Boeing has, at long last, revealed some details about the 737 MAX, most of which have long been talked about in various media. Boeing is further testing new wingtip designs–with or without winglets? And while readers cite this articlein our previous post linking AirInsight about winglets in an effort to discredit the conclusions, the last paragraph is noteworthy:
For the forward-fit market, LaMoria sees a “very healthy” business for Boeing 737s for the “next 5-6 years”, but there is no guarantee the company will select APB blended winglets for the GE Leap-1B-powered 737 Max, set for entry into service 2017. “We have a lot of long-lead future-oriented plans in place in hopes of working with Boeing for many years to come,” says LaMoria. “But Max is still an open question.”
Separately, see this Aeroturbopower article.
The whole wing tip thing is getting interesting. Boeing’s aerodynamicists never liked the winglet from AP and spent a lot fo time in the early days saying it wouldn’t work. They end up fitting a bunch of them and they sell very well. When the P-8 came along they took the opportunity to go with the swept tip on the 737, ostensibly due to icing issues although that seemed a weak argument at the time.
This week we get APB making a big deal about 100% embodiment and we get an article on here at the same time pointing out how useless the winglet is. Meanwhile, Boeing announce that they are sudying the wing tip. Sounds like lots of people are positioning themselves for a battle!. Should be fun to watch as long as we don’t take anyone’s statements too seriously.
We will point out that the Arvai piece doesn’t conclude the winglet is “useless,” and all the conclusions of readers to the contrary vastly overstates what Arvai wrote.
Airbus and Boeing have been clear all along that winglets are more efficient the greater the distance. In announcing sharklets, Airbus has always said the benefits are “up to” x percent based on distance (and therefore altitude). Arvai’s analysis says the same thing, but in detail publicly revealed for the first time as far as we can tell.
A reader emailed us this morning reminding us that winglets aren’t only about fuel savings; they also improve runway performance, ie, improving take-off run, a topic not specifically discussed by Arvai, who addressed instead landing performance.
We’re broadly aware of the sourcing Arvai used for his analysis and repeat that he didn’t pull his information out of thin air.
We have been tolerant of some of the comments’ tone because we are a colleague of Arvai and don’t want to appear overly sensitive to the hostile tone of some of the comment. We remind the readers of our comment policy to avoid personal attacks, which some comments have come close to and may have crossed the line of our standards. We remind readers to stick to issues, not personalities.
Didn’t realize I was getting personal! I thought I was commenting of the timeline of different perspectives on the wing tip and how it all seems to be setting up for a battle. If you read it another way, sorry about that.
IMO, the best thing Boeing could have hoped for is that the GTF fails to meet expectations. If Boeing now wants to put a GTF engine, incorporating an undersized fan, on the MAX, who says PW is ready to play. PW engines are de facto locked out from BCA’s products, not by the choice of PW but by the choice of Boeing. From PW’s point of view, they win “double” if the MAX sinks. Boeing would have to develop a new NB capable of using a right-sized GTF; all the while winning the market share battle on the neo.
A rather hilarious quote from aeroturbopower: 😉
If the initial version of the PW1100G — incorporating few, if any, fancy engine core technologies — is going to be 4 percent better in SFC than the the LEAP-1A, the MAX IMO is DOA. The LEAP-1B will be maxed out technology wise at EIS, while the PW1100G, with the expert help of RR, could easily be further improved in the SFC department, by another 5 percent a decade hence. What many people seem to have misssed is the fact that the GTF is a rather conservatively designed engine. The Ceramic Matrix Composite (CMC) technologies slated to be used on the LEAP-1B is unproven in flight conditions as of yet. The Technology Readiness Level (TRL) for CMC engine core technologieis is at TRL 5. The GTF is at TRL 7. After the the completion of flight tests for the C-Series, the GTF should reach TRL 8. The GTF will finally reach TRL 9 a couple of years after EIS of the C-series.
