Re: Railgun
Michael W., Mon Feb 13 2006, 03:38AM

Ok, for 4 photoflash capacitors you will only have about 14.4 Joules (not alot) which will mostly make a large bang, which is a potentially dangerous bang under perfect (or unperfect conditions) when fired but not alot of propulsion, I think a better bet for you would be a rudimentary coil gun which would give more visual results for of electromagnetivity. Although If a rail gun is a must, use tin foil as a projectile. (It will give the most visual results)

Re: Railgun
J.Lanum, Mon Feb 13 2006, 04:01AM

Thanks for the Input. I have to do a railgun because I've already sent the forms in. What do you think about using Solar Power?

Re: Railgun
Bjørn, Mon Feb 13 2006, 04:15AM

Forget about a classic rail-gun, it is to complicated. Take a look at this: 10 minute rail-gun

The title of the thread is not very informative, it says nothing about what you wonder about.

Re: Railgun
..., Mon Feb 13 2006, 04:48AM

You are going to have problems getting any rail gun action to happen with 15j. I would recommend saying you are using a 'plasma armature' (use a plastic [nonconducting]] projectile using a plasma [created by vaporising a small amount of a conductive material]), and use a closed bore so you use the pressure surge created from the armature exploding to propel the thing.

I would make it (because that is what I have laying around) by:
take a piece of 1/4" plastic (lexan, delrin, whatever), and cut 2 pieces 1" wide and 2" long, and a strip 1/4" wide by 3"
take a piece of 1/4" copper plate and cut 2 pieces 3/8" wide and 2.5" long
Stack the copper in between the plastic leaving a 1/4" gap in the middle
Put the 1/4" piece of plastic in the middle and press the copper up against it to there is a perfect 1/4" gap left
clamp one half in a vise and drill 1/8" holes every 3/8", and bolt it together with stainless hardware
drill the 1/8" holes every 3/8" and bolt that half together, and remove the plastic spacer
then cut a piece of plastic that is 1"x3/4" and set it on the back. Drill holes through to the copper, and tap then for 1/8" 32tpi screws and bolt it on.
Hook the cap bank (though a relay) to the Cu bar hanging out the other side
Glue a piece of Al foil to one side of the 1/4"x3" bar
Cut the 1/4"x3" copper bar into 1/4" long pieces. If they are a really tight fit in the bore sand them down a little
Push one piece down the bore so that it is like 1/8" from the end
Charge up the caps and close the really.
If all goes well you should get a nice sound bang an a piece of plastic shooting out the end with a bunch of sparks...

Good luck and be safe!

Re: Railgun
J.Lanum, Mon Feb 13 2006, 05:14AM

The 10 minute railgun offers no challenge in my opinion. I like to be challenged which is why I've taken on in my opinion a large task to be done in a month.

Question:
Would I get better results using a plasma armature?
Is it possible to use solar energy to power it?
Do I need an injection mechanism to overcome the static friction?

Thanks for the input so far guys it's really been helpful, but keep it coming. I'll try to have a list of parts up by tomorrow. Oh and sry about my not so informative thread title.

Re: Railgun
Bjørn, Mon Feb 13 2006, 05:32AM

Would I get better results using a plasma armature?

You will get no result at all unless you get a proper power source. With a few photo capacitors you will get some sparks and a small bang. If you get any detectable movement you will wonder if it is the result of electromagnetism or becaus of rapidly expanding hot air.

Is it possible to use solar energy to power it?

It is not practical, you need hundreds of large solar panels to get the required current. Solar energy can be used to power it indirectly by charging the capacitors. Car batteries are much better than solar energy for driving it directly but then you need to make a rather impressive switch.

Do I need an injection mechanism to overcome the static friction?

It is a well know trick, let the injector do 99.9% of the work and let the sparks fool people into thinking that the capacitors made a difference. You do not need it but it makes life a lot simpler.

Re: Railgun
J.Lanum, Mon Feb 13 2006, 10:40AM

Ok so I need a proper power source. Where can I find one that is practical yet not expensive? I asked the solar panels question because I could relate it to NASA using solar panels for its launch it would also greatly reduce the cost. I've seen some of the capacitors that like rollette use but I don't think I can afford that.

*edit* How many joules do I need to have a decent launch?

Re: Railgun
Michael W., Mon Feb 13 2006, 03:31PM

By decent launch I'm guessing you mean a real railgun, I would guess on a very good rail gun about 25 KiloJoules....

