Boeing 737MAX

While Boeing officials continue to say the company is more likely to replace its 737 than outfit it with new, more efficient engines, the company last week built a 737 with a series of upgrades intended to boost fuel efficiency by 2 percent.

That would mean new 737s would be 7 percent more efficient than the first Next-Generation 737s, 737 chief project engineer John Hamilton said at the company's Renton, Wash., plant on Tuesday.

The upgrades include an improved CFM56-7BE engine, and redesigned wheel fairings, exhaust duct doors, wing surfaces and anti-collision lights that reduce drag.

"You're not going to get the big bang with any one of these changes," Hamilton said. "They're all going to add up."

And, while 2 percent may not sound like a lot, that adds up to a savings of about $120,000 per year for one airplane, with a net present value of $1 million over 20 years, he said.

Boeing completed a Continental Airlines 737-800 with the upgrades last week and plans to start ground testing next month, with flight testing from December to April. The company plans to phase the improvements into production from mid 2011 through early 2012.

And engineers are looking into other changes, such as changing the tail size, incorporating carbon fiber-reinforced plastics and using new materials to cut weight on the floorboards for what Boeing is calling a 737NG Plus, Hamilton said. "We think we can get something more out of this (plane). We haven't been able to really pin down a number yet."

These are just the kind of changes that customers want, rather than clamoring for whole new engines, which add cost and complication, he said. "You're not getting a strong response saying go re-engine. They like the incremental improvements."



Airbus executives have been hinting for much of the year that the company was likely to move ahead with a re-engined A320, called A320 New Engine Option, although recent reports indicate the company may be hesitating.

"We know we could get the same fuel burn as what the Airbus NEO could get," Hamilton said. "But when you look at the spares impact and you look at the operational impact, it doesn't always pay back."

Boeing hasn't set a timeline for incorporating more improvements into the 737, Hamilton said. "If Airbus decides to do their NEO, we're probably going to see how the market responds to that. We don't feel like we need to rush out with anything right away."

Asked about statements by executives at key 737 operators such as Ryanair that seem supportive of re-engining, Hamilton said: "If you listen to them carefully, what they're saying is they want fuel burn improvement."

Asked about Airbus' apparent cooling to re-engining, Hamilton said: "I think they're out talking to the same customers we are and they're getting a similar response, a lukewarm response."

A big reason Boeing and Airbus are looking at re-engining is that upstart planes such as the Canadian Bombardier CSeries and Chinese COMAC 919 are trying to eat into their single-aisle turf.

The CSeries may well not make its planned 2013 entry into service, Hamilton said. "Some of the lessons we've learned from the 787, they've still got in front of them, so their EIS is maybe a little questionable," he sad. "There are some customers out there that are listening to Bombardier, but they haven't really landed any big customer yet."

Republic Airways, which has ordered the CSeries, is "smart enoguh that they're probably going to have some caveats in those contracts," he said.

The COMAC 919 and Russian United Airplane Corp. MS-21 are unlikely to be strong competitors but will set their companies up to build competitive airplanes in the future, Hamilton said.

Jamie Jewell, director of strategic communications at CFM, said a survey the company conducted of customers last year confirmed airlines are concerned about much more then fuel efficiency.

In fact, fuel efficiency finished fifth on a list of priorities, while reliability was No. 1, she said. "That engine has got to be there, has got to be ready to go, or the business model doesn't work."

She noted that CFM's 737 engines have a 99.98 dispatch reliability.

Discussing eventual new narrow-bodies, Hamilton said Boeing continues to look at larger planes.

"Definately the sweet spot in the market is the (737)-800 today," he said. The 737-800 seats 162 in a typical two-class configuration.

Hamilton expressed some skepticism about open-rotor engines, saying: "I'm not sure I want to get on an airplane with a big fan spinning next to me."

He didn't dismiss the idea of a twin-aisle narrow-body, saying: "When you look at some timetables of moving people on and off an airplane, there's actually some benefits there."

Asked about the timing of a new single-aisle jet, Jewell said: "When Boeing says it's ready to go, CFM will be ready to go with them."

She was more positive about the open-rotor engine, saying it could cut fuel use by 25 percent or more from current engines, and issues such as noise could be solved.

"It has to be designed in conj we an airframer. ... We still think its probably 2025 to 2030 before you realize that," she said. "Is it possible? Yes. Is it probable? The jury's still out."

DUBAI -- Until now, Boeing has allowed artist to interpret the look off a re-engined 737, taking artistic liberties about what a major update to the narrowbody would look like.


