Unveiled at the Dubai Air Show this week, the collaborative effort between Stratasys and Aurora Flight Sciences is the largest and fastest 3D-printed aircraft so far. With a 9-foot wingspan and weighing 30 pounds, the unmanned aerial vehicle is also the first jet aircraft to be made through additive manufacturing. 80 percent by weight was made through the advanced process, the rest consisting of the engine, electronics and tires. Because the airplane was designed in a collaborative computer aided design process, the parts could be printed in Stratasys’ facilities even though they were designed primarily in Aurora’s Virginia headquarters. Besides saving weight, the process saves time, the complete aircraft going from initial idea to first flight in under nine months. Scott Sevcik, aerospace and defense business development manager at Stratasys, and a recent presenter at the ninth annual Electric Aircraft Symposium, says, “Aurora wanted to look at the feasibility of producing a vehicle tailored to unique mission requirements. They identified …
EAS IX: Neil Johnson of Navitas on Battery Safety
Neil Johnson of the Navitas Systems Advanced Solutions Group gave the gathering at the ninth annual Electric Aircraft Symposium an overview on battery reserve limits and gauging, and the methods necessary to address the different failure modes for lithium batteries, all of which could be problematic for electric aircraft. Navitas includes some legacy technology adapted from 123 Systems, typically 18650 format batteries, an 18-millimeter by 65-millimeter cylinder with active materials separated by a dialectric separator material in a “Tootsie Roll” configuration. Some of the chemistries involved were developed for Formula 1 racers, and according to a talk given by Bill Dube’ and Eva Håkansson, are considerably more powerful than “conventional” lithium cells. According to Neil, the five billion cells out there now have been vetted using failure mode and effects analysis (FMEA) and fault tree analysis (FTA), two methods of statistically analyzing failure modes and of determining what might become failure modes in new designs. FTA. As Neil shared with the audience, …
EAS IX: David Calley’s Innovative Design and Use of Electric Motors
David Calley is member of the CAFE Foundation Advisory Board, with a great deal of technical expertise to offer. His small wind turbine sold over 150,000 units. His patented design for the TrailerTail® increases fuel economy on semi-trucks and trailers by 5.4 percent at 65 miles per hour, according to SAE tests. Last year at EAS VIII, he showed the potential for small motors with incredible torque that could power Sky Taxis. At this year’s EAS IX he described, in depth, the type of motor design he has been developing to power things like his three-wheel electric/pedal-powered commuter vehicle and landing-gear wheels on Sky Taxis and even rocket fuel pumps. He asked the not-too-rhetorical questions, “How high can electric motor power go?” and “Where do these forces come from?” His answers took attendees on a high-level look at electromagnetic and permanent magnet (PM) materials theories. Electric motors rely on interactions between fields to produce power. “Fields” in this case are …
EAS IX: Tyler MacCready on Swarm Science
One of your editor’s favorite books is An Exaltation of Larks, James Lipton’s compilation of venereal terms (not what you think) for plurals of animals. Squires who aspired to become knights had to learn over 100 such terms, according to Sir Walter Scott. Terms of venery (references to animal flesh) include a school of fish, a litter of puppies, and a nest of vipers (going back to at least the King James version of St. Paul’s words). One lesser known term, a murmuration of starlings, relates to Tyler MacCready’s talk on how control of the Future Crowded Skies at EAS IX might mimic the flocks of birds we see swarming and precipitously changing directions in swooping formations. Obviously, the numbers of Sky Taxis envisioned by Dr. Brien Seeley will not come close to equaling the flocks of starlings over Rome or any other major city, but we’ve also seen that air traffic control is becoming saturated with increased traffic and …
EAS IX: Pete Lynn’s Tethered wing aircraft
Pete Lynn delivered a talk at the 2015 Electric Aircraft Symposium on tethered wing aircraft that could provide long-range transport for large-scale cargo (Pete envisions shipping containers) and VTOL operation – electric flying trucks. He works at Otherlab, a wildly inventive operation at the historic Schoenstein Organ Factory, identified as San Francisco Landmark #99 and located in the Inner Mission District. The group works with extremes of technology and design, “attracting research funding for early and risky ideas in areas such as ‘programmable matter’, robotics, solar energy, wind energy, energy storage, computational and advanced manufacturing, medical devices and more. These non-dilutive investments allow us de-risk the very early exploratory phase of our projects.” Pete cautions, however, that despite his work on things like pneumatic robots for Otherlab, the ideas expressed at EAS IX are his own and not necessarily those of his employer. The system trades top speed for extremely light weight in the lifting structure. This allows hoisting a weight much …
