Bell Nexus Debuts at CES 2019

This year’s Consumer Electronics Show (CES) had over 4,500 exhibitors, and one major aircraft company showing off its Bell Nexus sky taxi and its Autonomous Pod Transport (APT)Fast Company reported that three major trends emerged: the thousands of devices that link to “virtual assistants” such as Alexa (28,000 apps), the introduction of a slew of Apple products, and the changes in transportation new technology will bring.

Bell Nexus drew crowds at CES 2019

Fast Company noted, “This long-term–and wildly futuristic–strategizing was on full display at CES. For starters, the Uber partner Bell showed off a second-stage concept of its flying car that both companies swear they will begin testing in 2020. (This has been on the docket for a while.) A full-scale model on the CES floor promised to fly five people at speeds reaching 150 mph.  Of course, it didn’t actually fly, but it’s being taken seriously for an important reason: Bell is an established aircraft developer that makes the propulsion technology behind the V-22 Osprey (the crazy-expensive military helicopter plane thing).”

Bell Nexus – A Team Effort

The Nexus team effort, comprising Bell Helicopter, Safran, EPS, Thales, Moog and Garmin, focuses on crafting Bell’s VTOL aircraft and promoting on-demand mobility.  The Nexus is a five-passenger (or four-passenger, one pilot) electric vertical takeoff and landing (eVTOL) vehicle designed to fulfill the vision of on-demand mobility.  Powered by a hybrid system developed by French manufacturer Safran, the six tilting ducted fans will enable roof-top operations and speedy transit.

Safran, a major supplier of aviation engines, with over 72,000 produced since the company’s founding, has developed a hybrid system multi-rotor VTOL system capable of producing more than 600 kilowatts total energy and 100 kilowatts of electric energy for recharging the onboard batteries.

Jean-Baptiste Jarin, Safran Helicopter Engines Vice President, Hybrid Propulsion System Program explained the significance of the Bell-Safran partnership.  “This partnership with Bell in the on-demand mobility sector is a strategic opportunity for Safran.  Nexus is the first of a new breed of aircraft, it opens the doors to new markets and new missions. Fully committed to these challenges and sharing a common vision with Bell, we now look forward to seeing it fly”.

Scott Drennan, Vice President of Innovation, added, “Bell is excited to unveil the Bell Nexus at CES and to share this exciting time with our partners. The Bell Nexus delivers a nexus of transport and technology, comfort and convenience. “We look forward to continuing the development of technology with Safran to bring this nexus to life.”

According to Safran, the “Hybrid-electric propulsion solutions (HEPS) being explored by [their] teams are the most efficient way to enable multi-rotor VTOL aircraft to meet future safety, emission and affordability standards.”  By 2025, Safran is committed to becoming the market leader in HEPS technology.

EPS will provide the energy storage systems, Thales will provide the Flight Control Computer (FCC) hardware and software, Moog will develop the flight control actuation systems and Garmin will integrate the avionics and the vehicle management computer (VMC).

Autonomous Pod Transport (APT)

APT is a family of transport vehicles, varying in size and payload to “serve many mission sets from medical, law enforcement, offshore missions and on-demand delivery services.”   CES attendees were told, “Bell is expanding into a new industry to show the full spectrum of our capabilities and the real-world challenges APT will address.”

Bell treated visitors to a demonstration of Future Flight Controls in simulators that collected data to “determine what actions and interfaces are intuitive to the average potential operator and what prior experiences and abilities contribute to these opinions.”

The partnership will help explore the aerodynamics, power, and control of this new vehicle, but most important, the public’s willingness to accept this new leap in transportation.


Derek Piggott MBE: 1922 – 2019

Fred To, who crafted the first solar-powered aircraft to carry a pilot, alerted your editor to the passing of Derek Piggott MBE (Most Excellent Order of the British Empire).  Derek was a master sailplane flight instructor, movie stunt pilot, the first human to successfully take off and fly an aircraft on muscle power alone, and a pioneer in electric aviation.

Your editor met Derek at a Soaring Society of America convention in Seattle, Washington in 1980, and has an autographed copy of his autobiography, Delta Papa: A Life of Flying, as a cherished memento of that event.  It covers his years in the Royal Air Force starting as a cadet, rising to pilot officer, and flying in Canada and India in a variety of gliders and powered aircraft.

An Engine and Pilot

Following his wartime experiences and discharge from the RAF, Derek taught flying in powered craft and gliders.  His experience in what finally amounted to over 300 types of aircraft and his excellent physical condition earned him an offer to fly Southampton University’s Man Powered Aircraft (SUMPAC).

