Pipistrel’s triple alliance with SF Express, a Chinese package delivery enterprise, and Amazilia, a software/hardware firm in Germany, will help fulfill high-flying ambitions. Pipistrel, a well-established company with its roots in Slovenia, already has affiliates in Italy, China, and the USA. Now, its partnership with SF Express and Amazilia has obvious links to the need to keep things on track in transporting people and cargo with the new eVTOLs (electric Vertical Take Off and Landing) vehicles Pipistrel is developing. SF Express is a huge “logistics” firm, delivering packages throughout all of China. “Amazilia Aerospace is a young engineering company in the heart of Munich, Germany, developing digital flight control, flight guidance, and vehicle management systems for civil manned and unmanned aircraft.”
Pipistrel is crafting a “heavy cargo hybrid VTOL drone” for SF Express, capable of taking products anywhere in China within 36 hours – a significant challenge in such a huge country. It needs to be able to climb over mountains and traverse long distances in that quest. It will carry over 300 kilograms (660 pounds) of cargo in a 2.3 cubic meter (81.2 cubic feet) space – equivalent to the space in a minivan. Pipistrel’s cargo hauler has a range of 500km (310 miles) with cruising altitudes up to 6, 000 meters (19,685 feet) and VTOL capability up to 2500 meters (8,200 feet) above sea level.
For each of the 1,000 projected cargo hybrids, eight European Aviation Safety Agency (EASA)-certified Pipistel E-811 vertical lift packages will be required. “Highly efficient and redundant battery packs [will] assure safe operation even if two rotors are inoperative.” Building a thousand airframes and 8,000 motors will put Pipistrel in the front ranks of aircraft production in the next few years.
This makes Pipistrel Founder and CEO Ivo Boscarol proud and happy. He points out “To be chosen by one of the largest logistics companies globally to design and produce a tailor-made line of vehicles for aerial cargo transportation is a solid recognition of Pipistrel’s capability built up on more than a decade of achievements in electric flight. We look forward to becoming even more involved in strategic business solutions on a global scale, where our vehicles will change how aerial logistics work and have further significant impacts to sustainability and quality of life.“
Pipistrel’s V300 cargo hauler will deliver payloads across China for SF Express. Amazilia avionics will control and guide autonomous craft
To help guide these cargo haulers on their way, “Amazilia Aerospace will deliver an advanced digital flight control and vehicle management system, their Automatic Flight Control System and Vehicle Management System (AFCS/VMS). Both the avionics hardware and software are capable of automating the entire cargo mission. Designed for VTOL or conventional aircraft configurations, the system seems well-suited for Pipistrel’s design which combines both types of operation. Designed specifically for large scale logistical operations by logistics companies such as SF Express, Amazilia’s systems seems almost melded to such needs. The system partially results from, “Years of research at the Technical University of Munich (TUM) reinforced with aerospace industry experience.”
Pipistrel will flight test the eVTOL, “With the Amazilia Aerospace system in Europe followed by operational validation in China starting in 2022. By 2023, SF Express intends to deploy the HVTOL cargo drone fleet in their domestic and non-domestic business operations.” This will be a connecting flight between large-scale operations with jet cargo planes and “last-mile” deliveries with smaller drones.
Li Dongqi, SF Express Vice President and SF Unmanned Aircraft Systems Chairman, sees great promise in these plans. “Our efforts to achieve 36-hour countrywide delivery throughout China face significant challenges, such as natural barriers, underdeveloped logistics infrastructure, and more, especially in rural China. SF Express intends to adopt cargo VTOL drones to solve this bottleneck due to their flexibility and high speed, which is on par with helicopters, and has low costs which are competitive with truck delivery. The high-altitude capability allows us to extend our civil air cargo service coverage to even difficult to reach mountainous areas. We believe VTOL drones will become a major vehicle in China, and SF Express alone will need more than 1000 in the next 10 years.”
Two French manufacturers are reverting to bois et toile (wood and fabric) for ultra-modern aircraft. Both of their aircraft will be electrically powered, and both will use non-traditional approaches to construction. In the meantime, both have fairly traditional demonstration models.
The French have done wonders with wooden aircraft from the very beginning of aviation. Santos Dumont built the petite Demoiselle with bamboo longerons, for instance, and Henri Mignet crafted his diminutive Pou du Ciel (flea of the sky, or flying flea) from available wood. After World War Two, Messrs Joly and Delemontez fashioned a small single-seater, the Jodel D-9, from wood and ply and powered it with converted VW Kubelwagen engines, Jeep-like German vehicles which littered scrap yards and former battlefields. Avions Mauboussin and Aura Aero use more modern power systems and vastly different approaches to bois and toile structures.
The Jodel D-9 was part of the rebirth of postwar French amateur aviation, being built by hundreds of enthusiasts.
Mauboussin goes back to prewar times with small aircraft that look as though they could have come from a home shop Even their latest endeavors are aerobatic machines with wood and carbon fiber frames that combine traditional looks with modern aerodynamics.
