakthrough in making lithium-air batteries – theoretically the most energetic of lithium chemistries – into long-lasting, energy-dense energy storage units.
So far, lithium air batteries have a limiting weakness, the use of lithium peroxide, something that ends up being “an insoluble substance that clogs the battery’s electrode.” This “clogging” reduces electro-chemical reactions and finally stops them altogether, effectively killing the battery. Argonne battery scientists created an alternative battery “that produces only lithium’s superoxide, not peroxide, as the battery discharges. Unlike troublesome lithium peroxide, lithium superoxide easily breaks down again into lithium and oxygen, thus offering the possibility of a battery with high efficiency and good cycle life.” Note that this is a lithium-oxygen, rather than lithium-air battery, with no need to take in outside air for maintain electrochemical reactions.
One obstacle was proving the claim by showing the superoxide reaction took place, and that’s where UIC scientists came in. Realizing that any measurements outside the actual cells were not accurate enough to see the reactions, Amin Salehi- Khojin, an assistant professor, and postdoctoral research associate Mohammad Asadi “devised a state-of-the-art mass spectroscopy apparatus to measure the electrochemical reaction products in situ during charging or discharge of the battery.” Operating in an ultra-high vacuum, the system is “very sensitive to the tiniest change in oxygen concentration,” according to Asadi.
Their spectroscope was precise enough to show one electron per oxygen atom produced in the reaction, an indicator that the battery was producing superoxide rather than peroxide. They also showed no other lithium compounds being generated as side-products.
Salehi-Khojin sees promise in the results. “This is going to be a valuable system for continuing the study of this battery and other types of metal-air batteries. Not only can we analyze the products of the electrochemical reaction, we can elucidate the reaction pathway. If we know the reaction pathway, we’ll know how to design the next generation of that battery for energy efficiency and cost effectiveness.”
The work was funded by the DOE’s Office of Energy Efficiency and Renewable Energy and Office of Science and the University of Illinois at Chicago Chancellor’s Proof of Concept Fund.
Others contributing to the January 11, 2016 Nature article include Argonne’s Jun Lu, Dengyun Zhai, Zonghai Chen, Khalil Amine, Xiangyi Luo, Kah Chun Lau, Hsien-Hau Wang, Scott Brombosz, Larry A. Curtiss, Jianguo Wen and Dean J. Miller; Yun Jung Lee, Yo Sub Jeong, Jin-Bum Park and Yang-Kook Sun of Hanyang University in Seoul; Zhigang Zak Fang of the University of Utah; and Bijandra Kumar of the University of Kentucky.
Charge-discharge cycles for the UIC lithium-oxygen battery shows high energy density, low losses over multiple cycles. Image C shows scanning electron microscope image of discharge material on electrode
Because the lithium superoxide does not cause reduction in performance for the electrodes in the battery, the battery could be a closed system, recycling the use of LiO2 alone, and not requiring the intake of additional oxygen. “Our results demonstrate that the LiO2 formed in the Li–O2 battery is stable enough for the battery to be repeatedly charged and discharged with a very low charge potential (about 3.2 volts). We anticipate that this discovery will lead to methods of synthesizing and stabilizing LiO2, which could open the way to high-energy-density batteries based on LiO2 as well as to other possible uses of this compound, such as oxygen storage.”
The closed system could lead to a “new type of battery” that was a true 5x energy storage device, with the use of a “suitable graphene-based cathode.”
Larry Curtiss, a group leader at Argonne says, “This discovery really opens a pathway for the potential development of a new kind of battery. Although a lot more research is needed, the cycle life of the battery is what we were looking for.” The research teams may well have found it.
Deltawing’s four-seat car has lines similar to Nissan’s ZEOD Le Mans racer
Deltawing is an outgrowth of Panoz Racing, a team often associated with Garage 56 at LeMans, a non-standard entrant allowed for its innovative approach to reaching high speeds. Their latest efforts have turned to achieving the CAFE (in this case Corporate Average Fuel Economy) goals of the federal government for 54.5 miles per gallon by 2025. The swoopy car follows the look of Nissan’s Garage 56 entrant which raced (but not for long) in the 2014 Le Mans race. It had topped 300 kilometers per hour (186 mph) on electric power alone, the first car ever to lap Le Mans on electric power only.