“It was late in the evening on 9 November 1961 that our first real flight was made.  I was one of the most thrilling and memorable moments of my life.”  Filmed by ex-Pathe News cameraman Lawrence Wright, the moment is preserved for posterity.

“Pedaling the machine was rather like riding a tandem bicycle up a gradual slope with the girlfriend not bothering to pedal.  Then as I eased back on the stick, pedals suddenly started to slip a little and it all became easier.  Tremendous excitement!  I pedaled harder trying to make it stay up for as long as possible.  One wing began to drop and we turned slowly off the line of the runway….  I was puffed out with trying so hard to keep up, but by no means exhausted.  I kept saying to myself, ‘It will fly!  It will fly!’”

An Anonymous Film Star

Almost by chance, he became involved with film making, flying all the aircraft in Those Magnificent Men and the Their Flying Machines (1965) except for the Santos-Dumont Demoiselle, which required someone even lighter than his jockey-size heft.  That job was filled by a petite female pilot, Joan Hughes, who like Piggott and the other pilots in the film went unaccredited.

His work on The Blue Max (1966) involved mass aerial combat scenes and a literally death-defying stunt flying a series of Fokker Triplanes under a bridge between two pillars that left precious little room for error.  In such movies, one must remember that an additional helicopter or airplane is always present – the camera craft, which like the stunt aircraft must be carefully choreographed to prevent unintended collisions.

Darling Lili was a much less successful film and again left Derek unaccredited.  After performing in several other films that relied on his skills with vintage craft, he filled out his movie work playing Sir George Cayley’s coachman in an Anglia Television dramatization in 1972.  Cayley’s “Governable Parachute.”  Since he had little control over this machine, this may have been one of his more dangerous film flights.

Piggott flying replica of Sir George Cayley’s “Governable Parachute” 1974

An Electric Edgley

Derek flew an Edgley EA-9 Optimist sailplane with no less than 16 motors for a project created by Queen Mary University of London college students.  He had flown the glider first in 1994, then again in September 2008 with the brushless Graupner motors powering it.  Note that Derek would have been 86 at this time, making him possibly the oldest test pilot in history.

Edgley EA-9 Optimist fitted with 16 Graupner model airplane motors, controlled wirelessly by Piggott

Finally, from Lasham Gliding:

“We are sad to announce that one of our UK (and Lasham) gliding legends has passed away.

“Derek Piggott MBE enjoyed a very full and happy life for 96 years and passed away this afternoon with Maria at his side, in the Princess Alice Hospice having suffered a severe stroke on the 15th December. Up until then, he was fiercely independent, still drove and visited (and flew) recently here at Lasham.

Derek Piggott and Roy Cross flew a Stemme S10 at a combined age of 171

“Many of you will have known him personally and all will know his reputation as a fantastic glider pilot, instructor and aviation writer. He had flown over 5,000 hours on over 150 types of powered aircraft, and another 5,000 in more than 180 different gliders. Included in those flights were several stunts for Chitty Chitty Bang Bang, Those Magnificent Men in Their Flying Machines and Von Richthofen and Brown (The Red Baron). He was Chief Flying Instructor here at various times between 1953 and 1989, and set various national records including the single seat altitude record of over 25,000′ in an active thunderstorm in a Slingsby Skylark; and completed a Nationals 505Km task in a Fedorov Me7 Mechta glider at the age of 81.

“He will be sorely missed, having made huge contributions that have made Lasham and Gliding as a whole as safe and successful as it is today. We pass our heartfelt condolences to his family.”


N Is For Noise, D is for Deliveries*

A July, 2017 article in New Scientist reported that a small test group found “the noise of drones more annoying than that of ground vehicles.”  This has implications for enterprises such as Amazon and Google that hope to perform home deliveries of various goods, including food.  Almost as a refrain, the Wall Street Journal reported in December, 2018 that, “Wing – the  drone delivery company that spun out from Google — was annoying residents in the Australian town where it tests its services.”  Folks in Bonython, the down-under township where the company had set up shop, “Likened the sounds of the original delivery drones to a “chain saw gone ballistic.”  This caused some to spend less time outdoors, and dogs evidenced signs of “a considerable amount of anxiety.”

The Business Insider added that a Wing spokesperson “confirmed… that it has begun testing a quieter drone that ‘blends in’ with nearby sounds.”  The unidentified spokesperson explained, “We’ve developed and are testing a new propeller that results in a quieter, lower-pitched sound that blends in with other sounds that commonly occur in residential neighborhoods.”  Wing will also alter flight routes and lower airspeeds, meaning customers might not get that pizza in 30 minutes.