A tres racy poster for Mauboussin fly-in highlights pretty woman, Porsche, and historic airplane. Mauboussin went on to develop jet trainers
The company has two machines, one very much realized and the other on the virtual ramp. They make a mission statement for both. “Alérion M1h and Alcyon M3c are personal means of transport dedicated to interurban mobility. Their performance allows them to cover a large distance and operate from a reduced infrastructure: small airfield, heliport, sports field, parking lot, public park or lawn of a residence.” The company foresees reduced environmental impact from their machines through the use of natural materials, reduced fuel consumption, and minimum emissions “thanks to electricity and hydrogen.” Although the video is in French only, the graphics convey the tidy surroundings in which the airplane is being developed.
The Alérion M1h is a modern interpretation of traditional two-seat touring aircraft, with a modern adaptation of the fuselage in wood, but wrapped in high-strength composite materials and “bio-sourced resins.” Power will come from a single Zephyr hydrogen-hybrid engine system – not yet well defined or seeing the light of day. Composites World reports the powerplant will produce a total power of 80 kilowatts (110 horsepower), for electrically-powered takeoffs and hydrogen fueled cruising speeds of 250 kilometers per hour (155 mph). The company suggests trips like Belfort to Toulouse (around 390 air miles) would take two and a half hours. By car, the shortest route is 795 kilometers (493 miles) and takes at least nine hours.
A press release from Mauboussin explains their schedule for the next seven years. “The creation of Zéphyr (hybrid hydrogen propulsion) will lead to the marketing of Alérion M1h (the first of the Mauboussin aircraft), in 2025 for the kerosene hybrid version and 2027 in the hydrogen hybrid version.
“Alcyon M3c will be launched in 2026 for the kerosene hybrid version and 2028 for the hydrogen hybrid version.”
In artist’s rendering Mauboussin Alcyon shows off its grass field abilities
The company promises, “Avions Mauboussin will offer the Zéphyr propulsion drive train to other aircraft manufacturers, helicopter manufacturers, manufacturers of VTOL flying taxis or drones, as well as other manufacturers in the maritime and automotive sectors.” This would help build a customer base for the powerplant and help reduce manufacturing costs through economies of scal
Maurboussin’s Alcyon M3c makes no bows to tradition, exhibiting thoroughly modern, if not outright futuristic, lines. It will carry five in probable luxury, lift off from an STOL (short takeoff and landing) airstrip and cruise at 370 kilometers per hour (229 mph) for up to 1,500 kilometers (932 miles). It will share with the M1h HOTAS (Hands On Throttle and Stick) control, a heads-up display and Wi-Fi, satellite and 4G connectivity.
Aura Aero’s 19-seat commuter liner bears resemblance to AEG’s Bird of Prey, would provide swift regional transit
Its aerodynamic partner is starting with a series of two-seat aerobatic aircraft much like Mauboussin. Aura Aero has a slightly more ambitious follow-up, though, with its 19-passenger, six-motor regional airliner. Aura’s enterprise will begin in an historic hangar at Toulouse Francazal, where the hangar’s rebirth as the center of a high-enterprise soon take place. Like many other energy-efficient startups, Aura Aero is being supported by its local region, the Occitanie, known for its Pyrenees Mountains.
Electric-Flight.eu reports, “Aura Aero plans to become a ‘key player’ in the low-carbon sector, it says, ambitiously aiming to carry out a maiden flight of the 19-seat transport in 2024 for service entry in 2026.” Its partnership with Verkor highlights its use of their “specially-developed batteries.” The company also proposes a freighter version of the larger craft.
Both companies show that wood aircraft are in no way outdated, and can suit modern needs quite well.
A New Crew of Magnificent Men in Their Flying Machines
Fred To, former head of the British Human Powered Flying Club, has shared a major announcement.
“The Great Human Powered Aircraft Race will take place in June 2022 and is now open for entries. Teams will attempt to cross the Channel from England to France in an aircraft powered solely by the pilot’s pedaling. They will compete for a £50,000 ($68,785) prize awarded to the team that crosses the Channel fastest, with £10,000 ($13,757) for the second fastest team and £5,000 ($6.878) for the fastest female pilot.
“The first and only crossing of the Channel in a human powered aircraft (HPA) was 42 years ago by Bryan Allen in the aircraft Gossamer Albatross designed by Paul MacCready; no successful attempts have been made since.
Human-powered flying remains one of the world’s most exclusive sports, with more people having flown into space than have flown a human powered aircraft. This is largely due to the sheer difficulty flying for any length of time in a HPA. The race will combine extreme engineering with extreme athletic ability.
“The race will mark the 60th anniversary of the first flight of human-powered aircraft by Derek Piggott in the Southampton University student’s aircraft SUMPAC, it will also celebrate the original Channel crossing in 1979 by pilot Bryan Allen. It is kindly supported by Anne Williams, one of the creators of SUMPAC. The race is also endorsed by Marshall MacCready, son of Paul MacCready who designed Gossamer Albatross, the first and only HPA to cross the channel.
“‘Crossing the English Channel in a human powered aircraft — it has been done, once before. Barely. It was one of the most amazing athletic achievements of our time. To think that several international teams are going to attempt the same feat, on the same day, in a race to see who is the fastest, seems almost a bit bonkers. It will be a huge technical and logistical challenge, but most of all a supreme test of athletic and piloting skill. It is going to be fascinating to watch, and thrilling to participate in.’