Deltawing’s four-seat “economy car” looks a great deal like Nissan’s racer, and will use a DHX motor, compact and light enough to complement the car’s design. DHX touts its motors as the literal equivalent of getting “a quart in a pint pot,” or more precisely, “a gallon in a quart pot.”
Don Panoz, it should be able to accelerate from 0-60 mph in six seconds and hit a top speed of 130 mph using an engine that produces just 85-110 horsepower, while delivering fuel economy as high as 70 mpg with a gasoline motor.
Using a novel and proprietary cooling approach which apparently dissipates heat efficiently, DHX pulls more than ordinary levels of power from its motors. Green Car Congress explains the physics, incorporating the unique measurements employed by DHX:
“DHX traction motor technology is based on proprietary direct-winding heat exchange cooling technology that is able to remove motor heat at the source—the stator windings. The technology is based on the advanced micro-feature heat exchange research and development efforts of Dr. J. Rhett Mayor (DHX CEO) and Dr. S. Andrew Semidey (DHX VP of Engineering) at the George W. Woodruff School of Mechanical Engineering at Georgia Tech.
20-horsepower DHX motor with Panoz cup, 1.5-hp conventional motor
“The direct-winding heat exchange system uses micro-feature technology to increase the area of the cooling surface by up to 4 times that of a standard cooling channel. The micro-feature technology also helps to increase the relative flow velocity of the coolant, by a process of localized turbulence.
“As a result, the DHX cooling technology removes more than 10 times the heat of a standard coolant channel, the startup claims. More heat removal means more current (about 4 times more) leading to 4 times the torque. From another view, the DHX motor is 4 times smaller than a standard motor of the same power, the company says.
“Our DHX Falcon electric motor features standard materials, not exotic steels and magnets. It achieves power densities of 120 horsepower per gallon (25 kW per liter) and extraordinary torque of 195 lb-ft/gallon (70 N·m/l). In simple terms, it delivers the power and torque of the standard sedan’s powertrain in the space of a one-gallon can of paint,” according to J. Rhett Mayor
Incidentally, Apex Drive Laboratories of Portland, Oregon worked with a cooling system called “micro-channel cooling,” a multiply-patented approach several years ago. Unfortunately, attempts to reach the company show that it may no longer be in business. Their axial-flux permanent magnet motor showed some promise at the time.
DHX claims their 30-pound motor can put out 80 horsepower, not particularly greater than Roman Susnik’s motors or what is promised for Chip Erwin’s 25-pound motor, but still creditable for being lighter than equivalent car propulsion units and in a much smaller volume.
The video shows construction of DHX’s 3950 motor, a much larger unit perhaps intended for high-speed racing. Anticipation grows.
We can hope that the competitive urge will bring us more and better motors, and with increasing production, lower prices.
Dr. Yi Cui of Stanford University has expanded the idea of “battery” to include conductive ink on paper, fruit-like clusters of energy-storing capsules, and now, nano-sized graphene cages in which the energy can romp like a hamster in a plastic ball.
His pioneering work with silicon as an electrode material goes back at least ten years, and has focused on overcoming silicon’s two major problems in battery use. Silicon expands and begins breaking down during repeated charge-discharge cycles. It reacts with battery electrolyte to form a coating that progressively destroys performance. The combination of crumbling and coating finally makes the battery inoperable.
In scanning electron microscope image, “Caged” silicon in graphene container is allowed to break apart, but kept in enough constraint to function as anode. GIF from Hyun-Wook Lee/Stanford University
His group at Stanford had found a way to “wrap every silicon anode particle in a custom-fit cage made of graphene, a pure form of carbon that is the thinnest and strongest material known and a great conductor of electricity.
The team created a three-step way to build microscopic graphene cages large enough to let the silicon particle expand during charging, but tight enough to hold the particle together if it does crumble. That maintains functionality at high capacity. The cages are also barriers to electrolyte getting in and coating the anodes.
Building a graphene cage around a silicon anode. Illustration: Nature Energy
Looking a “great deal” like the pomegranate batteries Cui and his team developed two years ago, “with silicon nanoparticles clustered like seeds in a tough carbon rind,” as Phys.org reported, the graphene cages may be a significant improvement over the 2014 configuration.
The Stanford-SLAC (Formerly Stanford Linear Accelerator Center, and now the National Accelerator Center) press release quotes Dr. Cui explaining the advancement. “In testing, the graphene cages actually enhanced the electrical conductivity of the particles and provided high charge capacity, chemical stability and efficiency. The method can be applied to other electrode materials, too, making energy-dense, low-cost battery materials a realistic possibility.”
