Rocket Triggered Lightning / General Science and Electronics / Forums

Forums

4hv.org :: Forums :: General Science and Electronics

« Previous topic | Next topic »

Rocket Triggered Lightning

previous 1 2 3 4 next last

Move Thread

LAN_403

Proud Mary

Wed Apr 02 2008, 02:20PM

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

Why go to all the noise and pollution of a rocket?

On 10th June 1752, Benjamin Franklin proved that lightning was electricity by flying a kite in a thunderstorm, which caused sparks to fly from a key on the end of the kite tether. Franklin was able to collect the charge in a Leyden jar - an early capacitor.

Franklin was lucky to avoid death or serious injury with so dangerous an experiment, so it is not recommended here.

Logan Kennedy

Wed Apr 02 2008, 03:09PM

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

I wonder if a capacitor bank would supply the needed energy for my experiment though. I'm looking to use/harness the enormous heat of the plasma from the lightning bolt. Wikipedia cites the heat generated in the plasma to be around 30,000C, and I really do not know any other way to generate such an enormous amount of heat!

However, if the heat generated during a high energy capacitor discharge is near this amount, then I might consider using capacitors. Does anybody have any approximate temperature estimates? Let's say I built a 20KJ capacitor bank, I doubt the discharge would be near 30,000C.

I slightly feel like Doc Brown from Back From the Future!

Dr. Emmett Brown: Marty, I'm sorry. But the only power source capable of generating 1.21 gigawatts of electricity is a bolt of lightning.
Marty McFly: [startled] What did you say?
Dr. Emmett Brown: A bolt of lighting. Unfortunately, you never know when or where it's ever gonna strike.

--------------------

wrote ...
Why go to all the noise and pollution of a rocket?

I suppose a large rocket wouldn't be needed, I'm actually looking to use 3 or 4 foot rocket that can be bought at hobby stores for this experiment. It would only need to travel a few thousand feet in order serve its purpose.

wrote ...
Dude, Logan, I've got to drive out to your house one day and see all yer goods.
Maybe you and me need to do a Houston Teslathon.

Hey, Ultra7, that would be cool. I didn't know Houston had a teslathon! I will send you a PM.

Tesladownunder

Wed Apr 02 2008, 03:47PM

Registered Member #10 Joined: Thu Feb 02 2006, 09:45AM
Location: Bunbury, Australia
Posts: 1424

In the shock wave phase for the first 5-10us of a lightning stroke the high pressure results in a temp up to 30,000C. This rapidly settles to around 8000 C or so regardless of current as the central channel just expands to accomodate, but keeps the temp the same. No reason why a cap bank shouldn't do the same at least over a short distance.

TDU

Logan Kennedy

Wed Apr 02 2008, 03:57PM

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

Tesladownunder, thanks for the reply.

So I can assume the temperature of the main bolt of lightning once it nears the ground is around 8,000C?

Is there any possible way to measure the temperature of a high energy pulse discharge from a large capacitor bank? It seems unlikely to me, but I assume that perhaps the vaporization of electrodes may act as some sort of indicator. The type of pulse/heat I'm looking for would need to completely vaporize metals like Tungsten.

Mates

Wed Apr 02 2008, 04:36PM

Registered Member #1025 Joined: Sun Sept 23 2007, 07:53PM
Location: Czech Rep.
Posts: 566

Logan Kennedy wrote ...

The type of pulse/heat I'm looking for would need to completely vaporize metals like Tungsten.

Every stronger plasma discharge generates enough heat to vaporize tungsten (you can use MOT, or high power fly-back). The question is how quickly and what amount of vaporized tungsten you need...

But, otherwise I like the rocket trigger idea. In the right wether time this must be an easy job. You could use also a baloon with long metal antenas filled with helium or even better with H2 to make the show really atractive

The guys triggering the power lines would than look like total loosers in case you could get it on a camera...

Proud Mary

Wed Apr 02 2008, 05:01PM

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

Logan Kennedy wrote ...

wrote ...
Why go to all the noise and pollution of a rocket?

The rockets used in the triggered lightning experiments at Fort Blanding are about 1m4 long, and ascend to a height of about 600m during thunderstorms. The wire is a copper-kevlar composite, (as in wire-guided missile technology), and completely vapourizes during the transmission of the lightning pulse, leaving an ionization trail which facilitates the return earth-sky stroke containing most of the energy.

Logan Kennedy

Wed Apr 02 2008, 05:02PM

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

wrote ...
The question is how quickly and what amount of vaporized tungsten you need...

You make a decent point there, and I guess I should've thought about that before I asked!
I'm not too sure how long I need to the pulse to be at this point. Perhaps a 5-500 milliseconds, but I'm just giving a rough estimate.

wrote ...
In the right wether time this must be an easy job. You could use also a baloon with long metal antenas filled with helium or even better with H2 to make the show really atractive

Yes, I assume it would be quite easy to achieve this in cloudy weather. Heck, I'm sure a storm wouldn't be needed if you can send the ground wire up to a decent height.

wrote ...
The guys triggering the power lines would than look like total loosers in case you could get it on a camera...

LOL, I guess there could be possible bragging rights if I capture this on camera. I wouldn't want to be anywhere near the lightning when it hit. I'd probably use some type of remote control system to launch the rocket. Or if I use a large balloon, I could anchor the nylon string and high gauge magnet wire to the ground and let it ascend a few thousand feed. Of course, I would probably need a slew of small balloons, or one large balloon to overcome the weight of the string/wire.

wrote ...
The wire is a copper-kevlar composite ...

