{"id":2165,"date":"2010-11-12T08:31:34","date_gmt":"2010-11-12T15:31:34","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=2165"},"modified":"2010-11-13T07:51:00","modified_gmt":"2010-11-13T14:51:00","slug":"a-sweet-look-into-the-future","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/a-sweet-look-into-the-future\/","title":{"rendered":"A Sweet Look Into the Future"},"content":{"rendered":"

Zach Hoisington, an engineer with Boeing Research and Development, proposes an electric airliner concept through the Subsonic Ultra Green Aircraft Research (SUGAR) program.\u00a0 \u00a0During the CAFE Foundation’s fourth annual Electric Aircraft Symposium in Rohnert Park, California in April this year, he shared an amazing array of alternatives.\u00a0 \u00a0Making airliners viable in an era of disappearing fossil fuel\u00a0has caused NASA and aircraft producers to explore different design approaches, including joined wing aircraft, strut-braced wings, and hybrid wing-body configurations.<\/p>\n

Strategies for\u00a0doing more with less\u00a0may include aerial refueling for extended range flight with larger payloads, and formation flights on common routes like those of migrating birds to reduce induced drag.\u00a0 New sources of power may include hydrogen fuel cells and podded or integral batteries.<\/p>\n

Although the last option filled most of the talk, it came with the caveat<\/em> that given current levels of battery development, it would take 5.5 million pounds of cells to produce the same energy derived from 60,200 pounds of Jet A. \u00a0\u00a0That fuel figure is based on Hoisington\u2019s example airliner with 154 passengers and a range of 3,500 miles.\u00a0 The airliner\u2019s takeoff weight is185,000 pounds \u2013 about a third of that in fuel.\u00a0 Converting that substantial fuel load to batteries will test the best engineer.<\/p>\n

\u00a0An interview <\/a>with Hoisington in TechNews Daily shows the implications inherent in this scenario.<\/p>\n

\u201cThis is because jet fuel supplies a lot of energy for its weight \u2014 technically, some 11,900 watt-hours per kilogram \u2014 while those batteries offer about 200 times less.<\/p>\n

\u201cHowever, in light of rising fuel prices and concerns about the environmental impact of fossil fuel use, researchers are taking the concept more seriously.<\/p>\n

“\u2019We’re trying to predict the far-out future airliner,\u2019 Hoisington said.\u201d<\/p>\n

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SUGAR Volt sometime in the not-so-near future<\/p><\/div>\n

As with George Bye\u2019s electric Cessna, there are some factors in the plus column for electric airliners.\u00a0 Jet engines make Jet A into thrust with about 40-percent efficiency.\u00a0 Electric motors can extract kilowatts at efficiencies in the high 90-percent range.\u00a0 Even with those advantages and high-efficiency batteries possible in the future, the electric airliner will have to pull out all the stops in becoming a reality. \u00a0<\/p>\n

Hoisington made reference in his talk to the \u201cN+3\u201d program initiated by NASA as a challenge to industry and academic research groups.\u00a0 Taking \u201cN\u201d as today\u2019s airliner and \u201c+3\u201d as the third generation from current practice, NASA desired several goals.\u00a0 These include a 70-percent reduction in fuel burn performance, 75 percent lower nitrous oxide emissions, a 71-decibel reduction in noise, and reduced congestion around airports.\u00a0<\/p>\n

Investigators from Boeing and its partner Georgia Institute of Technology, and three teams comprising Grumman, Cessna, MIT, and others devised concept vehicles.<\/p>\n

According to Aviation Week<\/a>, \u201cNASA says that the concepts from the four teams were able to meet either the fuel burn or the noise goal, but not both, so it will be reassessing the overall goals to determine which need more time to get from the lab to operational use.\u201d<\/p>\n

Hoisington shared the amusing range of acronyms that came with the SUGAR project.\u00a0 An early turbofan effort was dubbed Refined SUGAR, but fell short of NASA goals.\u00a0 Subsequent efforts produced SUGAR High, a long-winged, strut-braced airplane with advanced turbofans that should become available in a few generations.\u00a0 The final design is SUGAR Volt, a turbine-electric hybrid which would use electric power for short-range flights and turbines for long range trips.\u00a0 Some payload would be displaced by almost 21,000 pounds of batteries.<\/p>\n

Despite these limitations, Hoisington thinks that SUGAR Volt could easily exceed the NASA goals for reduced fuel use.\u00a0 The hybrid configuration echoes the serial hybrid configuration employed in Boeing\u2019s PhantomEye <\/a>High Altitude Long Endurance (HALE) research vehicle now being tested at NASA Dryden Flight Research Center.<\/p>\n

In a final\u00a0thought to TechNews Daily, Hoisington\u00a0explained this research “is the most far out piece of work at Boeing Research & Technology. It’s definitely not near-term. If it does happen, it probably won’t happen for 20 or more years.”<\/p>\n