Boeing 737 MAX dual-feather winglet teleconference highlights

Beverly Wyse, Boeing 737 programme vice president (VP) & general manager (GM)

-       This kind of improvement is consistent with our demonstrated performance on delivering increasing value to our customers on-time throughout the life of the programme.

-       Since entry into service on the 737, we continue to improve the Next-Generation aircraft for our customers, including anything like carbon brakes and the passenger-preferred Boeing Sky Interior.

-       We also continue to improve fuel burn. Back in 2001, we introduced winglets, blended winglets, to the Next-Generation 737, giving our customers an additional 4% fuel burn improvement.

-       Last year we also introduced our latest performance improvement package which gave customers an additional 2% fuel burn advantage.

-       Today’s 737 is now 6% more fuel efficient than when we first introduced the Next-Generation airplane and we’re going to continue to look for opportunities to innovate to maintain our customer advantage in the marketplace.

-       With the MAX we have the opportunity to give our customers even more fuel efficiency upfront by producing a new winglet design based on the concept the Boeing team identified through our product development activity.

-       Right now we do not intend to retrofit this on the Next-Generation airplane, we may change that decision in the future but right now we’re just focused on introducing it on the MAX. We continue to have a strong relationship with APB, they’ll continue to be our partner for the winglet we have on the 737 Next-Generation, the 757 and the 767.

-       We’ve looked through the various ground support equipment, the height and just make sure that the clearance to the ground is no different than what we had on the Classic. Given the fuel burn benefit, feedback we’re getting from the airline they are comfortable with that.

-       The aerodynamics shape, the team has spent time on and perfected that in wind-tunnel.

-       This is a unique Boeing design. We are not currently with Aviation Partners Boeing on it.

-       Prior to this announcement, we’re looking at a 10%-12% fuel burn improvement, this adds 1-1.5% depending on range of the aircraft. We’re continuing in a measured way to look at what are those things we can add to the airplane to make it more efficient to the customers.

-       But there’s always the potential, you know, we’re very careful with our performance commitment and there’s always the potential that either the winglet or the engine or some of the aerodynamic improvement could outperform our prediction.

-       More like a fairing, than blister.

Image Courtesy of Boeing

Michael Teal, Boeing 737 MAX chief project engineer

-       The 737 MAX will give customers the latest engine technology and now we have a plan in place to bring customers the most advanced wingtip technology in the single-aisle market, the Boeing Advanced Technology winglet.

-       Boeing aerodynamicists used computational fluid dynamics or CFD, to combine the wingtip technology used on the 787 and 747-8 – the dual-feather concept winglet.

-       This dual-feather concept has an upper and lower piece that makes up the body of the winglet. To give more efficiency with just an upper winglet, you have to add more height to the top of the winglet. This adds weight and negates any additional benefit. The lower part of the winglet, in essence to a bit, by balancing the effective spans increase uniquely between the upper and lower parts.

-       This makes the system more efficient without any more weight, thereby reducing drag and improving the overall fuel burn.

-       The dual-feather winglet creates the fuel burn improvement that could give a total fuel burn improvement of up to 5 and half per cent relative to having no winglet at all.

-       For comparison, our competitor has just their first production airplane with a winglet and they claim the device will give customers up to a 3.5% fuel burn improvement relative to no winglet. Clearly the Boeing Advanced Technology winglet is another advantage the customers will have over the competition.

-       The formal design before we move forward with the wingtip design it took a measured approach to weigh the risk and benefits. As Beverly mentioned, we recognise there’s an opportunity for the new winglet to give our customers a substantial additional benefit. Engineers using the computational fluid dynamics to design and predict the fuel burn improvement on the advanced design did that analysis and then we fabricated scaled wind-tunnel model and tested the concept at both the QinetiQ at Farnborough at low-speed, and the Boeing transonic wind-tunnel in Seattle at high-speed.

-       The showed the winglet concept performed as expected, making the new technology very promising for our airplane. While testing is underway, our airframe and structure and manufacturing team met with the aerodynamic team to make sure we have plan in place to integrate the winglet on the wing and overall airplane design as the MAX in a produceable way.

-       Most importantly, the team validated that we could do this within our existing schedule for the MAX. Now the next step for the winglet team is to finalise the winglet configuration details in the build plan, which will firm up by our firm configuration in 2013.

-        The fences they have on the A320 series airplane are much smaller in size which is at the end of the wingtip. If you look for scale size here, this winglet, the upper winglet is very close to the size of today’s NG winglet. It’s a much bigger winglet and the forward piece is significantly bigger as well. One concern people may bring up if you have the winglet coming down below you have ground clearance issue. The ground clearance will be equal or better than the 737 Classics which fit into all our existing airport infrastructure. So this winglet is significantly bigger than the fences.

-       The wingspan of the MAX will remain in the Code C airport definition that the NG fits in today. Slightly [bigger] in terms of inches.

-       As we announced before, to install the new engine, we’ve increased the nose gear landing gear 8 inches and of course it folds up and forward when it folds into the wheelhouse. So we didn’t have, I’ll say, have a significant structural change to allow the nose gear to come up and attach and in the stowed position that could tie the stuff up just pushing out a bit compared to the NG today. So what we did was take the door and local to the door just created a blister that allows that landing gear to fold which is 8 inches longer without significantly changing the structure of that doghouse of the airplane. The aerodynamic impact on that is negligible to the airplane.

-       The 1 to one and a half per cent that you get from the winglet depending on range you get 1.5% improvement on the airplane. That is depending on the mission that the airline will fly and it’s not a significant advantage in terms of additional range. It’s small though. The fuel burn benefit forward the airline typically flies the 737 in that sort of range.

-       It is completely new and that we’re taking advantage of the wingtip technology from the 747-8 and the 787 and the lower portion of the winglet. So it’s new.

-       To clarify, the span of the 737 MAX will remain within the Airport Code C of the NG. It could be a couple of inches more, but we have some room for the NG into that code. So it is not a significant span you’re talking into difference than the 737 NG. It’s the effective span that this new technology gives you that increases the aerodynamic efficiency by reducing the drag that gives us the benefit.

-       We continue to work with our customers to determine that the capability. The payload is going to be comparable to the 737 NG, we’ll continue to work with customers, understand their requirements. As far as the range capability, the MAX will have the same capability of the NG and capacity for more. We’re working with customers understand their requirements and requests to finalise that configuration in upcoming months. They’ll have more range, the question is effective how much. We’re still working through it.

-       When we quote the up to 1.5% of additional fuel burn [saving], that is an integrated airplane fuel burn. So we’ve taken into account the additional loading of the upward wing that winglet will produce to gain that aerodynamic benefit.

-       The amount of change, because of the way the technology works, the amount of weight that is added by the winglet itself is very minor on the airplane and the wing load to the side-of-body is not significant at all.

-       [The 18% fuel burn advantage] That’s our estimate in comparison against the existing Airbus A320 family.

-       As we’re closing in and finalising the configuration of the airplane to ensure that we meet our commitment on schedule, the window is closing fast. So it’s pretty much it.

-       As we firm up the final configuration, we’ll continue to optimise the concept to maximise the performance benefits.

-       It’s a very small blister, and aerodynamically negligible.

-       Our major trades aerodynamically are done now, now that the final architecture changes will be done by 3^rd, 4^th quarter this year.

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Image Courtesy of Boeing