Silicon anode cracking apart, being constrained. Illustration: Nature Energy
Encapsulating silicon anodes in graphene cages allows the anodes to flex, break, and be kept together within the cage – maintaining electric contact and the ability to charge and discharge. It’s a counter-intuitive approach, allowing the purposeful disintegration of the anode rather than trying to hold it together as in previous approaches.
Cui explains how silicon sawdust enables the new anode to perform well while using what otherwise would be waste material. “This new method allows us to use much larger silicon particles that are one to three microns, or millionths of a meter, in diameter, which are cheap and widely available. In fact, the particles we used are very similar to the waste created by milling silicon ingots to make semiconductor chips; they’re like bits of sawdust of all shapes and sizes. Particles this big have never performed well in battery anodes before, so this is a very exciting new achievement, and we think it offers a practical solution.”
To fit the cages to the anodes, or vice-versa, SLAC personnel coated silicon particles with nickel in “just the right thickness.” They then grew layers of graphene on the nickel, which turns out is a catalyst that aids graphene growth. They finally etch the nickel away, leaving space inside the cage for the silicon particle to expand. That all this takes place at a nanometer-sized scale leaves one more than slightly astounded.
Stanford/SLAC quotes Stanford postdoctoral researcher Kai Yan, who carried out the experiments with graduate student Yuzhang Li. “Researchers have tried a number of other coatings for silicon anodes, but they all reduced the anode’s efficiency. The form-fitting graphene cages are the first coating that maintains high efficiency, and the reactions can be carried out at relatively low temperatures.”
The team is now working on optimizing cage sizes and devising ways to grow enough of them to make commercialization possible.
Other researchers contributing to the study were Stanford’s Hyun-Wook Lee, Zhenda Lu and Nian Liu. The research was carried out by SIMES, the Stanford Institute for Materials and Energy Sciences at SLAC, and funded by the Battery Materials Research program of the DOE’s Vehicle Technologies Office.
The Nature Energy paper by Yuzhang Li, Kai Yan, Hyun-Wook Lee, Zhenda Lu, Nian Liu, Yi Cui, “Growth of conformal graphene cages on micrometre-sized silicon particles as stable battery anodes” can be viewed gratis, a rarity in scientific publishing.
Your editor has several friends who lay claim to the appellation, “ferroequinologist,” (student of the iron horse), meaning they fancy miniature trains and the layouts that support them. One friend helped construct a layout that takes up most of a good-sized building in Portland, Oregon – but even he would be dumbfounded by the massive installation in Hamburg, Germany – which includes an international airport in its midst that accounts for 180 takeoffs and landings per day and handles 1.2 million “passengers” per year.
Blogmeister Klaus Burkhard oversees a wonderful web site based primarily on ultralight sailplanes. His writings have alerted your editor to the twin-motor self-launching ultralight Holliday Obrecht and his compatriots are building at EAA Chapter 309 in Charlotte, North Carolina; Snow White, an electrically-powered flying wing inspired by the Horton Brothers, and produced an expansive entry on the Volocopter that included detailed photographs and specifications.
Miniatur Wunderland’s airline terminal, emulating an international airport in miniature
A recent entry on Hamburg’s Miniature-Wunderland told of the remarkable airport that has aircraft landing and taking off on slender wires, appearing from and disappearing into “clouds” at the ends of the runway. This particular airport may be the only opportunity for plane spotters to see a Concorde “fly” several times a day, along with a Super Constellation – one of Burkhard’s favorites, an AN-124, and Red Bull’s DC-6B. The mix of aircraft is a tribute to the designers’ interest in providing a grand fantasy experience.
One of the cleverest bits of execution in all this is the trade-off from the two rods that hold the airplanes in place as they approach and depart the 14-meter (46-feet) runway to the link that connects to the nose wheel and guides the aircraft along as it taxis. This part is similar to the nose-wheel or main gear motored devices that allow real jets to turn their engines off while on the ground.
The imaginary Knuffingen International Airport operates 365 days a year, encapsulating its own 20-minute “days” into repetitions of its well-choreographed routines. With orderly precision in the comings and goings of its aircraft, the site’s access roads and parking lots resemble the chaotic bustle of real-world airports. Service trucks perform all the tasks one would see at a grand airport.