Any idea why they used a copper-kevlar composite? Perhaps for the tensile strength? I'm wondering if a nylon + high gauge magnet wire would accomplish the same thing. I'm sure it would, but I don't want the wire to snap while in flight.

Proud Mary

Wed Apr 02 2008, 06:52PM

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

Logan Kennedy wrote ...

Any idea why they used a copper-kevlar composite? Perhaps for the tensile strength? I'm wondering if a nylon + high gauge magnet wire would accomplish the same thing. I'm sure it would, but I don't want the wire to snap while in flight.

From United States Patent 4653379

...the rocket adapted to the system for artificially triggering lightning flashes according to the invention, more particularly comprises a tubular power plant 1 which is open at a lower or rear end thereof to provide a gas discharge outlet and contains black powder 2, and which is provided at its lower end with stabilizing fins 3. As is well known combustion of the black powder results in the expulsion of combustion gases from the discharge outlet, and the reaction to this discharge propels the rocket forward and upward. A reel body 4, preferably made from plastic and especially PVC, is mounted on the lower end, centered on the central axis of the rocket. The reel diameter exceeds that of the rocket body and is less than the apparent diameter of the guidance fins. Because the diameter of the reel is larger than that of the tubular rocket body, atmospheric air flows through the reel, along with and in surrounding relation to the flow of discharged propulsion gases to maintain the temperature of the reel substantially below that of the discharge gases at the outlet from the body.

The reel body is fixed by embedding in the guidance fins and then by bonding with Cyanolit. The simplified installation of the reel on the rocket makes it possible to choose and install the reel in the vicinity of the rocket launch point.

In the case where the rocket is a Ruggieri 614 rocket, the reel dimensions are body diameter 120 mm, body length 110 mm.

For a use of the system according to the first principle referred to hereinbefore, a Kevlar-sheathed, 0.2 mm diameter copper wire 6 is wound onto the reel and together there is a diameter of 0.4 mm. The wire length is approximately 700 m.

For a use according to the second principle, the insulating part of the Kevlar wire has a diameter of 0.4 mm and a length between 50 and 300 mm, whilst the conductive part is a copper wire of approximate length 400 mm and a diameter of 0.2 mm and is Kevlar-sheathed. The assembly has a diameter of 0.4 mm.

The conductive or mixed wires have an ultimate or breaking strength of approximately 18 daN. Because the reel itself is kept well below the temperature of the discharging combustion gases by the above-described flow of air through the reel, any filament wound on the reel will obviously be protected by that same air flow from damage by the heat of the discharging gases.

The outlet of each reel is mechanically fixed by a safety level which breaks when the rocket is launched.

The completely insulating wire, as used in the case of the second principle, is unwound first. It is therefore wound over the copper wire and its free end is attached to the ground. The insulating wire is fibreglass-sheathed over the first five meters which are unwound, in order to prevent damage by the impact of the heat occurring during the launch of the rocket from launcher 7. The launcher essentially comprises a plastic and preferably PVC tube 8, the material being readily commercially available. Three or six launchers in star-like configuration can be installed on the same support 9. FIG. 2 shows such a support with several plastic tube launchers.

When using a Ruggieri 614 rocket, the tube dimensions are internal diameter 238 mm and external diameter 250 mm, with a length of 2.5 m.

In order that the rocket is guided within the tube during launch, a guidance system 5 is installed on the nose cone 10 that closes the body tube 1 at its front or upper end. The guidance system comprises 3 or 4 spring steel "moustaches", the length thereof being such that once placed on the surface of nose cone 10, their apparent diameter is equal to the apparent diameter of the rocket guidance fins 3. The explosive in the Ruggieri rocket nose cone 10 is removed.

Thus, safety during storage, transportation, etc are increased. Moreover, the speed is increased by reducing the weight. The available volume within the nose cone is increased to 500 cm 3 , which enables telemetry experiments to be carried out. Instead of shattering the rocket into small pieces at the end of the trajectory, a parachute 11 is provided which permits a slow descent of the complete assembly constituted by nose cone 10, power plant 1 and reel body 4. This eliminates any danger on the ground and the reel body and parachute can be reused after recovery.

The parachute is housed in the rocket nose cone and connected to an ejection system 12, which operates at the end of combustion. Its straps are connected to the rocket body.

Logan Kennedy

Wed Apr 02 2008, 07:27PM

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

Thanks a ton Harry. I guess I should've searched for the patent, but I didn't even think one would be available.

I could always locate the HV ps in the nose cone of the rocket. Probably something like a small camera flash unit attached to a voltage multiplier. I'm wondering if the lightning will trigger without the high voltage, but I don't know. I think it would, but it might not trigger successfully with each launch.

Connect the ground from the voltage multiplier to the wire attached to earth ground, and then connect the hv+ to some kind of conductive material on the nose cone.

ramses

Wed Apr 02 2008, 08:03PM

Registered Member #1208 Joined: Thu Jan 03 2008, 05:30PM
Location: Chesterland, OH
Posts: 154

I really don't think a high voltage source would be necessary, but I wonder if one could substitute the string from cheap kites for some or most of the wire. they would obviously be soaked in salt water to improve conduction.
to be honest, I was thinking about this for coin shrinking.

ramses

previous 1 2 3 4 next last

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob