In my previously published books, I have sometimes put on my rose-tinted spectacles and dared to suggest what may happen in the years to come. In 1979, for my book The Guinness Book of Motorboating Facts and Feats, Chapter 16 was called “AD2000” and ran to 7 pages. Forty years later, most of the projections have still to be realized. My book The Harwin Chronology of Inventions, Innovations and Discoveries, published in 1987, had a section at the back titled “The Shape of Things to Come…,” which included “Civil airliner (VTOL, composite plastic construction and hydrogen-fueled).” As this book goes to the printer, over a dozen projects and patents for the electric airplane have been announced, filed and obtained. In ten years’ time, readers of this book will look back, as this historian has looked back, and say either “Nothing ever came of that,” or “The progress made with that aircraft puts this book completely out of date.”
Here are just some of those projects and concepts, updated to early 2018. In 2028 I shall be 78 years old and may have had the chance to update this book again. If not, then the blank page at the end (of the paper edition, of course) is therefore for those with private copies they may like to add to.
On July 26, 2016, Dr. Peter Harrop, Chairman of IDTechEx, gave a Webinar titled “Electric Aircraft Reach a Tipping Point”: “About 20 companies make or will soon be making electric aircraft. Nearly all are pure electric and fixed wing, the motorized hang-glider and the self-launching sailplane being typical with one hour endurance. A bigger value market being addressed is training planes and bigger still will be hybrid fixed wing and vertical take-off aircraft, hybrid and pure electric, with the pure electric ones only managing 30 minutes. In this webinar we discuss possible uses, improvements and other types too.” It is now clear that the manned electric aircraft (MEA) business will be around $24 billion as early as 2020, but the new analysis by IDTechEx sees truly hybrid and pure electric aircraft being a $24 billion business in 2031. Half of that will be relatively low-priced craft such as leisure and small work aircraft, and the high-priced half will be a mix of such things as helicopters, military aircraft, and feeder aircraft, according to IDTechEx projections, with large airliners not quite there. “Manned Electric Aircraft 2016–2031” reveals how much of this will no longer be a reworking of land-based technology, but will be based on such things as superconducting power distribution and traction motors with at least four times the kW/kg and Distributed Electric Propulsion (DEP) along the full length of the wing. However, new concepts being progressed first on land, such as supercapacitor bodywork and some other structural electronics, may have a place in these new ultra-lightweight aircraft.
Here is my own review of e-aircraft power systems and design configurations, although the two are inextricably interlinked.
The concept of a supersonic commercial airliner powered by superconducting hybrid electric propulsion is championed by English-born Richard Lugg with his HyperMach (Mach 4 cruise) SonicStar. Lugg’s Patent 8636241, filed in 2006, describes a fixed-wing VTOL aircraft, featuring an array of electric lift fans distributed over the surface of the aircraft. A generator is (selectively) coupled to the gas turbine engine of the aircraft. During VTOL operation of the aircraft, the engine drives the generator to generate electricity to power the lifting fans. Power to the lifting fans is reduced as the aircraft gains forward speed and is increasingly supported by the wings. The airliner also has supersonic double delta laminar flow, electromagnetic drag reduction technology and boom reduction. Lugg followed his father into the U.S. aerospace industry, via a detour into medical research that led him to work with NASA on how the impact of deep-space flight could affect the design of ships. But perhaps his most important experience was his involvement in the early stages of the NASA Hyper-X program in the mid–1990s, which would eventually produce a world-record-beating unmanned aircraft—the scramjet-powered X-43A—which flew at almost 10 times the speed of sound for 11 seconds in late 2004. Making some improvements in SonicStar’s turbine to increase the maximum capacity from 24 to 32 passengers, and bringing the cruising speed up to around 3,431 miles per hour (5,522 km/h), meant that the original entry date was pushed back from 2021 to June 2024, depending on the $220 million financial commitment from aircraft manufacturers. SonicStar will be able to fly from New York to London in all of 71 minutes.
Leik N. Myrabo with his Lightcraft sees laser flight carrying people around the globe and into space by 2020. Ground-based lasers called LightPorts would provide the energy needed to propel the crafts.
On June 30, 2015, Boeing patented a laser nuclear fusion jet engine, fitted with one or more free-electron lasers for providing pulsed laser beams to vaporize pellets comprising the propellant (deuterium and tritium). As a result of the compression of the deuterium and tritium, the gas mixture reaches sufficiently high temperatures to cause a release of energy beyond the “break-even” level, so increasing the overall thrust and exhaust velocity: a specific impulse of 100,000–250,000 seconds may be provided. No one is building this yet, but the patent lays the groundwork for a new kind of jet engine which could change the way jet engines are designed in the future.
In September 2015, Boeing also filed a patent for generating electricity from airport noise. Chin H. Toh, an inventor at Boeing, has worked out a way to harness the noise emanating from an aircraft to generate electricity. His invention achieves this by installing the acoustic electricity generating system on sides of a runway. The acoustic electricity generator of Boeing consists of four parts: acoustic wave collectors, an acoustic converter, a turbine and a generator. The device collects acoustic waves from the noise produced by aircraft on a runway, and directs the collected waves to an acoustic converter. The acoustic converter receives these waves to produce output airflow. For producing output airflow, a vibrating drum is mounted within the converter assembly. The drum moves up and down when excited by the incoming acoustic waves. As the drum vibrates, it acts as an air pump to draw the air in, and then pushes the drawn air down to form an output air flow. This output air flow is then directed to the turbine chamber, where it rotates the turbine shafts. The turbine shafts are further coupled to the generator, which generates electricity.1
The European Aeronautic Defence and Space Company (EADS) also announced its long-term plans to develop their ZEHST, a zero-emission hypersonic airliner, that could be whisking passengers from Tokyo to London in under 2.5 hours by the year 2050. In the short term they would be working on the VoltAir, a proposed all-electric airliner that could be flying within 25 years. Two next-generation lithium-air batteries would power two highly efficient superconducting electric motors, which would in turn drive two co-axial, counter-rotating shrouded propellers at the rear of the aircraft. An advanced carbon fiber composite airframe design, aerodynamics and low weight would make the airliner as easy to push through the air as possible. The batteries would be housed in the lower front section of the VoltAir, where they could be removed and installed just like baggage, at the airport. Recharging would take place when the batteries were out of the aircraft, so planes would simply land, swap out their depleted batteries for charged ones, and take off again. Not only would this arrangement make turnaround times similar to those of conventional refueling, but it would also reduce the weight and technical complexity of the aircraft. With advances currently being made in the field of high-temperature superconducting (HTS) materials, however, EADS saw a potential solution on its way. While certain materials are able to achieve superconductivity—an electrical resistance of almost zero—at very cold temperatures, others can achieve it at higher (but still cold) temperatures. These are the HTS materials. In the VoltAir’s electric motors, HTS wiring would take the place of conventional copper coils, and would be cooled to the necessary temperature with liquid nitrogen. This would result in an almost lossless electrical current, and emissions that would consist of nothing but harmless nitrogen gas. EADS anticipated that as the technology is developed, high-density superconducting electric motors will actually exceed the power-to-weight ratio of existing gas turbine engines. The streamlined VoltAir’s rear-mounted propellers would be able to “ingest” the wake from the fuselage, while the wings are able to remain streamlined and engine-free.2
Among those who reserved their judgment about the future of electric airplanes was Pratt & Whitney of Connecticut, the U.S. aero-engine manufacturer since 1925. In May 2014, Alan Epstein, P&W’s vice-president of technology and environment, stated that three technological “miracles” must occur before electric flight could go mainstream. First, battery technology must improve by 50 to 100 times, with a commercial aircraft like a Boeing 737 requiring about 10MW of energy during cruise. Battery-powered aircraft could be viable with current technology only. Epstein continued:
P&W had also spoken with engineers at the Massachusetts Institute of Technology about developing an electric engine capable of powering large aircraft. Such powerplants could be built, they have determined, but would require new, complex superconductivity technology. Also, engineers would need to remove the engine’s magnetic shielding to reduce its weight. But without magnetic shielding the engine could kill the people sitting next to the motors. Three miracles are about two-and-a-half too [many] for an industrial organization and one-and-a-half [too many] for most companies. I don’t see major commercial [electric aircraft without innovations] that have yet to be invented. Still, P&W’s parent company United Technologies will be at the forefront of electric-aircraft design when, and if, the technology becomes viable.3
In his paper “Are electric airplanes possible in the future?” published in Quora in December 2014, Joseph Guindi, a thermodynamics engineer for airliners such as the A350, pointed out:
The energy density of jet fuel far exceeds that of any battery. That means, you would need to carry far more weight to have an electric aircraft. More weight means exponentially more fuel. Even supposing the energy density were the same, jet fuel has an additional very useful property: once it is consumed, it is no longer on the aircraft, resulting in weight loss, resulting in reduced fuel consumption over a flight. This would be impossible with batteries. Additionally to all that, batteries require a long time to be recharged; the turnaround time for an Airbus A320 is as little as half an hour. At present, no commercially available battery offers that degree of performance. Any new technology to replace jet engines and jet fuel with electric motors and batteries would significantly alter the entire structure of an aircraft. Before that is allowed to be done, rigorous testing, lasting at least a decade, would have to be done before it is approved for civilian commercial use and proving that it is as safe and as reliable as jet engines. Since none of the milestones laid out above have occurred, I wouldn’t expect an electric commercial aircraft in the next quarter century at a minimum, if at all.
