Dr. Ann Marie Sastry, CEO of Sakti3, Inc. of Ann Arbor, Michigan, has been quietly working on a high-energy-density battery that would use mass production platforms with “fully scalable equipment” that would take us to the next level of development.
Dr. Ann Marie Sastry with laboratory-scale equipment
Sakti announced this week that its new battery can store over 1,100 Watt hours per liter (Wh/l) in volumetric energy density, about two to four times that for conventional cells. Scientific American reports 1,143 Wh/l. According to Sakti’s release, “This translates to more than double the usage time in a wearable device like a smartwatch, from 3.5 hours to more than 9 hours. It also translates to almost double the range in an EV like the Tesla Model S, from 265 miles to 480 miles.”
Besides the performance improvement, Sakti claims to be able to produce the new, solid-state battery that would rely on a “full scale plant layout to avoid any high cost materials, equipment or processes.” Professor Wei Lu from the University of Michigan is a battery expert knowledgeable about the process – and also having no financial or other interest in Sakti3. “It’s not either/or in cost and performance in batteries anymore – Sakti3 has both. They built a really high performance device on a really low cost platform – like building millions of high end processors in a factory that produces ordinary plastic wrap. It was quite a scientific feat.”
He vouches for the accuracy of the Sakti numbers. “They have a very rigorous testing facility. Their results are highly impressive and very accurate.”
No, that’s a statement and not a question. Taja Boscarol of Pipistrel sent the following announcement this morning. WATTsUP, their new two-seat electric trainer took its maiden flight on August 8th. As part of its 25th anniversary celebrations, Pipistrel will display the airplane at the Salon de Blois airshow, France, on 30-31 August 2014.
Looking a great deal like the Pipistrel Alpha trainer, WATTsUP makes its maiden flight
This is the third announcement of an electric trainer by a major aircraft manufacturer, counting Airbus with its anticipated e-Fan developments and American Electric Aircraft Corporation (AEAC) with its Sun Flyer. We could count four with Adventure Aircraft’s EMG-6 under development in California for the ultralight market. This would mark a potentially historic turnaround for General Aviation, with promised operating costs significantly lower than for internal-combustion powered machines, and by inference, lower rental costs for student pilots.
One of the most exciting parts of the announcement – the price: “Pipistrel expects to bring the final product to the market in 2015 with a target price below 100,000 EUR ($135,000),” according to their press release. Sun Flyer and e-Fans are also expected to be within the upper range of Light Sport Aircraft prices, making for a potentially competitive and technologically rich new market segment.
Siemens, a partner in the endeavor, may also supply the electric motor and other components for the Hypstair (anyone notice a Slovenian tendency to pun?), the hybrid version of the Pipistrel Panthera. With two motors in the 85 kilowatt (114 horsepower) and 150 kW (201 hp. continuous) ranges, Siemens seems dedicated to becoming a participant in this new area. The 85 kW motor weighs only 14 kilograms (30.8 pounds), more powerful and much lighter than the Rotax 912 series engines typically found on microlights and LSAs. It’s heartening that the motor is being built by Siemens, 53rd on the Forbes’ list of the Global 2,000 companies. For comparison, General Motors is 67th on the list.
Siemens 85 kW motor takes up little space under the cowling
Much of that weight savings will be offset by the 17-kilowatt-hour battery, a “dual-redundant” package that can be swapped in a few minutes or recharged in less than an hour, “thanks to the next generation of Pipistrel’s Battery Management technology.” The motor/battery combination will give an hour’s endurance with a 30-minute reserve. Tailored for flight schools, WATTsUP will take off quickly, climb at over 1000 feet-per-minute, and, it’s claimed, recover 13 percent of the energy from every approach. Tine Tomazic, the company’s Chief Designer, emphasized at last year’s Electric Aircraft Symposium that regeneration would depend on a steep descent and a special training regimen for students learning in the electric trainer.
Propeller on WATTsUP seems to follow design concepts of Jack Norris, who holds 50 NASA patents, may contribute to regeneration on approach
Because it’s based on existing Pipistrel airframes, Ivo Boscarol, CEO of Pipistrel, may be correct in saying: “With the ever growing cost of fuel it is time to rethink pilot training. Our solution is the first practical all-electric trainer!” As do AEAC and Airbus, he advocates the economy of operation for the craft. “Technologies developed specially for this aircraft cut the cost of ab-initio pilot training by as much as 70 percent, making flying more affordable than ever before. Being able to conduct training on smaller airfields closer to towns with zero C02 emissions and minimum noise is also a game changer! WATTsUP meets microlight and ASTM LSA criteria, as well as standards for electric propulsion and is already certified in France. More countries will follow soon and we are applying for an exemption with the FAA to allow training operations as an S-LSA. WATTsUP is our 5th electric aircraft project and the second to result in a commercial product.”
