Airbus's fanfare a few weeks ago when the first completed A350 XWB widebody jetliner came out of the paint shop was mostly a PR event. At the time, the two things the company announced were that the plane had received its final paint job, and ground tests were about to begin, with flight tests expected some time this summer. This gave us an excuse to check up on the progress of this record-breaking aircraft's production.
The A350 XWB's airframe consists of a bigger proportion of carbon-fiber-reinforced composite structures than any other commercial jet to date: over 53 percent by weight. Carbon fiber composite leader Hexcel is supplying all of the carbon-fiber composites, both prepreg and fibers, used in the plane's primary structures. According to a video made by the company, these include fuselage panels and barrel, wing upper and lower covers, wing spars, center wing box, keel beam, main landing gear door and bay, and the vertical and horizontal tail plane.
But composites are not the only materials story for the aircraft. Titanium and advanced aluminum alloys combine with carbon composites to achieve more than 70 percent of the A350 XWB airframe's weight in non-traditional materials. This plus a new aerodynamic design are aimed at reducing fuel consumption and operating costs by 25 percent compared to other aircraft in the same category of midsized, widebody, twin-aisle passenger jetliners.
This plane has a couple of possible advantages over the problems encountered by its composites-heavy predecessors, the Airbus A380 and Boeing's problem-child 787. In the first case, the advantage is experience: Airbus's chief executive Tom Enders admitted at a press briefing last year that the A380's cracked wings were due in part to not understanding carbon fiber materials and their interface with metals, and not realizing this lack of understanding, as well as a lack of the right design controls. That admission impressed me: Boeing has tended to avoid such public mea culpas.
In the second case, the advantage is also experience, but here it has to do with battery choice. Boeing's much-publicized problems with lithium-ion main batteries led Airbus to promptly conclude that it should abandon its own plan for Li-Ions and switch to proven nickel cadmium main batteries. I conclude that Airbus will probably learn from its own mistakes and the mistakes of its main rival.
Here are some highlights from the evolution of the plane's construction, including its use of composites, from the most recent events back to the project's earlier days. Click on the photo to begin the slideshow.
The first completed A350 XWB widebody jetliner, dubbed MSN001, comes out of the paint shop on May 13, 2013 in Toulouse, France, after its final painting. For the aircraft's exterior, Airbus is using an environmentally friendly, chromate-free primer, and a new base coat/clear coat system needing less paint and solvent. Less detergent will be required when the plane is washed. Interior paint will be water-based to the extent possible. This event, which followed flight-test-instrumentation (FTI) verification, marked a key milestone before the aircraft's maiden flight scheduled for this summer. Still to come: final ground tests. (Source: Airbus)
At one time corrosion was a problem with some composites, and so they had to be painted. The corrosion was quite different from what we see in metal, and it surprised a few people. In addition the assembly of composite structures is different from the metal ones, just look at the stress/strain curves. Sort of like bolting to plate glass. It can be done quite well if you do it exactly right.
Of course another very smart move is keeping the production of those things relatively in house, because a lot of the Boeing problems were from outside suppliers.
It always pays to learn from other peoples mistakes, and that certainly holds true with batteries. Of course there may be alowances made for a future upgrade, which would not be mentioned until it was ready to happen.
You beat me to explaining why composites need to be painted. American Airlines planes were unpainted aluminum for decades. I recall it was more maintenance intensive than paint, but the weight savings paid off and surface drag of polished aluminum was similar to paint. The one exception was their Airbus A300's. The grain orientation was different in the various fuselage skins and the planes were painted gray to avoid a "quiltwork" appearance. The latest AA color scheme is gray across the entire fleet to get ready for the 787 which must be painted.
The illuminated tail is called a "logo light" and greatly improves visibility of the plane.
patb2009, composites have saved lots of weight which is why they've been used in military aircraft for decades. http://www.designnews.com/document.asp?doc_id=235863 Yes, they're difficult to recycle, but efforts are underway to solve this problem by the time it becomes an issue for commercial aircraft. http://www.designnews.com/document.asp?doc_id=235280 And the lightning strike problem is not a problem anymore. See slide 2 of this slideshow for one method and this article for others http://www.designnews.com/author.asp?section_id=1392&doc_id=253665 Design News has covered these subjects extensively: see the list of related posts at the end of the article, or search our site on 'composites'.
Excellent slide show Ann. The video was cool also. OK--I'm going to ask an "off-the wall" question. Can these airlines deduct from their expenses logo-types as advertising? Even a percentage of the cost to paint and maintain the exterior? I have always wondered if this can be done. While in the Air Force, we pondered paint vs. no paint as far as extended range. (Of course this was long before "stealth" was a priority or even possible.) As far as battery type, I think you go with tried and proven if there is any possible issue with liability or in-flight damage.
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