Go to the link above to read Klaus’s detailed review of this imaginative and beautifully done layout. The airport at 125 square meters (1,345.5 square feet) is a small part of the overall Wunderland, which will eventually cover 2,300 square meters (24,757 square feet). It seems well worth the 13 euro (about $14.15) entrance fee.
When you visit Klaus’s site, be sure to check out his literary recommendations. He’s also quite a bibliophile and avid collector of aviation literature.
Doping in this case means coating a graphene sheet with nitrogen, and crumpling those sheets seems to help provide places to hide energy. Not as tidy as the “tootsie roll” cylindrical battery or the pouch cell with which we’re familiar, but this new approach from Pennsylvania State University researchers embed these messy cathodes into efficient Lithium-sulfur (Li-S) batteries.
Three steps in making doped, crumpled cathodes
Researchers synthesized “highly crumpled” nitrogen-doped graphene (NG) sheets with “ultrahigh pore volume” and large surface area (1,158 square meters– about 12,465 square feet or about one-third the area of a football field) per gram. This large area and high porosity “enable strong polysulfide adsorption and high sulfur content for use as a cathode material in Li-sulfur batteries.” Interwoven rather than stacked, the wrinkled material provides ample room for “nitrogen-containing active sites.”
The batteries, according to the researchers, “achieved” a high capacity of 1,226 milliamp-hours per gram and 75-percent capacity retention after 300 cycles. This demonstrated capacity and longevity is something other experimenters with lithium sulfur batteries have tried unsuccessfully to achieve.
Green Car Reports quotes Jiangxuan Song, one of the researchers on the techniques used. “Lithium–sulfur battery cells using these wrinkled graphene sheets as both sulfur host and interlayer achieved a high capacity of 1227 mAh/g and long cycle life (75% capacity retention after 300 cycles) even at high sulfur content (≥80 wt %) and sulfur loading (5 mg sulfur/cm2). A high capacity of 1082 mAh/g was still achieved with an ultrahigh sulfur content of 90 wt %, and a capacity of 832 mAh/g was retained after 200 cycles. Areal capacity was 5 mAh/cm2. A paper on their work is published in the ACS journal Nano Letters.”
Nitrogen-doping the graphene in the cathode apparently improves the electrochemical performance and helps yield the results shown above. Such doping improves otherwise lackluster conductivity and leads to better energy density, cycling stability and Coulombic efficiency. The process deposits nitrogen in the lattice-work-like structure of the graphene and depending on the amount of nitrogen deposited, makes a positive change in the material’s characteristics.
Penn State researchers think this can be applied to supercapacitors with the hope of similar performance improvements.
Why Lithium Sulfur?
Next to Lithium-air, Lithium-sulfur offers greatest potential energy density
Lithium sulfur (Li-S) are, with current technology, the most likely successor to lithium-ion batteries. Penn States’ approach might help overcome Li-S battery’s poor cycle stability and low rates, and seem to show, in this instance significant performance improvements.
Comparison between Li-ion and Li-S batteries shows much greater theoretical energy density
Energy Technologies Area (ETA) at Berkeley state that lithium-sulfur batteries have a very high theoretical specific energy (2,680 Wh/kg), much higher than that of the best Li-ion cell (~580 Wh/kg). “Thanks to this high energy per weight, Li/S batteries could store more energy, and therefore, provide greater vehicle range as well as longer operating times in all applications.
‘Sulfur is inexpensive, non-toxic, safe, and environmentally benign, so Li/S batteries would be cheaper than current Li-ion batteries, and they would be less prone to safety problems that have plagued some of today’s Li-ion batteries, such as overheating and catching fire.”
These pluses, coupled with developments at Penn State, might make lithium-sulfur batteries a plausible route to take for the near future.
Intel recently earned a Guinness World Record for lofting 100 drones at one time. To make it hard, they did it at night and to an orchestral accompaniment. Musical purists (your editor) might become vexed with the liberal reinterpretation of Beethoven’s score (the original symphony didn’t have a piano or a harp), and the added “bits” to a piece that’s been considered OK as-is for over two centuries.
The orchestra played what they were given with great style, however, and the electronics wizards who put the aerial show together pulled it off with precision, playing well to the home crowd – apparently composed of Intel employees. One wishes Intel would release a complete performance video without the music-video-style editing and the reluctance to share the event with the outside world.