One of the first applications of this promising technology was created by an Australian Mexican fast food dispenser, Guzman y Gomez, taking burritos and nachos directly to the Outback’s consumers.

This was presaged five years ago in the San Francisco bay area as part of a Yelp experiment gone aerial, the Burrito Bomber.  The delivery required the recipient to chase a parachute.  Was there a deposit return on burrito containers, though?

Wing’s demonstration video highlights the way things might work in suburban Oz.

Wing takes a broader and grander view of their drone deliveries.   “Wing was first unveiled in 2014, under the name Project Wing, as part of the Google X skunkworks. In 2015, X moved under the auspices of Alphabet, Google’s newly-formed parent company, taking Project Wing with it. In mid-2018, Alphabet dropped the “project,” spinning Wing out into its own fully-fledged company.”

Starting with more humanitarian objectives, in 2012, the team tried first to see if self-flying vehicles could safely and quickly deliver everything from medicine to food, even trying to fly defibrillators to people having heart attacks.  Wing took on more mundane tasks:  “The team soon learned that integration into emergency medical services was it own huge task — developing safe and reliable drone technology was a challenge unto itself. So, they honed their focus on redesigning the system to transport small packages, across many everyday situations, where the speed of delivery was a significant factor.”

An early flock of Wing drones under test in Australia

“Real-world deliveries began in 2014 in rural Queensland, Australia during which the team successfully delivered a first-aid kit, candy bars, dog treats, and water to farmers. In September 2016, the team delivered burritos to students at Virginia Tech as part of the largest and longest drone delivery test in the U.S.  The team considered food as a “great test case for drone delivery technology” because speed and temperature maintenance are essential.

Designated as a competitor for Amazon, Wing will expand its U.S. and Australian tests and launch its first European delivery services in Finland in spring 2019. Seeing it as a successor to earlier advancements in delivery services such as the Pony Express or FedEx and DHL, Wing’s developers see their system as being as beneficial.  “Whether it’s the parent stuck at home with two sick kids and no dinner, the farmer out in the field with a broken tractor and no tools, or emergency service workers that need medical supplies at the scene of a crisis, current methods of road transportation are not always fast enough to solve the problem at hand.”

Wing could even provide an answer for the soaring amount of greenhouse gases clogging the atmosphere.  “The transportation of goods has also added to the increase of CO2 gases emitted into the atmosphere — in the U.S. alone, 27% of greenhouse gas emissions come from transportation.”  If something as common as pizza delivery can be done on a zero-emissions basis, this might be as important as hybrid cars or Teslas and Leafs in bringing lower CO2 levels.  Now, if drone deliveries can be a silent as they are emissions-free, the world will be a cleaner, quieter place.  Larger, faster drones on the horizon will probably allow tools and medical equipment to be delivered with all dispatch.

*With apologies to Sue Grafton, whose “alphabet” series of crime novels ended prematurely with her passing.  “Y is for Yesterday” was published a few months before she died on December 29, 2017.


Rolls-Royce ACCEL Program Goes For the Gold

Rolls-Royce’s ACCEL program and a consortium of partners want to create the world’s fastest electric airplane.  The concept has a recent series of predecessors, and a fascinating tie to an American speed champion.

About five years ago, something called the TEACO (The Electric Aircraft Company) Bat, a formula 1-type raceplane powered by an electric motor, generated a great deal of interest.  It initially housed a single 80-horsepower electric motor, but once affiliated with Williams Engineering; the project added a twin-motor unit on a set of sleeved parallel shafts swinging contra-rotating propellers.

Spirit of Innovation will go after world electric flight speed record

Now, a partnership led by Rolls-Royce seems to have added a third motor, with all three singing in unison to drive a three-bladed propeller.  The airframe is new, too, comprising a shape that looks a great deal like the U. S racing champion, Nemesis NXT.  Powered by a Lycoming IO-540 engine that airplane set a world speed record of 397.40 mph at the Moriarty Airport in Moriarty, New Mexico on October 1, 2015.  Called Thunder of Moriarty, the effort fetched a total of four other world speed records, three of which were over 400 mph.

Those records were all broken in a small plane with a big engine, a Lycoming usually found under the cowlings of craft such as the Van Grunsven RV-10, big Lancairs, or larger Pipers and Cessnas in single and twin-engine configurations.  Changing this to electric power reduces the weight of the powerplant considerably, but requires a significantly energy dense battery pack.

