Paul,
Points to remember about lightning strikes :-
1. Aircraft rubbing against the air generate an electric charge and this
will attract a bolt of lightning from an oppositely charged Cb. Expensive
aircraft have static discharge wicks to dissipate this charge
2. From personal experience I know that lightning can strike over 10 miles
laterally out of a Cb.
3. A metal aeroplane is bonded together and so the electricity has the full
run of the whole aeroplane. You will, of course remember from your school
days that like charges repel each other and so any electric charge, such as
a lightning strike will repel itself and stay in the outermost atoms of the
metal structure. You will therefore be safe unless wing-walking at the time.
4. A non conducting, plastic aeroplane struck by lightning will disintegrate
and the occupants will die.
See you in the bar on thundery days,
best wishes,
Martin Shaw.
----- Original Message -----
From: "Paul Atkinson" <paul@theatkinsons.demon.co.uk>
Subject: Europa-List: Re: Europa-List Digest: lightning strikes to composite
aircraft
<paul@theatkinsons.demon.co.uk>
>
> I am very hazy about the science of all this, so don't quote me, but
> metal aircraft rely on good bonding to ensure that lightning has
> somewhere to go without affecting the contents (i.e. passengers, radios
> etc). As Carl suggested, I assume that the presence of metal in a
> composite aircraft can have disastrous effects because there is nowhere
> for the energy to go once it has entered.
>
> My "Handbook of Aviation Meteorology" suggests that lightning strikes
> can occur anywhere if the conditions are right, even in clear air,
> though much more likely in CBs. It also suggests that a good way of
> attracting a strike is to trail a long aerial or cable out the back :-).
>
> The only strike I have had, happened flying through an innocent looking
> cu (it was no more than 2000' in extent). Our passage through it set it
> off, and all the others nearby.
> Existing thunderstorms are not too difficult to avoid but we have no
> way of telling when the conditions might be right in other
> circumstances.
>
> So I have a fairly fatalistic approach to this, in that if my Europa is
> struck by lightening it probably won't do me much good, but on the
> other hand the chances of that happening are relatively slim,
> particularly flying VFR most of the time. On the other hand I am more
> concerned about the turbulence that CBs produce. Even a quite small CB
> can produce enough turbulence to make flying a light aircraft very
> difficult, not just in the cloud; windshear near the ground can
> seriously damage your health.
>
> Paul Atkinson
>
> ps I heard a story once about a metal glider that broke an altitude
> gain record in Argentina. The pilot thermalled into the base of a CB.
> When he regained conciousness the tail of his aircraft was at an odd
> angle but it was still flyable. The barograph, which had been running,
> showed that he had broken a record by a considerable margin. I suspect
> that he would have enjoyed the experience far less if he had had his
> oxygen mask on.
>
> > From: n3eu@comcast.net
> > Subject: Re: Europa-List: Lightning Strikes to Composite Aircraft
> >
> >
> >> Hi All,
> >> According to the AAIB at the last PFA Rally at Kemble, aircraft do not
> >> attract lightening, so it will only strike if the aircraft flies
> >> through the
> >> path of lightening when it is already travelling. This is my
> >> understanding
> >> of what was said. I therefore try to give CBs a wide birth.
> >> Regards,
> >> William
> >
> > Perhaps the AAIB guy didn't come across so clearly, or the "dog ate
> > his homework."
> > The below research document is long and technical, but the very first
> > sentence
> > will do: "Not until the 1980's was it convincingly demonstrated that
> > the
> > vast majority of lightning strikes to aircraft are initiated by the
> > aircraft,
> > as opposed to the aircraft's intercepting a discharge in progress."
> >
> > http://plaza.ufl.edu/rakov/ProgressinAerospaceSciencespaper.pdf
> >
> > Regards,
> > Fred F.
> >
> >
>
>
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