I believe I said in another blog I thought the Blended winglets may not be installed on the MAX/
I would not be surprised if AP is taking a business position here. They sense the MAX badly needs the winglets, Boeing wasn’t overly supportive sofar and now AP has them by the b.lls asking a premium. Boeing responds by looking brave and letting people say they can do without.
Re the GTF, I’m still surprised by the PW come back. 30-40 yrs ago they dominated the industry. Then were washed away by GE/CFM and RR. Everyone laughed about their GTF adventures for 20 yrs. They didn’t give up and are now set to be king of the hill in the NB segment again. Inspiring.
I said it before looking at the numbers sofar I expect Boeing to do some extra homework on the MAX
The MAX may not need blended winglets, or the extra weight they bring to the airframe. Boeing may decide to go with their own designed raked wingtips they put on the USN P-8A. The P-8 uses the B-737-800 wing, so the design engineering has already been done. Raked wingtips could be even more fuel efficent than blended winglets or sharklets, as they add a lot less weight than either of the two winglet designs.
Concerning the GTF on a version of the B-737MAX, it is possible if P&W can work on an engine just for the B-737 series. They already have the PW1521G/1524G almsot ready for the C-Series. It has, I believe a 72″ or 74″ fan section that could be clipped down to about 70″. But they will have to increase the thrust as the PW1524G only has about 23,000 lbs of thrust.
A wing extension for the MAX might be more efficient then a winglet, but as someone else mentioned, there is the restrictions of standard ICAO gates. Airports are designed around it and neglecting them introduces operational problems or global airport reconfigurations. The competing NEO still fits them.
In the GTF fits the, at last until recently undisputed, conventional wisdom giving a .5% sfc gain for every extra extra inch fan diameter that means a 5% better sfc for a 81 inch GTF NEO over a 70 inch GTF fitted MAX. No magic here. Just like on the CFM56’s fitted on A320s vs those on 737NGs. http://www.togo84.com/spec05_gas_turbines.pdf
The wingspan of the P-8A is about 123′, including the raked tips. The wingspan of a B-737-800 without blended winglets or raked wingtips is 117′ 5″, with the blended winglets add about 4′ to the wingspan, and it comes out to about 120′-121′.
Since Southwest is the launch customer for the MAX, what direction will they take it in? The -800 seats 175. In five years what will they want, more range or a few more rows? A five foot stretch on the MAX 8 would seat 187 and provide a 7% increase of revenue potential.
As for the wingtips, I’m sure Boeing would just use the P-8 wingtips if gate space were not an issue. If blended winglets produce to much float on landing, couldn’t the flap settings be reduced so the wing produces less lift.
It seems to me the 737-800 is right sized for the SW model. It gives a capacity boost over the existing -300/ -500 / -700 models. Apart from that, the 737-900 isn’t a dramatic stretch (2.6m) and provides reasonable growth if the -800 capacity becomes is too small.
IMO Airbus has a bigger issue. The A320 has become on the small side during the last 25 yrs for airlines willing to replace them. The A321 is a dramatic 7m, 7 seat row stretch. And it is significantly heavier and more expensive too. I’ve said it for yrs, an Airbus A320 NEO Plus, seating 200 passengers can become more filling a growing market demand then doing a risky extra investment. Easyjet, Ryanair and Jetblue have explicitly asked Airbus for it. And even went public to increase the pressure.
Maybe Airbus keeps it under cover to prevent Boeing biting the bullet and go NSA afterall.
That might be the wrong way around. Very big flap settings don’t usually add much lift but they do add a lot fo drag. If you are floating, reducing the flap setting may actually have the opposite effect.
Well, I’m just a layman so maybe Arvai is right about winglets increasing landing distances. The 8″ front gear increase on the MAX will angle the wing up slightly, so I’d assume that would be a landing issue to deal with too.
It may depend on whether Boeing signed a 777W type exclusivity deal with CFM which could paint them into a corner.
Very interesting piece on the aeroturbopower blog and surprisingly harsh on the max.
Brings me back to what MOL remarked about the max a while ago.
GTF is indeed a key driver for Airbus and if it performs in service could be the differentiator between the two products.