Rolls-Royce hopes to top Siemens’ record of 210 mph (338 kilometers per hour) set in 2017.  That was with a thick-winged aerobatic craft, so R-R has a grand opportunity with its ACCEL (Accelerating the Electrification of Flight).program

Rolls-Royce is no stranger to speed records, its “R”-type engine having been used in the 1932Supermarine S.6B floatplane racer to reach 343 mph (552 km/hr.)  as revolutionary as the S.6B was 88 years ago, The Spirit of Innovation will be as spectacularly new.

1931 record holding Supermarine S.6B in London’s Science Museum under wing of Spitfire fighter it helped to inspire

Matheu Parr, ACCEL Project Manager for Rolls-Royce, says, “This plane will be powered by a state-of-the-art electrical system and the most powerful battery ever built for flight. In the year ahead, we’re going to demonstrate its abilities in demanding test environments before going for gold in 2020 from a landing strip on the Welsh coastline.”

As shown in the company video, the aircraft uses three 750 R YASA motors putting out a combined 750 maximum kilowatts – enough to power 250 homes.  All that power will be absorbed by a single adjustable-pitch, three-bladed propeller turning at 2,400 rpm.  6,000 cells in the battery pack that Rolls claims to be the most energy-dense to ever be installed in an aircraft will provide 750 Volts. Sensors monitoring 20,000 in the power train will provide lots of data for engineers to ruminate on.

Battery pack will be the most energy dense ever produced, according to Rolls-Royce

High voltages produce heat, and an Active Thermal Management System cooling radiator will keep things cool during even a 200-mile flight of which the airplane is capable.  .

As Rolls-Royce explains, “ACCEL is partly funded by the UK government and involves a host of partners including electric motor and controller manufacturer YASA and the aviation start-up Electroflight.”  The Aerospace Technology Institute provides government and industry consultation and assistance.

Three YASA (Yokeless and Segmented Armature) motors are products of Oxford University research

“The team brings together some of the top minds from the world of Formula E racing to help design the e-racer.”

 The record runs may bring back the glory days of British aviation and the Spirit of Innovation might be the precursor of something as consequential as the Spitfire that sprang from the mind of the S.6B’s designer, Reginald Mitchell.


Two European states that will benefit from the electrification of short-range airline flights are becoming strong proponents of new technology.

 Norwegian Would

The Guardian headlined its article on greener airlines this way: “Norway aims for all short-haul flights to be 100% electric by 2040.”   A subheadline explained, “It already has more electric cars than any other country in the world and also has shipping projects underway.”  That’s in terms of market share, with electric and hybrid vehicles representing more than half of new car registrations in 2017.

A Norwegian Airlines Boeing 737. The country’s short-haul airliners are set to be entirely electric by 2040. Photograph: Alamy

 Avinor, the public operation of Norway’s airports, says short-haul airliners should be entirely electric by 2040, cementing the Nordic nation’s role as a pioneer in the field of electric transport.  Chief executive Dag Falk-Petersen promised Norway, “Aims to be the first in the world” to make the switch to electric air transport.

He added, “We think that all flights lasting up to 1.5 hours can be flown by aircraft that are entirely electric,” noting that would cover all domestic flights and those to neighboring Scandinavian capitals.  Even more promising, “When we will have reached our goal, air travel will no longer be a problem for the climate, it will be a solution.”

Electrification will help reduce the 2.4-percent of greenhouse gas emissions for which aviation is responsible in the country – double that amount when international flights are included.  Icing on the cake, noise and operating costs can be halved.

Even though the country is the largest oil and gas transporter in Western Europe, Norway is dedicated to leading in electric transport, and plans on testing commercial routes with 19-seat electric airplanes starting in 2025.

While ultimate electric aviation is in the wings, Avinor said it would need to use intermediary technologies, such as biofuels and hybrid fuel-electric solutions.

The Netherlands Opens a Living Lab

The Netherlands Aerospace Centre (NLR) has opened an 18,000 square meter (175,300 square feet) research installations and offices in Marknesse.  Together with PwC, a multi-disciplinary consulting firm, NLR revealed its electric Pipistrel Alpha Electro, which will be deployed as a research aircraft in NLR’s new Living Lab for Electric Flight.  Cora van Nieuwenhuizen, Dutch Minister of Infrastructure and Water Management, opened the Lab, stating,  “The Netherlands is highly successful in aerospace technology. This is precisely how it should be, because demand for air transport is continuing to grow. But we can’t simply go on building more and more planes. The aircraft also need to be lighter, must be equipped with new technology and have more economical engines. They present new challenges and we must look for the answers. Wherever new ideas must lead to new possibilities, there is a need for incubators. This new NLR complex is such an incubator.”

