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Ejector
16th Jun 2006, 11:08
On the nose radar dome of Jets, what are the 6-10 lines going from the nose back. I have heard they are for de-icing.

They are very clear on the F100ís.

What are they for and how do they work???

Gary Lager
16th Jun 2006, 11:44
The radome is not made of metal, since it (usually) contains the weather radar and a metal cone would affect radar operation.

The strips are 'conductor strips' used to provide protection to the structure in the event of a lightning strike and to help dissipate static.

Nothing to do with de-icing AFAIK.

captjns
16th Jun 2006, 14:14
Also referred to as bonding straps.

ICT_SLB
17th Jun 2006, 03:59
Or diverter strips

glhcarl
17th Jun 2006, 04:18
Lockheed calls them "ARRESTORS".

DC-8
17th Jun 2006, 23:25
Thinking about static electricity... this question came to my mind:

How do aircrafts with fuselage made of composite conduct static electricity through it (e.g. Airbus)?

Redflyin
17th Jun 2006, 23:46
I would think that they would still have to have some type of bonding strap system to protect the aircraft. The bonding allows the strike to enter at one spot, then continue to an exit point theortically protecting the avionionics, px., etc.

DC-8
18th Jun 2006, 00:12
Could any Airbus pilot (or other composite aircraft pilot) tell us how do their plane conduct electricity through the fuselage to the static dischargers?

And another question: If in metalic aircrafts the damage caused by a lightning strike may be a little hole of about 2mm, how severe is the damage in a composite acft?

TopBunk
18th Jun 2006, 04:53
AFAIK, the fuselage on all current generation Airbus products is metallic.

captjns
18th Jun 2006, 09:00
Thinking about static electricity... this question came to my mind:

How do aircrafts with fuselage made of composite conduct static electricity through it (e.g. Airbus)?

If you know of any Airbus engineers, talk to them. They may even be able to break out one of their maintenance manuals to provide you with a detailed example.

DC-8
18th Jun 2006, 10:55
AFAIK, the fuselage on all current generation Airbus products is metallic.

Yes! You're right TopBunk, I've been looking for some info about Airbus structures and I found that composite materials in the 320 are just a 10%, much less than I used to think!

However the 380 contains a 25% of composites, and the 350 will contain a 35% (wings, rear fuselage and tail cone).

But anyway, I still have the doubt of lightning strikes damage in composite structures...

For more info: http://www.airbus.com/en/aircraftfamilies/a350/advanced_materials.html

Thanks!

ICT_SLB
19th Jun 2006, 00:02
Composite construction is present on the majority of current aircraft - it's just the percentage that is getting higher. Most aircraft have a thin copper mesh embedded under the gel coat to provide the required lightning and electrostatic protection. Bonding straps or metal to metal connections to main structure provide the necessary continuity to ground for the panel. Static wicks are normally attached to some metallic structure as they require low bonding resistance.

All-composite aircraft such as the Starship have particular problems as they require all power returns to be brought back to grounding plates near the power supplies as there is no convenient metal structure. It will be interesting to see how Boeing gets over this on the 787 especially with the "all-electric aircraft" requirement for very large amounts of power.

DC-8
19th Jun 2006, 11:34
Most aircraft have a thin copper mesh embedded under the gel coat to provide the required lightning and electrostatic protection.

So that's the trick... Thanks for your reply!

nzmarty
19th Jun 2006, 11:47
some aircraft with high amounts of carbon fibre or other composites have a strip embedded in the gelcoat, which is in turn earthed to the nearest metallic part of the airframe, and usually ends in a static wick.

and yes, the strips on the radome are 'diverter' strips, diverting electrical energy to the metgallic airframe. any lightening strike into the radar head could end up with the radar screen blowing in the cockpit (along with everything else!) - not a good look.

nzmarty
19th Jun 2006, 11:48
apologies for the double post.....

Ejector
20th Jun 2006, 11:43
Thanks folks for the info.
So, I presume that the nose, (leading edge of the plane) doesn't have an ice problem then? Is that because it's so 'blunt'?

EJ

Mad (Flt) Scientist
20th Jun 2006, 13:09
Thanks folks for the info.
So, I presume that the nose, (leading edge of the plane) doesn't have an ice problem then? Is that because it's so 'blunt'?
EJ

You'll get some quite impressive ice shapes on the nose if you wait long enough in icing, but the effect of ice on the nose (compared to, say, wing or tail) is relatively minor.