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Inductive storage unswitched coilgun

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Jack A

Thu May 26 2011, 08:20AM

Registered Member #2975 Joined: Wed Jul 07 2010, 12:19AM
Location:
Posts: 28

Hi all!
I went back and thought about what you all said about the possibility of an inductive power source.
I came up with what I think is an interesting new idea and hopefully a fulfilling DIY project.
My idea is to have a coil that is very long with only one layer, but the end is a short section of around 10 layers. So that the 'Magnetic centre' is in this chunky section.
The idea is that the main coil is powered up until it is storing enough energy, then the projectile is injected. The hope is that either:
1. All of the energy is used before the end is reached.
2. As was originally planned, some of the energy is used, but the coil is still charged and the fact that the coil is stacked means that the pullback is minimal.
What do you guys think?
Thankyou for any comments,
Jack Allison

Shrad

Thu May 26 2011, 09:38AM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
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Posts: 780

I'd say that if you can somehow make your projectile short the coil (be one of the terminals) while moving freely would compress the magnetic pulse as it reaches the end, and accelerate exponentially

the end of the coil would need to sustain enormous amounts of current, but the pulse doesn't have that fast

the greatest difficulty is to make the projectile a terminal for the coil, so you would need to make a kind of moving bed for it with a slit along the rail for shorting the coil, which would be variac-style with a connecting brush (coil unisolated in the path of the brush)

Jack A

Thu May 26 2011, 10:30AM

Registered Member #2975 Joined: Wed Jul 07 2010, 12:19AM
Location:
Posts: 28

I think I understand what you mean, it is also a very interesting idea and well worth exploring.
Your post also made me think of another idea, what is the projectile was on rails that completed the coil circuit, so when they end the coil will instantly deactivate. Here is a cross-section:
Crossection

The grey area is the barrel tubing, the brown is the rails, the blue the projectile, and red is the coil. The pojectile is pulled onto the rails by the magnetic field.

So, do you guys think variably layered coils could work?

Forty

Thu May 26 2011, 04:10PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

so you'd need a segmented rail then, right? with one segment per wire/coil region.
i think shrad was on to something there with the variac brush approach. how about instead of the moving sled, have your brush be a long bar or stick of graphite (with a couple small springs on the other side.) then you could have this brush rail be opposite the uninsolated coil.

Shrad

Thu May 26 2011, 08:57PM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

I think the most reliable way to do that would be combining a coilgun with a railgun, but one rail would be segmented and each segment connected to an equal portion of the coil (or sections exponentially smaller, or again in a fibonacci arrangement...)

if someone gets something done with the principle, please tell me I'm curious ;)

but beware of the EM pulse generated

EMP were, back in time, generated by a big capacitor discharging in a big coil, where you had a fusing cylindrical core lit by the pulse... combustion speed was carefully chosen to be synchronous with the discharge propagation delay through the coil, so each unit of distance burnt on the core shorted the equal distance of coil, compressing the magnetic pulse t o get a massive EM pulse at the end (I can guarantee you that even a shielded computer couldn't whitstand it)

Forty

Thu May 26 2011, 09:11PM

Registered Member #3888 Joined: Sun May 15 2011, 09:50PM
Location: Erie, PA
Posts: 649

fibonacci gun. someone do it!

Jack A

Fri May 27 2011, 04:26AM

Registered Member #2975 Joined: Wed Jul 07 2010, 12:19AM
Location:
Posts: 28

fibonacci gun. someone do it!

Sounds epic, please give a link or eleborate.

Shrad

Fri May 27 2011, 06:58AM

Registered Member #3215 Joined: Sun Sept 19 2010, 08:42PM
Location:
Posts: 780

length of coils going from long to short in a fibonacci sequence

like 13cm 8cm 5cm 3cm 2cm 1cm

I think that if you have each section of contact rail be half its coil length, it will accelerate the projectile in an exponential fashion

think of it as a self-triggered segmented coil gun if you have a capacitor for each coil and the segmented rail just connects capacitors to their coil in sequence, or fibonacci pulse compressed gun if the segmented rail shorts the coil linearly

the only problem I see is the magnetic center of each coil section would prevent the projectile to accelerate further than the coil segment it is in at the moment, so each turn of the coil would have to be shorted in sequence

anyway, the fibonacci sequence would be good for a segmented coil gun, as well as the self-triggering rail ^^

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