Cora van Nieuwenhuizen opened NLR’s Living Lab with challenging remarks

PwC’s donation to NLR enabled the purchase of the Pipistrel– a testbed for development of sustainable aviation.  According to the NLR, “The donation fits in with PwC’s ambition to be a circular and CO2-neutral business in 2030. PwC has been  monetising its CO2emissions since 2017 and uses this budget firstly to reduce and then to offset emissions. Among other things PwC is stimulating on-line conferencing, international travel by train and electric driving. The company is additionally investing in sustainable mobility innovations by bringing in knowledge and money. ‘There’s a lot more to gain in aviation’, said Michael de Ridder, CFO and COO of PwC. ‘With this donation, PwC wants to make a contribution to accelerating the transition to electric flight. As a user, an international organisation with clients worldwide, we want to take our responsibility by pursuing CO2 reduction, offsetting and innovation.’”

Jeffrey Engler of Wright Electric and Easyjet are collaborating on a near-future electric airliner.  Will this be it?

NLR will use the Pipistrel Alpha Electro to research how to increase the craft’s  range “by using new battery technology or a fuel cell and aerodynamic enhancements.”

Jeffrey Engler at the NLR Electric flight Symposium
The Living Lab’s opening  included a mini-symposium called “Electric flight in 2050: dream or opportunities for the Netherlands?”   A “sizeable representation of the Dutch aerospace sector” attended, and heard  Jeff Engler, CEO of start-up Wright Electric of Los Angeles, who gave a presentation.  Wright Electric partners with easyJet and has a goal to “develop a completely electric aircraft capable of operating flights with 150 passengers over distances of around 540 kilometers, such as between Amsterdam and London or Paris, within 10 to 20 years.”

The Delft Hyperloop, Solar Car Twente, and Ehang  attended the opening and displayed their models.


With over 125 electric vertical takeoff and landing aircraft in various stages of design and even flight test, we thought we would check in on three interesting prospects.

The Lift Hexa

Lift Aircraft of Austin, Texas promotes its 18-rotor single seater as, “THE WORLDS FIRST PERSONAL FLYING EXPERIENCE FOR EVERYONE.”  Looking a great deal like a skinny Volocopter, the Hexa shares many of its design attributes.  It’s “… triply redundant autopilot computer with a single, 3-axis joystick is all that is needed to fly. Or tap on the seven inch touchscreen in “Look mom, no hands!” mode.”  According to the firm’s web site, one can learn to fly Hexa with a few hours on a flight simulator and a brief session of personal instruction.

If things go wrong, Hexa can maintain flight with six motors out.  Airbags and a ballistic parachute will provide a rescue.  The four perimeter floats that comprise the landing gear will help soften any impact, as well as enable amphibious operation.

Flights will be limited to eight to 15 minutes, with ground monitoring and even remote control if a pilots gets in trouble.  Saqib Shah of  Engadget describes those short hops this way: “Lift is promising flight experiences at hubs located in “scenic, uncongested areas” in 25 cities across the US. Because the Hexa doesn’t count as a “real” aircraft (it’s a “powered ultralight”) it doesn’t require a pilot’s license. However, you also can’t go past a few hundred feet of altitude or fly over populated areas.

Hexa batteries plug in under each motor/rotor combination

Here’s how it will work: if you decide to fork out around $150-$200 for the experience on a day out, you’ll first have to complete a VR training simulator. Budding pilots must be over 18 years of age, up to 6 foot 5 inches in height and weigh under 250Ibs. You’ll then be able to take to the skies for up to 15 minutes at a time, controlling the drone using a joystick and an  iPad, while its onboard computer keeps it stable.”

CEO Matt Chasen told New Atlas that communities around these flight centers might have to get used to these not totally silent aircraft buzzing overhead.  Even as small and light as they are, the worries of a fairly substantial lump falling on one can bring about local resistance.  That is still an obstacle Uber and other flight services will have to confront.

Skylys AO

Presented as YouTube video without a great deal of technical insight, this is so far a computer generated image, but with a promise to fly an actual craft on January 12.  Stay tuned.

 Bladeless Drone: First Flight

Stefano Rivellini is a student at Valley Christian High School in San Francisco, California.  Concerned about the flailing blades on conventional multicopters, he worked to evolve a safer approach something a bit like a Dyson bladeless fan, but with applications for Uber or Amazon flights.