Frank Anton, Executive Vice President Traction Drives, Large Drives, Siemens AG is quoted as saying: “Siemens is developing electric drive systems with highest power-to-weight ratio for aircraft propulsion. Only with innovation we can solve the problems of rising fuel costs, rising passenger demand and rising environmental regulations. Innovations used in the WATTsUP will be instrumental in making aviation more sustainable in the long run. As electric drives are scalable, we can expect that in the future also larger aircraft will use electric propulsion. The world is becoming electric, whether in the air, on land or at sea.”
The StroudLife headline reads, “Williams F1 boffins link-up with Nympsfield world record electric plane bid.” A boffin, in English parlance, is “a person engaged in scientific or technical research,” or “a person with knowledge or a skill considered to be complex, arcane, and difficult.”
Two years ago, the Blog reported on the TEACO Bat, a Formula 1 race plane to be powered by batteries and set to take on the world speed record for electric airplanes. Since then, the company has changed its name to Electroflight, partly because Internet inquiries often sent inquirers to TESCO, a grocery retail company. There should be less confusion now.
Electroflight Bat could hit 306 mph if builders’ plans prevail
“The ‘current’ speed record for electrically-powered flight stands at 220 mph but the tie up means they are aiming high.
“Williams Advanced Engineering is the technology and engineering services business of the Williams group of companies that includes the world famous Williams Martini Racing Formula One team.
“’Our calculated level flight speed for our Electroflight Bat, will be 306 mph,’ said Roger Targett of the firm based in Nympsfield.
Bat on display at trade show drew large crowds, including school children who took “rides” in F1 racer
“’We have just had a great weekend exhibiting our Bat project at the Red Bull Air Race at Ascot.
“’There was a huge amount of interest and large numbers of people, mainly children, queuing to sit in the cockpit of our space allocation fuselage.’”
Electroflight anticipates using advanced technology to achieve a level-flight speed of 306 mph with its dual-motor, dual contra-rotating propeller racer. The motor setup, while not well-defined in the press reports, appears to be similar to that used in American Electric Aircraft Corporation’s Sun Flyer, but with obviously greater power than the training aircraft requires.
Dual, contra-rotating props powered by Electropulsion power system will set new speed records, builders hope
The carbon composite airframe will manage the 10 G’s stress imparted by the “unique maneuvering capabilities” of the dual propellers. As Electroflight explains, “The airframe is designed for pure electric propulsion and the ground up design contains no elements attributable to piston or jet engine technology.” It includes a whole aircraft ballistic parachute system with pilot safety cell (similar to those of F1 cars and at least partly attributable to their partnership with Williams), and purpose-designed compartments for batteries, controllers, and electronic equipment.
The company will build “a range of single and multi-person units” powered by their “single and dual contra-rotating propulsion systems for sale through an associated company – Electropulsion.”
We look forward to more in-depth information on the company’s motors and batteries. Their ambitions are noteworthy and, we hope, will lead to increased performance for electric aircraft.
Calin Cologan and George Bye staged a joint press event on the Sunday evening before AirVenture started. Held in the Redbird Tent on Wittman Field, it drew hundreds who saw the Redbird flight simulators and a Diesel-powered Cessna, but were stopped short by the yellow and blue Sun Flyer, a single-seat proof-of-concept version of what will soon be a two-seat battery/solar training aircraft.
Forming a new firm based on the strengths of PC-Aero in Germany, and Bye Aerospace and Redbird Flight Simulators in America, they promise an electric training aircraft for the near future. Unlike the tandem two-seaters PC-Aero is developing in Germany, American Electric Aircraft Corporation will produce a side-by-side craft, often preferred for communication between instructor and student.
In this Da Vinci Institute presentation, George Bye discusses the keys to performance for his aircraft, which include clean aerodynamics, high efficiency, a light carbon structure, and solar energy. Nest will come a “big performance step – endurance” – and possible perpetual flight like that demonstrated by the much bigger, less practical Solar Impulse and being approached by Eric Raymond’s Solar-Flight Duo.
Part of AEAC’s strategy is to use proven off-the- shelf components, advanced technology, miniaturization, and emerging aerospace design to bring a complete, modern machine onto the training scene. The strategy will bring flexible, innovative, and scalable design and manufacturing techniques to the fore, enabled by an experienced team with years of aerospace expertise.
Stealth is Good for Civilian Aircraft, Too
Sun Flyer, as with other electric aircraft, has several aspects that make it commercially-viable for training or unmanned use, including a low heat signature that comes from the lack of hot exhaust. Large, wide propeller blades turn slowly, giving half the acoustic signature of conventional small General Aviation aircraft. The unobtrusive nature of the airplane allows the unmanned version to stay, listen, and watch – highly attractive to the Defense Department.