Tesla CEO Elon Musk has said that once batteries are capable of producing 400 watt-hours per kilogram, with a ratio of power cell to overall mass of between 0.7 and 0.8, an electrical transcontinental aircraft becomes “compelling.” Indeed, Tesla engineers continue to work towards this goal. They have developed a new battery cell in partnership with Panasonic now in production at the Gigafactory in Nevada. The new 2170 format cell features a new battery chemistry slightly different from the current 18,650 cells used by Tesla in its vehicles and energy storage products. Powerpack 2.0 has a higher energy density and a capacity of 200 kWh. In Musk’s terms, they are only halfway there.
In 2014, NASA launched the University Design Challenge: All Electric Aviation Vehicle competition to design a four-seat, all-electric aircraft capable of entering service by 2020. More than 20 universities entered the competition, including Georgia Tech, University of California Davis, and Virginia Tech. The winner was Tom Neuman, a 24-year-old engineer at Toyota’s Technical Center in Michigan, who had completed co-ops at Boeing, Sikorsky, and Rolls-Royce while studying aerospace engineering at the Georgia Institute of Technology in Atlanta. In 2008, aged 17, Neuman had already worked on another electric plane—one with a 9-foot (3-meter) wingspan, and designed for a remote-controlled aircraft competition. For the NASA challenge, Neumann incorporated the technology of the fuel-cell-powered Toyota Mirai automobile, which delivers 800 Wh/kg at 55 percent efficiency. That was certainly better than 400 Wh/kg for the best lithium-based batteries. He then installed it into a Cirrus SR22 composite aircraft. He ran yet another analysis and found “a sweet spot in efficiency” using two rather large propellers attached to a pair of motors. Instead of mounting them conventionally, on the wing or fuselage, he put them atop the plane’s V-shaped tail, where the airflow is cleaner. That is when Neuman dubbed his V-tailed, hydrogen-powered design Vapor. Neuman’s Vapor could theoretically carry at least 400 pounds (180 kg) of extra cargo, fly at least 575 miles (1,000 km) during a single flight, cruise at a speed of at least 150 mph (250 kph), and be able to take off in less than 3,000 feet (900 m) under normal conditions.4
To further encourage the DEP, NASA’s University Aeronautics Design Challenge 2015–2016 took in their concept of an electric-powered, commuter-sized airplane featuring “green aviation” technologies. Sponsored by NASA’s Aeronautics Research Mission Directorate, the engineering design contest specifically asked students to incorporate distributed electric propulsion, or DEP, in their concept for an airplane that could enter service by 2025. The proposed aircraft design also had to be able to carry 19 passengers, cruise at 250 mph (400 kph), fly as high as 28,000 feet (8,500 m), take off or land on a runway no longer than 3,000 feet (900 m), and be able to fly in all types of weather, including icing conditions.
First place was taken by a team of 13 students from the University of Virginia in Charlottesville, with BLItz, a distributed electric propulsion commuter aircraft with eight fans partially embedded in a smaller wing that has a turboelectric generator at each wingtip. The fans’ placement would duct air over the wing to improve lift, and also enable boundary layer ingestion, which takes advantage of the airflow over the aircraft to make the fans operate more efficiently and reduce drag. Second place went to a seven-member team at Virginia Tech in Blacksburg. Their concept was for an aircraft called Ion, which would use ten electric motors covering 90 percent of the wing’s surface, with six of those folding away during cruise. Third place went to another seven-member team at Virginia Tech for their concept called Partior Q-1, which incorporated on its wing leading edge eight propellers for takeoff, six of which would not be needed during cruise. In early November 2016, the winners presented their papers at a student conference at NASA’s Langley Research Center in Virginia. Plans for the University Aeronautics Design Challenge for the 2016–2017 academic year included two technical areas: a supersonic challenge and a low-noise subsonic challenge.5
Another line of R&D, taken by Philip J. Masson of the Department of Mechanical Engineering at the University of Houston, with Cesar A. Luongo, senior superconducting magnet engineer at Jefferson Lab, Newport News, Virginia, concerns superconducting motors. They believe these could solve problems of weight and autonomy by using liquid hydrogen to run an electric fuel cell. Liquid hydrogen is cold enough to make the superconducting magnets work, but also has four times as much energy, weight-for-weight, as aviation fuel.
In their paper “HTS machines as enabling technology for all-electric airborne vehicle,” published in 2007 in Superconductor Science and Technology, Volume 20, Number 8, they concluded:
Electric propulsion for aircraft would require the development of high power density electric propulsion motors, generators, power management and distribution systems. The requirements in terms of weight and volume of these components cannot be achieved with conventional technologies; however, the use of superconductors associated with hydrogen-based power plants makes possible the design of a reasonably light power system and would therefore enable the development of all-electric aero-vehicles. A system sizing has been performed both for actuators and for primary propulsion. Many advantages would come from electrical propulsion such as better controllability of the propulsion, higher efficiency, higher availability and less maintenance needs. Superconducting machines may very well be the enabling technology for all-electric aircraft development.6
Funded by the USAF Research Laboratory and NASA, a team coordinated by Masson and Luongo has developed design concepts for a revolutionary aircraft using distributed propulsion whereby the very high specific power required for the airborne generators and motors can be achieved by using superconductors. Analytical 2D sizing models were created and showed very promising results. The next step was 3D modeling, where the magnetic flux distribution is calculated using Biot-Savart’s law coupled with the magnetic moment method for the back iron. The code also includes thermal and mechanical models, allowing for a full and accurate design. Masson adds that the team is now looking for an industrial partner to build a prototype of the superconducting “turbofan.” “The technology is there,” he says, “it is a matter of finding a source of funding.”
In 2009, researchers at the U.S. Navy Research Laboratory located in southwest Washington, D.C., developed the Ion Tiger, a UAV whose fuel cell was powered by gaseous hydrogen stored at 5,000 psi. This enabled it to stay aloft for 26 hr and 2 min. The team continued to work on their prototype so that by April 2017 Ion Tiger had been refitted with liquid hydrogen fuel in a lighter weight, cryogenic fuel storage tank and delivery system. This enabled Ion Tiger to stay aloft for 48 hours and 1 minute. The NRL LH2 flight capability is being developed by NRL’s Tactical Electronic Warfare and Chemistry Divisions, and is sponsored by the Office of Naval Research.
Rod Badcock and researchers at the Robinson Research Institute, Victoria University, New Zealand, are collaborating with NASA’s Electric Aircraft Technology Roadmap in Wisconsin on superconductivity for electric airliners.
Alongside the X57, NASA is looking other projects for the coming thirty years. The SUGAR (Subsonic Ultra Green Aircraft Research) Volt, a hybrid aircraft being developed by Boeing Research & Technology, uses both jet fuel and batteries, longer wings for lift, and open-rotor engines. It plugs in at the airport, charges its batteries up, and flies its mission. To enable portions of flight with low or zero emissions, electricity is used as a supplement or replacement. Dual-turbine engines would be powered by traditional jet fuel, and at cruising altitude, the system could turn over to electrical power. The wings can fold when landed to accommodate airport gate space. Boeing is looking at a 2030 to 2050 time frame for the SUGAR Volt.
Then there is a fully turboelectric, superconducting aircraft called the N3-X, with its hybrid or blended-wing body. Two wingtip-mounted superconducting electric generators would drive the distributed fans to lower the fuel burn, emissions, and noise. Building on the R&D from the N3-X is the partially turboelectric STARC-ABL, a subsonic commercial aircraft concept with conventional underwing gas turbofan engines powering a ducted aft boundary layer propulsor in the tailcone. Attached to each turbofan is a generator that extracts mechanical power from the fan shaft and converts it to electrical power. Electrical wires send it to a rear-mounted boundary layer ingesting, electrically powered fan. In October NASA awarded Aurora Flight Sciences a contract to perform a comprehensive evaluation of the STARC-ABL design. The turbofans provide 80 percent of thrust during takeoff and 55 percent at the top-of-climb. The rest is done via the aft-fan propulsor located at the end of the aircraft below the tail.
In May 2016, Blaine K. Rawdon and Aaron J. Kutzmann, engineers at Boeing Phantom Works in San Pedro, California, filed a patent application for an electric-powered plane with solar cells covering its wings, including winglets that stick up from the ends. The winglets can be angled more directly into the sunlight, even when the sun is at a low angle, so extending the range.
