787

[den]

Boeing 787 sure is a nice looking plane.

Comments

[dewhitton.livejournal.com]

Comet gave us the term "metal fatigue." They'd sorted out the problem by Comet 4 but it was too late for the company; Boeing had the 707 by then.

I wonder if there is such a thing as "composite fatigue."'

[hafoc.livejournal.com]

I don't think anybody knows. That's the problem.

Thing is, with the Comet it wasn't even the new technology that did them in. It was cabin pressurization, which Boeing and others were already using. Combined with the high altitudes that the high performance jet engines could deliver, and then combined with the fact that the Comet's designers innocently chose to use rectangular windows in the passenger cabin.

The new tech didn't make the plane crash. What made it crash was the combination of new tech with old tech, plus bad luck, plus the day after day, month after month pounding and grinding hard work to which commercial aircraft are uniquely subject. And that's what worrkes me. You just never know what's going to happen until you put all the parts together.

[klishnor.livejournal.com]

It was cabin pressurization, combined with the fact that the Comet's designers innocently chose to use rectangular windows in the passenger cabin.

If someone had actually learnt a lesson from history, then the designers would have known they were heading for trouble.

Victorian engineers had used strain gauges on ships to show how stress built up around sharp corners when a structure was put under repetitive loads.

But I'd certainly trust my life to the structural integrity of a Nimrod (the military version of the Comet, and still flying very happily).

[hafoc.livejournal.com]

As would I, or one of the later Comets for that matter. They got that little window problem all fixed up, yeah. (Rather I'd trust them as much as anything. I LOVE flying, but I'm a very nervous flyer. Figure it out if you can, I can't.)

I think the problem wasn't the structure per se. It's that nobody made the connection that in a pressurized fuselage, even a minor crack at a window corner can "run," propelled by the interior pressure, and then the whole fuselage ruptures like a punctured balloon. Unless they incorporate rip stoppers into the structure, which I understand they now do.

Composite fatigue.. hrm. The worst I've heard of so far is that some of the composites in light aircraft have a short lifespan because they take damage from ultraviolet light. One would hope that's something Boeing has considered. I think it's probably only a problem with the more basic composites like fiberglass, but... (shrugs)

[klishnor.livejournal.com]

I wonder if there is such a thing as "composite fatigue."'

Just about any material can fail due to fatigue fracturing.

Composites should be more resistant, but will probably not show signs of imminent failure as well as the more traditional materials.

[hafoc.livejournal.com]

Or at least not until 20-30 years of experience tells the techs what the signs of impending fracture are.

[jamesb]

Well ... When it comes to composite aircraft parts, we already know the signs of post "impending fracture" ...