Alec Proudfoot- HPA Designer.
‘One of the aims of the competition is to use the race to inspire the next generation of engineers and scientists.’
Fred To- Race organizer
“Entrants will have to fly 35 kilometers (21.7 miles) from Folkestone across the Channel to France. All aircraft will take off on the same day to ensure no team has an unfair advantage due to weather though take offs will be staggered to ensure there are no mid air collisions. It is the first human powered aircraft time trial in history with multiple teams in the air simultaneously which will prove incredibly exciting. Prize money will be awarded based on the quickest crossing. Teams will be followed by speed boats with rescue divers standing by in case an aircraft ditches.
“Prospective teams should contact the organizers if they are interested in competing in the world’s first and only time trial HPA race across the Channel. On account of the risk and difficulty teams will have to demonstrate past experience in HPA building to qualify. Teams from all countries are invited to apply.
“‘Flying a human powered aircraft is the most amazing experience: a bit of appropriate nervousness before take off, followed by swift pedaling and the noise of the wheels on the tarmac, and then suddenly it becomes quiet and you are floating, like a magic carpet ride. It’s virtually silent except for your own labored breathing, and the receding excited shouts of your teammates. Magical.’ (Above, we see Alec’s Dash HPA in flight at Moffett Field in 2016, piloted by Craig Robinson.)
Alec Proudfoot- HPA Designer
“The race will mark the 60th anniversary of the first flight of human powered aircraft by Derek Piggott as well as celebrating the original Channel crossing in 1979. It is kindly supported by Ann Williams (one of the creators of SUMPAC, the world’s first human powered aircraft) and Marshall MacCready (son of Paul MacCready, designer of the Gossamer Albatross, first and only HPA to cross the channel).”
“As aircraft are powered entirely by pedaling, HPA racing is one of the world’s most sustainable airsports with each HPA being a miracle of efficient engineering. As humans have a much lower power to weight ratio than conventional engines the aircraft will have to be incredibly light. It is common for a HPA with a 30 meter wingspan to only weigh 40 kilograms (88.2 pounds), less than the pilot. Every gram saved reduces the amount of cycling power that the pilot needs to produce and will be vital to determining whether the aircraft will make it across the Channel.
“It is the largest prize announced for human powered airplanes since the Kremer Prizes were created in 1959 and organizers are hopeful that the race will inspire the next generation of HPA pilots and engineers along with increasing STEM engagement among students.”
Those excited by this announcement have over a year to prepare themselves and their machines for a great challenge and a festive occasion. Peleton® should add a new category to their trainers.
Since we have compared the Great Human Powered Aircraft Race to Magnificent Men in their Flying Machines, here is a review of that 1965 film, an expensive production with Derek Piggott as the flight chief and more than occasional pilot for all the craft. Shot in high-grade 70-millimeter with excellent production values, the film, despite its age, holds up well, and the flying is… magnificent.
Electrifly-in, formerly the Smartflyer Challenge, is on for September 11 and 12, 2021, in Grenchen, Switzerland. The event, even held in 2020 despite the pandemic, is a compact showing of the latest in electrical aircraft and technology. Watch as this 2019 video as a Φnix (the Greek letter phi + nix –a clever bilingual pun) takes off, circuits the area and makes a landing – all the time flying with other electric aircraft.
In this flight, you can see the compact airport (including a grass landing strip) and a lovely setting for a great event. Started as the Smartflyer Challenge* in 2016, the gathering has changed its name to be more inclusive.
Last year, even with travel limitations imposed worldwide, saw a healthy turnout of all-electric flyers, ranging from ultralight electric “trikes” to cross-country tourers.
And in another example, the Birdy motorglider flown by Toni Roth at last year’s event, the self-launcher flies on a mere 16 kW (21.6 horsepower). All these and more could attend this year’s Electrifly-in.
Other manufacturers, including Pipistrel with their proprietary line of power systems, YASA, R0lls-Royce, MGM-Compro and others may provide insights into the future of battery and possibly hydrogen aviation power.
Pioneering Pilots and Speakers
Last year, Eric and Irena Raymond showed up in their Sunseeker Duo, Klaus Ohlmann flew a Lange 20e self-launching sailplane, and Bertrand Piccard, co-pilot of Solar Impulse flew an ultralight and discussed Ten years ago, Eric and Klaus flew the second-place winning e-Genius in the NASA Green Flight Challenge sponsored by Google. They flew a 200-mile course around northern California and averaged 375.8 passenger miles per gallon, using the energy equivalent of a little more than a gallon of gasoline for the flight. This kind of energy efficiency and economy will continue to draw attention to the new technology, now becoming entrenched.
Members of the record-breaking Pipistrel Electro Velis team were there for a discussion on electric aviation, just part of a larger symposium that provided a socially-distanced learning experience for all. Speakers from government, industry and academia filled out the program. Hangars full of displays and aircraft on the flight line helped make the two-day event a full one. Your editor wishes he could be there this year, and it’s not too early to start making travel plans.