In 2011, Miguel Sánchez of Madrid, an aeronautics engineer and private pilot, formerly the project engineer and project manager at Airbus, and his friend, electronics engineer Daniel Cristóbal, discovered that the aeronautical industry had still not delivered the answer to preventing accidents caused by gas engine failure. Together the Spaniards created AXTER, and working with Andrés Barrado and researchers at Carlos III University in Madrid, developed a hybrid propulsion system that adds up to 30 kW of combustion engine extras or turbo-boost for short takeoffs, high ascent ratios or compensation of the main engine power loss during the hottest months. By December 2013, AXTER carried out its first flight of an ultralight airplane EC-ZEL with the AX-40S parallel hybrid propulsion system. “Our airfield has a very small runway and the weight of our aircraft is 600kg. During the summer (40°C) it is very difficult to take off. Thanks to our hybrid system we reduced the runway by 70 meters. We launched our product on the market at AERO 2015, by flying from Madrid across the Pyrenees to Friedrichshafen.”
Since then the Spanish system has been installed in a Tecnam P2004 Bravo (EC-ZRE) and a 4-seater Australian Jabiru light aircraft from Casarrubios Airfield, near Toledo. In the future, this new hybrid electric system could prevent 600 accidents, 70 deaths and 24 million euros in losses recorded per year.7
Funded by DARPA and NASA, Seth Kessler and a team at Metis Design Corporation (MDC), a small technical consulting firm in Boston, has developed a microturboalternator which drives a lightweight permanent magnet generator and consumes only one pound of fuel per hour per kilowatt output. This gives it a power source 12–15 times the energy density of Li-Po. The MDC design places the power turbine driving the bypass flow at the front of the combustor rather than at the engine exhaust. A compact recuperator recovers heat from the exhaust and decreases fuel consumption. Given company figures, a 20-kilowatt microturboalternator would weigh under 12 lb. (5 kg) and consume 20 pounds (three gallons) of fuel per hour at full output. With electrical output ranging from under 10 kW to over 100 kW, the microturboaltenator would be ideally suited to the next generation of hybrid light-sport aircraft and UAVs, as well as hybrid road vehicles and stationary power generation.
Sergio Bortoluz of Konner Helicopters in Amaro, Italy, is also equipping his 90 hp TK-150 gas turbine helicopters with a hybrid electric back-up. The hybrid version, called TG-250HY, integrates in the complex turboshaft an electric motor that can deliver 50hp in case of need.
There is retrofitting. Kevin Noertker and a team at Ampaire, housed in the Los Angeles Cleantech Incubator, are developing a process for retrofitting a standard turboprop airplane into one that would operate solely on electric power. Ampaire’s team originates from top institutions including Caltech, Stanford, Penn, USC, Northrop Grumman and SpaceX. A retrofitted six-passenger regional airplane with a range of up to 100 miles would be used for both passenger and cargo flights. The company has also designed an all-electric aircraft called TailWind that will come in two models—the all-electric TailWind-E and the TailWind-H hybrid electric, which is designed for longer-range flights.
Millionaire Martine Rothblatt founded United Therapeutics Corporation in an effort to commercialize a pill for her daughter’s disease, a rare life-threatening form of pulmonary hypertension. She is the founder of Sirius satellite radio and vehicle navigation company GeoStar, launching several satellite communications companies including the first nationwide vehicle location system (GeoStar, 1983), the first private international spacecom project (PanAmSat, 1984), and the first global satellite radio network (WorldSpace, 1990). Owner of 7 Tesla automobiles, Rothblatt decided to electrify a helicopter for the purpose of delivering transplantable organs much more cleanly and quietly. Rothblatt is experimenting with growth of kidneys, hearts and ultimately lungs in laboratories for transplant, in an attempt to solve the problems of supply and rejection. In September 2016, Lung Biotechnology Tier 1, the red Robinson R44 helicopter, retrofitted by Glen Dromgoole of Tier 1 Aviation, with its 200-lb payload, made a five-minute flight at 400 m altitude above Los Alamitos Army Airfield. Five months later, with Rothblatt and Dromgoole at the controls, it increased its duration to 30 minutes at 800 feet and flying at peak speed of 80 knots with 8 percent battery state-of-charge remaining after a safe hover landing. On March 4, 2017, Rothblatt and Ric Webb set a world speed record for electric helicopters of 100 knots at Los Alamitos Army Airfield under an FAA experimental permit for tail number N3115T.
According to another IDTechEx report, “Electric Vehicle Energy Harvesting/ Regeneration 2017–2037,” electric vehicles will make their own electrical energy using daylight, wind, waves and more: energy harvesting for regeneration (EH/R). The report presents several technologies for this: electrodynamic, GaAs photovoltaics, triboelectric, dielectric elastomer nano-generators, thermoelectric and piezoelectric. One example would be solar cloth for electric airships.
Dale Martin Walter-Robinson of Guildford, Connecticut, has invented an in-flight energy-cell regenerative system for electric airplanes. When Walter-Robinson found that the cooling fan in the nose of his electric car was not efficient, he improved it and then tested it in a Cessna 152 for eventual application in electric airplanes. His system works by capturing propeller-blasted air rushing beneath the cowling in flight and converting it to electrical power to recharge on-board batteries, using a special alternator and centrifugal fan that is rounded to reduce drag. This continuously produces 2,000 watts, fed to a series of batteries. The system automatically switches away from fully-charged batteries to feed others, supplying a continuing source of power for the aircraft’s propulsion and on-board electrical systems including a cooling device. It is similar to the Ram Air Turbine (RAT) designed by Alexander Lippisch for the rocket-powered Messerschmitt Me163 Komet in early July 1944. In December 2015, Walter-Robison was awarded World Patent 2015195856 for his system and trademarked the words Eviation and ElectronAir.
Another approach has been taken by a team of 35 scientists and engineers, working at four NASA centers and led by Patricia Loyselle of NASA’s Glenn Research Center in Cleveland, Ohio. The project is called M-SHELLS (for Multifunctional Structures for High-Energy Lightweight Load-bearing Storage), and the quest is for a material that is as strong as today’s aircraft-construction materials, can store large amounts of energy, and can both charge and dispense that energy rapidly.
QinetiX of Memmingen, Germany, is developing their QPD-40 unit in which the controller is integrated in the casing along with the 40 kW engine, with a total weight of 12 kg (26 lb.), so facilitating installation.
In October 2016, France further stepped up its commitment to hybrid-electric airplanes. Led by Xavier Roboam, HARTEC (Hybrid Aircraft, Academic Research on Thermal and Electrical Components) is a €1.5 million, five-year project, involving 6 theses and 2 postdoctorates, whose aim is to identify promising technologies and to develop new tools to reduce the fuel consumption of aircraft and reduce nuisance factors (CO2 and noise on the ground). Part of the European Commission for the Aeronautics Industry under the Clean Sky 2 program, this research will be carried out by the Toulouse laboratory consortium of CIRIMAT, specializing in materials and batteries, by the LAPLACE Laboratory, involved in the field of electrical energy conversion, working together with the Poitevin-based Prime Institute, dedicated to thermal management. The goal is, in particular, to double the power/mass ratio of the machines and their power supply, which will reduce the on-board weight of the aircraft by approximately 1.8 tons, thereby reducing fuel consumption. For a regional flight, fuel consumption would decrease by 3.5 percent.
In 2017, the Netherlands Aerospace Centre (NLR) and Delft University of Technology launched a project called NOVAIR (Novel Aircraft Configurations and Scaled Flight Testing Instrumentation) to design aircraft configurations with hybrid propulsion as part of Europe’s Clean Sky 2 joint undertaking. With this system, a gas turbine motor generating electricity to power an aircraft by electric motors has the potential to reduce fuel consumption by approximately ten percent. As the e-propulsion will be detached from a gas turbine motor, it is possible to position the propulsion on the wing or fuselage in a way that improves the aerodynamic properties of an aircraft. A hybrid aircraft configuration will thus make an extra contribution to reducing aircraft fuel consumption and emissions. The first demonstration model of such an aircraft concept is expected to be tested in 2021.
