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No Bias FTW

Wire enmeshed top cover for convertibles?

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Posted (edited)

Fatal lightning strikes may be rare, but they do occur even while one is driving near thunderstorms.

As most of you probably know, regular convertibles do not form a 'perfect' Faraday Cage and - while the such roofing would provide you comfort when it rains - the fabric would just be an open area in the view of the lightning strike.

 

I have a few questions regarding cars and lightning strikes overall:

1. Was the idea of wire meshes ever borrowed from the airline industry and implemented on the top covers for convertibles? In the modern world, airplanes made of flexible, composite materials have copper wires running through them.

 

https://www.youtube.com/watch?v=OXrqTUVN7G8

 

2. I don't quite understand how even normal cars would form 'perfect' Faraday Cages. Wouldn't the windshields and side glasses be viewed as open areas by the lightning strikes? 

 

3. Perhaps this would answer question 2 but it is quite a distinct problem. I am aware that people were still electrically shocked by lightning strikes even while they were inside fully-enclosed (normal) vehicles. Even if a person were to touch metallic objects within the 'perfect' Faraday Cage, why would some lightning strikes 'chose' the person to travel through rather than remain in the Faraday pathway? Are there cases of individuals still being shocked while inside airplanes and metallic ships?

Edited by No Bias FTW (see edit history)

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Benefits of AACA Membership.

Just how long have you been "Sheltering at Home" ?

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1 hour ago, 1937hd45 said:

Just how long have you been "Sheltering at Home" ?

A while....

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I say you are overthinking this. The convertible does have top irons that are connected through joints to the chassis, so there is a "ground" terminal above your head. 

 

 

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I wouldn't "over-think" this too much. If one lives in a seriously lightning prone area, and is worried about being struck, one should do some serious research on the subject. High voltage discharge can be funny stuff. Thousands of variables, many things most people would never think of (like ozone pathways) make it very difficult to predict. My Dad was an electrical engineer, with specialties in high voltage and often consulted after-the-fact in lightning damage to determine who got to pay for the repairs.

A typical convertible top car will roughly double your likelihood of being hit by lightning over a steel roof car. If for instance, your circumstances would make you a one in ten thousand target? Doubling that would make you roughly a two in ten thousand target (not actually 1 in 5000, but close enough for discussion's sake). Still not high on the "worry-o-meter". In the first place, one is already sitting low to the ground. The car is somewhat isolated from the ground by rubber tires (although wet dirt in the rain can make a good pathway itself). Lightning (sky to ground type) usually aims for a high point that is somewhat grounded. Your sitting low somewhat insulated self is not a favored target, however, certain circumstances can make you a target.

My Dad used to say that if one is in a lightning storm, and it is striking at the ground? Of course, look for a lower place. In a field near trees is good, NEVER under a tree or right next to a building or other structure. Then, pay close attention to how you "feel". IF the hairs on your neck (or head or arms or?) begin to stand out (or up) DROP TO THE GROUND and assume FETAL position (HUG YOUR KNEES!)! (Don't be driving when you do this!) This protects your heart, and minimizes the likelihood of a fatal discharge. MOST people killed by lightning are not actually struck by lightning. Everything on Earth has some amount of static electrical charge. The differentials in those charges can become extreme during lightning storms, and a lightning discharge nearby can shift the differentials of everything in the vicinity, thus resulting in a discharge of its own.

 

To rephrase my first sentence.  Don't over think this. If you worry too much about a remote possibility of being struck by lightning? Your panic is more likely to cause you to make a foolish mistake, like crashing the car, or running recklessly and slipping or falling,  or worse yet, hiding under something the lightning will want to hit.

