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Rocket Triggered Lightning

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Proud Mary

Fri Apr 04 2008, 08:41AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

Logan Kennedy wrote ...
I'm 100% balloons would accomplish the same thing.

In the experiments at Camp Blanding, where rockets are fired into pre-storm clouds, paying out the line from a spool as it ascends, the line is not in fact placed under any significant tension, allowing a very light weight line to be used.

If a balloon were to be used, then the balloon tether would have to cope with all the stress of controlling the balloon in conditions of atmospheric turbulence and its shock loads. A much stronger wire would be required, which would be heavier, and so need a bigger balloon to lift it, and so on, and so on, until the balloon's lift was cancelled by the increasing weight of the line it has take aloft with it.

I am not saying that it is impossible, only that if this was an effective way to do it, perhaps with meteorological balloons costing perhaps $100 a time including fill gas, why would Camp Blanding use potentially dangerous rockets, costing perhaps $5,000 per firing - when they can be recovered and re-used - and a lot more when they can not? Accountants dictate the action in science too!

Steve Conner

Fri Apr 04 2008, 10:49AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

I agree, I think the legal threat is overblown. If I was doing this, I'd be far more worried about getting fried by lightning, than the law!

In fact, I'd be even more worried about not being able to get a lightning storm when I want to do the experiment.

Rocketry in the UK probably isn't as restricted as you think either:

There's even a Scottish Rocket Weekend! I must put that on my geek calendar

Logan Kennedy

Sat Apr 05 2008, 02:50AM

Registered Member #1103 Joined: Mon Nov 05 2007, 06:02PM
Location: Houston
Posts: 80

wrote ...
I agree, I think the legal threat is overblown. If I was doing this, I'd be far more worried about getting fried by lightning, than the law!

Yes, I agree with your assertion. I really don't think there would be much of a legal issue if all precautions are taken. Safety is a big issue though, and perhaps that's the most troublesome part of this whole experiment.

wrote ...
If a balloon were to be used, then the balloon tether would have to cope with all the stress of controlling the balloon in conditions of atmospheric turbulence and its shock loads. A much stronger wire would be required, which would be heavier, and so need a bigger balloon to lift it, and so on, and so on, until the balloon's lift was cancelled by the increasing weight of the line it has take aloft with it.

A very valid point, and one that I didn't consider. I will have to do some calculations to determine whether or not it would be possible to use balloons, or whether rockets would be the better choice.

HV Enthusiast

Sat Apr 05 2008, 02:59AM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Why use a balloon or rocket anyways? Just take a long metal pole and take a walk to the golf course during a storm.

Logan Kennedy

Sat Apr 05 2008, 03:21AM

Registered Member #1103 Joined: Mon Nov 05 2007, 06:02PM
Location: Houston
Posts: 80

wrote ...
Why use a balloon or rocket anyways? Just take a long metal pole and take a walk to the golf course during a storm.

Because that's stupid?

I'll leave that one for you to try Dr. Shock, why don't you report back to us after you've succeeded?

Bjørn

Sat Apr 05 2008, 03:28AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

Using a rocket means that you need to know that lighting will be triggered when you launch it. Otherwise you would need to launch hundreds of expensive rockets. That means added instrumentation and complexity and a lot of things to go wrong.

A balloon can hang up there until it strikes or until you get tired of it all as long as there is not too much wind. That would depend on where you do the experiment, some places are windy, some are not.

There are other solutions, like compressed air rockets and cannons that can reach hundreds of metres very cheaply while carrying a spool of wire.

How do do it safely is really a different discussion, I doubt it is possible to do it safely unless you have a very favourable location or lots of money.

The third discussuion is the suitability for using lightning to power experiments, at which I will say completely unsuitable in every imaginable way. The only reasonable reason for triggering lightning is to study lightning itself.

Logan Kennedy

Sat Apr 05 2008, 03:33AM

Registered Member #1103 Joined: Mon Nov 05 2007, 06:02PM
Location: Houston
Posts: 80

wrote ...
Using a rocket means that you need to know that lighting will be triggered when you launch it. Otherwise you would need to launch hundreds of expensive rockets. That means added instrumentation and complexity and a lot of things to go wrong.

I think the way to get around this problem is to use a high voltage source attached to the nose cone of the rocket. This should provide enough charge to do the job of triggering lightning.

Wind is a problem regardless of whether or not I use a rocket or balloon. If it's too windy, then the rocket will stray off course and could complicate things much more. If I use balloons and it becomes too windy, then I take the risk of snapping the ground wire.

HV Enthusiast

Sat Apr 05 2008, 03:48AM

Registered Member #15 Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068

Logan Kennedy wrote ...

I really think you need develop a better understanding of the actual physics of how lightning strikes before moving forward with your project. From the posts and replies made by you on this subject, it is clear you lack the very fundamental basics on just how lightning is triggered and what happens during a strike. If you are proposing such as complex and dangerous project as rocket triggered lightning, you should at least do your homework and have a VERY thorough understanding of lightning.

Launching a rocket with a HV source, as you stated in numerous posts, is not going to do anything, and only shows your lack of understanding in the physics of lightning.

The reason rockets with a wire cable attached "draws" lightning is that the wire acts as a leader strike for the lightning as opposed to allowing the leader to form itself. Has little to do with charge on the rocket itself. You're just creating an artificial path from the ground to the cloud for lightning to initiate on. When the rocket launches, provided sufficient electrical field is measured at the ground (some sources state a mininum of -5kv/m), once the wire becomes sufficiently long (usually on the order of several hundred feet), the rocket tends to enhance the electrostatic field enough to initiate an upward positive leader from the ground. This in turns connects to the cloud and allows continous current to flow from cloud to ground, thus creating a lightning strike which follows that path - that of which is usually comprised of several downward leaders from the cloud and their resultant upward return strokes.

Bjørn

Sat Apr 05 2008, 03:51AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

I think the way to get around this problem is to use a high voltage source attached to the nose cone of the rocket. This should provide enough charge to do the job of triggering lightning.

That assumes that there is a large charge over the launchpad, but you can't know that. The charge changes all the time. So if you fire at random times it would be a lottery if you trigger lightning or not.

Wind is a problem regardless of whether or not I use a rocket or balloon. If it's too windy, then the rocket will stray off course and could complicate things much more.

I have launched several hundred rockets in strong winds and rarely had any problems at all. The rocket is so much faster than the wind that it goes more or less straight up.

The main problem is that the rocket can come down quite far from where it was launced and if it is heavy it is a problem. The rockets I have launced are one time use rockets that will only dent a head slightly when coming down as they come down sideways.

I do agree with Dr. Shock that at this level of knowledge it wopuld be completely suicidal to trigger lightning.

Logan Kennedy

Sat Apr 05 2008, 04:08AM

Registered Member #1103 Joined: Mon Nov 05 2007, 06:02PM
Location: Houston
Posts: 80

wrote ...
I do agree with Dr. Shock that at this level of knowledge it wopuld be completely suicidal to trigger lightning.

That's why I'm researching and asking questions.

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