How Green was GFC Electricity?

Dean Sigler Diesel Powerplants, Electric Powerplants, GFC, Sustainable Aviation 2 Comments

The blog received several comments about the relative energy use of electric aircraft, and how NASA and the CAFE Foundation might have overstated the efficiency and low emissions for the electric aircraft in the competition. Reader Robert Swanson thought the conversion between kilowatt hours and gasoline created a discrepancy. “The discrepancy in performance of gasoline and electric powered aircraft is due to an absurd conversion factor between kWh and gallons of gasoline.  The conversion should be calculated from the number of gallons of gasoline consumed by the engine driving the generator used to charge the batteries.” Steven Crow added this objection.  “Even after reading the relevant pdf’s, it is far from clear to me how CAFE computed ‘mileage’ for the electric aircraft. The right way of doing it is clear enough: base the mileage on the fossil fuel used to charge the batteries.  Electric motors and batteries are not subject to Carnot efficiency limitations.  They can seem to be nearly …

Green Flight Challenge Final Results

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation 15 Comments

Steve Williams, CAFE Foundation board member and e-totalizer guru, released the final results for the NASA Green Flight Challenge sponsored by Google, held at the Charles M. Schulz Sonoma County Airport from September 25 through October 1, 2011.  Figures show a profound difference between the two electric winners and the two gas-powered and hybrid runners-up. All competitors flew extremely clean motorgliders with demonstrated lift-to-drag ratios between 25:1 and 35:1.  Possible explanations for the large differences in energy use include low cooling drag for electric aircraft and the efficiency of electric motors – but the differences are still surprising. Note that a little over 11 US gallons of gasoline (energy equivalent) were used to fly seven people (Embry Riddle’s Eco-Eagle flew with only one pilot) over a total of 725.5 miles (Embry Riddle flew a shorter total distance on both “runs”).  This is an enormous achievement for all concerned and a significant increase in efficiency over even the best general aviation craft available today. Congratulations are …

NASA Adds Some Numbers to Green Flight Challenge

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation Leave a Comment

NASA’s Mark Moore sends this link to NASA’s press release on the recent NASA Centennial Challenge Green Flight Challenge sponsored by Google.  The CAFE Foundation organized and managed the event. “Today we’ve shown that electric aircraft have moved beyond science fiction and are now in the realm of practice.” – Chief technologist at NASA Joe Parrish. The lead quote is informative, as are some figures from the release.  “The competition resulted in the world’s most efficient aircraft, beating the state of the art of approximately 100 pmpg (passenger miles per gallon) which is achieved by the newly released Boeing 787 airliner.  Essentially this contest showed the ability of small aircraft to achieve twice the efficiency of the most efficient production automobiles today, while traveling at over twice the speed.” Part of this efficiency came about because of inspired design.  NASA explains, “The Taurus G4 used a multi-body concept (reminiscent of the twin Mustang, or an inverse P-38); this accomplished a 61% useful …

AVweb Readers Weigh In on Electric Aircraft, Green Flight Challenge

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation Leave a Comment

Mary Grady of AVweb started an expanding dialogue with her recent opinion piece on NASA and the CAFE Foundation’s Green Flight Challenge sponsored by Google.   The stimulating and varied points of view reflect what is probably floating around in the general public’s perception of “green aviation,” ranging from total ignorance of what has been done already, to confusion about what it all means, to well-honed, technically aware arguments on both sides of the issue. Her thought that electrification is, “the first step down a long and bumpy road that could take general aviation in new directions,” was reinforced with the following reflections that might be similar to those that readers of this blog often experience. “For people who fly for fun — presuming there are many of those left, it seems to be one of the fastest-shrinking segments of GA — electric airplanes are sure to appeal. They are easier to deal with, and quieter, with less vibration. A few …

Green Flight Challenge Winners

Dean Sigler Diesel Powerplants, Electric Powerplants, GFC, Sustainable Aviation 1 Comment

Monday, October 3 was the second day of Nobel Prize announcements, but also marked the Green Flight Challenge Expo, sponsored by Google and staged under the control tower on Moffett Field, home of NASA Ames Research Center, Mountain View, California. The four airplanes that flew in the Challenge at Charles M. Schulz Sonoma Country Airport in Santa Rosa, California were joined by Greg Stevenson’s full-size mockup of his GFC design and a Pipistrel Virus that had won an earlier NASA/CAFE Personal Air Vehicle (PAV) Challenge.  Stevenson’s airplane was a reminder that there were numerous entrants that, for a variety of reasons, could not attend.  There is a huge number of aircraft in the wings, so to speak, that will fill these pages in the next months and years. 20 exhibitors showed off their visions of a greener future, and three rows of tents protected exhibitors and their displays from the rain that started mid-afternoon. At about 11:00 a.m., attendees were bussed to  Building …