 

Also. IF by (remote) chance, the car you are in is hit by lightning? (Or a downed power line?) DO NOT simply open the door and step out! Unless there is a compelling reason to leave the car, it is best to open the door, and remain inside the car. Warn anyone that comes along to not touch the car. After awhile, it will normalize its static charge, or someone that knows how, can ground the car carefully to make it safe. If you MUST leave the car (like there may be a fire? Or medical attention is needed?). Try not to touch the metal of the car, and jump out, not touching the car and the ground at the same time. Rubber soled shoes help a lot.

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I've taken lightning strikes 5 times in an airplane. Gets your attention for sure but usually little or no damage. Never felt so much as a tingle and one strike was to the nose radome about 5 feet in front of me. I actually felt the heat from that one ............Bob

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One of my college roommates was struck and killed by lightning on a beach in Nova Scotia on a sunny day.  His wife noticed dark clouds on the horizon and thought it was time to leave the beach.  My friend stood up,  picked up their sandy blanket and snapped it over his head to get rid of the sand.  He died instantly.

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Let me know if you need to get rid of a convertible or need a place to store it were thunder storms are rare. I'll even take it out weekly to keep the battery up

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11 hours ago, wayne sheldon said:

I wouldn't "over-think" this too much. If one lives in a seriously lightning prone area, and is worried about being struck, one should do some serious research on the subject. High voltage discharge can be funny stuff. Thousands of variables, many things most people would never think of (like ozone pathways) make it very difficult to predict. My Dad was an electrical engineer, with specialties in high voltage and often consulted after-the-fact in lightning damage to determine who got to pay for the repairs.

A typical convertible top car will roughly double your likelihood of being hit by lightning over a steel roof car. If for instance, your circumstances would make you a one in ten thousand target? Doubling that would make you roughly a two in ten thousand target (not actually 1 in 5000, but close enough for discussion's sake). Still not high on the "worry-o-meter". In the first place, one is already sitting low to the ground. The car is somewhat isolated from the ground by rubber tires (although wet dirt in the rain can make a good pathway itself). Lightning (sky to ground type) usually aims for a high point that is somewhat grounded. Your sitting low somewhat insulated self is not a favored target, however, certain circumstances can make you a target.

My Dad used to say that if one is in a lightning storm, and it is striking at the ground? Of course, look for a lower place. In a field near trees is good, NEVER under a tree or right next to a building or other structure. Then, pay close attention to how you "feel". IF the hairs on your neck (or head or arms or?) begin to stand out (or up) DROP TO THE GROUND and assume FETAL position (HUG YOUR KNEES!)! (Don't be driving when you do this!) This protects your heart, and minimizes the likelihood of a fatal discharge. MOST people killed by lightning are not actually struck by lightning. Everything on Earth has some amount of static electrical charge. The differentials in those charges can become extreme during lightning storms, and a lightning discharge nearby can shift the differentials of everything in the vicinity, thus resulting in a discharge of its own.

 

To rephrase my first sentence.  Don't over think this. If you worry too much about a remote possibility of being struck by lightning? Your panic is more likely to cause you to make a foolish mistake, like crashing the car, or running recklessly and slipping or falling,  or worse yet, hiding under something the lightning will want to hit.

 

Also. IF by (remote) chance, the car you are in is hit by lightning? (Or a downed power line?) DO NOT simply open the door and step out! Unless there is a compelling reason to leave the car, it is best to open the door, and remain inside the car. Warn anyone that comes along to not touch the car. After awhile, it will normalize its static charge, or someone that knows how, can ground the car carefully to make it safe. If you MUST leave the car (like there may be a fire? Or medical attention is needed?). Try not to touch the metal of the car, and jump out, not touching the car and the ground at the same time. Rubber soled shoes help a lot.

Very informative!

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Posted (edited)
29 minutes ago, No Bias FTW said:

My Dad was an electrical engineer, with specialties in high voltage and often consulted after-the-fact in lightning damage to determine who got to pay for the repairs.

