The battle of wing extensions for new single-aisle

"Dual feather winglet."

This is the new solution proposed by Boeing for the new 737MAX. The winglet on the 737 MAX will have two tips, one bending up, the other down.

The company previously had estimated the MAX would offer fuel savings of 10 percent to 12 percent compared to the current 737, with this solution the additional saving is 1.5 percent on fuel.

"Incorporating this advanced technology into the 737 MAX design will give our customers even more advantage in today's volatile fuel-price environment," Jim Albaugh, president of Boeing Commercial Airplanes, said in the statement. Boeing launched the upgraded 737 MAX last August to compete with the A320 new engine option, or A320neo, which rival Airbus announced in late 2010. Both re-engined single-aisle jets are expected to offer improved fuel savings.

"The concept is more efficient than any other wing-tip device in the single-aisle market because the effective wing span increase is uniquely balanced between the upper and lower parts of the winglet," said Michael Teal, chief project engineer for the  737 MAX. Boeing said the dual feather winglet was validated during wind tunnel testing of the 737 MAX. The new winglet fits existing airport gate constraints "while providing more effective span, thereby reducing drag," the company said. "We have assessed the risk and understand how to leverage this new technology on the MAX within our current schedule," said Teal. "This puts us on track to deliver substantial additional fuel savings to our customers in 2017." The company estimates the 737 MAX will use 18 percent less fuel than the current Airbus A320.

In 2009, Airbus announced it would offer fuel-saving wing tips that the company calls "sharklets" as an option on the A320. The neo adds winglets — Airbus calls them "sharklets" — to the current A320 design, but they are very similar to the upward swooping winglets on today's 737s.

Because the 737 already has winglets, Airbus executives have argued that the MAX cannot gain the extra 3.5 percent fuel-burn improvement the European plane-maker will gain by adding winglets to the neo. Wednesday's announcement of a radical new Boeing winglet design undercuts that argument. Boeing had previously claimed a 5 percent fuel-burn advantage over the neo. Spokeswoman Lauren Penning said the new MAX wingtip's incremental fuel-burn advantage adds up to a further 1.5 percent advantage compared with the neo. Airbus hotly disputes Boeing's figures. Before news of the "dual feather" winglet, Airbus had been claiming the neo would burn 8 to 11 percent less fuel than the MAX, depending on which sub-models are compared.

Airbus hotly disputes Boeing's figures. Before news of the "dual feather" winglet, Airbus had been claiming the neo would burn 8 to 11 percent less fuel than the MAX, depending on which sub-models are compared.

Airbus spokeswoman Mary Anne Greczyn said Wednesday the company's engineers looked at the option of a split-tip winglet for the neo but decided on the "sharklet" design. Separately, Boeing revealed that the MAX will require a slight bump in the door of the nose landing gear. That's because the nose gear must be extended by 8 inches, compared with the current 737, to lift the wing and allow sufficient ground clearance for the new, bigger CFM engines. To fit the longer nose gear into the wheel well without major structural changes, Boeing is shaping the landing-gear door so that it bulges outward to accommodate the tires. That will add some drag, but Teal said the impact is "negligible." The projected fuel-burn improvement takes into account all the changes, negative and positive.Airbus has produced the first new-build A320 with Sharklets. Depicted here at its roll-out in Toulouse, MSN 5098 will be one of several A320 Family aircraft in the certification flight-test campaign starting in May this year and lasting around 600 flight hours. These Sharklet tests follow the successful ‘early flight-test’ campaign with Airbus’ A320 MSN 001 test aircraft.

In a conference call with journalists, Michael Teal, chief project engineer for the 737 MAX, called the concept "the most advanced wingtip technology in the single-aisle market." The design is innovative. No commercial airplanes in service today have anything similar, though the concept resembles a split-tip winglet design Seattle-based Aviation Partners is flight testing. Winglets in general add extra wing surface without extending the overall wing span. They increase the wing's lift while their shape reduces the drag caused by air vortices at the wingtip. Teal said the split ends of the new wingtip maximize the aerodynamic gain without adding as much weight as a longer, single winglet would.