*The Original Namesake
The people behind the Smartflyer hybrid touring airplane have kept the appellation for the craft, featured at past events on the Grenchen field. This airplane should be on display at this year’s fly-in, and may have started flight testing by September.
Specifications (from their web site)
Cruise Speed 120 knots (138 mph) / 222 km/h
Take off Power 160 kilowatts
Max Cont. Power 120 kW (161 hp)
Range 400 NM (460 statute miles) / 750 km
Endurance 4 h
Empty Mass 1000 kg (2,200 pounds)
Take off Mass 1400 kg (3,086 pounds)
Battery Mass 160 kg (353 pounds)
Range Extender Rotax 914 with YASA (Yokeless and Segmented Armature) Generator
The specifications may change during the construction process.
This year’s Electrifly-in should be even bigger once travel restrictions are lifted. Again, it seems like two days filled with a glimpse of future, green flight.
What if the weight of the batteries in an electric airplane could virtually disappear? Researchers at Chalmers University of Technology in Gothenburg, Sweden have come up with an improved structural battery that exceeds the results of earlier research. So-called “massless batteries,” although not as energy dense as cylindrical or pouch lithium-ion batteries, could be worthy substitutes.
The idea of making airplanes from materials that would provide energy from their inherent properties has been of interest for years. Your editor wrote an article on “The Grand Unified Airplane” for Kitplanes magazine in 2013 based on the idea of combining solar power, piezoelectric flexing of wings, and structural batteries. The ultimate goal was to create a machine that would move through the air on the energy of flight itself. This might seem an unreachable fantasy, but material scientists are bringing us closer to the dream.
Chalmers University points out, “Structural battery composites cannot store as much energy as lithium-ion batteries, but have several characteristics that make them highly attractive for use in vehicles and other applications. When the battery becomes part of the load bearing structure, the mass of the battery essentially ‘disappears’”. Illustration: Yen Strandqvist
Headlining their report with a rather non-academic boast, Chalmers University promotes its, “Big breakthrough for ’massless’ energy storage. ”They follow with an intriguing first paragraph. “Researchers from Chalmers University of Technology have produced a structural battery that performs ten times better than all previous versions. It contains carbon fiber that serves simultaneously as an electrode, conductor, and load-bearing material. Their latest research breakthrough paves the way for essentially ’massless’ energy storage in vehicles and other technology.”
Before getting too excited about that “10 times” claim, recognize that previous structural batteries did not display high energy densities, the property that keeps the Energizer Bunny hopping. Chalmers notes the new battery has an energy density of 24 Watt-hours per kilogram, only about 20 percent that of comparable lithium-ion batteries. It’s slightly less than one-tenth that of the best battery packs used in state-of-the-art aerial vehicle.
Chalmers structural battery shows considerably higher strength, energy density than those of previous researchers
Chalmers explains why this is not a total loss. “But since the weight of the vehicles can be greatly reduced, less energy will be required to drive an electric car, for example, and lower energy density also results in increased safety. And with a stiffness of 25 GPa (GigaPascals equaling 3,625,943 pounds per square inch), the structural battery can really compete with many other commonly used construction materials.” Depending on the weight of composite materials used, the structure might be no weightier than a more conventional equivalent.
Consider, though, a possible application of such energy-storing materials. Let’s use the 24 kW/hr materials applied to Calin Gologan’s Solar Elektra One, introduced in 2012. The plane was a 3/3 machine, 1/3 structure, 1/3 batteries, and 1/3 payload including pilot. Each third was 100 kilograms (220 pounds). Imagine being able to replace half the structure with Chalmers’ structural battery material. 50 kilograms (110 pounds of the airframe would be capable of storing 1,200 Watt-hours per kilogram, shaving 4.6 kilograms (10.1 pounds) from the battery weight. Not a big number, but still 1.5 percent of the total aircraft weight. Chalmers researchers predict up to three times the energy density for future products, so that would equal a 4.5 percent reduction. As on the Grand Unified Airplane concept, if those structural panels were also solar collectors, even more benefit could accrue in terms of extended range.
Calin Gologan’s PC Aero One, a 2012 design, light as it is, would benefit from structural batteries. Greater strength and energy density are coming, according to researchers
Leif Asp, Professor at Chalmers and leader of the project explains, “Previous attempts to make structural batteries have resulted in cells with either good mechanical properties, or good electrical properties. But here, using carbon fibre, we have succeeded in designing a structural battery with both competitive energy storage capacity and rigidity.”
Doctor Johanna Xu with a newly manufactured structural battery cell in Chalmers’ composite lab, which she shows to Leif Asp. The cell consists of a carbon fiber electrode and a lithium iron phosphate electrode separated by a fiberglass fabric, all impregnated with a structural battery electrolyte for combined mechanical and electrical function. Image: Marcus Folino
The new battery has a negative electrode made of carbon fiber, a positive electrode made of a lithium iron phosphate-coated aluminum foil, separated by a fiberglass fabric, in an electrolyte matrix. Researchers “did not choose the materials to try and break records – rather, they wanted to investigate and understand the effects of material architecture and separator thickness.”