 

Our North American Sabreliner seemed especially prone to lightning strikes. Our CEO and chairman decided to do something about it. He hired "Lightning Experts" ($$$$$) to examine the plane. It was grounded for a week while they "skin mapped" the plane (whatever that is). They added foil "burn strips" to the plane. He had the "experts" give a seminar on the subject, all pilots and mechanics on the field invited, coffee and donuts provided by our company.

By God he had showed old Mother Nature who was who.

Not long after all this grand buffoonery I had the CEO aboard. As we were climbing out of ABE in a light FEBRUARY snow shower we took a very loud strike. I went back to talk to the CEO. He said "Bob, what the Hell was that".... I said "Ed, we just took a lightning strike."... All he said was "oh".

Man plans and God laughs.

And so it goes................Bob

 

Edited by Bhigdog (see edit history)
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Top Gear actually tested this out several years ago.  Not with a convertible though.

 

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Not anything I'd worry about, not like wiring a car and parking it inside my garage.

 

Bob 

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Posted (edited)
11 hours ago, Bhigdog said:

Man plans and God laughs.

And so it goes................Bob

 

It is well known, that electricity "generally" follows the path of least resistance (not entirely true). However, ALL electronics are based upon "balancing resistances". Some of the electricity goes this way, some goes that way, other goes other ways. The problem with very high voltages, and also high energy (power, not the same as voltage which is "push") is that resistances get overloaded in a millisecond and force the power to go elsewhere. Dad used to say that lightning pathways were about as predictable as bouncing a freeze-dried pea shaking it inside a tin can. 

 

Airplanes get hit by lightning so often that most people that know about it simply don't worry about it. They get hit often, usually in cloud to cloud (not cloud to ground) lightning because the horizontal  discharge in cloud to cloud finds that mostly metal airplane frame and skin the "path of least resistance" for the full length and/or wingspan of the plane. It is a very inviting "least resistance" and will actually divert lightning some significant amount (roughly a football field or even more). MOST of the times, the charge will dance around the outer shell and frame of the plane. This is partially by design. For more than a half century, airplane design has taken lightning into account and a combination of isolation and grounding protects vital systems and occupants. Even before such engineering was figured out (think 1950s), even without the isolation and grounding (not nearly as simple as the words make it sound!!!), usually, planes were not harmed seriously enough to cause crashes or serious injuries to occupants. There were some exceptions to that. I can recall news stories from my childhood about emergency landings, deaths on board, and even crashes before those things were worked out. Today's planes are far more reliant upon technology to be flown. Those systems today would be a nightmare if the isolation and grounding hadn't been worked out a half century ago.

 

I never went for a degree. But having grown up around it have a fairly decent understanding and have had fun playing with the stuff my whole life. When I was in grade school, using a science kit I begged for, I made a little box with aluminum foil on the four outer sides. Two pieces of foil, isolated. It used a (today we would call it a AA) penlight battery, with a step up circuit. the 1.5 volt penlight battery was stepped up to nearly 2000 volts at nearly zero current (power). I would sit the box on my desk at school, and just wait for someone to pick it up. Practically speaking, "voltage" cannot hurt a person. It is "current" or power that does the damage. 2000 volts even at almost zero power does bite. The most fun was after everyone became wise (they thought) to it, they would dare me to pick it up, and I would. It never bothered me to get the shock. I knew it was safe. They would think I had shut the battery off and then they would pick it up again.

To this day, I will sometimes touch spark plug connections on a running engine just to mess with people. Antique automobiles are so much fun! They didn't cover the top of the spark plug!

Edited by wayne sheldon (see edit history)
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I was crossing the Hudson on the Tappenzee bridge. A barge was passing under the bridge below me. It was struck by a massive bolt of lightning that looked like it was about  6 inches in diameter.  Only time I actually witnessed a strike.

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6 hours ago, wayne sheldon said:

Dad used to say that lightning pathways were about as predictable as bouncing a freeze-dried pea shaking it inside a tin can. 

 

On one occasion I witnessed the proverbial "bolt out of the blue".