StratoAirNet UAV with potential military and civilian uses
This leads to a concept developed by Bye and Gologan, StratoAirNet, a persistent network of medium-to-high altitude aircraft that can provide applications in “communications, border patrol and homeland security, maritime search and rescue, visual and thermal reconnaissance and forward air control. Potential civil applications include traffic control, pipeline and power line inspection, aerial law enforcement, wildlife and natural resource monitoring, forest fire detection, weather monitoring and aerial photography.”
Characteristics that allow low-cost surveillance equate to reasonable operational costs for flight schools. Part of that is the low empty weight of the concept airplane, 150 kilograms (331 pounds), with batteries adding 80 kilograms or 176 pounds to that. In the surveillance version, this allows a payload of 150 pounds. For the trainer, LSA-type numbers will prevail, with an empty weight of 280 kilograms (616 pounds) empty weight including batteries, a payload of 200 kilograms (440 pounds), and a flying weight of 600 kilograms (1,320 pounds). The poster at the Redwing tent showed a power output from the Eck/Geiger HPD-25 motor of 26 kilowatts (34.8 horsepower) continuous and 30 kW (40.2 hp.) peak power for a limited time.
Shari Rossi, a member of the AEAC Board of Directors, shows a light touch on the Sun Flyer
The nine-kilogram (20-pound) motors give twin-motor safety with single-motor operation. Dual controllers add about two pounds to the power system. Two throttles can be individually operated, or combined to use the full power of both motors for takeoff or climb. Since the clean, light airframe requires only six kilowatts (8 hp.) to maintain level flight at 50 knots (57.5 mph), the airplane should be able to stay aloft for over three hours on its 18 kilowatt-hour battery pack at that speed. At full throttle(s) it can climb 700 feet per minute. Of course, normal training regimens will include tough-and-goes, maneuvers, and higher-speed operations that will reduce that best-glide-speed type endurance. Some indicators show a 52-kW (70-horsepower) version of the dual motor may be available, which would certainly enhance climb performance.
To augment that, the airplane has Solar World thin-film photovoltaic cells that can add a maximum of up to 1.3 kW of energy. These cells add minimal weight for their 7 square meters (75.3 square feet) of conservatively-calculated area. According to Calin Gologan, “The cells weigh about 0.5 kilogram (1.1 pounds) per square meter, the layers 0.2 kg (0.44 pounds).” Wiring adds about 0.1 kg (0.22 pounds). This totals about 0.8 kilograms (1.76 pounds) per square meter, or about 0.16 pounds per square foot. The seven square meters of solar cells thus add about 12.3 pounds to the aircraft’s weight. Since they are 22-percent efficient, Calin calculates them as providing 220 Watts per square meter, or a maximum of 1.54 kW, about 20-percent of the energy required for low cruise. Calculations for endurance are based on the currently installed batteries and their 250 Watt-hour per kilogram performance. AEAC anticipates having 400 Watt-hour per kilogram batteries soon.
The cells cost about 350 euros ($465) per square meter, two layers of thin glass laminations which form a flexible and protective matrix cost about 660 euros per square meter, and this totals about $1,000 euros ($1,330) per square meter ($124 per square foot). The solar cells add 7,000 Euros ($9,310) to the cost of the airplane, but allow free recharging of the batteries as the airplane is parked, and add to the endurance and range in the air.
Note that Charlie Johnson estimates a price for the two-seat trainer at under $180,000, certainly not out of touch with the market or out of line with other LSA-type aircraft. AEAC has a truly disruptive card up its sleeve, though – an operating cost of $10 per hour, including an hourly allowance for battery replacement. Calin, George and Charlie all hope this will lead to a resurgence in flight training and a rebirth of the General Aviation market. Coupled with new aircraft promised from Airbus and rising interest in electric ultralights, we may soon witness a quiet buzz at our local flying fields.
Call it Kismet, but three aircraft builders in wide-spread locations have recently announced similar approaches to putting a pusher propeller on the tail boom of three different ultralight sailplanes. Each enjoys the benefits of mounting a propeller on a rear portion of a pod-and-boom fuselage: streamlining the folded propeller into the wake of fuselage/wing junction, enabling use of a large propeller, and turning the prop slowly to get the greatest efficiency from a small motor.
Moyes Tempest from Down Under
“Bodex,” a pilot in Brisbane, Australia write, “A mate and I managed to acquire two old Moyes Tempests last year. Although they fly well for what they are, we wanted to see if it could be converted to electric in the hope of getting a self-launch from it.
Moyes Tempest is ultralight sailplane that might lend itself to self-launching
“Originally the idea was going to mount the motor behind the fuselage under the boom, but ground clearance was a problem. Then we thought nose mounting, ground clearance again…even with a dolly launch idea.
“We then thought about a boom mounted pusher prop…. The idea was to have the reduction pulley mounted on the tail boom using a roller bearing, the carbon prop blades then bolt to the pulley which is driven from the drive shaft below.