Stefano explains his process: “With 4 ducted fans, and some carbon fiber, I built a bladeless drone that I think is one of safest in the world. It uses 4, 90mm ducted fan propulsion units buried deep inside what I call a ‘bent tube’ propulsor. The fifth ‘leg’ is a parachute can. Hopefully I will never need it. With some help from my dad, we built the entire airframe primarily out of carbon fiber and some balsa wood.  I bought all the electronics on line and was able to design the drone so that it would operate with a standard DJI multi rotor flight controller even though it doesn’t have vertically oriented propellers. With its top mesh installed its virtually impossible to get fingers and objects in contact with the blades. I submitted a patent application for my invention. I think a drone like this could have industrial applications where a drone needs to operate close to people, objects, and in confined spaces to do inspection and other activities.
I am in the middle of applying to Aerospace Engineering schools right now so I don’t have much time to keep working on this until my applications are all in. I hope you like the video.

One thing to note: the centralized mass of motors and fans concentrates weight in the center of the machine, possibly leading to enhanced maneuverability.  Kudos to Stefano for thinking about operational safety – a prime concern if we’re to see more of these machines flying.


Things are Looking up in Dubai

Clean Technica recently examined whether the United Arab Emirates, and especially Dubai could become a world leader in clean mobility. It lists factors such as one of the heaviest concentrations of concentration of EV charging facilities in the world, and the sizable discounts the state gives on EV ownership. The state’s relationship with electric car suppliers and readiness to test sky taxis from eHang and Volocopter add to the mix. Dubai has its homegrown flight vehicles that will add to the aerial circus in its desert skies. DGWorld, a major source of robotics in the country, has two such craft on the horizon.

DG World’s Contribution

The smaller of the two, the “flagship drone of DGWorld,” the UAD M20 has a 19.5 kilogram (43 pounds) maximum weight borne aloft on 2.15 meter (seven foot) wings. At least two of its six motors can tilt to allow vertical takeoffs and landings and its fixed wings enable high-speed forward flight. Able to carry a five kilogram (11 pound) payload, the machine offers flexibility in mission.

UAD M20 can carry five kilogram (11 pound) payload and clean windows

What caught your editor’s eye was the possible use for washing windows, a useful application for all the 2,000-foot plus skyscrapers in the urban area. Fully autonomous flight and a “powerful” autopilot “allow “personalized missions.” A return-home function and parachute enable missions without “fear of damages or injuries,” according to DG World.

A People Carrier

DGWorld’s largest Drone, the UAD M470, is equipped to deliver people and bulky items to various destinations. Its six rotatable motors, producing almost 400 kW (536 horsepower), enable VTOL operation or up to 215 kilometer-per-hour (134 mph) forward flight. Like its smaller cousin, the M470 has an array of fail-safe devices and a full-aircraft parachute to reduce or eliminate harm to the craft, its cargo, or most importantly, its passengers.

DGWorld promotes its crafts’ ability to communicate with other aircraft automatically, “preventing its presence in the airspace from interfering with any other aircraft unnecessarily.” One can only wonder under what circumstances necessary interference would take place.

UAD M470 has six rotatable propellers of apparently advanced design

Like its smaller cousin, it can leap over tall buildings, and its size enables “a huge leap in the fire-fighting field in terms of ease, safety and accessibility as a first responder for reacting to the fire sources in high-rise buildings, towers, metro stations, etc…” Recent fires in Dubai’s high rise dwellings show the necessity for equipment that can reach far beyond conventional hook-and-ladder type units.

DGWorld has an impressive lineup of ground and aerial robotics and government backing that might make them a firm competitor for the German and Japanese drones and sky taxis testing Duaian skies. Similar in configuration and operation to the Joby S2 or S4, the M20 and M470 will be interesting to see in actuality.


Look What Fred To Started!

Forty years ago today, Fred To’s Solar One flew the length of the runway at Lasham Airfield in Hampshire, England, solely on the energy derived from the weak winter illumination and stored in a small set of ni-cad batteries..

With his partner David Williams, he had built the wooden, model-aircraft-like structure in a farm building, visited by the farm’s horses and pigs.

Flanked by pilots Ken Stewart (left) and Bill Maidment (right), David Williams and Fred To display their successful solar aircraft

The airplane went on to be displayed at various airshows, and Fred went on to build an inflatable 100-foot-span flying wing that was the first to use “fly-by-wire” technology.  His inventiveness and design skills have informed many projects, as we reported in our November 2018 report on the award ceremony Fred recently attended.

