Lightning protection - static discharge

[SAF_Zoom]

Ok while researching accident report involving a LE, I can up on this one:

 

http://www.bea-fr.org/docspa/1996/n-vn960917/htm/n-vn960917.html

 

For those of you that don't speak/read French it tells of a LE flying at 9600' when it got hit by lightning. There was evedence of electric arcs on one of the control tubes... According to the report one of the wing exploded from the strike.

 

I know that these planes were buil for VFR flying away from conditions where one would expect lighting to be a danger. But lightning can strike a good distance from a storm... Ive seen holes the size a 25 cent in the fuselage of widebodies from lightning strikes.

 

Do any of you know of a way to protect against such a risk ? Also what about static dischargers ?

 

As always just looking for what as been done before.

[Arbiter]

I don't know.... Doc said 1.21 Gigawatts of electricity is a lotta juice :-P... If god reaches out and touches you like that while flying amongst the angels, isn't it your time?.... Kinda like a giant bug zapper for little planes I would think. Then again, I am not an expert at all in this area. I am just picturing all sorts of bugs bunny cartoonish scenes where a person is flying along in their long EZ and lighting up like a lightbulb skeleton when struck.... Hopefully it doesn't happen because my first inclination is it's not good news for an aircraft of the LE size...

 

-Chris

[SAF_Zoom]

Pretty much how see it too, but who knows... an once of prevention is worth .....

[krwalsh]

I searched Canard Zone for "lightning" and came up with 26 thread hits.

I searched the Cozy Archives for "lightning" and came up with 144 hits.

I searched the Canard Aviators List and found 137 hits.

 

That is over 300 different ways (admittedly with a high degree of overlap) to see what other folks have encountered or thought about lightning. The most publicized incident (Kriedel) has a very well written explanation on what happened, and what could have been done to prevent it (don't fly in weather that may produce lightning).

 

I assume you read through at least the majority of those posts and formed your question as to what can be done about it. The conclusion was that nothing specific could be done to significantly minimize the damage from a lightning strike, and that the best action was to minimize the probability of a lightning strike occurring by not flying in weather that is conducive to lightning strikes.

 

So, what exactly was your question that was not answered in the archives?

[longez360]

Do any of you know of a way to protect against such a risk ?

 

No. Leave your Long EZ in the hangar that day or select the appropriate aircraft for the task. . .

[SAF_Zoom]

I searched Canard Zone for "lightning" and came up with 26 thread hits.

I searched the Cozy Archives for "lightning" and came up with 144 hits.

I searched the Canard Aviators List and found 137 hits.

 

That is over 300 different ways (admittedly with a high degree of overlap) to see what other folks have encountered or thought about lightning. The most publicized incident (Kriedel) has a very well written explanation on what happened, and what could have been done to prevent it (don't fly in weather that may produce lightning).

 

I assume you read through at least the majority of those posts and formed your question as to what can be done about it. The conclusion was that nothing specific could be done to significantly minimize the damage from a lightning strike, and that the best action was to minimize the probability of a lightning strike occurring by not flying in weather that is conducive to lightning strikes.

 

So, what exactly was your question that was not answered in the archives?

Ha yes the 26 thread with a mention of the word "lightning" but no discussion of the subject except avoid at all cost... Could be just that, but maybe there is a way to reduce the impact/effect of mild stikes... I'm weel aware that fully immunizing an LE from Lightning stikes is less then likely. But this was only part of the question...

 

But what I'm mostly interested in... was what is being done to discharge static electricity build up... Surely there as been advances made in 30 years...

 

And I'm not just talking about proper grounding and refueling techniques thats just common sence, I'm talking about the use of aircraft static discharger and their installation...

[Spodman]

...the use of aircraft static discharger and their installation...

I guess it hasn't been discussed because I don't expect they would do anything. In a metal aircraft the static charge is conducted around the airframe and supposedly discharged by those thingies, and I understand they will work in carbon fibre airframe as well. In an airframe that is not a good conductor the charge can't get to them. I've said it now, but I've probably got it wrong again, and somebody will post so shortly...

 

If you do a web search on 'lightning mesh' you will encounter the concept of lightweight alloy mesh that goes between the fibreglass and the filler, making the airframe conductive. I have read it wass standard on the Columbia, when it existed as such. You would have to put your antennae on the outside but. Still wouldn't fly through a thunderstorm either.

