While there are obvious drawbacks in carrying heavy batteries as a power source on long-haul flights, Boeing has taken up the challenge of designing a concept hybrid-electric-powered commercial aircraft. Boeing calls the project the Subsonic Ultra-Green Aircraft Research aircraft, or SUGAR Volt. Much of the vehicle relies on technologies that would require further development to bring the concept aircraft to reality, but it is intended as a forward-looking project. That said, Boeing engineers targeted 2030-2050 as the timeframe that could see such an aircraft built and target a 70-percent improvement in fuel burn as a primary outcome. Along with powerplant innovations, Boeing's design also incorporates aerodynamic innovations.
Because battery weight is expected to pose a challenge for electrically powered aircraft for the foreseeable future, the Boeing team has worked to offset that load with improved aerodynamics. The SUGAR Volt uses a high-aspect-ratio wing long enough that it would be strut-braced and have to be folded to allow the aircraft to fit at a standard airport gate. The aircraft also seeks to offset weight with savings in structural weight. Ideally, a more efficient wing, structure and powerplant could lead to the targeted fuel savings. And that fuel might also come in another form. The team has also considered the possibility of liquefied natural gas. However, that fuel would require significant changes in fuel-tank engineering and the fueling infrastructure. According to comments from the team's report, hybrid electric engine technology "is a clear winner." The SUGAR Volt study is being funded by NASA and led by Boeing's Marty Bradley. Bradley says the design incorporates some technologies for the sake of making sure they are developed enough to become viable options at some time in the future.