I am really looking to the order battle this year. I have a feeling both OEMs are storing some surprises for the FAS.
Randy, it doesn’t add up, they don’t believe it.
My guess about “what is going on” is that B is moving toward re-winging the 737 MAX, with entirely new, longer landing gear, while keeping the basic fuselage, a la the 777-7/8X Why, I speculate ?
1. All the reasons stated in the Av/Week article. Which means that if B bites the bullet and lengthens the landing gear they can get any fan diameter they want. If they add a new CF wing, the 737 X will be noticeably superior to the NEO and carry B through to the end of the 2020s when they can do something new.
1. The cost of doing the MAX is rising to the point that it does not justify the maximum improvement B can get without re-winging.
2. The GTF option is unavoidable in light of the Av/Week article.
3. The only way at this point in technological time to significantly increase efficiency, other than better engines, is to improve the wing. A carbon fiber center wing box and wing would be lighter than it’s metal equivalent, thus off-setting some of the weight gain arising from the new engines. No doubt B has done work on such a wing re the NSA.
4. When the MAX was announced, Spirit said they know the fuselage inside and out, and wanted to be involved in improving it as part of the MAX process (I’m paraphrasing). Spirit may be uniquely qualified to make the changes in the fuselage needed to add the new wing and box.
5. B has done well with the 787s composite wing (as opposed to problems with fuselage design and production), and ought to be able to deliver by 2017 or 2018. In any case, the 737 X will be so much more efficient that B’s customers will wait a little longer.
6. The combo of Spirit’s fuselage work and B’s CF wing work will mean that B will be able to get close to 60/month within an acceptable time, something they could not do with the NSA.
Now something close to fact: Who is going to believe B when they say they can do this by 2017-8? What will Albaugh say to a customer who is skepticle because of B’s past failures? What specifically will Albaugh say when a customer says, “You say you can do this 737 re-wing on time. But you guys just delivered the first set of new wings for the A-10 Warthog late. That job was the functional equivalent today of re-winging the Wright Flyer, yet you could not execute. What the ****is going on!?”
Christopher, I support your view something must be done to get the engines where they can compete, I differ on the roadmap. The 737 wing isn’t a bad one. Composites aren’t all to everyone. Apart from that, a new wing / wingbox would make it a new aircraft. If Boeing had had the choice they would have gone for a new aircraft, up to point when AA, SW and a few others confronted them (“no, we won’t wait until 2020-24”).
A significant modification on the current wing and wingbox seems necessary to get competitive engines on though. This has been an issue hanging above the 737 for a long time. It seems upper management choose to ignore/ dismiss it (also in the nineties) and started believing in their own storylines (again..), everyone loyally closing the lines.
In a 2010 sketch I suggested a more dramatic upgrade, making possible bigger fans. It has a new cockpit too. Folks said the current one is just fine. However the same folks thought the tail, Leap were fine and FBW a pipe dream. The market balking changes everything.
There are people having more influence then SUH, O’Leary and Tinseth on Boeing strategy. When they call, McNerny picks up his mobile / leaves the meeting/ stops eating. CEOs/COOs of big airlines pushed by their staff if they think B isn’t listening. I think those calls have been made already.
Chris, the wing generally accounts for about one third of the total development costs for an all new civilian airliner. Even the 737NG wing wasn’t “all new” in the sense that the design was constrained by the choice of not changing the dimensions of the centre wing box and retaining the main wheel well from the classics.
An all new composite wing and new Main Landing Gear (MLG) for the Max would mean that the whole centre fuselage assembly would essentially be of an all new design, with little, or no commonality with the 737NG. IMO, such an undertaking would cost at least half of what it would take to develop an all new narrowbody.
In the IMO unlikely event that Boeing would follow your “advice”, please do note that weight-wise, composite structures do not scale down as well as metallic ones and that the design trade-offs for high cycle NBs are different than for long range aircraft.
FWIW, the subcontractor that both helped design the 787 wing and which now builds it as a Tier-1 sub-contractor for Boeing, had planned to use the know-how acquired on the 787 for its own MRJ project, but in fact, later abandoned the use of composites on that MRJ wing.
