kjburns(at)btinternet.com
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 Posted: Mon Feb 20, 2012 3:59 pm Post subject: Lightning Strike K21 and Puma |
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I agree with Frans, avoid Cu nims, one response on this subject suggested 20 miles, I would suggest observing (preferably from the ground) how far away the effect of a large cu nim can be felt , ie downdrafts, swirling winds, gusts etc and preferably fly another day!
As a glider pilot for 37 years I have been fortunate to not encountered lightning, with high performance "glass ships" suddenly becoming bricks (when laminar flow wings get wet) common sense results in heading for a safe landing if rain / or associated storm clouds approach.
When early gliding records were attempted, flights inside cu,nims were used to gain height, and one particular Skylark 3 (wooden built Slingsby glider) that soared from southern England to Scotland, was struck by lightning that later examination found damage to wood that had its moisture vaporised damaging structures and also fusing of various metal parts.
Cross bonding of control junctures in sailplanes has been in practise since back then (1958 ish) .
My aircraft have cross bonding ( that I am sure would not protect from much other than a very low energy lightning strike, if at all).
One of the suggestions considered in the AAIB report on the K21 glider break up, was to have non conductive materials at the extreme control connections (ailerons specifically studied in this report),my thoughts are that such a massive energy discharge would find an alternative path.
Another AAIB statistic is 1 strike per 100,000 flight hours ( is that more chance than winning the lottery)?
I will still choose to fly (when the weather is suitable) including winch launching gliders, with up to 3000 feet of steel cable from an earthed drum attached to a chunk of metal within a foot of my gonads,(ottfur tow hook) but with a parachute and good weather information and observation.
I would enquire with the boffin types out there with an understanding of electrical static discharges creates a compact personal device to warn us of this possible threat.
After the K 21 incident the AAIB called for and received information on the electrical activity / energy levels so some one out there already has an interest in producing a related product.
Link to the AAIB K21 incident ( and mention of Puma helicopter Carbon fibre rotor strike).
http://www.aaib.gov.uk/cms_resources.cfm?file=/dft_avsafety_pdf_500699.pdf
My aircraft have cross bonding ( that I am sure would not protect from much other than a low level lightning strike).
Fair weather !
Kevin Burns
From: Frans Veldman <frans(at)privatepilots.nl>
To: europa-list(at)matronics.com
Sent: Tuesday, 14 February 2012, 10:37
Subject: Re: Europa-List: Lightning Strike
--> Europa-List message posted by: Frans Veldman <frans(at)privatepilots.nl (frans(at)privatepilots.nl)>
On 02/13/2012 11:17 AM, Martin Olliver wrote:
| Quote: | Hi All. Has anyone experienced a lightning strike in a Europa? If not
what is the perceived result of such a strike?
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The result is impossible to predict. Lightning stikes comes in all sizes
and shapes. You can get a little protection against very light strikes
(for of course a weight penalty), but since you don't know what is going
to strike you there is just one effective measure: stay away from
anything that looks like a TS.
If you embed copper mesh in your wings it will make your wings much
heavier, and of course if the strike is heavy enough the mesh will melt
anyway and take the wing with it. Any strike generates heat, and as we
all know our Europa's can not tolerate much heat, not much what we can
do about it except for using aluminium instead of glass fiber.
As much as the size and direction of lightning strikes vary, so do the
results. The best in terms of survivability are vertical strikes. They
don't search for your airplane, you just have to fly through a strike in
progress. Alas, they are the least occuring stikes in airplanes. Much
more occuring are spanwise and lenghtwise strikes. Your airplane offers
an electric charge a comfortable path to find its opponent. Also, your
exhaust fumes leave a trail of extra conductive air, due to the carbon
and extra moisture in it. Any charge following that trail will find your
airplane. Spanwise strikes bring the risk of welding the aileron
controls, and of course the heat expands the air in the wings and the
wings may just blow apart. Lenghtwise strikes will likely travel via the
rudder cables. Apart from taking the ruddder out when the tiny cables
melt, they might melt through the fuel tank which is just an inch away.
Heat and fuel don't go along very well. And of course the rudder cables
end at the rudder pedals, so I hope you don't have wet feet when it happens.
The avionics and electric systems are the least of your concerns, but
anything might fail, if not everything. It is likely you can't talk to
anyone anymore, have no navigation anymore, and have to land your
crippled airplane trimmed for cruise speed and possibly without rudder
or aileron control without assistance. If you survived the initial
strike at all of course.
I remember the story of someone who got hit by lightning. They found his
airplane with all the controls welded. Some research revealed that the
poor pilot had flown for at least 10 minutes after all the controls
where welded inmovable before he crashed...
So, I will avoid thunderstorms at all costs.
In my airplane I installed a stormscope. If it indicates anything
threatening closer than 100nm, I will ju= the many List utilities such as List http://w="http://forums.matronics.com" target="_blank">http://forums.matronics. -Matt Dralle, List Admin.<======
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