In short form, much has happened since then  Larry Mauro flew his Solar Riser ultralight at Flabob Airport, California on April 29, 1979.  Much like Fred, who had limited funds, Larry could could install only 350 Watts of solar panels on his wing, a limitation that required three hours to charge the craft’s batteries, and allowed an 800 meter (2,600 foot) flight at between one-an-one-half and five meters (five to 16 feet) altitude.

Solar Riser lifting off at Flabob airport, 1979

Both had to make do with small motors (Solar Riser had on five-horsepower motor: Solar One had four small motors ganged together with a belt drive).  Their solar cells were low-efficiency items and ni-cad batteries stored a fraction of the energy today’s best lithium-ion cells manage.

Fred and Larry were true pioneers who had grand aspirations.  Even they could not have seen the rapid progress started by their early efforts, though.  In 1981, Paul MacCready’s team flew Solar Challenger from Paris to England.  In 1991, Eric Raymond flew Sunseeker 1 across the United States.  With the kind of financing Fred To and Dave Williams would have only dreamed of, Solar Impulse flew around the world on solar power – the pinnacle so far of what’s possible.

But we owe Fred To the honor of that grand first – the first solar-powered, human-carrying flight 40 years ago.


Simulations May Stimulate Better Hybrids

Phillip Ansell, assistant professor in the Department of Aerospace Engineering in the College of Engineering at the University of Illinois explains the benefits and downsides of fossil fuels. “Jet fuel and aviation gasoline are easy to store on an airplane. They are compact and lightweight when compared to the amount of energy they provide. Unfortunately, the actual combustion process is very inefficient. We’re harnessing only a small fraction of that energy but we currently don’t have electrical storage systems that can compete with that.”

Ansell and colleagues are striving to use simulations to increase the range of hybrid aircraft.     Batteries provide their own set of problems. He explains that adding more batteries to go farther may have a certain logic, for example, but increases weight – a big detriment.

“That’s one of the big barriers we run into when designing battery-powered electrified aircraft. The current technology has very significant range disadvantages. But strong fuel-burn advantages.”

eVTOL News recently noted that over 125 electric or hybrid eVTOL aircraft are under development or now flying. Because a large proportion of these craft rely on lifting the total weight of the vehicle and its occupants with only downward-pushing rotors or fans, the lift has to equal the weight, obviating the use of only batteries for energy storage.

Hybrids rule for this application, and several groups are researching and developing improved hybrid technology to meet the need. Since Uber is leading the way on a great many fronts, and asking for vehicles that might weigh 5,000 pounds at their all-up weight, hybrids are currently the only way to haul the load any appreciable distance.

Gabrielle Wroblewski and Phillip Ansell

Ansell, former aerospace undergraduate student Tyler Dean, and current doctoral student Gabrielle Wroblewski, set a baseline performance simulation of the twin-engine testbed in its original configuration, and then performed a series of simulations to model the performance of hybrid-electric variants of that aircraft.

Modeling some of their work on that of the X-57 team at NASA’s Armstrong Flight Research Center at Edwards Air Force Base in the Mojave Desert of California, the team chose a Tecnam P2006T as their base aircraft. Interestingly, the Illinois team is investigating both parallel hybrid and serial hybrid propulsion on their model – Parallel hybrid systems combine the output from the internal combustion engine with that of the electric motor. Serial hybrids power their motors from a central engine/generator that charges the batteries for a number of electric motors.

Ansell explains the process. “We started with an existing twin-engine aircraft and looked at how we might create a hybrid-electric drivetrain for it using existing off-the-shelf hardware. We wanted to know how well it would perform. If I used a certain set of drivetrain components, I want to know how far the aircraft could fly, how much fuel does it burn, how fast can if climb—all of the overall flight performance changes.”

This figure shows the a) parallel and b) series drivetrain models.

The University reports, “After configuring the simulator to collect baseline performance data, a parallel hybrid drivetrain was integrated into the simulation. The researchers compared the sensitivity of range and fuel economy to the level of electrification, battery specific energy density, and electric motor power density. The same sensitivities were studied with a series hybrid-electric drivetrain.”

Ansell looks for “substantial improvements in fuel efficiency in a given aircraft configuration” for a given configuration, with variations for the amount of electrification and the required mission range. Short-range missions are best for fuel efficiency, evidenced by the 25-percents propulsive power coming from an electric motor in the current version – but only for 80 miles range. Ansell and his team anticipate that by 2030, battery advances will increase that range “two and a half to three times.”