In southeast Queensland, Australia, Dr. Jason Chaffey and his team at magniX, a subsidiary of Singapore-based Heron Energy, have developed an electric aero engine with a power density of more than 5 kW/kg—more than twice as high as the best conventional motors. MagniX believes that it could eventually achieve power densities of 25 kW/kg—three times higher than modern aircraft engines. Located in Arundel, magniX received a A$2.5 million (U.S. $1.9 million) grant from the Australian government as part of a A$12 million (U.S. $9.1 million) three-year collaborative project—indicative of the significance of the breakthrough. The “magniXmix” combines permanent magnet and superconducting motors and generators, all based on precision placement of the magnetic field. The aim is to maximize the field strength where it is useful and to minimize it where it is not, thus boosting power densities. This in turn reduces the amount of steel in the rotor, and thus its weight, resulting in fast transient responses and the ability either to reverse direction quickly or to switch rapidly from motoring to generating. The project, also involving both the University of Queensland Composites Group and Ferra Engineering in Tingalpa, aims to optimize the design, thermal management and materials needed for the high-power-density motors. In March 2017, magniX began by testing its 50 kg, 250-kilowatt prototype simulating aircraft takeoff and landing procedures to test speed capacity and reliability. Further funding will be needed to commercialize the technology when magniX plans to offer two commercial versions of its motors with lower power densities. One, weighing 210 kg (463 lb.), delivers 150 kW and 1,500 Nm continuous (200 kW and 2,500 Nm peak), with an efficiency of more than 97 percent. The 480 mm/19 in-diameter and 450 mm/17.7 in-long motor has an operating speed of 900–1,000 rpm (with a maximum of more than 2,700 rpm). The other version, aimed at high-speed applications around 4,000 rpm, weighs 220 kg (485 lb.) and can deliver 200 kW and 485 Nm, with an efficiency above 96 percent.8
On February 1 and 2, 2017, an international More Electric Aircraft conference “vers des aéronefs plus électriques” was held at the Palais des Congrès in Bordeaux. The MEA colloquium gained its technological and international credibility in a particularly strong competitive context (German and American competition). This credibility is due to the success of the three previous editions: Toulouse in 2009, Bordeaux in 2012, and Toulouse again in 2015. Their diffusion can only have a positive effect.
At ONERA, the French Aerospace Lab based in Lille, Jean Hermetz is leading a team to develop a DEP aircraft named Ampère. Thirty-two small motors have been mounted on the 2.9 m (10-ft) wing of a 1/5 scale model which was wind tunnel tested between September 2016 and February 2017. The full-scale airplane will be propelled by 40 motors powered by ten fuel cells, one for every four motors. A 4- to 6-passenger flying taxi version of Ampère with a range of 300 miles (500 km) should be ready by 2030. The Ampère model was exhibited at the Paris Air Show in June 2017.
In May 2016, Blaine K. Rawdon and Aaron J. Kutzmann, engineers at Boeing Phantom Works in San Pedro, California, filed a patent application for “Solar Power Airplane” with nine propellers along its staple-shaped frame, which is essentially one giant wing with upturned edges. There is no cockpit and no pilot on board. Instead, the plane is controlled remotely from the ground. Like the Pathfinder (see Chapter Ten), Boeing’s plane is designed with solar panels on its upper side to soak up and store energy for unusually long flights. But the Pathfinder’s relatively flat design made it difficult to absorb sunlight that came in at low angles. To overcome this challenge, Boeing has designed large winglets at each end of the main wing, which should allow the plane to maintain a stable flight path and high altitude while absorbing sunlight even when the sun is low on the horizon. If the design works as Boeing has planned, the plane may be able to collect and store enough energy during the day to sustain flight at night. It may never need to land.9
Another wing format would be based on the Custer Channel Wing, developed from the late 1920s by Willard R. Custer, whereby eight semicircular ducts channeling airflow around the rotating propeller enable extremely short takeoff and landing (STOL) airplanes. Hop Flyt, led by Rob Winston, a U.S. Naval aviator and former lead engineer at Helix Aero, and his wife Lucille, based at Chesapeake Ranch Airport, Maryland, is building a short-range (200 miles) commuter airplane electric version of the Custer Wing, using eight DEP motors. In 2005, Winston designed a Surface Independent Extremely Short Takeoff and Landing (XSTOL) Aircraft (patent 7,487,935) based on the advanced concepts of the combination of an aero-morphing variable incidence wing with an air-cushion landing system.
Norway, with its vast fjords, could well benefit from an electric amphibian. Inspired by the designs of Guenter Poeschel, in 2008 Tomas Broedreskift of EAN (Equator Aircraft Norway) in Oslo, an industrial designer with a passion for gliding, teamed up with Oeyvind Berven to start work on the new EQP2 Xcursion. A 100 kW (approx. 130 hp) Engiro DMG60 generator will power output of the prop, and a Wankel Super Tec (WST) KKM 352 engine running on bio-diesel fuels will produce 57–60 kW of power charging the Kokam batteries, which in turn drive the tail-mounted motor with its custom DUC propeller. All of this is controlled by a single lever in the cockpit, a kind of hybrid FADEC. The P2 Xcursion aircraft is the first aircraft design made by the cooperative EAN (Equator Aircraft Norway SA). The wing uses a NACA laminar flow profile, with a 1.4 deg blended twist. The span is about 10 m dependent on the type of winglets chosen; they are modular and can be exchanged simply. With the flaps extended the aircraft should reach a stall speed of 45 kt, and on cruise should be able to fly comfortably at 130 kt.
The Synergy airplane, its double boxtail configuration designed and patented (U.S. 8657226; 9545993) by John McGinnis of Kalispell, Montana, is a proposed five-seat, single electric engine, kit aircraft. In 1995, McGinnis commercialized the world’s first thermoplastic carbon fiber snowboards and invented several other profitable, high-volume composite production processes. He founded Synergy Aircraft in 2010. The double boxtail arrangement allows a simpler, stronger wing of the minimum induced drag for a given wingspan loading. The two horizontal tails intentionally push down, moving air upward at the wingtip in opposition to wake vortex. To date, a working model of the Synergy has been built and flown. It is planned that the full-scale airplane would use aluminum-air batteries.
Another configuration may be a triplane with a cross-box tail and interconnected winglets. In the 1980s, Trevor Cloughley had developed ASVEC to design and build innovative UAVs. Now his son Neil, based near Bristol, has started up Faradair (after British scientist Faraday) to develop the 5-passenger BEHA (Bio-Electric Hybrid Aircraft). Power will come from a biofuel-burning 200 hp Hybraero H600, designed and built by Prodrive Motorsports, coupled to two electric motors for takeoff and landing. BEHA’s three wings are positively staggered (top wing foremost, lowest wing rearmost) with ample space for solar cells. Annular shrouding of the pusher propeller at the stern enables vectoring thrust sideways or up and down. Faradair’s Cloughley plans to have the BEHA in service by 2020 to revive Britain’s regional air services so popular during the interwar years.
Vision has been conceived by English inventor and pilot Michael Waters. Waters has built a number of different types of aircraft and also flown over 200 different aircraft including general aviation, experimental, low-wing, high-wing, mid-wing, bush-planes, seaplanes, hang-gliders, ultralights, paragliders, microlights, biplanes, aerobatic, tail-draggers, trikes, twins, autogyros, and helicopters. He was also a competition sailplane pilot for over 12 years. The Vision’s fuselage is off-the-shelf, the controls are off-the-shelf technology, the motors are off-the-shelf, and now that energy storage has reached a certain milestone, Waters claims that he has what he needs to put all these things together. The Vision would use 8 electric motors, 4 for thrust and 4 for rotor tilt, which allows maximum performance and flexibility. There are no control surfaces or conventional wings, even though the ducted fan shrouds are, in fact, highly efficient circular wings.
Following experience with over 600 remote-controlled extremely maneuverable working models in the range of 25 to 50 feet (7 to 15 m), a team led by former schoolteacher Daniel Geery of Salt Lake City has developed the ultra-efficient Hyperblimp, using various envelope materials, propulsion from Li-Po batteries, solar panels, and eventually fuel cells (separately or in combination). Always on the lookout for advanced materials, these ships already work as short range UAV platforms. The Hyperblimp’s rear prop, mounted to move in all directions, propels the airship with great responsiveness, including vertical takeoffs and landings. Though presently on hold, Geery’s next large goal is a 24/7 high-speed solar version to fly by remote control around the world. The technology is all there, as this company works on more funding and locating knowledgeable, interested personnel.
For his final year project for Transport Design BA (Hons) in 2013 at the University of Huddersfield, England, Mac Byres conceived of a luxury airship called the Aether with Vertical Electric Take Off and Landing propulsion. Dining areas feature giant windows, and the inside has the mixed feel of a modern office complex and an upscale hotel bar. Large bedrooms feature their own sitting areas and the windows extend to right behind the pillows, so passengers can wake up from their falling dreams and find themselves face to face with clouds. Byres has also designed an airship called Hemera, designed to land solely on water, which he aims to unveil at Expo 2020 in Dubai.
Andrew Winch Designs of Barnes, London, which works on private jets and super-yachts, has conceived of the Halo, a residential airship with a living area the size of four soccer fields comprising 20 bedrooms, a spa, a cinema and a ballroom. A 266-ft/81-m-long prototype made a test flight four years ago and received certification by the U.S. Federal Aviation Administration. It is slated to be capable of vertical takeoff and landing, and be eight times more fuel efficient than a jet plane with a range of 6,000 miles (10,000 km).