The samples of Chalmers structural batteries shows different materials used
Further research financed by the Swedish National Space Agency will attempt to enhance the performance of the structural battery. “The aluminum foil will be replaced with carbon fiber as a load-bearing material in the positive electrode, providing both increased stiffness and energy density. The fiberglass separator will be replaced with an ultra-thin variant, which will give a much greater effect – as well as faster charging cycles. The new project is expected to be completed within two years.”
Leif Asp, leading this project too, estimates that such a battery could reach an energy density of 75 Wh/kg and a stiffness of 75 GPa (10877830 psi) – about as strong as aluminum, but at a much lower weight. He takes an optimistic view. “The next generation structural battery has fantastic potential. If you look at consumer technology, it could be quite possible within a few years to manufacture smartphones, laptops or electric bicycles that weigh half as much as today and are much more compact.”
And in the longer term, it is absolutely conceivable that electric cars, electric planes and satellites will be designed with and powered by structural batteries.
Lief Asp concludes, “We are really only limited by our imaginations here. We have received a lot of attention from many different types of companies in connection with the publication of our scientific articles in the field. There is understandably a great amount of interest in these lightweight, multifunctional materials.”
Making the Chalmers structural battery at the laboratory level. The processes should be able to be scaled to industrial levels
The structural battery uses carbon fiber as a negative electrode, and a lithium iron phosphate-coated aluminum foil as the positive electrode. The carbon fiber acts as a host for the lithium and thus stores the energy. Since the carbon fiber also conducts electrons, the need for copper and silver conductors is also avoided – reducing the weight even further. Both the carbon fiber and the aluminum foil contribute to the mechanical properties of the structural battery. The two electrode materials are kept separated by a fiberglass fabric in a structural electrolyte matrix. The task of the electrolyte is to transport the lithium ions between the two electrodes of the battery, but also to transfer mechanical loads between carbon fibers and other parts.
The project is run is a collaboration between Chalmers University of Technology and KTH Royal Institute of Technology, Sweden’s two largest technical universities. The battery electrolyte has been developed at KTH. The project involves researchers from five different disciplines: material mechanics, materials engineering, lightweight structures, applied electrochemistry and fiber and polymer technology.
Funding has come from the European Commission’s research program Clean Sky II, and interestingly, from the U. S. Air Force.
eHang 216 approaching Baobab-inspired landing site
Basing its design on the Baobab tree, native to Madagascar, Africa, and Australia, GZDG’s structure will fit into urban and rural environments equally well. The 30-meter (98.4-feet) tower, built of laminated wood and steel emulating the shape of the “Tree of Life,” the vertiport will be topped with a multi-purpose landing deck. The structure will incorporate a waiting room, café, a 200-square-meter (2,153-square-foot) panoramic restaurant and connecting lift. Non-slip photovoltaic panels will generate over 300 kilowatts of electric power per day.
Avenue of the Baobabs (UNESCO World Heritage site), Madagascar. Trees are also found in Africa and Australia
GZDG’s vertiport is a green design made of sustainable construction materials, “and can generate energy to recharge the EH216 passenger-grade AAVs.” According to the partner’s joint press release, “Vertiports will play a significant role in the Urban Air Mobility (UAM) market and the new era of flight. When integrated into the existing transportation infrastructure, vertiports can serve as aerial hubs for tourists.”
Plan view for eHang’s Baobab landing zone shows charging modules, central lift
With the first Baobab vertiport being built in Italy, EHang and GZDG aim to enter the emerging global eco-tourism sector, with multiple projects being planned in Europe and Southeast Asia.
eHang is already exploring those projects with a strategic partner based in Hong Kong.
Real-estate company Greenland Hong Kong Holding Limited operates a tourism site called Forest Lake (translated as Yuehu Town) located in Zhaoqing, a popular tour destination city in Guangdong, China. eHang will provide aerial sightseeing and aerial media shows. Beyond this site and the first Baobab vertiport in Italy, the partners hope to expand to other locations in Europe and Southeast Asia.
With green building practices and green aviation in partnership, tourism might flourish in a way that is actually helpful for the planet.
Two electric regional commuters are nearing reality. A Scylax design from Calin Gologan reflects its “clean sheet” origins: the other, derived from an existing Tecnam design, honors its Italian craftsmanship heritage.
Calin Gologan, Rosario De Luca and the Scylax E Series
Calin, designing and building solar-powered aircraft since 2011 , and Rosario De Luca, Co Founder and CEO of EADCO GmbH and EADCO US LLC., and CEO of SCYLAX GmbH, have joined forces to create two small airliners, the Scylax E6 and E10, each enumerating its passenger capacity. Joined by the airline FLN FRISIA-Luftverkehr GmbH Norddeich, they will begin flying their pure-electric craft soon with existing batteries enabling 300-kilometer (180-mile) trips. Within the next decade, cell improvements will allow 600-kilometer with the same battery volume and weight.
The pair foresees a five-percent increase in battery capacity every year, making an easy case for ongoing improvements in energy storage, aircraft range, and greater power for safer takeoffs and climbs.