[SAF_Zoom]

Thats what I was looking for.

 

As anyone here done this to his LE (or other)? And what are the risks or downside ?

[TMann]

hmmmmmm ............ I s'pose if I was so inclined I could add these to the trailing edge of my wing (Carbon Fiber) but most likely not.

 

There are many REAL dangers and issues that should be addressed well ahead of the possibility of being struck by lightling.

(example: Going down in saltwater and being attacked by sharks infected with an STD.)

[SAF_Zoom]

hmmmmmm ............ I s'pose if I was so inclined I could add these to the trailing edge of my wing (Carbon Fiber) but most likely not.

 

There are many REAL dangers and issues that should be addressed well ahead of the possibility of being struck by lightling.

(example: Going down in saltwater and being attacked by sharks infected with an STD.)

Thats why you should always have a rubber....... dinky

 

But seriously, I was reading up on surface films... some say they can cut done on the sand/fill/sand cycle a lot... Some can be used when vacuum-bag process is used... and some even have embeded conductive metal mesh for LSP (lightning stike protection)...

[Neverquit]

I know that these planes were buil for VFR flying away from conditions where one would expect lighting to be a danger

Well, first these planes are VFR if you equip them as such. They can be great IFR planes and many fly "above the weather" this way.

 

As for lightning strikes I would rather avoid at all costs regardless of the aircraft material. You're speaking of a very powerful electrical shock that can do extreme damage.

 

Your idea of fine metal mesh is getting confused with static buildup from friction from air across the surfaces. You will see all GA and commercial planes with "wicking" rods or wires extending from the trailing edges. What I'm going to do in this case is put some of the fine mesh across the leading edges of my wings and strake then run them to a wick. You can get it from Aircraft Spruce. Whether it works or not we'll see. It may end up shielding and screwing up my wing antennas. Nevertheless, none of the static discharge ideas will save your butt from lightning. When its time, its time.

[SAF_Zoom]

Thks Neverquit, but I'm not confusing anything,

 

Just jumping from one subject to the other...

 

Let me know how in works out for you,

[Big Steve]

I have a simple solution to lightining strikes in a small airplane. Dont fly in the area where there is a problem. Very easy solution STeve build on

[TMann]

I have a simple solution to lightining strikes in a small airplane. Dont fly in the area where there is a problem. Very easy solution STeve build on

.... WE HAVE A WINNER!

STeve is soooooooo right. Rather than invest in technology to defeat a lightning strike, invest in technology to avoid it.

 

I've been using AnywhereMap for my GPS solution and combined with XM Weather I can see where the lightning strikes are relative to my position.

 

Prior to that you could turn up your ADF and listen for it.

 

Bottom line is you won't find me anywhere near those objects in the sky that make the lightning. They make other nasty stuff that will make lightning seem like the least of your problems. Any pilot could tell you the same.

[steve]

Thats what I was looking for.

 

As anyone here done this to his LE (or other)? And what are the risks or downside ?

i found a rusin guy here that is doing a cool looking thing. i translated his web page and copy past here (?)

 

The company Veesn (USA) in the construction of aircraft Starship widely used composite materials, largely based on the carbon fiber with epoxy matrix (ugleplastiki). Наиболее крупными агрегатами из углепластиков являются крыло и фюзеляж. The largest unit of ugleplastikov a wing and fuselage. В применяемых углепластиках используются препреги различного вида: однонаправленная лента, ткань и жгуты. In applying ugleplastikah used prepregs different kind: odnonapravlennaya tape, fabric and wire harnesses.