If an airplane can morph its wings like a bird, then it will need less electrical power. In 1905, Orville Wright steered the brothers’ pioneering airplane by lying prone in a saddle and twisting the tips of the plane’s fabric-and-wood wings with a sway of his hips. A century later, from 1996 to 2005, the U.S. Air Force had been collaborating with NASA to develop an Active Aeroelastic Wing, which used the power of the airstream to twist itself for better roll control during high-speed maneuvers. But that technology was intended only for fighter jets, and the program eventually lost support. From 2010, two research projects continued to investigate this potential. With €51 million in support from the European Union, Smart Aircraft Structures (Saristu) is coordinated by Piet Christof Woelcken of Airbus and bringing together 64 partners from 16 European countries. This resulted in the design of a morphing flap for an imaginary 90-seat airliner of the future in which just the final 50 cm (20 in) of the flap is adaptive—and performed extensive wind tunnel tests on a 4.9-m/16-ft-long section of it in a massive Moscow wind tunnel. The morphing part had 10 electric motor-driven actuators that were used to change the profile of the flap’s adaptive section in different flight conditions. In the USA, the aerospace firm Flexsys of Ann Arbor, Michigan, worked with NASA and the Air Force Research Laboratory (AFRL) and came up with a wing surface called FlexFoil that is able to shift shape in midflight, thanks to seamless bendable, twistable materials. The testing has involved 22 research flights that have been completed over the last six months at the Armstrong Flight Research Center in California. The advanced lightweight materials used to build the flexible wings will not only reduce the weight of wing structures, but allow engineers to tailor them to improve fuel economy. The technology can be retrofitted to existing airplanes.
NASA is taking its investigation of aeroservoelasticity and flutter suppression into the sky with the X-56A, nicknamed “Buckeye,” a 7.5-foot drone with a 28-foot wingspan, with highly flexible, lightweight wings built by Lockheed Martin. From November 2017, test flights have taken place from the Armstrong facility.
Going one further, NASA’s Mission Adaptive Digital Composite Aerostructure Technologies (MADCAT)—comprised of researchers and students from MIT; University of California, Davis; University of California, Berkeley; University of California, Santa Cruz; and Cornell University—has developed a morphing aircraft wing. This is made of a lattice of tiny, lightweight subunits that robots could assemble. The subunits are covered by overlapping parts reminiscent of scales or feathers. The wing components are made from advanced carbon-fiber composite materials. Computers and motors can help change the shape of the wing for better efficiency even while an aircraft is flying. The new wings could also be manufactured using much simpler and more streamlined processes. In 2016, following tests in a 12-foot tunnel at NASA Langley, a demonstrator was successfully demonstrated at NASA Crows Landing facility in Modesto, California. The MADCAT demonstrator utilizes a wing-twist actuation mechanism that generates a linear span-wise wing-morphing capability, thereby producing both lateral and longitudinal directional control authority. In addition, the aerodynamic lift/drag can be modulated by varying wing-tip twist oscillation frequency. During the flight test, the pilot reported that, overall, MADCAT flew quite easily with sufficient control authority, and did not seem to fly any differently from conventional aircraft with ailerons. Additional flight tests are planned with instrumentation of an advanced onboard video camera and sensing devices.10
Professor Bharath Ganapathisubramani and Southampton University’s Aerodynamics and Flight Mechanics Group, working with Dr. Rafael Palacios and Imperial College London’s Department of Aeronautics, have developed a 50-cm (19.7-inch)-wide working seaplane drone with its wings working like artificial muscles, changing their shape in response to physical forces they experience. They use electroactive material that changes shape when an electric current is passed through the polymers. The drone is powered by rotor engines on the front, but as the voltage alters the shape of the wing membranes, the aerodynamic characteristics can be altered as the drone flies. The design biomimics the wing movements of bats.11
Another biomimic approach has been taken with the monocopter, first tested by Papin and Rouilly in 1913. In 2009, almost a century later, students from the University of Maryland’s Clark School of Engineering unveiled their samara (maple seed)-inspired micro air vehicle, which was billed as “the world’s first controllable robotic samara monocopter.” In August 2011, at the Association for Unmanned Vehicle Systems international conference in Washington, D.C., Lockheed Martin performed the first public flight of its Samarai Flyer, a disc-like unit that contains its battery and electronics, joined to a single wing with a propeller mounted at the far end. The Samarai can take off from and land on the ground, or be launched by being thrown into the air like a boomerang. It is 16 inches (40.6 cm) long, weighs less than half a pound (around 227 grams), and has only two moving parts, so it lends itself to being stuffed in a backpack, then pulled out for use. A team of students from the Singapore University of Technology and Design, again inspired by the samara or maple seed, have developed their Transformable HOvering Rotorcraft (THOR) or two-winged monocopter. The THOR’s opposing wings are mounted at right angles to each other and rotate into alignment when making the transition from helicopter-style hover to fixed-wing-style cruising. The students have also created a passive system to shuffle weight around based on flight mode. When the craft switches from hovering vehicle to fixed-wing aircraft, or vice versa, the centrifugal force involved in the switch is used to move the ballast into a position to keep the aircraft balanced.
Boeing’s 777X airliner, forthcoming in 2020, will not be a morphing plane per se, but it will change shape on landing. The 777X will have a 3.5 m long (11.5-ft) wingtip that is folded up vertically when the plane is on the stand or taxiing, but is locked down for flight.
In England, in March 2016, Airport Parking and Hotels Ltd. unveiled plans for a new hybrid-electric commercial aircraft, which it said would carry as many passengers as a jumbo jet. The idea is the brainchild of Adam Omar—an aircraft design Ph.D. student at Imperial College, London. The proposed hybrid-electric aircraft with its blended-wing body (BWB) design would use small biofuel engines turning six electric fans, positioned in clusters along the back of the craft rather than mounted on the wings. This positioning would help to suck in the thick layer of air around the aircraft body to reduce drag. Omar’s proposal also takes advantage of superconductivity—a phenomenon of zero electrical resistance that occurs when certain materials are cooled below a critical temperature. This would mean that no electricity is lost due to friction when passing through the plane’s power system, leading to a reduction in fuel requirements. Boeing Microlattice—a metal that is considered to be the world’s lightest material—would be used across large parts of seating, flooring and walls to contribute to even greater fuel efficiency.
Oscar Viñals, a nuclear engineer and CGI designer from Barcelona, has projected his concepts beyond the year 2030. The AWWA-QG Progress Eagle design uses six hydrogen fuel engines—one to drive a central screw-type engine at the rear to achieve the thrust needed to take off. Once it reaches the right altitude, the central engine turns off and starts to generate electricity from the air flowing through it, powering five superconductive engines. It also has solar panels on the wings and a rear engine that doubles as a wind turbine. The three-deck airplane with its 314-ft (96 m) wingspan would have the capacity for more than 800 passengers along with beds and offices for crew. On landing, wing sections could be folded to make the aircraft easier to maneuver in airports. Excess energy stored in the aircraft’s batteries could be recovered by special electrical storage trucks on the ground when it lands. According to Viñals, the aircraft would be made from lightweight materials such carbon fiber, aluminum, titanium and ceramics. The Spanish engineer has even gone beyond this bold concept with his Flash Falcon, capable of carrying 250 passengers at Mach 3, in an airframe more than 130 ft. (39 m) longer than a Concorde and with a wingspan twice as wide. Its engines would even be able to tilt up to 20 degrees to help the aircraft take off and land like a helicopter. Its propulsion system would use a nuclear fusion reactor pumping energy to its six electric engines.
Of this second concept, Simon Weeks of the Aerospace Technology Institute warns there are some major issues that come with putting a fission reactor on an airplane. Not only would it require a “closed loop system”—a reactor that reuses the waste fuel—but it would also need large amounts of heavy shielding. Nuclear fission produces a lot of neutrons which can be very harmful.12
Inspired by airships and paragliding sports, the Sky Voyage concept, designed by Jet Shao of Yanko Design, aims to expand traffic networks to the sky by utilizing airspace to relieve urban traffic congestion on the ground. The hybrid glider/airship would take off vertically by inflating the gasbag in an upright position. Once airborne, the craft can be maneuvered through the wind with assistance from a hydrogen fuel cell–powered turbine engine.
Daphnis Fournier, a Paris designer, has developed what he calls the Ecologic Aircraft, an electric passenger plane using an inflatable structure above the main cabin that contains flexible photovoltaic panels to collect solar energy while flying above the clouds. For efficiency during takeoff (when the most power is lost) the “balloon” remains flat, inflating only after reaching a maximum altitude. Considering most of energy of a plane flight is spent on taking off, its balloon does not consume any energy of fuel for taking off. Fournier’s study suggests that this 65-m (210-ft) plane can transport up to 300 passengers. It is reminiscent of a design presented in the 19th century.