Re: Railgun
the_anomaly, Mon Feb 13 2006, 03:40PM

For a pneumatic injection I would get a 12g CO2 cartridge and devise some way to hold it, and then puncture it. Then as the projectile is moving it hits the rails and hopefully plasma will come out behind the projectile and the spectators would think the electricity was responsible. If it all went well 15juoles would contribute to the speed but as Bjørn Bæverfjord said that would be like0.01%.

Re: Railgun
Eric, Mon Feb 13 2006, 06:52PM

Since you want to showcase the electromagnetic action, don't bother with injection, it really doesn't make much sense in an amateur design such as this.

On the old board Andrew had a micro railgun he talked about. Sounded like it was very successful, considering the simplicity of it. You might ask him for particulars.

Re: Railgun
J.Lanum, Mon Feb 13 2006, 08:11PM

Sorry I'm new I don't know who andrew is or how to get in contact w/ him. Any help...

Re: Railgun
Eric, Mon Feb 13 2006, 09:15PM

Here he is:

Re: Railgun
Pete, Mon Feb 13 2006, 11:29PM

There's an easy way to get more capacitors if you need. Everyone pretty much knows it by now. Go to your local Walgreens, Kmart, Walmart, local photo place that develops disposible cameras, and tell them that you are building a project for school about electricity and power, ask for a few disposible cameras. When I do this I can usually drive around a 3 mile radius to my various 'suppliers' and haul in about 100 cameras in about 2 hours work. Taking them apart is fun and you usually end up with an ungodly pile of fully charged AA batteries to boot.

Just be careful when you do it! Charged capacitors across a screwdriver.. BAD. accidentally tripping flashtubes in the eyes... BAD. But a neverending supply of comedy to my roommate. Ater the first few you learn how to take them apart.

Have fun.

Pete

Re: Railgun
Ben, Mon Feb 13 2006, 11:32PM

I have seen working railgun, that used photo flash capacitors. It used 10 kJ worth of them plus some magnets with clever pole pieces. IT was done by a physics professor for an introductory physics class.



I can send it to you directly(but not post it here).

Re: Railgun
Quantum Singularity, Tue Feb 14 2006, 01:36AM

I was working on a railgun for my senior project at college along with some other friends. A railgun is not an easy project by any means. Our propsal got rejected due to cost, dangerousness, and many other factors. I had a talk with the dean of electronics about it, explained we already had most of all the expensive parts, and asked if I could make a crude working prototype by the end of the trimester, he would approve our proposal for senior project next trimester. We spent about 3 months and could not get a good working prototype. We werent begginers either, having built 3 telsa coils, 20kW jacob's ladder, a disk launcher with crazy power, em can crusher... etc. We even had two caps that were rated at 6kJ each. I know this isnt what you want to hear but your idea is very difficult. If you are even thinking about using 'solar power' you have no idea how much energy is involved in a working railgun. Not that it is impossible though. But to do it in one month would probably require you copying a good working railgun someone else has already made, because it will easily take a month to get all the materials, construct it, and get the bugs worked out of it. And most people who have built working railguns have custom fabricated many peices for it. Heck probably everyones first railgun has taken 6 months to a year to make that I am aware of. I know your probably already committed to this project so I hope it works out better than mine did. Its been about 5 years and I have still not finished mine. Due to the cost and the size of the project, it has gotten shelved. I am now persuing building a coilgun wich is alot more managable of a project IMO, and can be alot more 'practable' in shooting projectiles, as many people have already made handheld version that can fire rounds at respectable velocities.

Re: Railgun
J.Lanum, Tue Feb 14 2006, 02:00AM

Ok so what I'm gathering from just about everyone is that it is going to be next to impossible to get decent results. So my best bet is to go around and try and snatch up 100 disposable cameras from various one hour photo places and then hook them up? Is there any other power source that I could look into getting? No not a homopole generator or compulsator but maybe a capacitor that's larger that you would find in a everday item?

Re: Railgun
Wilson, Tue Feb 14 2006, 02:39AM

You can find caps medium sized caps in monitors/TVs. ranging from 200-500uF at 450V
If you can find an inverter air conditioner, they have a large cap bank of around 400V 4000uF in the inverter section.
Computer PSUs have 2 caps at 200V, at around 200uF.

For anything larger, you will have to go look on ebay.

