Kitplanes own Dean Sigler (Alternative Energies) attended this year's Electric Aircraft Symposium in Santa Rosa, CA as part of the faculty for the event, and filed this report in order to keep our readers up to date on the burgeoning new technologies in electrical propulsion and aircraft designed to use it. Watch for additional reports here and in the magazine as we keep abreast of the action in the world of "green flight".
Paul Dye, EIC
It was a humble effort in the midst of the intellectual horsepower and design know-how on display. Barnaby Wainfan, a regular contributor to Kitplanes, gave a brilliant review of what it would take to make an efficient STOL airplane. His experience with the Facetmobile and knowledge of other low-aspect ratio aircraft showed that airplanes that can take off and land in short distances and still cruise at reasonable speeds might look very different from our current ideas of such craft. https://www.linkedin.com/pub/barnaby-wainfan/8/190/911
Battery developers showed up with promising new developments. Dr. Qichao Hu of MIT and his start-up company, SolidEnergy, discussed his ultra-high energy density lithium battery – not five years out, but due later this year in small formats and next year in larger sizes. http://www.solidenergysystems.com/
Dr. Avetik Harutyunyan , chief materials scientist for Honda in Columbus, Ohio, talked about “Lithium Storage Capacity in Carbon Nanostructures,” showing research on possible structural, high energy materials including carbon nanotubes, boron and graphene flakes – all impressive and promising. http://www.honda-ri.com/news100109.php
Attendees saw a variety of motors, starting with Dr. Ajay Misra’s 3D printed ones, which incorporate nano-magnets for greater energy density. These technologies have the potential to increase the maximum energy product in magnets, new electromagnet design, and reduce volume, weight and costs for future motors. https://rt.grc.nasa.gov/main/people/dr-ajay-misra/
David Calley, CEO of PlanetRider, profiled his transverse flux low-RPM, high power density motor, something that could find a place on the electric STOL aircraft espoused by CAFE’s Dr. Brien Seeley and NASA’s Dr. Mark Moore. The ability to swing a big prop slowly is crucial to noise reduction and top climb performance. Smaller versions are in use bicycles and Calley’s idea for a hybrid commuter vehicle. He noted motors that could produce 40 kW per kilogram (24 hp per pound), a seeming fantasy, but coming to a reality near us sooner than we might think. http://myplanetrider.com/home
Dr Qichao Hu from the University of Miami, showed the work he and graduate students have been doing on forward-swept propellers, an approach to producing more thrust and lower noise. Wind tunnel and computer flow dynamics (CFD) simulations are bearing out these thoughts. So far the blades swept 20 degrees forward have the highest efficiencies and stall margin of the swept configurations studied.
Calin Gologan, CEO of PC-Aero in Germany, and George Bye of Bye Aerospace (America) did a joint presentation on manned and unmanned aircraft using practical solar-electric propulsion systems. Gologan’s firm has flown Elektra One, a single-seater offered with a retractable central main wheel or a fixed tricycle gear. Variations include a two-seater tandem airplane, with one scheduled to make record flights to 75,000 feet on battery and solar power. Other models include a side-by-side trainer, and an unmanned civilian version that could be autonomous under 30,000 feet.
George Bye told about the fate of his firm’s electric Cessna 172, which did fly 25 times and had a motor controller “the size of a grapefruit.” The project is now abandoned, replaced with a probably better alternative in a tricycle-geared, 440-pound Sun Flyer trainer that will cost $10 an hour to operate. Its 80-hp motor and 250-kilowatt hour per kilogram batteries would allow an hour’s training, and its quick-swap battery packs will enable rapid turnarounds to keep students flying. He hopes to have it at Oshkosh this year, where airshow goers will have to be told when Sun Flyer is in the air, since its projected 55-dBa noise signature won’t be heard over the general din. http://www.youtube.com/watch?v=UUz16polZyI His company also builds unmanned aerial vehicles and he discussed manually flying them at lower altitudes and allowing full autonomy, something also of interest to the next speaker.
John Langford closed out the pre-lunch festivities with a talk on manned unmanned aircraft – a direction he thinks UAVs are headed. His video of a modified DA-42 his company, Aurora Aviation, calls the Centaur, was a preview of what autonomous aircraft might accomplish daily in the near future. The pilot does not touch the controls from takeoff through cruise to a final perfect touchdown. The aircraft has a safety pilot, something the FAA will probably insist on for early applications of this technology. http://www.youtube.com/watch?v=5WlSMAsg10M
The company’s lineup of unmanned aircraft of various sizes is part of their over two score such craft built in their 24 year history. http://www.aurora.aero/Index.aspx
We’ll follow with two more reports – one for the afternoon sessions on Friday, April 25, and the second for the Saturday morning sessions. The breadth and depth of presentations was exciting and challenging, and worth noting for future reference.