EAS IX: Materials Design for Battery Breakthroughs
Dr. Yi Cui’s presentation title ended with, “from Fundamental Science to Commercialization,” an indication of the long, tough road that new developments are forced to take. Considering that Sony introduced the Lithium battery as a commercial entity in 1991 (and that following at least an 18-year slog from laboratory to mass production), mostly incremental changes have come for the chemistry, echoing Dr. Cui’s pronouncement at EAS III that lithium batteries followed a “growth curve” of about eight percent per year, meaning that about every nine years, they should double in performance. Cui’s estimate has been borne out in reality, Nature magazine reporting in 2014, “Modern Li-ion batteries hold more than twice as much energy by weight as the first commercial versions sold by Sony in 1991 — and are ten times cheaper. But they are nearing their limit. Most researchers think that improvements to Li-ion cells can squeeze in at most 30% more energy by weight.” Cui spoke of attempting …
EAS IX: Chip Erwin Gets Personal with Electric Flying
Light Sport Aircraft (LSA), alas, haven’t lived up to their early hype, 100 manufacturers selling only 235 units in the United States last year. That bothers Chip Erwin, who would like a Personal Sport Aircraft (PSA) option. He’s working through his company, Aeromarine LSA, to do something about that. Chip explains that high prices for LSAs, brought on by doubling Rotax prices over the last decade and quadrupling of once cheap European labor rates, has put what were to be $50,000 airplanes into the $150,000 price range, barely able to compete with used Cessnas and Pipers. Having demonstrated two-stroke engines and an Electravia motor on his imported Zigolo ultralight glider, he has displayed an alternative motor designed by Don Lineback, first at last year’s AirVenture as a mockup, then as an operating prototype at the ninth Annual Electric Aircraft Symposium in May. Now he’s displaying it at AirVenture 2015, complete with an e-Prop four-blade, asymmetric propeller reputed to cut noise. …
EAS IX: Dr. Seeley’s Magnum Opus
Your editor first met Dr. Brien Seeley, founder and President of the CAFE Foundation, at the Western Workshop for the Experimental Soaring Association in 2007. Dr. Seeley spoke about the CAFE Foundation and its many areas of research, including its first two Electric Aircraft Symposiums. Seven years later these events and this blog are among the few resources for people seeking information on this developing field. He spoke then about a novel idea, an aerial taxi service that would eventually become fully autonomous, hauling people on short-to-medium range trips in small, electric aircraft that would fly out of very small airports. This seemed a bit of science-fiction at the time, but Dr. Seeley has continued to promote this idea, gaining valuable allies and convincing growing numbers that this is a practical alternative to the wasteful clogs on our nation’s highways, taking their toll on time, treasure and the human spirit. At this year’s Electric Aircraft Symposium, he shared the mature …
EAS IX: Low Aspect Ratio Airplanes – Against the Grain
Barnaby Wainfan is a technical fellow with Northrop-Grumman, but possibly best known for the FMX-4, well known as the “Facetmobile.” His talk on “Low Aspect Ratio Electric Airplanes gave attendees at the ninth annual Electric Aircraft Symposium a great deal of counter-intuitive insights into how a successful airplane can look and work. The FMX-4, he pointed out, is a low-aspect-ratio, light weight, single primary structure, low-parts-count airplane with benign flying qualities. When, as he told his audience, he decided to stop talking and start testing, he began with X-Plane computer simulations to check out his theories and studied simple, fast-building structures that would get him into the air expeditiously. N117W was easier to build than curved sticks, and despite its angular lines, the airflow doesn’t separate over its flat surfaces. He could carry an approach at 10 degrees positive angle of attack (AOA) and still have 30 degrees available before reaching a stalling point. The airplane carries a payload equal …
EAS IX: Airbus Looks to a Light Electric Future
Ken McKenzie, listed as Deputy Chairman of Airbus US, has served as Vice President for Airbus Customer Services and as Chief Operating Officer for Airbus Americas, Inc. This high-powered individual comes across as a relaxed, congenial soul, though, and led attendees at the ninth annual Electric Aircraft Symposium through an overview of developments in light electric aircraft to come from the aviation giant. The e-Fan is the most visible effort for Airbus’s electric aircraft work so far, but the company is intent on carrying out a full E-aircraft program as part of its commitment to the European Commission’s Flightpath 2050 program,. which bullet-points these important goals for the next 35 years: “1. In 2050 technologies and procedures available allow a 75% reduction in CO2 emissions per passenger kilometer to support the ATAG (Air Transport Action Group) target10 and a 90% reduction in NOx emissions. The perceived noise emission of flying aircraft is reduced by 65%. These are relative to the …
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