Re: Railgun
..., Tue Feb 14 2006, 02:40AM

I am selling some large caps in my assorted components for sale thread... They are 1800ufd/450v which is 182j. They are decent for railguns with their .054 esr... I am only asking $5/piece

Re: Railgun
Maz, Tue Feb 14 2006, 02:44AM

i know monitors have large capacitors in them, but i wouldnt use those. the problem is that the caps your looking for must be pulse rated, like photo flash. if they are not, they will take longer to discharge or become damaged by the rapid discharge.

look on ebay for a while, its your best bet.
second best bet is to buy from the guys right here, they know their stuff and wont try to rip you off.

I have seen working railgun, that used photo flash capacitors. It used 10 kJ worth of them plus some magnets with clever pole pieces. IT was done by a physics professor for an introductory physics class.



I can send it to you directly(but not post it here).
-Ben

do you think you could send it to me i am rather interested.

Re: Railgun
Michael W., Tue Feb 14 2006, 03:13AM

I don't know if J.Lanum was wanting to invest in pulse rated Caps...

Re: Railgun
J.Lanum, Tue Feb 14 2006, 03:26AM


Hey anything that will give me hope as to get at least one successful launch because the disposable cameras aren't giving me much hope now.

Re: Railgun
Quantum Singularity, Tue Feb 14 2006, 05:37AM


In that case surplus sales of nebraska has some big maxwell pulse caps like mine and others here use for $500-$2,000 usually

Re: Railgun
williamn, Tue Feb 14 2006, 06:36AM

You might have chosen the wrong accleration implement for the purpose of your experiment. If your overall goal is to provide some sort of scaled data for launching items into orbit using electromagnetic accelerators the railgun would not be a good choice. Think about the tremendous forces the cargo of a railgun fired vehicle would experience. Remember Newtons first law? As Yohan and I discussed on the old forum, and this is why we felt switched reluctance systems would be better, you need gradual acceleration. A coilgun would be better suited to your study, not to mention you could build a decent coilgun with what you have. Now if someone could just break the dang 100m/s barrier.
William

Re: Railgun
Hazmatt_(The Underdog), Tue Feb 14 2006, 07:53AM

Check out my EM Ring Toss. Real easy project build, good results, 22 f.p.s rougly, 160J.

Uses 3 power supply caps, I think 6800uF at 450VDC each. You need over 120J for respectable results in my particular application. I dunno about a thin ring, that's much easier to move, but the coil would be smaller too.

Anyway, Takes about a day to build, and then you're on your feet.

Matt

Re: Railgun
Jasonr, Tue Feb 14 2006, 02:50PM

I would not get too discouraged. a small scale railgun is doable, but you need to get some caps! As there is not really such a thing as a small scale railgun :) If you are just doing it for a school, I would stick with photo flash caps. they are free, and all you have to do is ask for them nicely. Tell them it is for a school project and I am sure they will help you out, do not say much more than that however, telling them you are building a coil/railgun will not help your cause. I am sure you can get 25-50 of them with very little problems.

Remember current is king in a railgun, and the more caps you have in parallel the lower your ESR (resistance of your caps) http://wiki.4hv.org/index.php/Capacitor

next off use a very very very very light weight Aluminum projectile, or perhaps use aluminum dust and do a plasma armature.

also there are many selling caps on this board. 5-10 bucks a cap,

good luck
Jason Rollette
www.rollette.com/railgun

Re: Railgun
Pete, Tue Feb 14 2006, 08:20PM

Here is another link to the Wiki. It is a page showing what has different types of electrical components and parts that you could scavenge for projects. TV,s Radios. All sorts of stuff. Actually it's a good page we should all try to expand a bit.

Parts source on the Wiki

Pete

Re: Railgun
J.Lanum, Wed Feb 15 2006, 04:34PM

Holy crap...it's Jason Rollete. I like your work if you haven't noticed. Anyway I'm considering getting six of ...'s pulse caps. That would bring me in at a little over a thousand J's right? I think my bore will be a half inch and my 6" rails will be made of copper w/ some type of strong plastic holding it together.

Re: Railgun
Jasonr, Wed Feb 15 2006, 05:37PM

Hahahaha that is funny. Well I like doing railguns, and talking about them.
Those seem like ok caps and the price is right. I am not so sure you will want a ½” bore for that small of a bank. maybe .25” would be better. Also when building your rail you might want to consider how you are going to switch the power? Is it an armature switched design? Or scr? If armature you need to have some type of air injection. And you rail need to take that into account for rail design. Also if you are considering a multiturn rail? If not you might want to make you rail co you can do it later to test it.