 

Одной из проблем, связанных с использованием в конструкции самолетов полимерных композиционных материалов, является защита от поражения молниями, которая имеет два аспекта. One of the problems associated with the use of airplanes in the design of polymer composites, is the protection from lightning stroke, which has two aspects. Первый аспект - диссипация электрического разряда молнии внутри конструкции, поскольку его воздействие вызывает физические повреждения, а второй аспект -защита радиоэлектронного оборудования от действия тока очень высокого напряжения при разряде. The first aspect - dissipation electrical discharge of lightning inside the structure, because its impact is of physical injury, and the second aspect, the protection of radio equipment from the current very high voltage at discharge. В случае металлических конструкций алюминиевая обшивка обеспечивает необходимую защиту, тогда как углепластики являются очень плохим электропроводником. In the case of metal structures aluminum sheathing to provide the necessary protection, while ugleplastiki are very bad elektroprovodnikom. Данная проблема в углепластиковой конструкции самолета Старшип была решена за счет использования экрана в виде алюминиевой сетки во внешнем слое, при этом очень тонкая алюминиевая проволока (нить) вплетается в углеродную ткань с шагом 3 мм непосредственно в процессе ткачества. The problem in the design of the aircraft ugleplastikovoy Starship was solved through the use of the screen grid of aluminum in the outer layer, with very thin aluminum wire (thread) in the carbon weave fabric with a 3 mm step in the process of weaving. По заявлению специалистов фирмы Веесн такой экран обеспечивает надежную защиту от разрядов, так как возникающие повреждения, в худшем случае, требуют лишь 'косметического' ремонта. According to the specialist firms Veesn this screen provides reliable protection against discharges, as well as the resulting damage, in the worst case, require only 'cosmetic' renovations. Дополнительные средства защиты включают токопроводящие перемычки (металлизацию) между панелями. В результате созданная система защиты от молний самолета Старшип равноценна или даже превосходит обычные металлические конструкции современных самолетов. Additional protections include conducting jumper (metal) between the panels. As a result of a system of protection against lightning aircraft Starship equivalent to or even superior to conventional metal structures of modern aircraft.

[SAF_Zoom]

Thanks Steve, this article talks about this:

 

http://www.compositesworld.com/articles/lightning-strike-protection-for-composite-structures.aspx

 

It also give a glimps of how the Cirrus Sr-20 and 22 use this technology :

 

"Astrostrike aluminum mesh is produced by Astroseal Products (Chester, Conn.) from a solid foil, which is then perforated and expanded to increase formability and augment adhesion to composite structures. Astroseal claims that its product provides significantly greater conductivity than woven mesh, while offering weight savings vs. metallized fiber products (see "Metallized fabrics and fibers," p. 47). Cirrus (Duluth, Minn.) uses Astrostrike on the fiberglass composite airframes of its FAA-certified SR-20 and SR-22 single-engine, piston-powered aircraft. Astrostrike aluminum mesh is embedded in the composite layup, and 3-inch to 4-inch (76 mm to 102 mm) metal strips run the length of the plane to electrically bond the aircraft's surfaces to its frame. The company knows of two lightning strikes to Cirrus aircraft: one hit the propeller tip and went through the engine; the other went through the airframe and exited through metal flake paint on the plane's graphics. Both were conducted through the aircraft as designed, without causing injuries or seriously damaging structures or equipment."

 

At first glance looks to be a simple process... but first glance can be misleading

[TMann]

At first glance looks to be a simple process...

I think I would rather either avoid the lightning or take my chances with the lightning.

I don't like the Idea of placing foil (perforated or not) as a barrier between the glass cloth and the foam. From what I gather that bond is rather important. What about any antenna problems?

Build for the 99.99% of what you are REALLY going to encounter.

 

.......but if you want to have some discussion at your level, try this link on the subject:

http://76.12.66.186/showthread.php?t=3938&highlight

[Spodman]

ugleplastikov

Sounds brilliant, how can composite aircraft be popular in Russia if the builder has to admit it is made of 'ugly-plastic'...

I don't like the Idea of placing foil (perforated or not) as a barrier between the glass cloth and the foam.

I don't either, but i don't see why it couldn't go on top of the completed layup. Slap it on with micro, then apply the finishing micro over the top.

What about any antenna problems?

I was thinking this too, but reading the 'ugly-plastic' post @ the stuff about the Cirrus made me think. I had more-or-less dismissed the Aerostrike product, despite mentioning it, as I had visualised encasing the entire aircraft with the stuff. If I am just providing a path for the charge that doesn't have any aircraft structure in the way with 3-4" strips the Aerostrike seems more possible to me, with fewer issues.

 

Run the strips along the upper fuselage from nose to engine mount, bonded to a strip full span on the canard and the upper surface of the wings. Leave a gap then use the mesh for the winglet antennae like everybody does with copper tape.