Hence, if Boeing was now to proceed with a MAX featuring an all-new wing, it would IMO not be able to offer sufficient performance improvements over the neo to justify its development costs. Also, EIS would almost certainly be delayed by a couple of years which would mean that Boeing would have to set up an entirely new wing production system that would only be in use for slightly more than a decade.
All still under the grandfathering umbrella from the 60ties?
As long as they keep a few switches and rivets the grandfathering should still apply. That seems reasonable to me.
And the A320NEO will be grandfathered from the early 80s, so what’s your point?
Just like the question, can a 200 seat aircraft compete with 68′ engines, is, can a 200 seat aircraft compete with a 36m wingspan? If Airbus or Boeing do a new wing for MAX, NEO, or new airplane, I’m guessing it would be in the 40m to 45m range.
The B-757 has a 38M wingspan and the RR RB-211-535E4 has a 71″ fan. Thgat is almost to your numbers, and no one can deny the B-757 wasn’t a sucessful airplane.
I think the 757 was successful during a period fuel prices were low and stable.
Re wing span, if oil prices get high enough it will become profitable to increase wing span, reconfigure airports, make fuel stops, reduce flight frequencies, increase size etc.
IMO a short/medium range aircraft larger then the current NB’s is inevitable. Airbus as well as Boeing are pushed by the industry but have had different priorities sofar.
Winglets make sense for high lift coefficients, especially if the wing isn’t optimized for it. It makes even more sense (from aerodynamics point of view) to increase wing span and design a new wing. That is expensive. So the wingelt is a nice alternative. Further, single aisles are bound to the ICAO III box, which allows roughly 36m (or 118ft) of span. The A320 cucurrently currently stands at 34.1m, while the B737NG with winglets stands at 35.79m (34.21m without). So there is 21cm of fanatasy left.
The P-8A – not truly optimized for quick turnaround in Atlanta or Chicago – has a span of 37.64m, so outside the ICAO III box. Consequently, the solution used there cannot be used for the airliner.
In all finality extending span is the best wingtipdevice possible.( a carefull eye on tayloring lift distribution and low wingloading)
Uwe, are you actually endorsing Boeing’s raked wingtips over Airbus’s sharklets?
It is a question of hard limits. i.e. is your wingspan limited ( yes in the case of A380, A320 and 737) or is your design strain limited ( as in most refit cases ). Without span limitations and for a new design wingtip layout can go towards span extension and providing lift.
Anyway, the perfect wing would not have distinct wingtips, instead would be an overalll raked eliptical form.
The straight edges on todays wings are forced by mechanical limitations in high lift devices and control surfarces.
A320 certification reflects a snapshot from 1988.
B737 certification reflects a snapshot from 1968.
More significant cert changes happened before 1988
Nothing really new here, this basically confirms the changes that have been rumored for some weeks now.
The big difference is that the A320s design covers all current build regulations, thwe737 doesn’t.
Just when did Airbus say the NEO would comply with all the latest certification requirtements the A-380 and B-787 had to meet?
The key word here is “was”.
We are not talking about the specs of a plane that make it competitive in the 80’s and 90’s but for one that would be able to compete on the late 2010s, the 2020s and quite possible through some part of the 2030s.
Actually that is exactly what we are talking about. The B-737 has competed from 1967 and will still be competitive, as the MAX, into the 2020s. The A-32X has competed from 1987 and will still be competitive, as the NEO, into the 2020s.
Just because the B-757 is out of production doesn’t mean it isn’t marketable anymore.
For those who still doubt the benefit of winglets on the 737, I recommend the SWA approach – just fly them and measure
Sorry mate, YOU were citing 757 specs.
I hope that Boeing is no longer buying the cords & bear straps from AHF Ducommon as i have just seen on you tube about the cords bear straps (richardpearth2002)no wonder the 737 is having problems with miss alined drill holes rivets & coming apart in midair the latest is ryanair no wonder he got his aircraft cheep.