Jason Rollette
www.rollette.com/railgun

Re: Railgun
J.Lanum, Wed Feb 15 2006, 06:48PM

Yes, I want my armature to be injected into the rails. But does it have to be via air? You know when playing pinball the thing you pull back to launch the ball? What if I made something like that, that would use the same amount of energy each time? I don't know much about Coil guns...but couldn't they potentially be used as an injection mechanism? I'm not going to try and build a coil gun right now as I am currently...already short for time I am just asking.

Re: Railgun
Jasonr, Wed Feb 15 2006, 07:07PM

Yes you could do that. However a spring means you need to be right by the rail! I tell you what I have no desire to be with in 25feet of mine. But that is not an apples to apples compare.

the coil gun no, as a coilgun requires the projectile to be ferrious material which is bad for railguns.
you want copper, alum, or graphite for the projectile.

Re: Railgun
Maz, Thu Feb 16 2006, 02:23PM

if you could build your own injector that does not use compressed air, more power to you. however building a compressed air injector is the easiest part of the whole project.
you seem to know what you need for the spring injection so i wont suggest anything,
for the air however, forget about CO2 and just go with regular old air. it is much cheaper in the long run.
get
(2) 1"pvc end caps, and
(1) small peice of 1" pvc(hardware stores usually sell for repairs.
get 1 package of schrader valves, these are just replacement valve stems for tires. i bought mine at w@lmart.
(1)high pressure blower. your bore is 1/4~1/2 so you dont need a ball valve.
(1)tube of instant gasket used for small engines.
and assorted fittings for your connections.(brass)
cut the pvc so it is AT LEAST 2" long.
drill a hole in end cap 1 for the brass fitting to conect to your blower, tap it.
drill a hole for your valve stem. im pretty sure it was 3/8 but im not positve.
insert the stem into the hole and make sure its snug.
glue the end caps to the PVC tube, hammer with rubber mallet so its nice and tight.
teflon tape up your fitting to the blower and the pvc and thread it into both. the other end of the blower also has threads you can use, so you can machine a block or glue the nosel into your design.
just remember, you need an accelerating tube which ever way you choose. so choosing where the flyway ends and the copper begins is a big deal.

good night and good luck
-Maz

Re: Railgun
J.Lanum, Sun Feb 19 2006, 01:21PM

Ok so I'm looking at some copper barstock on McMaster-Carr. Do I need the Mirror Like quality or can I go w/ the Unpolished one?

Re: Railgun
Michael W., Sun Feb 19 2006, 03:24PM

It depends on whats cheaper, if the unpolished is cheaper, get it and polish it....You need a good contact surface between the rails and projectile so a surface without abrasions is probably best...

Re: Railgun
J.Lanum, Mon Feb 20 2006, 03:57PM

Part Number: 89275K113
$28.41 Each
ASTM Specification
ASTM B187
Shape
Sheets, Bars, and Strips
Sheets, Bars, and Strips Type
Square Bar
Length
36"
Length Tolerance
±1/4"
Width
1/2"
Width Tolerance
±.008"
Material
Alloy 110 Electronic-Grade Copper
Finish/Coating
Unpolished (Mill)
Straightness Tolerance
1/2"
Yield Strength
44,000 psi
Temper
Hard (H04)
Hardness
Rockwell F85
Tolerance
Standard
Specifications Met
American Society for Testing and Materials (ASTM)
Notes
Cannot be heat treated

Ok so this would give me a 1/2" bore, I'd be using a plasma armature, and I would be using 1092 J's. Any opinions?

Re: Railgun
Maz, Tue Feb 21 2006, 11:54PM

thats just a lot of power to be putting through anything

Re: Railgun
Self Defenestrate, Wed Feb 22 2006, 02:41AM

1.1kj sounds good. Your copper choice seems fine, a polished surface isn't any better. You also have to think of the bars leading to the rails, so you might want to look at some flat copper stock as well.

Re: Railgun
J.Lanum, Wed Feb 22 2006, 03:38AM


Do you mean "bars leading to the rails" if I were using an injection method, because right now I don't think I have the the time to make one. I have around 3 weeks and 6 days I think.

Re: Railgun
Self Defenestrate, Wed Feb 22 2006, 03:54PM

I was talking about the connections from the caps to the rails, it's a bit easier to use bussbar rather than a whole bunch of wire.

Re: Railgun
J.Lanum, Wed Feb 22 2006, 05:56PM

So what you're saying is that I can use some copper flatstock and hook my caps in parellel and hook them to the rails? If I where to get wire what type would I need?

