In a recent AVWeb Vodcast, Paul Bertorelli interviewed Embry Riddle’s Dr. Pat Anderson on the topic, “Why Electric Airplane Designers Are Turning to Hybrid Drives.” Battery energy-carrying capability has not fulfilled its promise yet, according to Anderson. The difference in energy density between fossil fuels and batteries is still too great to fulfill missions involving more than small craft and short distances for the most part. This outlook caused Dr. Anderson’s associates, Eric Lindbergh and Eric Bartsch to form Verdego Aero, dedicated initially to developing a Diesel-hybrid generator system. They corroborate Dr. Anderson’s sense of current battery technology, their web site answering “Why hybrid?” They explain, “Electric aircraft are at the forefront of aviation technology, but the energy density of current batteries isn’t yet high enough to support many mission types or aircraft designs. The power generation systems in the VerdeGo IDEP (Integrated Distributed Electric Propulsion) systems, which use Continental Jet-A Piston Engines, offer 4-8x the equivalent energy density of today’s …
A Weighty Matter
Several readers have asked for the weights of the Green Flight Challenge competitors. Here they are, pound for pound, among the most efficient flying machines on the planet. Those who wish can calculate different takes on that efficiency, including overall glide ratios for the course, ton-miles per gallon energy equivalent, or more exotic parameters. Empty Weight Takeoff Weight in Competition Pounds Pounds e-Genius 1670.2 2070.2 Pipistrel G4 2491.0 3294.1 Embry-Riddle 1970.0 2370.0 Phoenix 754.0 1199.7
Green Flight Challenge – Days Three and Five
As if in answer to the most fervent prayers by CAFE Foundation organizers, Tuesday, September 27 dawned as a bright, windless morning, perfect for the planned 200 -mile aerial trek that each of four teams would undertake in the Green Flight Challenge sponsored by Google. Each would fly a large, tightly-followed out-and-return loop around the Sonoma Valley, reaching the radio tower array on the peaks north of Geyserville, then returning for one of three passes (the fourth being the descent to land) over the CAFE Foundation hangar at the west end of the Charles M. Schulz Sonoma County Airport. Each would have to reach at least 4,000 feet at the end of a 17-mile climb and would need to track within one mile on either side of the Challenge course’s centerline. Pilots would need to stay on the outside edge of turnpoints, but shave their margin to within one-half mile on each pylon-type turn. To help monitor that precise flying, Steve …
Green Flight Challenge – Day Two
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
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 …