By James N. Krebs
Leeham News recently forecast that the next all new Boeing airplane will be a 757 successor with an entry-into-service around 2025, followed by a smaller NSA (New Small Airplane), a 737 MAX/A320 neo successor, in maybe 2027. I believe it will be clear in the next few years that the technology is and can be available here to build a reasonable-risk NSA with 20% fuel savings over the MAXes/ neos (at same seats) for initial service by 2025 (which will demand perhaps 40 more than 162 seats for even better economics). Its production would ramp up over ~5 years or so.
I hope this would be mainly a “Made in the USA” Boeing NSA: American engineering, American manufacturing, American jobs and American competitive edge. If that takes some helpful brainpower and/or investments from NASA, Northrop Grumman, Lockheed Martin, etc, good.
Boeing and Airbus might love to build a combined 100/mo. MAXes and neos “forever,” but technology and market forces aren’t likely to permit this. The companies won’t want to whet any appetites soon but I hope Boeing’s advanced design people are already at work–I’d be disappointed if they aren’t.
Airbus could certainly put an A320neo successor in service 10 years after their 2015 neo. A reengined A330 and a possible A350-1100 aren’t the only new projects they are capable of in the next decade. The market response to their A320neo family completely surprised Boeing a couple years ago. What’s next?
A few thoughts about this NSA:
For best economy, the NSA could be designed for 2,000-2,200 nm range (covering > 98% of 737 missions) and .72-.75 mach cruise. Don’t burden the fleet with the neo/max’s extra weight, fuel burned, carbon and costs for ~3,500 nm range and .8 mach cruise. Airlines can continue to use MAX/neos for transcon ranges.
The NSA’s wings could be more efficient high aspect ratio, composite designs, with less area and sweep and the current ~118’ span to fit airport slots — plus folding 8-10’ wing tips (why not) for ~138’ in flight. There will be significant weight benefits in fuselage and tail materials and construction–better than the A320/737s and even the 787/A350s–plus modest gains from some advances in practical laminar flow, riblets, more-electric systems etc. Technology moves ahead.
New twin ~20,000 thrust class engines could be mounted on-wing. Bypass ratios would be well above the A320neo’s 11-12, not only from smaller, lighter, more efficient cores but also from lower pressure ratio fans for higher propulsion efficiency. Propulsion and airframe integration will continue to improve. Further noise reduction will come automatically. Fossil fuels, better new biofuels and mixtures will be accepted. NOX will reduce. GE, RR and PW would eagerly serve up some beauties for 2025 service.
Until now, we have missed gains from the airplane configuration itself. If Boeing could get even 5% net fuel savings from a low risk configuration, it could provide an important edge. It isn’t cast in concrete that a NSA should be single aisle, or must await proof of some revolutionary new aircraft or engine concept. The NSA isn’t going to be a hybrid wing body (HWB) or flying wing or joined wing design and it isn’t going to be powered by two open rotor engines with two very large counter-rotating, reversing fans.
The best, practical NSA design could be twin aisle, eight abreast, 17” wide seats. Note the MIT D8 concept with its wide double-bubble (or alternatively, smooth ovoid) twin aisle cross section and Pi tail. Two recent issues of Aviation Week have reported NASA work on MIT’s later, more advanced, rear engine boundary layer ingestion (BLI) model. But note that MIT AIAA and SAE papers in 2011 reported that 10% fuel burned savings vs 737-800 could be realized from its wide body/ lifting nose/Pi tail configuration itself — with engines on-wing at 118‘span. Its aero, materials, structures, manufacturing, weight and cost details should be evaluated. It makes a good looking airplane. Also explore any other useful NSA concepts.
Regarding the 757: the NSA family and a 200+ PAX, 4,000 nm 757 successor might have high commonality — the same twin aisle fuselage, the 757 one with stretch — the same flight deck — the same engine family, the 757 type with growth and refan — many of the same subsystems –maybe the same wingbox but two different wings, the .85 mach 757 type with more area, sweep and span–and somewhat different tails. I see the 757 type as following the NSA, ideally, as a derivative. Put the major league market before the little league.
Considering that the NSA family’s global fleet might grow to 10-20,000 aircraft over several decades, I expect that this class could save way more fuel, carbon emissions, and dollars than any other class–even compared to several thousand 787/A350’s. And note: less CO2 generation will be even more important in 2025 than the public recognizes today.
James Krebs is retired from GE Aircraft Gas Turbines. He has four decades of experience in the design, development, marketing, manufacture and management of military and commercial jet engines.