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Jun 28, 2009

Dreamliner-An Impossible Dream?

The most alarming question to arise from the Dreamliner fiasco is whether high composite airliners are doomed to fail. Not fail as in fail to reach production, although that is a pos

Ben Sandilands — Editor of Plane Talking

Ben Sandilands

Editor of Plane Talking

The most alarming question to arise from the Dreamliner fiasco is whether high composite airliners are doomed to fail.

Not fail as in fail to reach production, although that is a possibility even at this stage, but fail as in start crashing after large numbers of the two high composite airliners in question, the Boeing 787 Dreamliner and its supposed sequel, the Airbus XWB A350, enter service.

lonely

The critical issues include thin gauge, load bearing, flexible components made from carbon fibre reinforced plastics and in places, their interactions with metal alloys.

The ‘lonely scientist’, Hans van der Zanden, has published a draft version of his book ‘The Impossible Dream’ on these issues online.

This draft was not written in response to Boeing management’s abrupt about turn involving the now cancelled first flight of the 787 Dreamliner announced last week. Van der Zanden’s website was last updated on 9 June, well before the evasive announcement of a ‘side of airplane’ minor, easily patched issue by Boeing suckered much of the media for all of 24 hours.

In some regards, the book will drive readers to distraction with irritations like referring to these high composite designs as all composite designs.

The 787s and less clearly defined A350s are already burdened with tonnes of extra metal to make them work. They are far from ‘all composite’ and it seems, further than ever from coming to pass. They aren’t producing the claimed benefits.

The author is primarily concerned with how these designs take composites where they have never been used before, and how this involves leaps of faith more than reliable predictive models of their behaviour in such applications.

It was the failure of a static test wing under stress at ridiculously low levels that sharply highlighted the modelling problem that wiped out the 787 first flight and any lingering vestiges of credibility in those charged with the project’s management.

If Boeing doesn’t know how the materials will handle aerodynamic stresses now and over the lifetime of the investment the airlines are, or were, making in 787s, the foundations of proper certification of the type and its maintenance in terms of fatigue and damage are washed away.

Certainty is required. Dreams and hype are one thing, a real airliner is another.

The early chapters of ‘The Impossible Dream’, are interesting, but probably overdone as context for the technical critiques which make gripping reading from Chapter 5 through Chapter 7 followed by the important Sudden Impact testing proposal which is found in the tool bar on his website.

The draft book dissects the main issues with composites. Have the executive branches of Airbus and Boeing been engaged by these issues, or have the key decisions been made by marketing and sent to the design and engineering departments for implementation rather than consultation?

How many of the airlines have engaged themselves with these issues in Dreamliners and XWB A350s? Most airlines have long severed any real connection between management and technical knowledge of aircraft design and engineering.

“Oops, that’s interesting” is not a plausible defence after tens of billions of dollars worth of these types have been ordered.

In a sense the design issues that now arise are those of the management classes of recent decades, as in a post modern re-invention of Taylorism, versus the rude mechanics (or designers.)

It is a divide between hype and reality which may have lethal relevance to the future of these projects.

Update: Hans Van der Zanden has responded to a request for more information about his study and assures us that he is not involved with any of the interested parties in use of composites or their alternatives in airliners. The 3000 hour study is self financed and driven by safety concerns over the materials dating back to the Columbia Space Shuttle disaster in 2000.

He says introducing a new construction material at this scale in airliners is a very dangerous undertaking.

In relation to the now cancelled first flight of the 787 he says, ” I was very nervous about the first test flight and it came as a relief when problems surfaced in time and finally at last engineers apparently found the courage [to say] that ‘enough is enough’.”

Van der Zanden says he will launch a more detailed web site concerning his study in the near future.

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