F-18 lightning strike
 

That made him jump


https://www.rt.com/news/447785-lightning-strike-fighter-jet/?utm_source=miximedia&utm_medium=miximedia&utm_campaign=Mixi media

I wonder if the seat cushion was ever recovered?

-RP

Great reaction time, ducking after the zap :rolleyes:

Did you expect him to duck before it?! :rolleyes:

I'm sure that when you fly fast jets you can see lightning coming and move out the way? :ugh:

:mad:

OvertHawk
 

The obvious, he was being sarcastic to the reply previous.

What effect does a lightning strike have on carbon fibre composite structures, if any?

There's always one.

Nutty
 

Translation please.

Most aircraft carbon fiber ' structures " and panels have built in conductive ' layer' or embeded ' metallic fibers- inks- ' or similar. penetrations which may cause sparking sometimes require special care and features.

Effects other than burn marks and surface 'roughness ' are minimal and rarely structurally significant.

It's more likely to do damage on carbon fiber composites than on aluminum (or other metals). Carbon conducts electricity fairly well, but has a much higher electrical resistance than aluminum (about two orders of magnitude if I recall correctly). This means there is much more local heating due to the strike and hence greater potential for damage.
I don't know about the F-18, but on the 787 there is a copper wire mesh incorporated into the composite layup during build to improve the electrical resistance and hence improve it's lightning protection. I suspect they do something similar on the F-18.
Shortly before I retired, I was observing a flight test on a 767 when we took a lightning strike during our descent to Paine (i.e. Everett). I was in the flight deck observing EICAS indications for my test when it happened - it didn't literally scare the crap out of me, but it came close :uhoh:
Based on the post flight inspection, it attached near the cockpit and exited at the wing root - doing a fair amount of damage to the (composite) wing-body fairing.

And similar arrangement on the A-6 carbon fiber re- wings built by Boeing a few decades ago . There was/and is a lot of public available papers and research on lightning strike protection on carbon fiber structural panels and the effects. And there is also a limited amount of related published information on an virtually all fiber ' paneled ' military airplane built in the 80's - a 3 foot model of which is on a pedestal across the street from the " Red Barn " portion of the Museum of Flight :) wuztheredunthat :cool:

And although it is not me- the following link may be of help explaining

https://patents.google.com/patent/US20050213278

It's the first bang that gets you. After two or three you get used to it.

Back when the 787 was being developed, there was a fair amount of debate as to exactly how much metal Boeing were going to have to put into this lightning protection layer. Obviously the more the put in, the heavier it was going to be, but it would be better able to deal with a lightning strike. I also recall that it had to be put in the very outer layer, so that heating of the metal layer didn't damage the structural strength of the CF itself.

Airbus's use of GLARE is quite interesting - it's still aluminium from the point of view of lightning tolerance / metal working, but it's a whole lot lighter than plain aluminium. Not a bad way to have gone about things (for the A380, which is where they used it).

On the A350 I think (corrections most welcome for my hazy memory) Airbus went for ribbons of thin metal tape wrapped around the airframe to form a sparse metal cage, instead of a fine mesh layered everywhere. I suspect that this works quite well. The lightning is going to preferentially strike / depart from sharp bits of airframe (the charge gets concentrated there), so it's probably quite easy to have sufficient metal at these points to protect any CF structure underneath.

Regardless of which approach is best, it seems that we're not having either 787s or A350s falling out of the sky or being grounded by lightning strikes. I presume that by now one or two must have got a zap.

RE major composite structures which have been flying for over two decades in commercial this may 2004 article may help


https://www.boeing.com/news/frontier...may/i_ca3.html