Carl,
Bit of confusion here I suspect.
Composite parts of commercial aircraft have separate provisions for
lightning strike and anti-static build up.
The first usually takes the form of aluminium strips, either solid or
segmented, which divert the strike along the external surface of the
composite, to metal parts of the airframe. This prevents the strike from
penetrating through the composite to metal parts within it, and doing big
bucks damage. The strips need to conduct several hundred thousand amps for
a short while.
The second provision, the subject of your Britannia men's offer, is a high
resistivity coating, intended to bleed away static electricity build up from
water and dust particles rubbing against the external plastic in flight.
Where the composite part covers antennas, or sensitive RF gear, the periodic
static discharge to nearby metal airframe parts causes interference. (or
sets light to fuel vapour in the case of composite kit planes). Such
coatings cannot conduct lightning strike currents.
Hope this helps.
Dave Simpson
-----Original Message-----
From: Carl Pattinson <carl@photos.prestel.co.uk>
Date: 26 September 2000 11:28
Subject: Re: Lighning Strike
>Only last year a glider flying out of Dunstable (UK) was hit by a lightning
>strike. This particular story was televised on national tv, with a first
>hand account from the surviving occupants - YES, they both survived as they
>had parachutes.
>
>At the time of the strike the Cu Nim clouds were about 5 miles away from
the
>glider. The lightning earthed on the control (aileron ) rods and they
>vaporised like a massive fuse. The occupants said that there was a bang and
>the glider exploded around them. They were both unharmed except one broke
>his leg on landing.
>
>The question seems to be "how close to a thunderstorm can you risk going ?"
>
>Incidentally one of my bulld helpers works for Britannia Airways and we
were
>going to get our Europa sprayed in their hangar. The paint tecchies offered
>to give us a coating of conductive paint. Apparently all composite
>components (covers fairings etc) on airliners use this stuff. Unfortunately
>we had to decline due to the weight factor.
>
>Carl Pattinson
>
>----- Original Message -----
From: Rob Housman <robh@hyperion-ef.com>
>Subject: RE: Lighning Strike
>
>
>> Last time I checked our Europas are not transport size aircraft, so this
>is
>> a no brainer: If you are close enough to a thunderstorm to get struck by
>> lightning, you will die anyway (except, possibly, by being fortunate
>enough
>> to be wearing a parachute at the time). Let's see, do I want to die as a
>> result of structural failure from turbulence or structural failure from
>> lightning? Obvious answer: neither!
>>
>>
>> Best regards,
>>
>> Rob Housman
>>
>> -----Original Message-----
>> From: owner-europa@aztec.houxou.com
>> On Behalf Of J R (Bob) Gowing
>> Subject: Lighning Strike
>>
>> There is a chapter on this subject in "Composite Airframe Structures" by
>> Michael C Y Niu.
>>
>> It seems the ideal would be to "have the entire exterior surface highly
>> conductive and electrically continuous". And the compromise "to a degree
>> that is consistent with system requirements and safe operation."
>>
>> It all seems to be a difficult or almost impossible exercise (and
>> expensive) exercise on composite aircraft.
>>
>> Is there anyone about please who doing anything about lightning risk on
>> their Europa?
>>
>> JR (Bob) Gowing UK No 327
>> 24 High St NSW 2550 Australia
>>
>>
>>
>
>
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