Plettenberg Motor drives larger diameter propeller drive mounted on large bearing around tail boom
After a two-stroke engine failed to live up to hopes, the builders used an available Plettenberg predator 37 brushless outrunner from an electric trike and within 10 minutes, the airplane was ready for a test run. The reduction drive was based on the gas engine’s 7,500 rpm to give about 2,600 rpm at the propeller. The Plettenburg would require 65 Volts to turn over at the appropriate speed, “So I decided on an 18s[eries] lipo pack. I ordered 8x 8s 5800 mah packs from Hobby King and wired them to a [battery management system -BMS] in a 16s4p[arallel] configuration to give me 23.2Ah of usefulness. The pack came out at 7kg (15,4 pounds) and charges and balances through an inbuilt BMS.”
“To control the power I used an Alien power systems 450A speed controller. A linear pot running through a servo tester provides the signal. A [high voltage] contactor provides a safeguard between the battery and controller; two switches on the throttle quadrant control everything in the aircraft. A Vincon battery monitor provides data on power used, current draw, voltage, time to go, etc.”
Two test flights showed that at least after an initial aero tow the airplane could manage a 200 fpm rate of climb, even though full power was not available because of a programming error. The second flight brought about an overheated controller, so the partners are taking time to regroup.
e-Sirius from France
The Club d’Ultra Léger d’Alsace, a group of French enthusiasts in Strasbourg, France, recently announced “A new concept of electric brushless outrunner motor mounted on the motor glider Sirius C with the motor around the tube fuselage and the propeller blades fixed on the outdoor circumference of the rotor.
Ultralight Sirius C motorized by Club d’ultra legere of Alsace, France
”The advantages of such a solution are:
- Use [of] a large folding propeller
- Minimum drag of all motor and propeller
Similar to system on Australian Tempest, large bearing, folding propeller on Sirius’ tail boom
- Good ventilation of the motor and the controller
The batteries are housed near the motor in the very sharp cockpit profiling.”
Unfortunately, the club did not give further details on the motor, controller, or batteries used.
Three-view drawing of GFW-4 shows the clean design, potential for great ultralight gliding performance.
The rear half of the GFW-4 will include 10 kW outrunner motor, with the three-blade propeller “lay at rest, streamlined in the recesses provided in the co-rotating outer rotor sleeve.” A “cooling air control,” mounted ahead of the motor, provides “sufficient cooling air. The battery is in a separate, removable housing.
The fuselage is a sandwich shell made of plywood, foam, glass-reinforced plastic (GRP), and carbon-fiber reinforced plastic (CFRP). Its 13.2 meter (43.3 feet) wing can enable the 239-kilogram (526 pound) airplane to reach a 34:1 glide ratio, certainly enough to find a thermal with a little electrical nudging.
Construction is well underway, and we’ll look forward to seeing how Dr. Wagner fares with his latest creation – and how similar efforts in France and Australia succeed. Good luck to all!
Aaron Singer, owner and operator of Seaplane Adventures, San Francisco with his wife Tiffany, gave an excellent assessment of why we don’t see more electric seaplanes in the mix of products coming into play. Pointing out that most water-borne efforts so far have been ultralights, such as Dale Kramer’s e-Lazair amphibian, he gave examples of the energy necessary to lift off from water and the how that plays in the daily use of a DeHavilland Beaver and Cessna 172 in which his team flies tourists around the Bay Area.
Their web site explains their mission. “The Singers bought San Francisco Seaplane Tours in January of this year and have rebranded the company as Seaplane Adventures and revamped the operation with a new logo, new energy and 100% passion for flying seaplanes in the Bay Area. We are in the Happy Business – it’s our job to bring to you a safe, exhilarating, beautiful, one-of-a-kind experience flying in a seaplane over San Francisco!”
For an 18-minute version of this video, try this link.
Singer gave a brief history of seaplane flight, showing that seaplanes were prevalent when there were no airports, even though they require more power to overcome the drag of water on their hulls during takeoff. Pilotfriend.comexplains the steps in getting a seaplane to lift from water.
The hydrodynamic drag builds to a “hump” at the apex of power required to break free from the water. A seaplane goes through four phases in taking off according to Pilotfriend.com:
(1) The “displacement” phase,
(2) the “hump” or “ploughing” phase,
(3) the “planing” or “on the step” phase,
and (4) the “lift off.”
Diagram shows engine thrust required to overcome drag of hull or floats on water, with critical “hump” to be overcome before flight is possible
A displacement hull is simply one that sits in the water, and can be motivated by oars, sails, or some type of paddle-wheel or screw arrangement. Its speed is limited to a number derived from the hull length (wildly oversimplified).