There are some free spirits whose thinking goes beyond conventional battery technology. Consultant Luke Workman, who had already come up with innovative lithium technology for Zero Motorcycles in Scotts Valley, California, is one of these. He has reasoned that instead of packaging cells with heavy lithium and aluminum, the wings of a large airliner could become the battery itself, using a composite sandwich of aluminum and copper. In this way, the entire cells are basically in contact with one another, conducting through their whole surface plane, instead of out through tabs. Workman calculates that using such a system would obtain around 13,300 amp hours per 0.2 mm of thickness for each foil layer. Nine hundred layers would then supply 3.3 kV nominal and around 44 megawatt hours of battery storage. The aircraft would have a total weight of approximately 104,000 kg, with an extraordinarily high percentage of that mass being active material; hence lower conduction losses would give 423 watt hours per kilo and a serious flight range. This is provided there are 300 m2 (3,200 ft2) of wing area, with a foil core about 20 cm (8 in.) thick and 1 cm current conductor plates on the top and bottom. The bigger the battery, the more efficient it becomes.
Arthur Léopold Léger and a team at Elixir Aircraft in the Industrial Zone of Périgny in La Rochelle, France, are adapting the use of boatbuilding techniques to airplane construction. The carbon wing with a span of 7.8 m (25.6 ft) has been made as a single piece and its rudders and fuselage are also one shot, eliminating riveting and reducing overall weight. Partners include Dassault Systèmes for electronics and software, C3 Technologies for composite structures and parts, and Simair (aeronautical equipment manufacturer) for metal parts.
Also in France, the Space Agency CNES is investigating the use of solar sails positioned between the nacelle of a stratospheric balloon to study the radiation of our galaxy from an altitude of 45,000 km (28,000 mi) where wind and oxygen are weak. The sails would use a patented high-efficiency ultralight flexible photovoltaic film developed by sailmaker Alain Janet of Solar Cloth System in Mandelieu-la-Napoule, and the orientation of the balloon will be made by two small electric motors.
One of the weak points of a solar-powered airplane might be a lightning strike during a storm. In 2016, Bertrand Rives and his team at Airbus Group SAS obtained a patent whereby the airplane fuselage, nacelles and wings would be covered by a layer of flexible polymer, a photovoltaic film, and a protective skin.
The ghost of pioneer electro-modeler Fred Militky (see Chapter Four) has been walking abroad in the form of the twin pusher-engined Hy-Fly he designed and that was marketed by Graupner in 1973. In 2014, forty years later, Gérard Risbourg, a veteran aeromodeler and multiple RC glider champion at the Aero Club Saint Remy of Provence based at the Aerodrome of Romanin les Alpilles, was invited to work with the European Association for the Development of Gliding (AEDEVV), Dassault Aviation and research lecturers and students at the ISAE Group (Higher Institute of Aeronautics and Space Group made up of SUPAERO, ENSMA, ESTACA and the Air School). Their joint goal has been to produce a French two-seater electric glider for pilot training. On February 21, 2016, the 8.80-meter-wide RC Euroglider scale model was loaded with four Mobius ActionCam cameras for varying angles. After ten minutes of flying above the Alpilles, the ASH 25 configuration completed its presentation flight without hindrance. Working groups are now dedicated to the preparation of the BEV (flying test bench); this will be used during the second half of 2018 to test the experimental class for the twin-engine configuration which will be presented to the DGAC, as well as for the validation of the onboard energy chain and its flight control systems. The Euroglider will be classified CS-22 and not ULM. At the same time, the AEDEVV, in accordance with its plan of action, will undertake contacts with potential partners for industrialization. With the Euroglider, the association wants to generate a production line as far as possible in France. The objective is to fly a first prototype in 2020.
If an airplane can be made feather-light and ultra-strong, it will need less energy for propulsion. In 2004, Konstantin Novoselov and team isolated the 2-dimensional material graphene, identified many of its extraordinary properties, and subsequently described other 2-dimensional materials. Their work is of such importance that both were awarded the 2010 Nobel Prize in Physics, knighted by the Queen and by the King of the Netherlands, and over the past decade have been showered with numerous honors and awards. A decade later, researchers at MIT have designed and tested Porous 36D forms of graphene, made by compressing and fusing flakes of graphene, a two-dimensional form of carbon. The new material, a sponge-like configuration with a density of just 5 percent, can have a strength 10 times that of steel. The team was led by Markus Buehler, the head of MIT’s Department of Civil and Environmental Engineering (CEE), and the McAfee Professor of Engineering, Zhao Qin, a CEE research scientist.13
UCLA researchers have developed a new grapheme-based material, holey graphene, enabling production of a capacitor that has unparalleled energy density, 10 times that of currently available supercapacitors. Holey graphene features superior electrical conductivity, exceptional mechanical flexibility, and unique hierarchical porosity, making it ideal for use as a cathode in electrochemical capacitors and batteries. These characteristics may give some credence to claims that a 10,000 Farad ultra-supercapacitor, smaller than a paperback book, has been produced—a major development if true and one with revolutionary potential for electric propulsion. Over the following decade, this is likely to have two far-reaching effects: firstly, it will be possible to store large amounts of electricity more efficiently generated from solar energy by more efficient solar panels, and secondly, the range, recharge time and reliability of electric vehicles (EVs) of all descriptions will be vastly improved and much cheaper.
The miniaturization of digital electronics over the past half-century has followed a similar exponential trend, with the size of transistor gates, used in computers, reducing from approximately 1,000 nanometers in 1970 to 23 nanometers today. With the advent of transistors made of graphene showing great promise, this is expected to fall further to about 7 nanometers by 2025—approximately the size of a human red blood cell. The increase in computational power and decrease in circuit size, when combined with progress made with 3D printing, will mean that tiny integrated computers powerful enough to control an aircraft will be possible in the next decade. Systems using a biologically inspired digital “nervous system” with receptors arranged over the aircraft to sense forces, temperatures, and airflow states are expected to drastically improve the energy efficiency of an airplane. In the future, they could even be paired with software and hardware mechanisms to change the shape of the aircraft to make it extra efficient.
In April 2016, Amazon Technologies Inc. obtained a patent for an “airborne fulfillment center” (AFC) or warehouse and drone airport, hanging from a blimp. It will hover at 45,000 feet (14,000 m), so that its delivery drones will glide down with Amazon packages, delivering goods within minutes of when they are ordered. Instead of having the empty drones fly all the way back up to the AFC, they instead would meet up with smaller restocking blimps for the flight back up. Such AFCs would be located above festivals or sporting events and smaller airships could act as shuttles taking drones, people and supplies to the warehouse.14
On December 29, 2016, Gregory Karl Lisso and the team at Amazon Technologies Inc. obtained another patent for a “Collective Unmanned Aerial Vehicle” (CUAV) configuration, capable of lifting virtually any size, weight, or quantity of items, and flying greater distances than smaller drones. Individual modules could detach from the collective drone body once they were no longer required, and operate independently to deliver smaller burdens, and would also be able to travel longer distances. Another Amazon patent, received December 20, 2016, addresses countermeasures to protect airborne drones against threats from hackers and from “malicious persons” armed with bows and arrows.15
The same month, Japanese mobile phone giant NTT DoCoMo, Inc., in a continuing quest to create new business, unveiled the “world’s first spherical drone display,” a drone inside an omnidirectional spherical frame, with 8 curved LED strips that spin rapidly to create the illusion of a spherical screen. The “resolution” is 144 pixels high and 136 pixels around the circumference with a maximum diameter of 88 cm. The highly maneuverable 4 kg drone can be operated virtually anywhere, including venues such as concert halls or arenas where it can fly around as part of a performance or deliver advertising messages and event information. Following a demonstration of the display at the Digital Content Expo in October 2017 at the Miraikan in Odaiba, DoCoMo aims to commercialize its product from March 2019.
In July 2016, Airbus filed a patent for a type of carrier aircraft, known as a high-altitude platform system, that could transport heavier solar-powered planes with more equipment up above 60,000 feet (18,000 m) and deposit them there. The advantage to this strategy is that the aircraft deposited by the carrier platform would not need the thrust capabilities required to reach the stratosphere on its own, allowing it to carry more science and communications payloads, which could remain airborne for months or even years.