(Of interest in the video, Dr. Frank Anton, leader of Siemen’s electric aviation effort, supports the Scylax program, now allied with Rolls-Royce, which purchased the Siemens program.)
They see their aircraft as environmentally friendly, and with increasingly cleaner sources of renewable energy, yielding not only reduced or neglible emissions by the aircraft – but from the sources for electricity themselves.
The simplicity of electric motors will be a boon to operators, with only a pair of bearings requiring long-term replacement. Scylax notes, “With no spark plugs, gears, belts, and other traditional mechanical parts that wear, SCYLAX’ electric propulsion systems are refreshingly free from the normal maintenance schedules that aircraft owners have become accustomed to.”
This level of reliability will be essential to safe flights on their Frisian airline’s routes. These are mostly over water and at relatively low altitudes. Some flights last mere minutes, but are the safest, quickest way to provide personal and cargo service to North Sea islands.
Frisian islands to be served by Scylax E6 and E10 aircraft
Looking beyond the immediate prospects for sales of Scylax aircraft, the partners project that, “The current market for single / twin engine aircraft is saturated with older legacy models and, due to the fuel savings associated with newer aircraft and models does not justify the cost of purchasing aircraft in the secondary market. The worldwide market volume was in 2018 ~1.740 units per year and USD 2.7 billion revenue. The all electric aircraft could build a real new market replacing the current old fleet with piston engines & turboprop propulsion.
“By leading the way to market and being a pioneer of electric aircraft, the E6 and E10 will be the natural replacement for companies looking to acquire or replace their existing aging small commuter fleet.”
Tecnam, Rolls-Royce and Norwegian Electricity
Building on their partnership in the H3PS Project, Italian aerospace company Tecnam is working with Rolls-Royce and Norwegian airline Wideroe to fly North Sea and West Coast routes. The craft, based on the Tecnam P-Volt model, “Will be ideal” for those routes and the short take offs and landings necessary for the fields served. The airplane should be ready for commercial service by 2026.
Wideroe’s route map shows numerous short routes and over-water hops
It’s of interest that similar aircraft will be flying similar missions in similar locations. Stein Nilsen, Chief Executive for Widerøe highlights the similarities: “Norway’s extensive network of short take-off and landing airports is ideal for zero emissions technologies. This aircraft shows how quickly new technology can and will be developed, and that we are on track with our ambition of flying with zero emissions around 2025.”
That timing would be on a fast track, considering that Rolls-Royce and Widerøe announced a joint research program in 2019, “to evaluate and develop electrical aircraft concepts that would fulfil the Norwegian ambition of having the first electrified aircraft in ordinary domestic scheduled flights by 2030 and 80 [percent] emission reduction in domestic flights by 2040.”
Developing clean electric aircraft may help Wideroe “build back better.” They note that before the pandemic, the airline “offered around 400 flights per day using a network of 44 airports, where 74 [percent] of the flights have distances less than 275 [kilometers] (170 miles). The shortest flight durations are between seven and fifteen minutes.” Again, the short flights are similar to those flown by FLN Frisia.
Based on the Tecnam P2012 Traveller aircraft, the electric P-Volt will be a short take off and landing (STOL) machine, able to land on grass strips. Like northern Germany, many hops require takeoffs and landings on unimproved island airports and at least short hops over frigid waters.
Rob Watson, Director of Rolls-Royce Electrical, expands on the hopes for this partnership: “Electrification will help us deliver our ambition to enable the markets in which we operate achieve net zero carbon by 2050. This collaboration strengthens our existing relationships with Tecnam and Widerøe as we look to explore what is needed to deliver an all-electric passenger aircraft for the commuter market. It also demonstrates Rolls-Royce’s ambitions to be the leading supplier of all-electric and hybrid electric propulsion and power systems across multiple aviation markets.”
Fabio Russo, Chief Project R&D and Product Development, Tecnam, adds: “It is incredible to see the interest around the P-Volt, not only coming from regional airlines, but also from smart mobility-based companies. This last year has demonstrated the importance of promoting capillary connections between small communities, while reducing the congestion of the main hubs. The P-Volt, like the P2012 Traveller today, will perfectly fit the scope of this program. We are honored and pleased to see the level of enthusiasm Widerøe and our partner Rolls-Royce are dedicating to this project.”
Between the industrial giants partnering in Norway and the relatively small but no less inspired designers in Germany, electric aviation is finding an immediate need in less-served small airports. The reliability and simplicity of electric aircraft will be a major factor in the future of air travel in such regions.
Hypoint proclaims, “We make zero emission air transport possible.” They do this by, “Building a next generation hydrogen fuel cell system that can deliver
“Both high specific power:
“2,000 Watts/kilogram and high energy density
Hypoint’s comparison between existing fuel cells, lithium-ion batteries and their new system
Exactly what aircraft designers are looking for.”
These numbers exceed what the best batteries can manage at this time, and according to the company’s white paper, even better performance is on the way.
Batteries vs. Fuel Cells
Hypoint proclaims, “The age of zero-emission aviation is currently being prevented by the industry’s reliance on Li-ion batteries, which have a fundamental barrier at the chemistry level.” The firm limits cell performance to 200 Whr/kg, although Bye Aerospace claims 260 Whr/kg for their full battery packs, battery management systems and all.
