Although Boeing may eventually introduce a commercial airliner designated with the number 797, and although the company's Phantom Works (advanced research and development) is researching various advanecd concepts, Boeing is not currently developing a 797. Boeing [and Airbus] have been granted a number of patents for advanced airplane concepts that may provide a preview of coming attractions. In June 2011 Air Transport World [ATW] reported "Boeing moves toward '797' to replace 737 ... Boeing appears to be moving toward an all-new solution for the replacement of the 737, the biggest selling commercial jet aircraft in history." Artwork has circulated since at least early 1996 proclaiming blended-wing-body (BWB) aircraft design to be Boeing's response to competition from the Airbus A380 in the commercial airliner business.
The Boeing SUGAR (Subsonic Ultra Green Aircraft Research) team was one of four that received contracts from NASA in 2008 to study subsonic concepts for the 2030 to 2035 timeframe. The other teams were led by GE Aviation, Massachusetts Institute of Technology and Northrop Grumman. All four teams have submitted proposals for a second phase of studies to begin developing new technologies that will be necessary to meet the national goals related to an improved air transportation system with increased energy efficiency.
In 2010 two teams led by Boeing Research & Technology completed 18-month studies on what future commercial airplane designs might look like 25 to 30 years in the future. They submitted their findings to NASA under a program called N+3, which denotes three generations beyond the current transport fleet. After examining various subsonic and supersonic concepts, the teams have come up with potential configurations that may offer dramatic improvements in operational and environmental performance over the aircraft of today to meet aggressive goals set by NASA.
The Boeing subsonic team, which includes BR&T, Boeing Commercial Airplanes, General Electric and Georgia Tech, looked at five concepts as part of the SUGAR project. The concepts included two conventional reference configurations, similar in appearance to a 737 (nicknamed SUGAR Free and Refined SUGAR), two versions of a new design high span, strut-braced wing aircraft (referred to as SUGAR High and SUGAR Volt), and a hybrid wing body configuration (called SUGAR Ray).
The team’s report provided detailed benefits and drawbacks as well as recommendations for further study, but doesn’t show favorites. No single concept met all of the study goals, so the team did not pick a preferred concept.
For the subsonic concept, hybrid electric engine technology was a clear winner because it can potentially improve performance relative to all of the NASA goals. However, the team found that the SUGAR Volt concept (which adds an electric battery gas turbine hybrid propulsion system) can reduce fuel burn by greater than 70 percent and total energy use by 55 percent when battery energy is included. Moreover, the fuel burn reduction and the ‘greening’ of the electrical power grid can produce large reductions in emissions of life cycle CO2 and nitrous oxide. Hybrid electric propulsion also has the potential to shorten takeoff distance and reduce noise. The SUGAR team’s report concluded that hybrid electric engine technology was a clear winner, because it can potentially improve performance relative to all of the NASA goals.
However, in order for the hybrid electric concept to be competitive, battery technology needs to improve many, many times over what is available today. Battery technology is being worked around the world, especially in the auto and electronics industries. The SUGAR team identified hybrid electric engine technology as a high-risk high-payoff technology.
For conventional propulsion, a combination of improvements to air traffic management, airframe and propulsion could reduce fuel burn by 44 to 58 percent. Other improvements include use of sustainable biofuels, which could reduce CO2 emissions even more and use of advanced combustor technology, which could reduce nitrous oxide emissions by 75 percent.
For noise reduction, the best performing concept is the SUGAR Ray (the hybrid wing body), which achieved a 37 decibel reduction relative to today’s aircraft. That’s well short of the NASA goal, so more work needs to be done in this area.
The Boeing supersonic team, which included BR&T, BCA, Pratt & Whitney, Rolls Royce, General Electric, Georgia Tech, Wyle and M4 Engineering, focused on four concepts that include a low fuel burn / low boom swing-wing “arrow” configuration, a low sonic boom concept with a V-tail to shield noise and control the sonic boom, a joined wing alternate concept and an oblique “scissor” wing alternative concept.
Based on conceptual design studies, the team recommended to NASA a fixed wing configuration (nicknamed Icon II) with V-tails and upper surface engines as the technology reference concept plane for N+3, said team leader Bob Welge of BR&T. The Icon II concept can carry 120 passengers in a two-class, single-aisle interior, and can cruise at Mach 1.6 to Mach 1.8 with a range of about 5,000 nautical miles.
The study acknowledges that supersonic aircraft inherently have less fuel efficiency than subsonic aircraft, but points out they offer offsetting productivity benefits because of speed. The study concludes that advanced technologies can reduce fuel burn enough that a supersonic aircraft could be viable, economically and environmentally, in multiple markets.
The study also indicates that these efficiencies can be achieved while meeting the same community noise certification limits as subsonic aircraft – with a reduction of the sonic boom noise en route to 65 to 75 decibels. That may make it possible for a supersonic transport to operate at maximum cruise speed -- even over land. The Boeing-led team was one of two that received contracts from NASA to study supersonic concepts. The other was led by Lockheed Martin. The NASA N+3 supersonic program did not provide the option for a Phase II system study, but technology development research announcements were anticipated.
Created in 2009 as part of NASA's Aeronautics Research Mission Directorate's Integrated Systems Research Program, the Environmentally Responsible Aviation (ERA) Project explores and documents the feasibility, benefits and technical risk of vehicle concepts and enabling technologies to reduce aviation’s impact on the environment.
To enable advanced aircraft configurations that might enter service by 2025, the ERA Project is working on technologies that will simultaneously:
- Reduce aircraft drag by 8%
- Reduce aircraft weight by 10%
- Reduce engine specific fuel consumption by 15%
- Reduce oxides of nitrogen emissions of the engine by 75%
- Reduce aircraft noise by 1/8 compared with current standards.
The ERA Project is comprised of three subprojects: Airframe Technology, Propulsion Technology and Vehicle Systems Integration. Work within the project is coordinated with system-level research performed by other programs within NASA's Aeronautics Research Mission Directorate as well as other federal government agencies.
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