Defense specialist BAE Systems is planning to chemically “grow” drones in large vats. The UK-based defense company is working with Leroy “Lee” Cronin, Regius Chair of Chemistry in the School of Chemistry at the University of Glasgow, one of the developers of the Chemputer. While a 3D printer physically makes the parts for a machine, the “chemputer” speeds up the chemical reactions from the molecular level. This would artificially emulate a life form, such as bumblebee, using a gel. Once grown, the drone would most likely combine a fuel-cell with trickle recharge solar energy. So far Cronin and his team are working in centimeter lengths, but later grown drones of several meters could be created from chemical compounds in weeks, rather than years. British warplanes are already flying with parts made from a 3D printer. The date for the first chemdrones is far into the future.16
In December 2016, Warren East, the CEO of Rolls-Royce, stated, “There’s a lot of chatter about hybrid electric flight, not just little airplanes but regional airplanes. I’m convinced we will see these things happen sooner rather than later. There is a race on. We need to be ready by 2020 because people are talking about entry into service by 2030.”17
Pierpaolo Lazzarini of the design company Jet Capsule in Naples has conceived a UFO-looking two-seater electric ocotocopter taxi called the IFO, or Identified Flying Object. On land, the carbon-fiber IFO, with its 4.70-m (15-ft) diameter, would stand 10 feet (3 m) high on six fold-in extendable legs. The doors of the cockpit capsule swing upwards, enabling passengers to climb in and out using detachable footbridges; or they can enter from underneath through an elevator that descends from the vehicle’s main body. IFO would have a battery life of 70 minutes and could hit a top speed of 120 mph (190 kph). It is equipped with an emergency parachute. Lazzarini has also designed an enclosed 740bhp diesel engined 13 passenger waterjet ski boat he calls a mini-yacht, with an all-electric option. One recalls Nikola Tesla’s circular electric airplane concept of 1911, while Lazzarini Design’s motto is “Think about the future, never forget the past.”
Then there is the lighter-than-air drone, one of which is the PLIMP. As identical twins growing up in Washington in the 1970s, James C. and Joel D. Egan flew model gliders and threw weighted balloons. While James became a prominent attorney in Seattle, the twins continued their passion for aviation. In 2013 they applied for a patent for a “plummet-proof” plane-blimp hybrid aircraft they trademarked as PLIMP and started up Egan Airships to promote it, first as a drone and later as a passenger aircraft. Weighing under 55 lb. (25 kg), the 28-ft. (8.5-m) prototype PLIMP is an airplane body attached to a helium-filled blimp, electrically powered by two housed lateral propellers that can rotate and travel in any direction. It can deliver forward speeds of more than 40 mph (64 kph) with at least an hour of flight time and offers an unpowered descent speed of only 9.5 mph (15 kph) should engines fail, as well as smooth flight and acceleration for nearly stable platform filming. The PLIMP was presented at Interdrone 2017 in Las Vegas. It is strangely reminiscent of ideas conceived in France in the 1890s.
Alongside aircraft using electricity, there are also aircraft that will be used to regularly generate electricity. It was in 1978 that Miles L. Loyd at the Lawrence Livermore National Laboratory, Livermore, California, applied for a patent (U.S. 4251040) for large-scale wind power production by means of aerodynamically efficient kites. Based on aircraft construction, these kites would fly transverse to the wind at high speed. The lift produced at this speed is sufficient to both support the kite and generate power. This would come to be known as crosswind kite power.
Twenty-eight years later, in 2006, Australian inventor Saul Griffith and kite designer Don Montague teamed up to build a similar type of generator, naming their company after the Hawaiian word for wind, Makani. Funded by DARPA, they built a 20-kilowatt turbine-carrying glider and flew it in 2009; the higher the altitudes, where the winds are stronger and more reliable, the more electrical energy is harvested. By 2011 Makani was testing developed models from the tarmac of the former Alameda Naval Air Station. In 2013 Google bought Makani. Although facing significant regulatory obstacles including wildlife preservation issues as well as the technological challenges, they were eventually able to produce their eighth generation prototype designed by Damon Vander Lind, a 600-kW carbon-fiber energy kite with eight rotors, each 7.5 ft (2.3 m) in diameter, and the 85-ft (26-m) wingspan of a small jet airliner. The turbine-driven generators would also function as motor-driven propellers in a powered flight mode, which could be used for vertical takeoff and landing. A perch adapted to facilitate the takeoff and landing would pivot such that the pilot is oriented towards the tension direction of the tether. On May 18, 2017, the Makani 600-kW kite produced power for the first time.
Alongside this is the European Ampyx tethered glider, the 250 kW AP3 power-plane, with its 12-m (40-ft) wingspan, developed since 2006 by a team led by Richard Ruiterkamp of TU Delft, Netherlands. Funded by the European Commission and E.ON, with their control center near Winchelsea, England, the team is conducting tests up to an altitude of 450 m (1,476 ft) in Mayo County, Ireland. Ampyx announced that a 2 mW commercial version would be available by 2020.
In southern Norway at Lista airfield, since 2008, Kitemill has been testing their Spark prototype airplane to harvest 30 to 100 kW of airborne wind energy at altitudes up 1,500 m (1 mi). Among the team are electrical power engineer and yachtsman Olav Aleksander Bu, and Jon Gjerde, a brewer and former world champion in acrobatic gliding.
Another approach is with a tethered aerostat floating at a great height above the earth without moving, but remaining stationed where the strong winds passing through its rotors generate electricity. In late 1979 Charles M. Fry and Henry W. Hise conceived and patented such a device (U.S. 4165468 A). Again the principle has been taken up thirty years later by aeronautical and astronautical engineer Ben Glass while conducting research on compact, efficient turbomachinery at the Massachusetts Institute of Technology’s Gas Turbine Lab. Glass conceived and patented a ring-like shroud with an airfoil cross-section filled with lighter-than-air helium gas to use a lightweight wind-harvesting electroturbine. Glass co-founded a start-up, Altaeros Energies, at Greentown Labs, a leading clean technology incubator located in Somerville, Massachusetts. They have built and tested BAT (Buoyant Airborne Turbine), or “Super Tower,” in partnership with the Alaska Energy Authority; it resembled the stern end of a conventional airship. The Alaska Project will deploy the BAT at a height of 1,000 feet (305 m) above ground, over the community of Fairbanks, Alaska, for 18 months, a height that will break the world record for the highest wind turbine in the world and also send down consistent, low-cost energy for the remote power and micro-grid market. Such aircraft have the potential harvest of 100kW of electricity, while others may be beaming the Internet to 4.5 billion people still waiting for it.
Although this book covers more than a century of electric aircraft, current development is happening at a fast pace.
The cruise wingtip motors that will power NASA’s first fully electric X57 Maxwell airplane are being tested on the ground. Passing through various modifications, the fifth motor will undergo testing on Airvolt at its full operational capability and will then be taken apart to have its components inspected as part of what’s called a “destructive inspection.” The state of the bearings, rotor and magnets will be observed and analyzed to see how healthy they are.
Boeing HorizonX, working with Zunum, has taken a stake in battery start-up Cuberg, based in Berkeley, California. Cuberg’s high energy, dense lithium-metal anode, high-energy cathode battery components are lighter and less flammable compared to current battery technology. It has also invested in Near Earth Autonomy of Pittsburgh, a company that focuses on technologies that enable reliable autonomous flight. Boeing is also continuing to test more than 30 new technologies aboard ecoDemonstrator, a FedEx-owned 777 freighter, equipped with Safran Electrical & Power’s more electric technology.
The famous 1919 England to Australia Great Air Race (30 days/18,000 km) is to be re-created but this time for electric aircraft. The race to be held in September 2019 will begin at Biggin Hill Airport in south East London and end in Darwin.
EViation of Israel has entered into a battery supply deal with Kokam to provide energy for their nine-passenger Alice aircraft. The 900 kWh battery pack should give Alice an autonomy of 650 miles (1,047 miles). The battery will have 9,400 cells distributed throughout the aircraft including the ceiling, floor and wings, weighing 3.8 tons, or 60 percent of the maximum takeoff weight. EViation aims to begin service in 2021.
Israel Aerospace Industries (IAI) is to develop an all-electric aircraft, an initial prototype of which will fly in around three years. Range will be about 500 nm (926 km).
Daan Moreels and the team at Magnax at Kortrijk, Belgium, working in close collaboration with Ghent University on next-generation axial flux direct-drive electric motor and generator technology for aircraft and drones, has won European funding in the ultra-competitive Horizon 2020 SME instrument program.
A report by MarketsandMarkets projects that the aircraft battery market will grow from an estimated U.S. $475 million in 2017 to U.S. $667.8 million by 2022.
S. Yokoyama, pilot for Aircraft Olympos, Ltd., has been test flying a conventional solar-powered airplane weighing 86 kg (189 lbs.) on only 2.2 kW above Takikawa SkyPark on the large island of Hokaido, Japan.
In March Pipistrel completed delivery of another four Pipistrel ALPHA Electro aircraft to Calstart in Fresno, California. Following certification, these aircraft are entering service as flight training aircraft in the local areas of Reedley and Mendota, making the first electric aircraft training base in the world.
Following a demonstration of its eAircaft in Chicago on March 27, 2018, Siemens USA CEO Lisa Davis projected that e-propulsion will be “the standard solution for all aircraft segments” by 2050.
California-based Joby, developing its 16-prop VTOL flying taxi, has received $100 million (£70 million) in funding from a group of investors led by Toyota, JetBlue and Intel. On January 31, 2018, Airbus’s A3 Vahana prototype made its maiden 53-second, five-meter pilotless flight from Pendleton in northern California. André Borschberg’s Hangar 55 (H55) has been awarded first-round funding by U.S. venture capital firm Nano-Dimension to develop an electric air taxi.