Even with the “Making Of” video, many points of how it was done are not readily apparent. It looks as though the human operators do little other than regulate the height of their individual drones, with electronics providing the cues for lighting and sequencing. In the dark, perspective is lost, and lateral movements could become problems.
Regardless of personal quibbles, Intel and its drone operators pulled off a symbolic victory (often associated with Beethoven’s Fifth) in controlling an imposing number of vehicles in close formation. That gives hope for future air traffic control where such drones will be intermingled with other, larger craft. We hope Guinness supplied congratulatory libations.
Seeing Google cars navigating our streets and highways, with their arrays of spinning sensors and antennas bristling from their roofs gives us the impression that the technology involved is complex and expensive. Until recently, they were, with Wired reporting that early Google cars had multiple $80,000 LIDAR systems, and entrants in DARPA (Defense Advanced Research Projects Agency) challenges often sported over a quarter-million in esoteric devices that could, on occasion, spot the Holy Spirit in the vicinity. (Your editor made that last part up.)
Sebastian Thrun, who oversees self-driving cars at Google (among other things), sitting on the 2005 DARPA Challenge winner. Note multiple LIDARs
“Quanergy Systems Inc., of Sunnyvale, Calif., says it will offer a light detection and ranging sensor — or LIDAR — next year that costs only $250 and is the size of a credit card. In 2018, it is promising a postage stamp-sized sensor for $100 or less. It’s all made possible by a solid-state laser system, says Chief Executive Louay Eldada, whose PhD at Columbia University is the basis of the technology.”
Even today, Ford and others testing self-driving systems use a series of whirring, somewhat myopic devices to find their way – a bit like a blind-folded person getting a tug from a near-sighted guide dog on one hand, an audible cue from a sensor on their cane, and myriad other clues from dozens of other individually-limited units – each squinting out into a series of obstacles and hazards.
Besides the expense of most LIDAR units, the cheapest running around $8,000, they don’t work well in rain or snow. People probably won’t be charmed by their cars looking like DARPA test vehicles. LIDAR measures objects a few hundred feet away, which would make it limited for in-flight use, where approaching objects are usually further away than in a typical driving scenario, and moving much quicker. The video below shows the 2007 DARPA Urban Challenge, with a collision between two competitors and interference from the Jumbotron preventing one entrant from even starting.
Consider the difficulties overcome in the last eight years to reduce the size of sensors and tuck them into the vehicles. Mom probably won’t want to pull up at Ridgemont High with the roof rack looking like something out of a bad sci-fi film. The kids would love it for all the wrong reasons. On an airplane, the weight and aerodynamic penalties would make this a non-starter.
Quanergy, though, has a little box measuring 3.5 inches by 2.4 inches by 2.4 inches, easily integrated into the contours of the vehicle. It senses things as close as 10 centimeters (4 inches) and as far away as 150 meters (almost 500 feet). Coupled with other sensors and cameras (especially useful for resolving distant objects), and fed through a miniaturized central control unit, the S3 could be a core unit in a very aware vehicle.
Quanergy’s S3 LIDAR unit – no moving parts but “superior in every way,” according to the company
Quanergy has signed supply or development agreements with Daimler AG, Hyundai Motor Co., Kia Motors Corp. and the Nissan-Renault Alliance, among others.
“LIDAR systems work by firing laser pulses out into the world and then watching to see if the light reflects off of something. By starting a timer when the pulse goes out and then stopping the timer when the sensor sees a reflection, the LIDAR can do some math to figure out how far away the source of the reflection is. And by keeping careful track of where it’s pointing the laser, the LIDAR gets all of the data that it needs to place the point in 3D space.
“In order to build up a complete view of the world, a LIDAR needs to send out laser pulses all over the place. The way to do it is to have one laser and one sensor and them move them both around a whole bunch, usually by scanning the whole LIDAR unit up and down or spinning it in a circle or both. You’ve probably seen these things whirling around on the top of autonomous cars. And they work fine, but they’ve got some problems: namely, they’re kind of big, they’re stupendously expensive, and because they have to be moving all the time, they’re not really reliable enough for consumer use.