As a boat, or seaplane hull or floats begin to move forward faster, the airplane develops enough lift to start pulling the machine out of the water, it reaches that “hump” phase, where the greatest power is required. Once the seaplane’s hull or floats are “on the step” and planing partly above the water like a high-powered speedboat, the airplane accelerates more easily and quickly reaches takeoff speed. According to Singer, the “hump” is the biggest problem for electrification, requiring 1/3 of the total power used in a flight for ½ the weight that an electric seaplane will carry for the necessary batteries. An air taxi, such as those he and Tiffany run, would require additional energy storage because of the repeated demands made on their seaplanes each day.
To start on what will probably be a long research study of how much additional power is needed to get a seaplane over the hump, look at this X-Plane’s tutorial on the Froude Number, a non-dimensional figure as important to boats and seaplanes as a Reynolds Number is to the aeronautical design of airplanes. In fact, the Froude Number can help define the transition from laminar to turbulent flow, a big consideration in airfoil design, for instance.
The need for quick turnarounds would require either battery swapping or fast charging capabilities. With tourists keeping Singer’s airplanes busy all day, downtime is not an option. For designers who want to create a personal seaplane, though, such considerations are simplified or even eliminated. Thomas Brodeskift, for instance, has been designing and crafting a two-seat, hybrid-powered amphibian for several years now, the Equator P2 Excursion.
Whether you decide to head for Mill Valley to ride with Aaron, or want to be the first to fly an Equator P2, seaplane flying brings an added dimension to aerial sports. Let’s hope that electric power can add further to that dimension.
Applied Materials, located in Sunnyvale, California, designs and makes equipment used in the manufacture of computer chips and other miniature electronic devices. Your editor worked there on assignment from his engineering firm for six months 15 years ago, documenting and verifying the equipment and control systems for their newest facility. Even then, miniature was wild understatement, with the company crafting machinery that could produce 0.18 µm lines in silicon chips. In the last two decades, line widths have shrunk to 0.03 µm, and the number of elements on chips has increased proportionally. This makes nano manufacturing a highly precise endeavor, and one which seems to defy credulity with lower costs for the ever-increasing number of chips being made.
Toyota’s chart showing promise of solid-state battery as interim device between current Li-ion and Li-Air batteries
It’s this type of manufacturing expertise which makes possible the electronic life we lead today and one that relies increasingly on energy storage technology. The very things that make solid state computing possible could produce solid state batteries – an advantageous storage medium – if they can be produced in commercially viable quantities at a reasonable cost. MIT Technolology Reports quotes an Applied Materials scientist on this challenge. “’The thing that’s holding [solid-state batteries] back is materials processing and the cost,’ says Andy Chu, head of product marketing for energy storage solutions at Applied Materials. ‘We’re addressing these problems. That will allow you to take this to high volume.’”
Such batteries are available, but at high cost and therefore in limited applications. Applied Materials thinks it can make these batteries much cheaper using its manufacturing expertise. The company’s confidence is interesting, considering that Sakti3, Ann Marie Sastry’s firm, has been forging ahead on the commercial realization of solid-state cells with “robust processes” and scalable production systems, and that Toyota was reporting on its solid-state battery in 2010 – although they’ve only tested one on a small scooter so far.
Solid-state batteries replace the liquid electrolytes used in normal lithium-ion cells with solid ones, which according to the MIT article, “make it possible to replace conventional electrodes with lithium metal ones that hold far more energy.” Liquid electrolytes help fuel the flames during thermal runaways in conventional batteries, so their absence in solid-state batteries results in greater safety.
Toyota scooter powered by prototype solid-state battery
MIT’s article doesn’t specify to whom the tools have been shipped, but notes, “The manufacturing tools shipped so far by Applied Materials, which perform extremely high-precision deposition of materials over large areas, will be used initially for prototyping and demonstrations of solid-state batteries.”
This ability to produce electrode and electrolyte materials “over large areas” is a big challenge. The process requires depositing layers of contacts, electrodes and solid electrolyte in succession, and without gaps in the electrolyte that would lead to short circuits. Applied Materials claims to have conquered this challenge, and that un-named customers are now producing batteries with its tools. The company is also reticent about how much energy these existing batteries can store, how much they cost, or how quickly they can be recharged. Applied Materials will admit that their solid electrolyte is not yet as conductive as liquid equivalents, and therefore limits power output. The firm would also like to increase the speed with which their tools can deposit “energy-storing materials” faster, to produce thicker layers that store more energy.
First commercial applications will probably be in wearable items such as watches, or even in the watch bands. Because the batteries don’t have to fit the cylindrical or pouch-type form factor of more conventional energy storage cells, they could be incorporated in say, wing-shaped areas, or tucked into form-fitting nose cones.