The EHANG 184 quadcopter has achieved a series of manned flight tests in Canton, carrying one and two passengers, including many Guangzhou government officials. In all, about forty people have been carried, not counting the thousands of pilotless test flights. German automobile maker Porsche, already involved with the Mission-E Cross Turismo sportscar with 310 miles on a charge and 800-volt DC fast-chargers, is planning a flying passenger drone. Audi has further invested in the Airbus/Italdesign air taxi program, Pop.Up Next.
Google co-founder Larry Page’s autonomous all-electric two-seater air taxi prototype, developed by a team led by Fred Reid at Zephyr Airworks Cora (N301XZ), has been making test flights over Christchurch, New Zealand.
Bye Aerospace has raised more than $5 million in a Series C financing round led by Galileo Global Securities and Ashanti Capital. On April 10, 2018, John Penney took Sun Flyer 2 on its maiden flight from the Centennial Airport in Englewood, Colorado. Sun Flyer is powered by EPS equipment including battery modules, battery management unit, and power distribution unit.
China’s RX1E-A light electric monoplane has been testing its two-hour flight range, while preparing its larger four-seater version.
UK-based Samad Aerospace, led by Seyed Mohseni, is developing the Starling Jet, the world’s first hybrid-electric business aircraft capable of vertical takeoff and landing, and of transporting ten passengers at 460 mph between 900 and 1,500 miles. With provisional orders placed, first deliveries are scheduled for 2024.
Electric aircraft startup Wright Electric has teamed up with Jetex, a flight support company from Dubai. The proposed design they are working on with Wright Electric aims for a range of 540 km or 333 miles, which would enable passengers to fly from Dubai to Muscat or Malaga to Casablanca on a single charge.
Thales Alenia Space is using the digital integration of the most advanced manufacturing technologies, including augmented and virtual reality and the robotic assembly of panels to prepare the Stratobus demonstrator for late 2018.
DJI’s 300gm Spark, its tiniest drone yet, is the first that can be controlled by hand gestures. If a user simply frames her face with her fingers, the hovering Spark will snap a 12-megapixel selfie.
In March, 180 U.S. Marines at Camp Pendleton, California, were training with prototype 7.5-lb. Drone Killer lasers with a two-mile range depending on visibility. They are built by IXI Technology at Yorba Linda.
Yates Electrospace has patented Silent Arrow® ER-700 (Electric, Reusable, 700 lbs. payload) cargo delivery drone product line that allows persistent operations from improvised airstrips as well as via airdrop from a variety of fixed and rotary-wing aircraft. YEC has been contracted by the U.S. government to build and fly ten of its tandem-wing Silent Arrows.
Following Hurricane Maria, workers from Duke Energy in North Carolina have been using five AceCore’s Zoe quadcopters to locate and repair fallen power lines across Puerto Rico.
To become the world’s first 100 percent solar-powered airport, Cochin International Airport Limited (CIAL), southwest India, started with a 12-megawatt project which expanded to 15.5 megawatts. The airport will eventually increase its capacity to 40 megawatts, including a solar-powered carport. CIAL is set to help Ghana take this clean energy path as well at its Kotoka International Airport at Accra, Kumasi International Airport, and the Navrongo Domestic Airport.
The state-run Norwegian aviation firm Avinor—which runs 45 airports in Norway—is planning to embrace electric aircraft as soon as they hit the market. In Oslo, Norwegian firms Haptic Architects and Nordic Office of Architecture have aimed higher, seeking to design Aerotropolis, the world’s first energy-positive airport city, for the Norwegian capital for both electric planes and driverless cars. Construction of the Oslo Airport City is expected to begin in 2019, with the first buildings completed in 2022.
Could reports in ancient documents provide the solution for future electric aircraft? For some concepts we need to tread very carefully. Telekinesis is moving objects while levitation is making the human body hover, both through mind power alone. The “Vimāna,” a flying palace or chariot as described in Hindu Yogic texts and Sanskrit epics, was controlled by the mind. From the ancient accounts found in the Sanskrit epic The Mahabharata, we read that a Vimāna measured twelve cubits in circumference, with four strong wheels. Their method of propulsion was “anti-gravitational.” It was based upon a system analogous to that of “laghima,” the unknown power of the ego existing in man’s physiological makeup, “a centrifugal force strong enough to counteract all gravitational pull.”
In 1895, on Chowpatty beach near the city of Mumbai (Bombay, Maharashtra, India), Shivkar Bapuji Talpade, a 30-year-old technical instructor in the art and craft department of Sir Jamsetjee Jeejeebhoy School of Art, with a passion for ancient Sanskrit manuscripts, is reported to have proved that heavier-than-air flight was indeed possible. While carefully researching the descriptions of Vimāna as recorded in ancient Indian scripts, the Rigvedādic Bhāshya Bhumikā and Rigved and Yajurveda Bhāshya, Talpade also read newspaper reports about the unsuccessful attempts of aviation pioneers such as Thomas Alva Edison or Hiram Maxim’s captive steam-driven aircraft as described in Chapter Two of this book. Taking the guidance of Vedic Acharyas from Karnataka, he built his own cylindrical-shaped aircraft, or Vimāna, which he called Marutsakhā, derived from the Sanskrit Marut (“air” or “stream”) and sakhā (“friend”), which together mean “Friend of wind,” and then test-flew it from the beach in Mumbai, reaching an estimated altitude of 1,500 ft. (457 m) before dropping back down to the sand. According to K.R.N. Swamy, “a curious scholarly audience headed by a famous Indian judge and a nationalist, Mahadeva Govinda Ranade and H. H. Sayaji Rao Gaekwad witnessed the event.”18 After Chowpatty, Talpade tried to raise funds to build another aircraft. He unsuccessfully asked for funds from the then Maharaja of Baroda, and there is even one recorded instance of his appealing to a group of businessmen in Ahmedabad. He died in 1917. Kindly analysis of Talpade’s device suggest that he was using a “Vedic Ion design,” apparently a concept similar to electric propulsion. More recently NASA has researched the Shuttle’s ability to use solar electric propulsion—solar power combined with mercury bombardment thrusters to deliver 600 kW.
E2 Lange’s experimental fuel-cell craft heads into the future (courtesy Large Aviation GmbH).
In the 1970s, Israeli Uri Geller became the world’s best-known psychic and made millions traveling the world demonstrating his claimed psychokinetic abilities, including bending spoons with his mind. One test was performed as Geller flew across the USA in an aircraft, reportedly using his mind to mend broken watches on the ground.
In 2009 a “telepathic” microchip that enables paraplegics to control computers was developed by Dr. Jon Spratley, a British scientist who assembled it while studying for a Ph.D. at Birmingham University. The chip is implanted onto the surface of the brain, where it monitors electronic “thought” pulses. It means paraplegics, amputees or those with motor neurone disease, such as the late Stephen Hawking, could be able to operate light switches, PCs and even cars by the power of thought alone.19 In 2013, Bin He and researchers at the University of Minnesota revealed a drone that can be controlled merely by thought. Published in the Journal of Neuro Engineering, the report of the project has implications in everything from unmanned vehicles to paraplegic mobility. To control the basic Parrot AR Drone, the “pilot” wears an electrode cap and controls takeoff, turning and landing.20 In 2016, Panagiotis Artemiadis and a team at the Human-Oriented Robotics and Control Lab at Arizona State University had progressed to mind-controlling small swarms of robotic drones using the human brain.21
Conception of Lilium parking in 2020.
Parallel researches had been made for full-scale aircraft. In May 2014, a team of researchers from the Technische Universität München and the TU Berlin in Germany, led by Professor Florian Holzapfel, developed the technology to fly full-scale aircraft with thoughts alone. Seven subjects wearing a cap connected to EEG electrodes (one with no cockpit experience at all) used a flight simulator; all of them navigated the virtual skies with enough accuracy to pass a flying license test. In November 2016, Wired’s Jack Stewart, wearing an electrode cap developed by Santosh Mathan, an engineer with Honeywell Aerospace, used his mind to fly a Beechcraft King Air C90 above Seattle. With what Stewart describes as “a tiny amount of practice in a simulator,” he could actually make the twin turboprop climb, descend and turn simply by focusing on certain areas of a tablet screen. After the flight, Stewart said the system followed his planned command about 90 percent of the time.22 The next stage would be for a pilot or passenger to wear a helmet to control his electric flying car or Vahana—but then, why not call it Vimāna? Perhaps vibration-free electrical propulsion will render mental communication more responsive.
Which brings us back to our question: when mythical Icarus moved his arms to flap his waxed-feathered wings, was he not also sending electrical messages from his brain?
Whatever the case, where the sky’s the limit, it’s up in the air.