The overall MAX wing span will be just a few inches longer than the current 737. Teal said the upper feather of the new winglet is close to the size of today's 737 winglets, which are nearly 8 feet tall. The lower feather will be shorter to ensure sufficient ground clearance. Boeing aerodynamicists came up with the design using computer simulations, then tested it in two advanced wind tunnels, Teal said.

He said the new winglets can be incorporated into the overall design within the previously announced schedule, which will see the MAX enter service in 2017. Final details for the jet's design and manufacturing will be pinned down next year. Last fall, at a Las Vegas business-jet conference, a somewhat similar design called the Blended Split-Tip Scimitar Winglet was showcased by Aviation Partners, which pioneered winglet technology and works with Boeing in a joint venture that produces winglets for the 737.

Boeing 787-10 or 777-8x: decision Likely This Year

A potential double-stretched 787-10 variant depends more on what Boeing decides to do with the 777 more than anything else.

Not for the first time, talk about a double-stretched 787 has entered the fray only this time, Boeing’s decision to establish a dedicated development team for the 777 puts the decision making into a rather grey area. Some of this is compounded by the ever-growing uncertainty over the rival Airbus A350-1000, which thus far is failing to make the grade on paper (or sales) against the 777-300ER.

There is equally the possibility that Boeing could do both moves and squeeze the big Airbus jet – it is a poor selling model in contrast to other 777, A350 and 787 variants. For whatever its worth, there’s more chance of a 787-10 and/or enhanced 777 emerging than there is of a so-called 150 seat CSeries.

Boeing hopes to make a decision this year on the 787-10 and aims to ensure that this larger-capacity 787 avoids cannibalizing sales of the 777, another family of Boeing aircraft that also may be getting new models, the 777-8X and 777-9X. While the 777 looks more than likely to benefit from a revamp rather than a full overhaul, this is paced more with the fact that the larger A350-1000 is still undefined and program sources attribute significant issues with the baseline A350-900 that have to be ironed out first before a stretch can happen, much less meet the advertised specifications Airbus has listed. 

Boeing is loathe to grow the 787 into 777 territory – a stretch too far, and you end up with a useless airplane like the A340-600 which trades passengers and payload for range and is saddled with higher costs.

A second stretch of the 787 would also raise engine thrust issues, affecting performance. As Boeing studies its options with 777, the company feels that a lower cost approach to improving that would be far more beneficial to countering the perceived angst any A350-1000 could cause.

Boeing Commercial Airplanes CEO Jim Albaugh said, “We will do the 787-10 by all likelihood. We’re now working through design concepts. Assuming the customer interest is there, later this year [a decision will be made], and we will have something to offer toward the end of the year.” He says the 787-10 will have a shorter range than the -9 but will be able to carry 40 more passengers, so “the economics are very good.”

The fact that the 787-10 is a stretch of the 787-9 means it will be in the realm of the 777 in terms of seating capacity. Albaugh, however, suggests otherwise. “We think we’ve got a good separation between the models. There’s 15% separation between the models. We’ve spread the sizing between them, so we don’t cannibalize any one aircraft.”

There have been some reports about a 777-8LX model, which promises more range, but Albaugh is dismissive. “I’ve seen something on a chart mentioning that, but I am focused on the 777-9X and 777-8X,” he says, referring to the new stretched version of the 777-300ER and 777-200, respectively. Albaugh was speaking to Aviation Week in Singapore yesterday during a media roundtable.

He says the 777-8X and 777-9X are hugely important to the company. Boeing sold 200 777s last year, and the aircraft is unbeatable in terms of efficiency, asserts Albaugh. But he also says Boeing is mindful of the fact that Airbus is planning the A350-1000, and declines to disclose details on the 777-9X, except to say “it will be a significant improvement over the 777-300ER.”

As for the 737 MAX, Albaugh says, “I hope we can have a couple of thousand orders before we deliver the first aircraft.” Boeing already has secured firm orders for the 737-8 and 737-9. Albaugh says it also has secured a 737-7 customer, but has yet to disclose who that is.

Albaugh declines to say when the 737 MAX specifications will be locked, but asserts they are already effectively firmed up because Boeing is giving MAX customers guarantees when it comes to the specs. He also says, “I don’t want to over-promise and under-deliver. I want to ensure that it is on spec and delivered on time.” Boeing has learned from the lessons of the 787 program, he adds.