Elon Musk disagrees. CNBC reports, “Tesla co-founder and CEO Elon Musk has dismissed hydrogen fuel cells as ‘mind-bogglingly stupid,’ and that is not the only negative thing he has had to say about the technology. He has called them ‘fool cells,’ a ‘load of rubbish,’ and told Tesla shareholders at an annual meeting years ago that ‘success is simply not possible.’”
Better Performing, Hotter Fuel Cells
Obviously, the folks at Hypoint are not dissuaded by the negativity. Perhaps most important in the newest fuel cells from Hypoint, “We are using a next-generation high temperature membrane (HTPEM) instead of a low temperature membrane (LTPEM), which increases the efficiency of a cooling system by at least 300%.”
Raising the temperature to increase cooling efficiency seems counterintuitive. On an over-simplified level, many low-temperature fuel cells use liquid cooling to disperse heat. That adds complications and weight, with a “traditional” LTPEM’s cooling system forming 53 percent of the fuel cell’s mass. Hypoint’s use of HTPEMs and “turbo-cooling” them reduces the cooling system to only six percent of the total mass. Hypoint claims a 61-percent reduction in total weight for its high-temperature fuel cells.
A Radial Arrangement
Early on, aviation pioneers attempted to lower the mass and size of engines. The radial engine was one answer, arranging cylinder around a central crankshaft which drove the propeller. Large cooling fins directly in the cooling blast of air helped keep temperatures in a working range.
Radial engine on the nose of a Stearman biplane. Cooling fins rely on air to dissipate heat
Hypoint has adapted this arrangement with multiple fuel cells around a central fan which forces air over the high-temperature membranes and out from each cell. This makes for a compact arrangement similar to that of early radial engines, but with far greater efficiency.
This turbo air-cooled (TAC) power system is the first, according to Hypoint, to use both air-cooling and turbocharging. Arranging the system in a radial fashion works well with their other material innovations.
Hypoint’s arrangement of fuel cells resembles radial engine, uses turbocharged air from central high-pressure fan to cool system
Hypoint’s specialized fuel cell bipolar plates work at 160°C (320° F) rather than the low-temperature cell’s 70° C (158° F), allowing for greater thermal efficiency. Both are lower temperatures than those found under the cowling of any internal-combustion powerplant. Compressing the air up to three times through turbocharging results in what Hypoint claims is a 70-percent increase in the system’s available power. Hypoint also claims an operational efficiency of 40- to 50-percent, depending “on the aircraft’s operational mode.”
Hypoint projects drive systems up to two megawatts, large enough to gang for airliners
Compact and lightweight, the system can generate power from lower-quality hydrogen, lowering operational costs. Systems can be sized from 50 kilowatts to two megawatts, assuming a small portion of the available “real estate” within the aircraft.
Two very different hydrogen-powered aerial vehicles have come to our attention, each with a different mission, but both with endurance and range as primary functions. Both use a fairly straightforward fuel cell/motor arrangement to power their flights.
Vicor/DMI Fuel Cell Drones
Doosan Mobility Innovation (DMI) is a major drone manufacturer, and their largest products push against the FAA’s 55-pound (24.97-kilogram) weight limit. Their DM30, powered with a DS30 fuel cell and a 10.8 liter H2 tank weighs 21 kilograms and can carry a five kilogram (11 pound) payload. Carrying a full payload may require using the smaller seven-liter tank.
Alessandro Mascellino, writing in EE Power, describes recent combination of resources that makes long-range drone deliveries possible. “The first machines built as part of the collaboration can fly two hours on a single charge and have already transported masks and emergency supplies between US Virgin Islands. The drones feature a number of power components by Vicor.”
Partnering with Vicor, Doosan provides the vehicle and the power system, Vicor finesses the regulation of that power. In the DP30 power pack, two of DMI’s fuel cells deliver a “highly variable output voltage (40 to 74 Volts).” This Power Delivery Network (PDN) consists of two separate power trains: the first delivering 12 Amps of 48-Volt power the drone’s rotor motors, and the second providing up to eight Amps of 12-Volt power to the stack’s controller board and its cooling fans.
Vicor provides pre-regulator modulation (PRM) via its pre-regulator modulation (PRM) buck-boost regulators and a zero-voltage-switching (ZVS) buck regulator. The PRMs, “can accept input voltages across the fuel-cell stack’s full operating range, up to its 74-V open circuit voltage (OCV), while providing a tightly regulated 48-V.”
Mascellino report,s “Looking forward, DMI plans to leverage Vicor’s modular approach to diversify product lines by power capacity, introducing other options to the 2.6kW DP30 power pack currently in production, and corresponding drones suitable for each power pack.” Obviously planning for a range of drone sizes, DMI will produce power packs from 1.5 kW to 10 kW.
Energy density comparison between hydrogen fuel cell and lithium power. Image used courtesy of Vicor
With humanitarian and commercial missions in mind, DMI has flown between the U. S. Virgin Islands, as described above, and delivered Automated external defibrillators (AEDs) to the top of Mt. Hallasan, the tallest mountain in South Korea (1,947.06 meters or 6,388.0 ft). This ability to haul a large payload to such an altitude is an impressive demonstration of the drone’s capability.