Despite all the caveats and side-steps, MIT suggests that these batteries may be capable of storing twice the energy of existing lithium-ion cells or lasting twice as long in use. It may not be the promised land of the 10X battery, but it would be a significant advancement for electric vehicles.
No hype, Pipistrel’s Hypstair (hipster) was introduced by Tine Tomazic and Gregor Veble at this year’s Electric Aircraft Symposium. The attempt to bring the world’s first certified hybrid aircraft to market is a joint venture by Pipistrel with partners Siemens, the University of Maribor, the University of Pisa and MB Vision, a specialist in providing visual information.
Hypstair will integrate batteries and power train into a modified Panthera airframe
Siemens, as might be imagined, is providing an “ultra-light weight integrated drive train” for the aircraft,” Slovenia’s University of Maribor the HIL (hardware in the loop) evaluation for electric motor control testing and dynamic emulation of mechanical loads, Italy’s University of Pisa for evaluation of hybrid technology advantages, and MB Vision for development and integration of the aircraft’s interior and human machine interfaces that will make the information presented to the pilot ideally selected and intuitively perceived.
Wing-mounted batteries follow spar to distribute load of 12 serial/5 parallel modules
Far removed from the days when homebuilt aircraft advocates drew a chalk outline of the steel tubing they would weld together on the garage floor, the developing discipline of mechantronics stives to unite mechanical, electrical, telecommunications, control and computer engineering to produce integrated products that function at high levels. Such an approach will lead to aircraft that perform at the best possible levels, and a piloting experience intended to meld the pilot and the airplane in a thoroughly new and different way.
HMI design will lead to standardized cockpit environments, lower workloads for pilots
Tine and Gregor focused on the hybrid propulsion system for Hypstair, a serial hybrid drive that would lead to much quieter aircraft with greater fuel efficiency. Hypstair will allow validation of components, many already integrated into the airframe. The power system will swing a low-RPM, five-bladed propeller, ensuring low noise. To make sure the internal combustion engine, electric motor, controller and batteries stay within safe operating ranges, the sleek cowling has three openings, each tuned to its respective need. A dedicated battery management system (BMS) will actively balance cells in the battery pack, maintaining optimum performance at all times.
Intuitive perception and response to graphics will make flying easier and safer
The airplane’s human-machine interface (HMI) will enable a pilot to “fully utilize the benefits” of the on-board systems, while adding to the safety of operation. Tine Tomazic is leader of the American Society for Testing and Materials International (ASTM) team creating standards for such interfaces. He noted that “Nobody likes to contribute to standards – but likes it when they’re done.” This HMI will be a first for hybrid aircraft, and is being designed “To elevate safety and improve user experience.”
Color and perception play a big part in the visual ergonomics and pilot recognition of different situations, both safe and of concern. Good design here can add to the safety of operation and lower the pilot’s workload. Hard-to-read avionics can increase the workload, lead to high cognitive stress, and even a hostile cockpit environment. Tine is working to replace the glut of text and numbers in displays with standardized icons and to introduce a common layer of infographics.
On a fast track for a complex project, Hypstair could be a seminal aviation event soon
Couple the perceptual simplicity of the cockpit with true single-lever power control of the total power train with protections for the engine, motor and batteries, and the pilot can concentrate on flying the airplane. The position of the power handle will directly correspond to the airplane’s power output, an intuitive signal to the pilot. High power depends on the battery charge status, for instance, and the system will reduce the rate of power after a set time to reduce high discharge rates, although the pilot can enable overboost to overcome potentially dangerous situations.
With significant advances in structure, powerplant design, ergonomics and human factors, the Hypstair will be more than just a speedy, great-looking airplane. It may mark the beginning of new ways of integrating the aircraft, pilot and systems into a new and unified whole.
As for a question about the electric version of the Alpha Trainer announced at last year’s EAS, Tine left the audience with a twist of wry: “Development goes at the speed of cash.”
Several electric aircraft graced the flight lines and display tents at Oshkosh this year, while several that had flown in previous years stayed home. It shows a growing market segment – one apt to continue growing as batteries and components improve. The ultralight area showed the greatest number of new developments, with two aircraft showing how one might achieve battery-powered flight on a budget.
Chip Erwin and the Aviad MG-12 Zigolo
Several have noted the Aviad MG-12 “ Zigolo” (named after a small bird – not as some surmise, a “gigolo”) from Italy has the look of a Mike Sandlin Basic Ultralight Glider, although it also has elements of other early Part 103 machines and carries a complete aircraft kit price of $14,500. “Complete” includes a two-stroke, single cylinder Vittorazi Moster 185-cc engine. $1,500 adds a more advanced BRS ballistic recovery parachute, and another $1,500 nets a more complete, more quickly finished kit. Aviad claims the basic kit takes only 100 hours to complete, so a more finished option would be nearly ready to fly.