A publicly available Boeing presentation hosted on the website of the Federal Aviation Administration on technologies to improve the environmental footprint of commercial jetliners, may provide an unintentional first-look at one of the potential configurations for a re-engined 737.


The presentation details the airframers plans for the Continuous Lower Energy, Emissions and Noise (CLEEN) program designed to use 737s and 787s are demonstrators for new technologies. Slide eight of 25 presents the timeline for the testing, which is set to last through 2014.


On the slide is a series of generic images, including one of a 737 undergoing wind tunnel testing at a Qinetiq facility, which on closer inspection features a landing gear nose blister and significantly larger engines. Could this be one of the 737 re-engining concepts Boeing was wind tunnel testing earlier this year?


According to a engineer close to the development of the 737, Boeing and CFM were wind tunnel testing the airframe and engine changes as recently as April of this year, while another engineer says some of those tests included a nose blister.


Most notable is the addition of a nose blister, which resembles that employed on the Airbus A330-200F, to accommodate the lengthened nose landing gear, which need to grow 8in to raise the larger nacelles to achieve appropriate ground clearance.


John Hamilton, 737 chief engineer, said in an Airshow China interview in Zhuhai last month the design must maintain 17in clearance from the ground to avoid contact with taxiway lighting.


Boeing has toyed with the idea of shifting some of the components in the forward electronics bay to the aft bay to make room for the longer landing gear.


The larger engines, which are almost certainly designed to accommodate the CFM Leap-X, appear to have an elongated nacelle sitting nearly on the same plane as the pylon, shrinking it significantly, allowing the engine to ride higher on the wing.


Boeing Business Jet president Steve Taylor said today a re-engined 737 could boost the range of the VIP configured jetliner as much as 10% over today's 6,200nm, opening a significant number of new city pairs, such as New York to Shanghai/Mumbai/Cape Town, Dubai to Sao Paulo/Miami/Sydney or Los Angeles to Tel Aviv/Sydney/Hong Kong.


Boeing has moved away from this concept in recent months, opting to focus on a series of smaller incremental improvements to the narrowbody, including the new Sky Interior, aerodynamic refinements and updated CFM56-7BE engine.


However, the model provides some insight into the amount of modification required to add the new engine to the wing of the 737. The airframer has promised a decision in 2011 that may give a green light to re-engining, an all new jetliner or another set of incremental improvements to the venerable narrowbody.

Boeing's customers may have given a tepid reaction to a 737 re-engining project, but behind the scenes the airframer has not slowed the pace on work to refine the design of an updated narrowbody.

A previously unreleased photo of the re-engined 737 being tested in a Qinetiq wind tunnel was presented in a public Boeing document on the US Federal Aviation Administration's website detailing the company's efforts to develop new quiet technology for its jetliners.

The image is the first visual clue to Boeing's thinking about how it might re-engine the 737. A key challenge is to gain enough ground clearance under the wings to accommodate the next-generation CFM International Leap-X or Pratt & Whitney PW1000G engines, which have a larger exterior diameter than the CFM56-7B powerplant currently available on 737s.

The wind tunnel model suggests Boeing may be able to buy extra ground clearance by moving the engines further forward, to tuck them up tighter to the wings, and also by lengthening the nose landing gear by some 200mm (8in) - a nose blister fairing to accommodate longer gear is clearly visible.

That approach would be similar to one taken by Airbus earlier this year when it needed to lift the nose - to level the floor - of its A330-200 when it developed the freighter variant.

However, Boeing sources indicate that new configurations undergoing wind-tunnel testing have done away with the blister fairing and its associated drag penalty, adding that only Leap-X configurations have been tested to date.

At the Zhuhai air show in November, 737 chief engineer John Hamilton said his team was considering moving some components from the forward electronics bay to the aft to help accommodate longer nose gear. Critically, he said, any design must maintain 430mm ground clearance to avoid contact with taxiway lighting.

The exact benefit of new engines is as yet unknown, but while some estimates envision a double-digit improvement in fuel burn, the overall operating cost reduction may end up in single figures.

Boeing will launch a program to replace its 737 in 2011 or early 2012, with entry into service in 2017 or 2018, a new analyst report predicts.

Responding to upstart competitors in the market for single-aisle jets with more than 100 seats, Airbus' last month announced that it would outfit its A320 family with new, more-efficient engines. But Boeing executives have said they're more likely to launch a 737 replacement that would enter service around 2020.

The new aircraft will replace the 737 and out-of-production 717 and 757, according to a Buckingham Research note that at Leeham News and Comment cited Tuesday.