Boeing has started delivering 787-8s, but has had to do some post-production fixes to the aircraft in response to concerns about delamination.

Boeing announces design changes for 737 MAX

Boeing has announced which will the engine for the 737MAX

The company released the new details Thursday to try to stem the momentum of the hot selling A320neo, Airbus' revamp of its single-aisle jet family that features an even larger new engine that will produce the most fuel-efficient and least-costly jet in the single-aisle market.

The current models of the Airbus A320 and the Boeing 737 split the single-aisle market roughly down the middle. Boeing needs the MAX to maintain that share against the neo. The 737 chief project engineer, said the current 737 is lighter and more fuel efficient than the current A320, and the new MAX design will leapfrog the neo and have 7 percent better operating economics. The engine for the 737 MAX will have a larger, 68-inch diameter fan and a lower weight affects about 30 percent of its operating costs, and more efficient, lighter design and requires less thrust than other airplanes in this class, which is important because weight and thrust have a significant effect on fuel efficiency and operating costs. Airbus decided two years ago to add a new engine to its A320 single-aisle jet and received hundreds of firm orders at this year's air show. Boeing followed suit and said Thursday that it now has 600 commitments for the new MAX, up from 496 when it launched the program in August.

John Hamilton, the 737 chief project engineer, said:"There's a much better structural efficiency that goes into the 737 design than into the Airbus design," Boeing will increase the engine fan size from 61 inches on today's 737 to 68 inches on the new MAX engine — called the LEAP, being developed by CFM International. A bigger fan sucks in more air, providing greater thrust. But Boeing's increase in engine fan size just matches the fan size of today's A320.

"Today, our (737) engine is 7 inches smaller than the Airbus (A320) engine, and yet we have lower operating costs," Hamilton said. "The 737-900ER is nearly 50 pounds lighter per seat" than the comparable A321. The MAX "doesn't need the high thrust requirements that the Airbus product has," he said. "When you look at drag, fuel efficiency and weight, the 68-inch fan is really the optimum solution for the 737 airplane going forward." It said in one year, a fleet of 100 will save 175 million pounds of jet fuel and save $85 million in fuel costs. Boeing said the amount of fuel burned should be 16 percent less than the competitors are burning now and 4 percent less than future offerings.

Airbus spokeswoman Mary Anne Greczyn dismissed that claim, saying Boeing is struggling to overcome a structural limitation: that the 737 wing sits closer to the ground than the A320's wing, so that a larger, more fuel-efficient fan won't fit. "If a smaller fan engine were to generate the appropriate level of efficiency, we could have easily incorporated that, since we are not constrained as our competitor, " Greczyn said. "The A320neo family is designed to benefit from the aircraft's inherent advantage." He acknowledged that Boeing is behind Airbus in its re-engine program, the A320neo, but said there's a lot of interest from airlines in Boeing's model. "It's a huge growth market," he said of single-aisle jets. "The customers are responding quite well, and we expect several hundred more commitments soon."

Hamilton said the engine will be the largest change for the 737 MAX, but he noted several smaller ones. Boeing will refine the 737 airframe design in relatively small ways without changing the overall size of the planes. The larger, heavier engine will necessitate strengthening of the wing and parts of the fuselage, as well as designing a heftier strut to hold the engine on the wing and making minor system changes. Boeing will also lengthen the nose landing gear to raise the wing slightly and reshape the tail cone to streamline the air flow. and it will introduce fly-by-wire spoilers — the hinged parts on the wing that rise on landing to increase drag — which means they will be operated by computer rather than by direct cable connections.

Boeing said Thursday it continues to work with customers to see what they want in a new model aircraft. Boeing launched the 737 MAX in August; Airbus launched the neo last December and by the summer had captured more than 1,000 orders from airlines eager for more fuel-efficient planes.


Hamilton said customers are "responding well" to Boeing's preliminary design and that he expects "several hundred more commitments soon." Boeing won't finalize the design until 2013, he said.

The neo, due to enter service in 2015, at the end of September had 918 firm orders plus an additional 319 purchase commitments. The MAX, scheduled to enter service in 2017, has no firm orders. But on Thursday Boeing said it has garnered 600 purchase commitments from eight airlines, including some U.S. carriers.