Green Flight Challenge – Day Two

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation 1 Comment

Monday morning, September 26, many of us had our first view of an electric airplane in flight. After the weighing team rolled Jim Lee and Jeff Shingleton’s Phoenix motorglider from the hangar onto its impound location and completed initial weigh-ins for the remaining three aircraft, the airplanes were staged for the first flying event of the Green Flight Challenge sponsored by Google. With technical inspections and weighing completed, the four airplanes lined up to check their noise levels and their ability to clear an imaginary 50-foot barrier atop a cherry picker  2,000 feet from the top of the number “9” on runway 19 at Santa Rosa, California’s Charles M. Schulz Sonoma County Airport.  As each aircraft rolled out to their takeoff point, the cluster of photographers under the cherry picker focused and waited for a green flag to fall at the takeoff point. All the aircraft passed cleared the 50-foot flag, and e-Genius was judged to be quietest of the entrants …

Green Flight Challenge – Day One

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation

  Sunday, September 25 marked the kickoff of the Green Flight Challenge sponsored by Google, a NASA Centennial Challenge managed by the CAFE Foundation, with a thorough technical inspection for each entrant, followed by a weigh-in.  Held at the Charles M. Schulz Sonoma County Airport, the event is an event of international importance, despite the small turnout. With only four entrants making an appearance out of the original 13 that had announced and made it through the rigorous design review, there might be cause for disappointment. Consider, though, the Berblinger competition held in April at the Aero Expo in Friedrichshafen, Germany. 36 teams signed up, 24 made it to the Expo, 13 started the course and eight finished. The GFC has a comparable start-finish ratio, with many of the same issues stalling non-starters here as in Germany: lack of funds  and schedule, regulation and fabrication difficulties. Despite the dropouts, Pipistrel, Stuttgart University, Phoenix Aircraft, and Embry Riddle Aeronautical University (ERAU) managed to field teams. In a …

Pipistrel Preparing for Green Flight Challenge

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation 1 Comment

Michael Coates, American distributor for Pipistrel, shares some pictures and videos of the G4, four-seat, twin-fuselage electric motorglider a “technology demonstrator” for the company and its entry in the Google/NASA/CAFE Foundation Green Flight Challenge, which starts Sunday, September 25 in Santa Rosa, California.  The Pipistrel team, headed by Jack Langelann of Pennsylvania State University, is working out Hollister, California’s airport, about 70 miles south of San Francisco and 150 miles from Santa Rosa.  The team expects to fly to Charles M. Schulz field on “Friday or Saturday of the this week” for the competition. Pilot Robin Reid guided the big bi-fuselage craft through its paces and brought back this in-flight video, which shows the visibility is better than one would expect – except of the other fuselage, the nose of which can be seen just under the central propeller. Coates reports, “Hollister airport has been our base for the last four weeks as we continue to extend the flight envelope …

A Seraph in the Earthly Sphere

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation 2 Comments

A Seraph is a six-winged angel in the first sphere of the celestial hierarchy, and while the earthly form in Richard Ike and Ira Munn’s vision may have fewer wings, it is no less inspired. In part, it’s inspired by biomimicry, imitating nature in its forms and even its structure.  The  airfoil-shaped profile of the fuselage “reduce[s] drag and optimize[s] aerodynamic efficiency, the blended-wing-body and lifting body (flying fuselage) maximize lift and produce minimum drag, according to Seraph’s web site. Seraph explains, “Flight with the Seraph will be made possible by two factors, lift generated by airfoil and lift generated by vortex.  The later factor is a return to a principle originally explored by Leonardo Da Vinci.”  Their site further explains that, “This new field of study is called ORGANIC AERONAUTICS, or ‘Green Aviation’ (Aerospace inspired by nature). It is also a discipline of the science called Biomimicry: using nature as Model, Mentor, and Measure.” Its exo-skeletal structure emulates insect …

Embry Riddle Begins GFC Test Flights

Dean Sigler Electric Powerplants, GFC, Sustainable Aviation Leave a Comment

On August 23, 2011, the Embry Riddle Aeronautical University’s Green Flight Challenge hybrid-powered modified Stemme S10, the Eco-Eagle, began its ground tests on the Daytona Beach International taxiways, “Getting ATC used to us!”   The next day saw several ground-skimming “flights,” starting at 2-feet, and rising to 10 and 50-feet high runs, all with the gear down.  The day’s flights ended with a trip around the pattern for the airport’s longest runway. August 25 saw a morning excursion of 45 minutes, with the airplane flying in the face of the approaching Hurricane Irene.  Test pilot Mikhael Ponso reported beautiful clouds and no high winds during the seven laps around the field.  As he tested the gear retraction and various flap settings, he was able to sort things out for the upcoming GFC flights in Santa Rosa, California during the last week in September. The school’s Eco-Eagle has a Rotax hybrid-power system originally developed for Flight Design, a German firm that builds …