MG-12 Zigolo ready to fly – as it did several times during AirVenture
Imported by Chip Erwin, it is one of a stable of three aircraft, each with a specialized mission: besides the MG-12, Erwin fields the Mermaid LSA amphibian and the SC3D LSA – both made in China. The Zigolo, though, is intended as a low-cost way to enter sport flying.
As shown in the video, Zigolo flies like an ultralight, and seems to be very stable and a great platform on which to enjoy the open air and the scenery below. Pilots are protected by the surrounding structure; an impact skid under the pilot’s seat protects against heavy landings and a Comelli pneumatically-actuated ballistic parachute allows a gentle let-down if things truly get out of hand. A simple twist throttle on the control stick modulates the engine’s or motor’s speed, simplifying control and giving a flying motorcycle feel to the proceedings.
An electric motor option under development will add to the overall cost, but the complete airplane will still be priced well under $25,000. The Agni motor shown at Oshkosh is no longer available through Electravia, Anne Lavrand limiting her business these days to supplying her popular e-Props. One can still buy a Lynch or Agni motor (virtually the same motor made in different countries) from various suppliers, and find an appropriate controller and batteries for a true do-it-yourself adventure. One can also look through the options becoming increasingly available, including one on display in the Zigolo tent.
Don Linebacker’s concept motor. The shaft running through the motor’s core slides in and out, pivoting the mounts for the propeller blades and providing variable pitch
Donald Lineback, the motor’s designer, hopes to power many different craft with his creation, suitable for a single push or pull propeller configuration, twin or hybrid. The motor package will include the I. C. E. (Internally-Cooled-Electric) Motor, “A true outrunner with a motor controller,” a smart battery with built-in protection and the claimed lowest available weight-to-Amp-hours ratio; a smart charger which can connect to a generator or AC outlet, and a propeller designed for the pitch adjustment capabilities of the motor.
Now under evaluation to determine its production cost, the axial-flux motor runs at maximum efficiency at any RPM, according to Don. New lithium air (LiO2) batteries are claimed to deliver three times the power of lithium-ion cells, and Don is investigating that claim.
He notes that, “While [overall] airplane sales were scarce at the show – we found nearly 200 people interested in the potential for electric flight.”
Brian Carpenter and the EMG-6
Brian has been developing the EMG-6 for over two years, building a machine that uses wing and tail components from Quicksilver and a purpose-built fuselage that houses the first of probably several electric motors. He does all the prototyping at his Corning, California hangar and has come up with unique methods of hand-crafting carbon-fiber fairings, extruded foam gap seals, and battery packs fitted to the contours of the passenger seatback.
Simple configuration with basic fairings. Builders should familiarize themselves with different regulations regarding different forms of the machine
Showing videos of his 55th and 56th test flights, Brian drew appreciable and appreciative crowds to presentations in the Honda Forum tents. A constantly changing crowd in the ultralight area viewed the machine, with the motor, controller and battery packs on a table near the two prototypes on display highlighting the light weight and compact nature of the sustainer power system.
Adventure Aircraft sells the basic kit requiring some fabrication and welding for $12,000 and a fast-build kit requiring only assembly for $16,000. Either provides a low-cost entrée to ultralight, Experimental Amateur Built (EAB) gliding, but neither includes a power system. As with the MG-12, the EMG-6 would require only about 100 hours to complete a ready-to-fly aircraft. As Brian finishes work on the power system, those components will become available.
In the meantime, builders wanting to get a head start can download plans on a subscription basis and rent building jigs for the welded parts of the fuselage to simplify even the most labor-intense approach to getting a completed machine. Brian claims, “Between 25% to 40% of the aircraft’s total cost could be saved depending on your capability.”
The builder can start construction with “a minimal cost outlay,” and under one plan, purchase components individually or as complete subassembly kits “depending on budgetary constraints.”
EMG-6 battery stack can be as desired – as long as it fits within weight and balance limits
With machines on the field powered by a variety of electric powerplants and possessing a wide range of sophistication and performance, AirVenture 2014 offered a world of electric flight possibilities.
JoeBen Bevirt, founder and CEO of Joby Aviation, Joby Motors, and related enterprises, has thought long and hard about the financial costs and lost productivity brought about by the daily automotive commute, a 1.6 hour per day ordeal for many in our urban centers. JoeBen and the Atlantic magazine agree that commuters squander 5.5 billion hours and 2.9 billion gallons of fuel annually, stuck in the fitful despair of slow or unmoving traffic, sharing only frustration and polluted air with their fellow motorists.
JoeBen told attendees at the April Electric Aircraft Symposium that several years before, he had the seeming pipe dream of moving people by air in a single-seat, eight-motorm, vertical takeoff and landing, electric commuter aircraft that would take one 100 miles at 100 miles per hour for one dollar. The combination of Greg Cole’s Sparrowhawk and electric power focused too much on efficiency, according to JoeBen, and battery technology had not evolved to allow the practical outcome to this dream. With 250 Watt-hour-per-kilogram batteries now a reality, though, JoeBen thinks he can make some magic, creating a two-seat, 12 pivoting motor craft that could carry two people 200 miles at 200 mph for $20.