 

If you get a strike on the winglet the airframe will perhaps be vaporised, and your descent will be an unhappy one, so regardless of this hopeful mod I would follow the advice of all those below and avoid thunderstorms.

 

If on the other hand the mesh does actually conduct the charge of an unexpected strike I visualise it jumping the gap from the winglet to the wing with local damage and exiting wherever else in the airframe it wants to. If the antenna it hit was connected to a radio it would probably start dripping bits on the passenger's legs.

 

This does not seem now like an unreasonable modification to me now, and would have the added benefit of permitting grounding of the filler cap to the engine, etc.

[schmeddz]

When Glassair was still in business, they tested an under the skin foil technology for their glass airplanes. (Oshkosh 93 I think I saw the factory demonstrator.) I think it's very similar to what you see on the Cirrus technology airplanes. My employer (a major aerospace manufacturer, won't say who, I'm not an official spokesperson! ) Is very much into composites lightning strike prevention technology.

It always involves some type of Faraday shield. Look up pictures of Nikola Tesla standing in lightning fields with his Faraday cages around him. Interesting stuff.

 

It always involves some serious cash outlay to protect from lightning.

 

Look at the stats. How many deaths due to lightning strikes in small planes have you heard about? I rest my case.

 

Avoid the storms. Are you really going to fly in thunderstorms??? Jeepers! I shure don't! Good luck with that too!

[schmeddz]

Here's a fun read about the Glasair III and NASA research.

20020080124_2002131887[1].pdf

[SAF_Zoom]

I have no intention of flying in thunderstorm... I don't have a death wish.

 

But I was just looking at the system that have metal inserted (inbeded?) in the fibers to conduct electicity. If the cost was reasonable I don't know why one would not won't to have such a protection. Not that one would intentionaly but himself at risk but...

 

What about the reduce sans/fill/sand cycle claim of some of these surface films? Could their be any benefit there ?

[schmeddz]

Do you consider reasonable cost to include possibly hundred hours of extra labor? Finish time will go up big time.

 

My time is at a minimum worth 25 bucks an hour. That's a cheap estimate of what I'll consider my time worth. It took me over 200 hours to refinish an already existing/flying long. That's just what I counted. It's going to be more on the one I'm doing now.

 

The material, (if you can find it cheap.) will not be as cheap as you hope. And your time won't be either once you get going.

 

Look up "Explosafe" on Google. That was a popular trend back in the 70's and 80's to put in EZ tanks. Nobody's doing that anymore either.

 

You like exercises in hard schooling don't you?

[Edge 513]

I almost guarantee that this idea will drop off SAF's list after 6to 8 years of building and building and building and building ....etc, an building. This aircraft wasnt designed to be a hard IFR platform, and steering clear of weather and cells, just makes sense. Getting pounded by turbulence is not my idea of a good time, let alone flirting with thunderstorm activity.

I regard this series of postings as the tossing out of ideas to see if they 'fly' and after several years of exhausting effort, will be viewed in a different light other than armchair musings.

My .02

centz

[SAF_Zoom]

I almost guarantee that this idea will drop off SAF's list after 6to 8 years of building and building and building and building ....etc, an building. This aircraft wasnt designed to be a hard IFR platform, and steering clear of weather and cells, just makes sense. Getting pounded by turbulence is not my idea of a good time, let alone flirting with thunderstorm activity.

I regard this series of postings as the tossing out of ideas to see if they 'fly' and after several years of exhausting effort, will be viewed in a different light other than armchair musings.

My .02

centz

Yep that is what they are... just getting you guys input.

[schmeddz]

I almost guarantee that this idea will drop off SAF's list after 6to 8 years of building and building and building and building ....etc, an building. This aircraft wasnt designed to be a hard IFR platform, and steering clear of weather and cells, just makes sense. Getting pounded by turbulence is not my idea of a good time, let alone flirting with thunderstorm activity.

I regard this series of postings as the tossing out of ideas to see if they 'fly' and after several years of exhausting effort, will be viewed in a different light other than armchair musings.

My .02

centz

 

Yeh! It's like fantasy football teams. "I wish I had....., if only..." I never saw the point.

My time gets more valued as I get older. I only fool around on this during breaktime at work.

When it ceases to be fun, you won't hear from me again!!