Boeing 797
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 advanced concepts, Boeing is not currently developing a 797. Boeing went back to the drawing board following the 737 MAX crisis.
By October 2019, Boeing was looking at a 767-X derivative to replace the NMA in Boeing's product development plan, which could potentially enable the company to allocate its resources towards development of a "Future Small Airplane", an all-new single-aisle to succeed the 737 Max.
BY October 2020, Boeing was looking at a single-aisle aircraft with improved engines. Moreover, it could carry between 200 and 250 passengers. Altogether, this capacity places the plane between the largest 737 MAX narrowbody and the 787 widebody.
New Midsize Airplane (NMA) �Middle of the Market� (MoM)
The �757-replacement� New Midsize Airplane (NMA) study is for an aircraft with more capacity than the 737-900ER/737-9 but with less range than the 787. The middle-of-the-market (MoM) space for Airbus would be at least 1,000 new dual-engine, single-aisle planes designed to fly thin routes (up to 5,000 nautical miles with 200 to 260 passengers).
- Boeing 797-6 that could carry 228 passengers to a range of 4,500 nautical miles (8,300 km)
- Boeing 797-7 that could carry 267 passengers to a range of 4,200 nautical miles (7,778 km)
Boeing was convinced that an un-addressed, and sizable, market for a new midsize airplane (NMA) existed between single-aisle Airbus A320 and Boeing 737 category and the medium-capacity twin-aisle Boeing 787 and Airbus A330 and A350. Boeing believed there would be a demand for around 5,000 to up to 7,000 units.
Bloomberg reported June 17, 2015 that at the Paris Air Show "much of the talk centered on a Boeing Co. plane nicknamed �Mom� that doesn�t even exist yet. The tag was an acronym used internally at Boeing for �middle of market,� a jet that would be sized to fit between current single- and twin-aisle offerings and succeed the discontinued 757. No matter that it wouldn�t be in service until the 2020s.... the jet would seat about 220 people and fly 4,500 nautical miles (8,300 kilometers)... upgrades of roughly 20 percent over a narrow-body 757.... A pair of aisles would eliminate middle seats in a six-abreast cabin, creating speedier boarding and unloading."
Aviation Week reported 12 November 2015 that John Wojick, senior vice president of global sales and marketing for Boeing Commercial Airplanes, said: �We see substantial demand. If we can produce an airplane with a range of 4,500-5,000 nm, seating about 220-280 passengers, then there would be an awful lot of demand. I�d say in the thousands. Easily more than 2,000.�
The configuration of the NMA, and whether the aircraft should be a longer single-aisle or a shorter twin-aisle, remained undecided. �Customers want the most efficient aircraft with single-aisle economics,� Wojick said. Fuel efficiency is a key driver of the design, so if the wider fuselage of a twin-aisle would incur greater drag, then the single-aisle feature could be retained.
The company�s commercial president, Ray Conner, told Aviation Week 11 July 2016 that the company had sought input from over 30 key airlines into a new midsize airplane (NMA), and recently disclosed a �sweet spot� preference for an aircraft seating between 200 and 270 passengers capable of flying around 4,500 to 5,100 nm. Boeing envisaged notional entry into service around 2024-2025.
The NMA would have a sixth-generation composite wing, more electrical systems and advanced, high-bypass-ratio engines. It might feature an elliptical fuselage cross-section, to provide twin-aisle capacity with single-aisle economics. The seat count would be between 200 and 260 to 270 max. a little bit bigger than a current single-aisle but not quite as big as a 767-type aircraft. The 4,800 to 5,000 nautical miles range is significantly longer than the 757 range, and the 767-300 seats between 260 and 300 passengers, soemwhat more than customers appear to need.
Fan size will be a key factor in the design of the NMA, which is baselined around a target fuel-burn performance 25% better than that of the second-generation high-bypass engines developed in the 1970s for the 757. Based on the approximate fan dimensions of the RB3095 initially proposed by Rolls for the NMA, CFM and Pratt are believed to be offering concepts with fan sizes close to 100 in. in diameter. This will make both offerings substantially wider than the Leap 1A�s 78 in. and the 81-in.-dia. fan of the PW1100G.
Patents
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.
SUGAR (Subsonic Ultra Green Aircraft Research)
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.
ERA (Environmentally Responsible Aviation)
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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