Airbus chief operating officer customers, John Leahy shared some interesting thoughts about advanced composite structures in airliners in Sydney this morning.
But at the outset, he made it clear he wasn’t offering a judgement on whether they were better or worse than the use of aluminium alloys, nor announcing a metal A350 XWB or launching into a detailed critique of the Boeing experience with the 787 Dreamliner project.
In relation to their use in the thin large scale structure of new designs, Leahy said :
“Composites technology in those applications has not in general been getting quite the weight savings that everyone had hoped for, however this may well reflect the limitations of current engineering thinking or trying to use composites in a closely similar manner to alloys, where new design approaches could ultimately realise their claimed potential.”
The Airbus A350 would hopefully avoid some of the issues that had arisen for Boeing’s 787, partly because on current indications it might follow it by two years.
The A350 test fuselage sections at Hamburg demonstrated a more conventional approach to design and construction, where composites were used in the floor, and the underlying ribs to which composite fuselage panels were attached.
This was easy to supervise for quality control in construction, and very easy for the airlines to support and maintain in terms of access and processes that offered many similarities to those used on existing fleet.
The Boeing use of large single piece composite sections was more challenging to manufacture and check, and was in his opinion ‘a bridge too far’.
Leahy did not directly respond when asked if Airbus was evaluating whether the more extensive use of composites in designs was going to deliver a worthwhile improvement over using the best alloys .
However he said Airbus was continually examining alternative materials, regardless of whether they were composite in nature or incorporated exotic alloys in its pursuit of weight savings in general in its designs.
He repeated, “We are always looking at all options to save weight including exotic metals.”
In 2004 and 2005 in presentations on the original Airbus proposal for an A350 family which would compete with the Boeing Dreamliner Leahy argued that the benefits it claimed for the high plastic content airliner could be delivered with more certainty and less cost by upgrading the A330 platform with new generation engines and a more evolutionary approach to composites.
In that campaign, which was swamped by orders for the 787, Airbus emphasised its leadership in composites, having gradually introduced them to its line up since the early ’80s, and argued that the Boeing plans were inappropriate as applied to the large sections of carbon barrel fuselages.
Leahy’s words today could fuel speculation that Airbus is at the very least ‘refining’ its approach to composites in the A350 XWB, or proceeding on the basis that it was confident of making them work much better in its design than appears to have been the case so far in the Dreamliner.
Which of course, is how Airbus would like to play it. The largest use of composite components in any airliner yet to fly is in the A380, notably in its central wing box area and wings. If it is working on a ‘surprise’ revision of anything in the A350 XWB, it certainly wasn’t going to announce it in Sydney this morning.