Quantergy S3 sees all, up to 120 degrees around. It still takes several to get a total world view. An airplane will require 360 degrees of coverage in all planes
“This is where Quanergy comes in: its solid-state LIDAR has no moving parts. Zero. Not even micromirrors or anything like that. Instead, Quanergy’s LIDAR uses an optical phased array as a transmitter, which can steer pulses of light by shifting the phase of a laser pulse as it’s projected through the array:
“Each pulse is sent out in about a microsecond, yielding about a million points of data per second. And because it’s all solid-state electronics, you can steer each pulse completely independently, sending out one pulse in one direction and another pulse in a completely different direction just one microsecond later. Essentially, you can think of Quanergy’s chip as acting like a conventional glass lens, except that it’s a lens that you can reshape into any shape you want every single microsecond.”
As these things are reduced to computer chip size and become available as consumer products, we’ll doubtless see their application in conventional light aircraft for unconventional uses.
Making a lot of column inches of traditional newsprint and reigning as clickbait on the Internet, the Ehang 184 is an eye-catching Autonomous Aerial Vehicle (AAV) causing a bit of controversy in the media. Unveiled at this week’s Consumer Electronics Show (CES 2016), it drew concentric circles of photographers who normally save their enthusiasm for the lovely models showing off the newest iPhone or PlayStation.
Coming from a firm that already makes hobby drones, the 184 (one passenger, eight motors, four arms) can carry its trusting passenger up to 20 miles, depending on who’s reporting. Its 14.4 kilowatt-hour battery pack (about half that of a Nissan Leaf) allows a maximum of 23 minutes of flight, and at 60 mph, a quick hop to a nearby destination, which Ehang describes as short to medium-range flight.
Cnet.com considers licensing. “Ehang said that it’s working with multiple governments around the world and that no pilot’s license will be required to use the 184 AAV. Passengers navigate by tapping a destination on an electronic map on the aircraft’s tablet interface, and the 184 handles the rest.
“Because of those regulatory issues, it’s not yet clear when the craft will go on sale, the company said. Pricing also is uncertain, but the company hopes the machine will be something ordinary people can afford more than a toy only for billionaires.”
The Ehang 184 conveniently folds for compact storage
OK, maybe multi-millionaires can put them on their gift lists, with reported pricing ranging from $200,000 to $400,000. One can get a used Learjet for that, although it does require the drudgery of obtaining a pilot’s license – and an advanced one at that. At a more practical level, the e-Gull from Mark Bierele, the ULS from Randall Fishman, or the EMG-6 from Brian Carpenter offer better range for far less money – and each allows personal control of the vehicle. They’re not VTOL, but don’t need huge tracts of land for their operations.
This ever-increasing idea of what is “affordable” keeps taking flying away from what otherwise would be a General Aviation market. The gadgetry is nice, but simplified and generally understandable systems might lure a broader range of buyers into making a purchase. A bigger range of customers will help bring lower prices and even greater acceptance.
Their editor, probably at home with apps, seems a bit astonished at their presence on this aerial vehicle. “And—get this—the Ehang 184 can be controlled entirely through a mobile app. In fact, Ehang says passengers only have to execute two commands: ‘take off’ and ‘land.’ Once you’ve set your course, the Ehang 184 will take off vertically, and use real-time sensor data (and presumably GPS) to keep you on course. “
Emulating displays such as those in Teslas and Leafs, user-friendliness is readily apparent
Your editor is not quite as smitten, despite the high technology lavished on this machine. For starters, the configuration seems a bit dicey – as in slicey and dicey – with the dual propellers at around knee and ankle height. Keeping the unwary safe from accidental truncation should be a primary concern.
Considering the earnest efforts made to keep the pilot safe, based on the founder’s loss of two friends in more conventional aircraft and helicopter crashes, this seems a strange oversight.
Second, while there’s room for a 16-inch backpack in the trunk, there doesn’t seem to be room for a ballistic parachute, the ultimate safety gear on something that will accelerate rapidly earthward when all else fails. Even multiply-redundant software packages are not as comforting as a BRS.
Ehang’s outrunner motors put out 17.75 hp each, would make items for EAA types to experiment with
If the designers will put these final safety enhancements on their next iteration, They will still have a short-range, expensive device that has some utility, but might be better used as a rental utility device, rather than as a privately-owned plaything.
In the meantime, your editor is impressed with the fact that the company builds everything, including motors and propellers, in house, and that they are willing to share their failures along with their accomplishments with the world. Sharing those motors, just the right size for ultralight experimenters, might be a way for the successful small drone manufacturer to gain acceptance in the experimental aviation sphere. Their current design will probably be licensed as experimental anyway.