We were diverting around and above a solitary rapidly forming build up. A bolt of lightning left it's side, mid level, and traveled horizontal at least 5 miles before curving down to a ground strike. 

To anyone on the ground it would have been lightning from a sunny sky.

It's not nice to fool with Mother nature..............Bob

 

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6 hours ago, wayne sheldon said:

 

It is well known, that electricity "generally" follows the path of least resistance (not entirely true). However, ALL electronics are based upon "balancing resistances". Some of the electricity goes this way, some goes that way, other goes other ways. The problem with very high voltages, and also high energy (power, not the same as voltage which is "push") is that resistances get overloaded in a millisecond and force the power to go elsewhere. Dad used to say that lightning pathways were about as predictable as bouncing a freeze-dried pea shaking it inside a tin can. 

I had a neighbor tell me years ago he saw lightning strike a grounding rod on the roof of the local school in North Battleford, Saskatchewan.  The "bad" was the students had been swinging on the ground cable and it was broken a few feet above ground level, fortunately pointing away from the building.  When the lightning struck the rod, a fireball which he described the size of a basketball shot from the broken end of the cable and bounced along the ground and over a hill where he was unable to see how its energy 'dispersed'.

 

Craig

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Was at the Grand Canyon rim and after suddenly found myself on the ground was told I took a lightning strike. Only injury were burns on my nose from glasses.

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From Wayne Sheldon post above...

"........Then, pay close attention to how you "feel". IF the hairs on your neck (or head or arms or?) begin to stand out (or up) DROP TO THE GROUND and assume FETAL position (HUG YOUR KNEES!)! (Don't be driving when you do this!) "

 

He forgot to add -- and try to kiss you assets good bye! 

 

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Would dragging a chain from the chassis or body to the ground, grounding the car, be better or worse? In other words would it help disperse a lightning strike or make it more likely your car would be hit?

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1 hour ago, Rusty_OToole said:

Would dragging a chain from the chassis or body to the ground, grounding the car, be better or worse? In other words would it help disperse a lightning strike or make it more likely your car would be hit?

 

It probably would actually do both, be better and worse! Electricity can be really funny stuff.

Your "dragging a chain" comment reminds me of stories Dad used to tell. High voltage and/or high power (remember, those are two totally different things!) engineers used to like to mess with people. RF (radio frequency and/or broadcasting) engineers when dealing with outsiders would sometimes wear an ankle or wrist chain, and make it be seen. The "visitor" wold comment about it and be told that it was for "grounding around the high power environment". They would also be told that since the engineer was "acclimated"  to the environment, only the small chain was necessary. Then shown a bit heavier chain and told to put it on his wrist. The chain would be a few inches too short to reach the floor so the person would need to walk around stooped over to keep contact with the floor. One time when I was about ten, an engineer my Dad was consulting with made a comment that maybe I needed my "wrist chain, just a couple inches short so he has to stoop over" (I was about ten), and I commented back that I would just wrap it around my ankle. The engineer had a stunned look on his face and turning to Dad said "He is already an engineer!" (Obvious simple fix!) Actually, I had a bit of time to think about it. I had accompanied Dad to places since before I was five, and had seen the trick chains in broadcasting studios. (Probably KRON channel four in San Francisco where Dad was the outside color television specialist that fixed problems the in-house engineer could not. Dad was one of the first independent color broadcasting engineers in the SF Bay Area.)

Dad could be very difficult often. However, he was brilliantly intelligent. With most "electrical" type engineers, they will be very good at either high voltage/high power, OR electronics. He was a master at both. 

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When I was a kid all the fuel delivery trucks dragged a short chain bolted to the under carriage. Later it was replaced by a rubber strap. Now not used. Whenever an aircraft is refueled the first act of the re-fueler is to bond the truck to the aircraft and to ground. I'm dubious about the dragged chain fire cause report............Bob

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Well, they have been observed (by me) to leave a shower of sparks at times. 😉

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