F-18 lightning strike
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F-18 lightning strike
OvertHawk
What exactly do you mean by ‘you can see lightning coming’?
Are you suggesting we should have some form of superpower or am I missing something obvious?
BV
Are you suggesting we should have some form of superpower or am I missing something obvious?
BV
Last edited by Bob Viking; 4th Jan 2019 at 09:37.
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The obvious, he was being sarcastic to the reply previous.
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Effects other than burn marks and surface 'roughness ' are minimal and rarely structurally significant.
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
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.
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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.
wuztheredunthat 
And although it is not me- the following link may be of help explaining
https://patents.google.com/patent/US20050213278
Last edited by CONSO; 4th Jan 2019 at 23:09.
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
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.
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
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.
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.
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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
https://www.boeing.com/news/frontier...may/i_ca3.html
In 1992, Boeing opened the state-of-the-art facility to provide composites solutions for the Boeing 777 empennage, which is made up of the vertical fin and horizontal stabilizer. Now just over a decade later, Structural Composites Frederickson is getting ready to celebrate the milestone delivery of its 500th 777 empennage.Part of the Fabrication Division for Boeing Commercial Airplanes, Structural Composites Frederickson today is focusing its manufacturing excellence for primary and secondary composite wing-like structures on a new dream: the Boeing 7E7 Dreamliner.