Delft Technical University’s Phoenix
Even longer ranges are possible with hydrogen-powered fixed wing aircraft. Delft Technical University students are busy building a 1/3-scale model of the Phoenix motorglider they hope to demonstrate this year. Their introduction video certainly makes that ambition seem plausible.
Before regular readers of the blog complain that the airplane looks a lot like Stuttgart University’s e-Genius, the student team credits that aircraft with inspiring the design for their craft. In fact, e-Genius was originally Hydrogenius, as presented in 2009. Originally designed with a range of 375 miles on 9.3 pounds of H2 (roughly equivalent to 4.2 gallons of gasoline). That would have equaled 178.6 passenger miles per gallon, a creditable achievement. In reality, during the 2011 NASA Green Flight Challenge sponsored by Google, the craft achieved 375.8 passenger miles per gallon. It’s since gone on to fly with a rotary-engine range extender mounted in an underwing pod. TU students think they can do better on hydrogen, though.
“Flying from Amsterdam to Casablanca (Morocco) on one tank of fuel? This can be done until today by not a single engine airplane!” The roughly-translated idea of traversing 2,327 kilometers (1,446 miles) in a single hop is part of what the AeroDelft team members hope to accomplish on a fairly ambitious schedule. First, they will fly their 1/3-scale PT this year. Then, by 2022, a full-size, 18.6 meter span two-seater will take flight on gaseous hydrogen, followed by a liquid-fueled version 2024.
Timeline for Aerodelft’s Phoenix. PT is 1/3-scale proof-of-concept model, FS is full-size
Even the skills of a richly-talented crew are challenged by the tech required for H2 operations. 44 students from 17 countries worked on the project so far. “The 1:3 scale prototype is powered by a 1500W fuel cell coupled with a battery pack for take-off power and safety. Hydrogen is kept in a cryogenic tank at -253°C and warmed to 0°C using a complex tubing system. ”The tank is insulated with a 20-centimeter (7.87-inch) thick layer of material to maintain the extreme cold.
One pound of H2 will fly the model for seven hours and as many as 500 kilometers (310 miles). Scheduled for this spring, the model will serve as a proof of concept for the full-scale aircraft. As though 700-bar pressurized tanks and complex fueling were not enough, the craft will feature, “boundary layer suction on the wings, consisting of 14 million fine bores… on the upper side of the wing,” which could add up to 14 percent to lift coefficients.
AeroDelft’s Chief Engineer Olga Lubbers with 1/3-scale PT. Hydrogen tank for full-scale aircraft will be much smaller, proportionally
TU students hope to, “Inspire the aviation industry to act on the changes necessary to achieve a global sustainable turnaround in aviation. After two years of dedicated research and manufacturing activities, the first prototype “Phoenix PT” represents an important milestone.”
Even more ambitious, perhaps, students predict the first H2 flight around the world by 2024 and the first flight of a commercial aircraft powered by H2 by 2035.
One thing stalling battery development, dendrites, may have met their match if University of California at Davis researchers have their way. Jiandi Wan’s research group allowed ions to flow through a microfluidic channel near a battery’s cathode to prevent dendrite growth. According the group’s paper, this, “…can potentially expand the safety and lifespans of these next-generation rechargeable batteries.” Their research may lead to safe lithium metal batteries, promising higher power and energy densities, but also struggling with safety issues.
Dendrites can grow to point where they short circuit battery and start fires
Lithium metal batteries might potentially produce twice the energy of lithium-ion batteries, but have greater risks because of the growth of tree-like dendrites on the cathode. An article in PV Buzz explains, “When they charge, some ions are reduced to lithium metal at the cathode surface and form irregular, tree-like microstructures known as dendrites, which can eventually cause a short circuit or even an explosion.”
Associate professor Jiandi Wan’s paper in Science Advances explains the problem and the fix. His Department of Chemical Engineering team theorized, according to PV Buzz,”…that dendrite growth is caused by the competition of mass transfer and reduction rate of lithium ions near the cathode surface. When the reduction rate of ions is much faster than the mass transfer, it creates an electroneutral gap called the space-charged layer near the cathode that contains no ions. The instability of this layer is thought to cause dendrite growth, so reducing or eliminating it might reduce dendrite growth and therefore extend the life of a battery.”
Wan’s team, by flowing ions through microchannel, suppressed dendrite growth appreeciably
The apparently uncontrolled and random deposition grows the dendrites in relation to the electrical activity, greater current seems to increase the growth. Flowing ions through a microchannel reduced dendrite growth by up to 99 percent. The microchannel consists of two strips of metallic foil.
The bad news – it really is not practical at this point to “directly incorporate microfluidics in real batteries.” The Chemical Engineering research group is searching for alternative ways to “introduce local flows near the cathode surface” and eliminate the space charged layer thought to be responsible for dendrite growth.
Wan concluded, “We are quite excited to explore the new applications of our study. We are already working on design of the cathode surface to introduce convective flows.”