As explained on Joby’s web site, “This environmentally-friendly personal airplane requires 5 times less energy than conventional auto transportation at 5 times the door-to-door speed.” The combination of speed and economy would make this a highly attractive alternative to the daily grind on the ground.
The systems seem more complex than the original Monarch, with 12 motors pivoting individually instead of being mounted to one pivoting wing. In “active development,” the S2 has garnered one of Popular Science’s Invention Awards for 2014, with the magazine listing the potential merits of the design.
“Supercomputer simulations of a full-scale, 1,700-pound S2 suggest it could fly two people about 200 miles (New York City to Boston) in an hour on 50 kilowatt-hours of electricity, or roughly equivalent to 1.5 gallons of fuel used by a typical two-seat airplane—which would make the new aircraft about five times more efficient.” They add, “Computers adjust motor speed 4,000 times per second to optimize efficiency, reduce noise, and improve flight control.”
In cruise mode, the S2 would take two passengers at 200 mph to their selected destination (Joby Aviation)
Many of the ideas for this aircraft were tested on a three-propeller machine flown above Joby’s Santa Cruz, California development site. Another outcome of this testing is the Lotus, a long-endurance unmanned aerial vehicle (UAV) inspired by Mark Moore’s Samara.
The split wingtip can add span length and lower wing and span loading when fixed in forward flight, but can turn into an upward-facing rotor blade when powered. The neat aerodynamic, robotic and power transition tricks involved can be found in the technical paper by JoeBen, Edward V. Stilson, Pranay Sinha, and lead author Alex M. Stoll, who showed much of the technology to your editor at last year’s AirVenture.
Finally, Leap Tech, also developed in conjunction with NASA, has 16 to 20 motors distributed along the leading edge (through varying artist concepts) of its high-aspect-ratio wing, with wide-bladed propeller blades sweeping most of the wing area, and high-lift flaps enabling a coefficient of lift greater than 5 for takeoffs and landings. Even though the combined motors might not exceed 300 horsepower, the four-seat craft could reach 300 mph and cruise at 200 mph at 12,000 feet. In fact, power required for landing is higher than that required for takeoff, according to the charts in the AIAA paper on the airplane, co-authored by Stoll and Bevirt for Joby, and by Mark D. Moore, William J. Fredericks, and Nicholas K. Borer for NASA Langley Research Center. This is probably due to the 40° flap deflection for landing compared to 10° for takeoff, and the need to maintain airflow over a more sharply deflected wing.
Mark Moore of NASA and JoeBen Bevirt have collaborated on the LeapTech, a highly-advanced, high-performance four-seater
Computational fluid dynamics (CFD) renderings show the effect distributed thrust has on the wing, allowing only 55 square feet of wing area, compared to 145 square feet compared to a Cirrus SR22. This gives a wing loading of 55 pounds per square foot, over double that of the Cirrus and similar to WWII fighters. Its laminar fuselage has about as little wetted area as practicable, further reducing drag. The high wing loading and sleek shape may work well with higher powered, higher performance derivations of this concept.
JoeBen has also actively been working on motors for more conventional ultralight aircraft. Mark Beierle of Earthstar Aircraft has a simpler solution to personal flight, his e-Gull 2000 sporting a new 30-kilowatt motor he designed with Thomas Senkel, a German physicist who also participates in development of the e-Volo multi-rotor craft in Germany and redesigned with improvements by JoeBen. Thomas was the pilot on the company’s first electric multi-rotor machine, proof-of-concept VC-1, balancing atop a “yoga ball” and spinning up the 16 rotors to achieve a one-minute, 30-second flight.
Beirele and Senkel first made an 18 kW motor that Mark flew successfully at the Arlington Fly in in 2010, and for several months thereafter. After 35 hours of testing, however, the motor showed signs of overheating at maximum power.
30 kW Joby motor shown on e-Gull at AirVenture 2014. Note cooling exhaust fins
A redesigned, 20 kW motor incorporated improved cooling and was able to run for 130 hours and loft the e-Gull to 9,000 feet at full throttle without overheating. After flying the airplane at the Arlington, Washington fly in and AirVenture 2013 after installing a 54 hp. Zero Motorcycle motor and battery, Mark took the Senkel motor to JoeBen, who did a complete redesign. The new, 30 kW motor has improved cooling, is able to climb the airplane at around 500 feet per minute, and seems to have all the characteristics which Mark finds desirable.
Joby’s motors are finding multiple uses, with the high number on any one aircraft (except for e-Gulls) pointing toward at least limited mass production.