Ansell adds one fascinating comparison. “One interesting and unexpected result we observed, however, came about when comparing the parallel and series hybrid architectures. Since the parallel architecture mechanically couples the shaft power of the engine and motor together, only one electrical machine is needed. For the series architecture, a generator is also needed to convert the engine power to electrical power, along with a larger motor than the parallel hybrid configuration to drive the propulsor. Unexpectedly, this aspect made the parallel architecture more beneficial for improved range and fuel burn almost across the board due to its lighter weight. However, we did observe that if significant improvements are made in maturing electrical motor components in the very long term, we may actually someday see better efficiency out of series-hybrid architectures, as they permit a greater flexibility in the placement and distribution of propulsors.”

The study, “Mission Analysis and Component-Level Sensitivity Study of Hybrid-Electric General Aviation Propulsion Systems,” was conducted by Tyler Dean, Gabrielle Wroblewski, and Phillip Ansell. It appears in the Journal of Aircraft.

This project was supported by NASA Neil A. Armstrong Flight Research Center under Small Business Technology Transfer in collaboration with Rolling Hills Research Corporation.


Sunnyvale, California-based Amprius kept a low profile for several years, despite its founder, Yi Cui, being a leading light in battery development.  Their December 4th press release, though, finds the company to be in a more open mood, their advanced lithium-ion cells with 100-percent silicon anodes having flown Airbus’ Zephyr High Altitude Pseudo Satellite (HAPS) for over 25 days, “setting a new endurance and altitude record for stratospheric flight.”

This milestone represents a great leap forward since Alan Cocconi flew his So Long solar-powered model for 48 hours, the first of many projects of which he would be an integral part, and the first solar airplane to fly overnight.  He worked on the General Motors EV1 and Eric Raymond’s Sunseeker 1 – just a small part of the automobiles and aircraft which he would help create or refine.

Amprius performance with silicon nanowire anode compared to that of battery with graphite anode

Your editor first saw Cui at an early electric aircraft symposium nine years ago.  Cui discussed the benefits of developing silicon anodes in batteries, with a potential 10X increase in energy density.  Pitfalls surrounding that hoped-for outcome were plentiful, including the granulation and crumbling of silicon after repeated charge-recharge cycles.  Cui and his graduate students at Stanford University worked to counter this problem, fielding several solutions.  At some point, Cui and his colleagues apparently found an answer.

Roll-to-Roll processing machine combines silicon nanowires with chemical vapor deposition

Their breakthroughs are reinforced by the installation of a “revolutionary” roll-to-roll manufacturing tool which enables high-speed forming of three-dimensional silicon anodes. The tool, created in partnership with Meyer Burger (Netherlands) B.V., uses a multi-step, Chemical Vapor Deposition (CVD) process.

In a 2008 Nature Nanotechnology paper, Stanford Professor Yi Cui and team unveiled a nanowire design that enables using ultra-high-capacity silicon in a lithium-ion battery in place of today’s carbon. The thin nanowire “hairs” allow the silicon to swell and shrink as it takes in lithium without fracturing. (Figure from Chan et al., 2008.)

Steven Chu, a Nobel Laureate and Amprius Board Member, explains this “very big step forward” enables Amprius to go beyond laboratory and pilot-scale manufacturing to “a significant advance towards high-volume and high-quality manufacturing.”

Silicon Valley venture capitalists provide funding, and Airbus has provided a huge platform on which to demonstrate Amprius’ capabilities.

The Zephyr Platform

The Zephyr platform is similar to other HAPS (High Altitude Pseudo Satellite) aircraft that almost hovers at stratospheric heights for indefinite periods.  Airbus points out that Zephyrs can be “used in a wide range of emerging applications, including maritime surveillance and services, border patrol missions, communications, forest fire detection and navigation.”

Sophie Thomas, Airbus’ HAPS Program Director, explains, “Our collaboration with Amprius in the application of their silicon nanowire based lithium ion cells to the Zephyr has been important to the success of the HAPS program.  The high specific energy of Amprius batteries enable the Zephyr to fly uninterrupted in the stratosphere which would not be possible with lower performance batteries. This will further extend the capability and utility of the Zephyr platform for our customers.”

Airbus is putting Zephyrs into series production, a plant at Farnborough,England  capable of turning out 30 of these persistent vehicles each year.  With the first to fly already having achieved 1,000 hours of flight time, those flight hours should grow with growing numbers of craft in service.  Just think of all the ground crews sending this largest of hand-launched aircraft skyward!