Hamiliton called the 737 the most popular and reliable commercial jet and said it has sold more than 9,000 of the Renton-built aircraft.

Boeing has not announced where it will build the new 737 model, although analysts say it would be difficult for it to meet its deadlines if it tries to build entirely new production facilities elsewhere. Boeing executives say they will decide by the spring. Company spokeswoman Karen Crabtree said Thursday that the Renton site "has the skill base and knowledge to incorporate the production changes" needed for the MAX.

Boeing 737 begins from three UPDATE

Boeing Selects Larger Fan, FBW, Nose Gear Extension for 737 MAX

Boeing Commercial Airplanes CEO Jim Albaugh has announced that the company will fit a 68in CFM Leap-1B engine on its 737 MAX family. In addition, the design will add fly-by-wire "one control surface" and the larger fan will prompt a 6-8in extension of the nose landing gear. Albaugh also says that the company now holds "north of 600 commitments" for the re-engined narrowbody. More via flightblogger

Boeing 737 begins from three

Will be ready in 2017 in the 7-8-9 configuration - from 126 to 215 seats. Consume up to 15% less than current NG and his name is MAX.

All started 51 years ago with the 737-100. At first, the 737 was called the "square" airplane because it was as long as it was wide. The new technology made the position of flight engineer redundant; the 737's two-person flight deck became standard among air carriers. 

The evolution is a new family of aircraft – 737 MAX 7, 737 MAX 8 and 737 MAX 9 builds on the strengths of the Next-Generation 737.

MAX7 will have 126 to 149 seats, MAX8 from 162 to 189 seats and MAX9 from 189 to 215 seats.

The 737 MAX will deliver big fuel savings that airlines will need to successfully compete in the future. Airlines will benefit from a 7 percent advantage in operating costs over future competing airplanes as a result of optimized CFM International LEAP-1B engines, more efficient structural design and lower maintenance requirements.

Boeing is evaluating two fan diameters of the CFM International Leap-1B engine: 66.1 in (168 cm) or 68.1 in (173 cm), both of which would be unlikely to require the modification of the landing gear: there is a need to maintain a 16.9 in (42.9 cm) ground clearance beneath the aircraft's engines and ground surface.

The 66 in (168 cm) diameter fan is an increase from the 61.8 in (157 cm) CFM56-7B engine on the Boeing 737 Next Generation. The updated jet is also expected to feature external nacelle chevrons for noise reduction, similar to those on the 787 and 747-8. While the 66 in (168 cm) fan will have a lower bypass ratio and higher specific fuel consumption (SFC) than the 78 in (198 cm) Leap-X and 80.7 in (205 cm) Pratt & Whitney PW1100G engine options for the A320neo, the smaller engine will weigh less and create less drag on the 737's airframe. The 66.1 in (168 cm) engine integrated on the airframe will offer an SFC improvement of 10–12% over the current 737NG CFM56-7B engine. Industry sources report that assessments are under way to revise the tail cone, natural laminar flow nacelle and a hybrid laminar flow vertical stabilizer for additional fuel burn and drag reduction.

LEAP-X

The LEAP-X incorporates technologies that CFM developed as part of the LEAP56 technology acquisition program, which CFM launched in 2005. The LEAP-X engine was officially launched on 13 July 2008. It is intended to be a successor to the CFM56-5B and CFM56-7B. Currently proposed for the LEAP-X is a greater use of composite materials, a blisk fan in the compressor, a second-generation Twin Annular Pre Swirl (TAPS II) combustor, a bypass ratio around 10-11:1, and 16% lower fuel consumption.

The manufacturer plans no modification in the flight deck as requested by customers  it wants to maintain commonality with the 737 Next Generation family. Boeing also plans to add more fly-by-wire systems but only for the spoiler. As production standard, the 737 MAX will feature the Boeing Sky Interior. The powerful appeal of the new interior comes from the most spacious cabin headroom, overhead bins that disappear into the ceiling yet carry more bags and LED lighting that brings any color into the cabin. based on the Boeing 787's interior, as well as blended winglets.

The Boeing 737 is the world's most popular and reliable commercial jet transport, with more than 9,000 orders to date. Boeing forecasts global demand for more than 23,000 airplanes in the 737's market segment over the next 20 years at a value of nearly $2 trillion.