Building the 787 | When lightning strikes

Seattle Times ^ | Sunday, March 5, 2006 | Dominic Gates

[orionblamblam]

> I'm sure there will be inter-fiber damage in a strike where the lightning jumps between fibers...

What seems more likely, at least to me, is the use of a copper or aluminum mesh on the outer surface. I was tangentially involved with lighting protection studies for a carbon-fiber-based military missile, and such a mesh ("Astromesh," IIRC) was used to give the missile the conductivity called for. This mesh does not need to be much... basically foil with holes. Still, it's added inert and structurally useless weight.

[PAR35]

I know that some fiberglass can be patched with some epoxy and a new piece. Of course, you aren't dealing with pressurization and structural issues. The patch would also likely create a bulge.

I'll confess that I don't know if that works with carbon fiber or whether it would work with aircraft applications.

[Question_Assumptions]

That's what bothers me about this whole thing. Sure, there is a lot of speculation about how the composites might react in a fire or how you might fix them, but I don't see anyone stepping forward to say that they've actually thought these problems fully through and they aren't a problem or they've figured out a way to deal with them. All I see is a void on the subjects and they are fairly important subjects.

[phantomworker]

Gillette said his team is perhaps only months away from agreeing with the FAA on an overall 787 certification plan, which will include proving that the risk of a lightning-induced fuel-tank explosion is less than one in a billion.

It does sound like they are addressing these issues. Any cert plan for the FAA has to be bullet proof. And the FAA always holds Boeing to the highest standards.

[cpdiii]

"They're going to paint every inch of the 787 fuselage no matter what. Unless they want a black aircraft."


You are right. I was thinking about an aluminium skin.
Senility is catching up with me.

[Yo-Yo]

Bondo.

[Question_Assumptions]

Fair enough, though I'd like to see the fire characteristics and repair methods described in some detail. Perhaps these are essentially trade secrets that Boeing will discuss once the plane is in general production.

[IonImplantGuru]

This occurred prior to 9/11. I'd hate to think of our reaction if it'd happen after that day. (Probably a sudden drop in cabin pressure as a few hundred sphincters tightened at once.)

That line brought a story I once read to mind. In the 1700s the question arose of how fast electricity traveled. The abbe of a French (IIRC) monestary was into science and decided to do an experiment: he called on his monks to gather in a circle with a Leyden jar (one of the earliest forms of battery) between him and nearest monk. He had them join hands while he held the Leyden anode, then he asked the last monk in the chain to grab the cathode ... and the entire assembly of monks jumped at the same time from the shock!

[baltodog]

Yes...from acompany in China...

[phantomworker]

A company from China off-loaded to Wichita!!! Is this a new trend?

[baltodog]

No, not really...

We make composite 747 parts for Mitsubishi and Kawasaki, as well.

We're also doing the door for the new US101 Presidential Helicopter...That's Agusta-Westland in England.

There are several composite assemblies we make for a company in Czechoslovakia, who in turn, installs them on new Sikorsky helicopters.

Aviation, especially the composite side, is truly global.

[GOP_1900AD]

I would imagine that the "must haves" for EMI/EMC would also tend to preclude any major issues due to lightning strikes.

[pepperdog]

That is hilarious! Wish I had it years ago when working in the composite arena.

[FlowerKrout]

How about gold plating cost and weigh? A super thin layer of gold will conduct much and not weigh so much. A gold airplane would be so cool ya wouldn’t need much paint.