Re: Railgun
Plasmaniac, Wed Feb 22 2006, 06:09PM

I use a spring-injector:





I dont use it to get higher speeds, the projectile wouldn't even leave the rails if I accelerate it just with my injector. I use the injector because I am a poor student who doesn't have enough money to buy a big scr I think it would be the best choice for you, if you don't have that much time left.

Re: Railgun
Quantum Singularity, Thu Feb 23 2006, 01:22AM

I have made some 'poor mans buss bars' before and they seemed to work fine. Didnt know if anyone else might have done something like this? I took copper tubing, like maybe 1" tubbing or so (cant remember exactly) and flattened out about 6" or so at each end and drilled hole for mounting via bolt. I cant remember if I flattened it with my 5" vise or by large hammer, or maybe both.

Something I was wondering, is it important to feed the rails with buss that feeds in fairly straight fromt the back to avoid a magnetic field that might interfere with the field in the rails? I ask because in my crappy prototype my projectile shot straight up out of the rails rather than going down the rails. I thought maybe because my power was comming into the rails from a 45* angle down and back from the rails. But it was a crappy design anyways though, i didnt really expect it to work. But maybe someday I'll start back in on the project

Re: Railgun
J.Lanum, Thu Feb 23 2006, 02:24AM

So buss bars are an option, but what type of wire do I need if I choose to go that way.

Re: Railgun
Self Defenestrate, Thu Feb 23 2006, 03:51PM

Some really big thick wire. Perhaps you could cut off the clamps on a jumper cable, and rip the bits apart. That would suffice.

Re: Railgun
Jasonr, Thu Feb 23 2006, 05:25PM

or copper water pipe put inside some type of clear plastic hose for insualtion will work ok. also you can crush the ends and drill a hole to make connection points.
You can also put extra wire inside the copper pipe (insulation stripped off) to be a better conductor.

Re: Railgun
Madgyver, Thu Feb 23 2006, 07:14PM


Well, you still could use something like a realllllly loooong stick or just a small piece of wood and a 25feet long rope.

Re: Railgun
J.Lanum, Fri Feb 24 2006, 03:14PM

When the capacitors discharge their energy into the rails, how long does that duration last?

Re: Railgun
M_Gargantua, Thu Mar 02 2006, 04:50PM

only an instant.


or you could use a swinging rubber mallet attacted to a cradle above the rails

Re: Railgun
J.Lanum, Fri Mar 03 2006, 12:13AM

How should I go about charging my caps? Can I use a standard 110v oulet? I'm pretty sure I can't but I need clarification on what I can and cannot use.

Re: Railgun
..., Fri Mar 03 2006, 12:24AM

you can't use a normal 110v outlet, however with a few modifications you can.
the first thing you will need is a diode rectifier, almost any diode will work, and you will need 4 of them. This will give you about 170v, but since you are using 450v caps you will not get even half of the energy available.
So you can use a voltage doubler, which will give you 340v, or a tripler which will give you about 500v.
Because the caps will appear as a short circuit to the mains when they first charge you also need to add a ballast resistor to them. To keep power to a reasonable .1a you would need about 5k worth of resistance, and this resistor should be able to dissipate about 25w. (assuming a voltage tripler charger).
You also need to include the simple safety devices, a fuse in series with it, a bleeder resistor on the caps, etc.

If you do go the tripler route, you will need to have a way to stop it charging when the caps get to a high enough voltage. If you have a variac it would be a good way to do it, and it would eliminate the need for a ballast resistor (just raise the voltage slowly). If you don't you can just use a switch to turn of the charger when they get full.

Good luck and be safe!

btw, the caps went out today

Re: Railgun
J.Lanum, Sat Mar 04 2006, 12:32AM

I'm having a hard time comprehending parrellel. From what I understand is that every cap needs to be seperately wired to the rails right? However I look at a lot of cap bands and the bussbar runs straight through the caps. Can someone link me to a pic and/or diagram?

Re: Railgun
..., Sat Mar 04 2006, 01:13AM

You just use a single piece of copper connected to the caps, which you connect to the rails using some heavy duty wire/pipe/busbar...

Re: Railgun
Steve Conner, Sat Mar 04 2006, 01:20AM

Parallel simply means that you connect all the + terminals of your caps together with one busbar, and all the - terminals together with another. So you have effectively a single daddy-o capacitor with one + and one - terminal. You connect these terminals to the rails of your gun at the breech end, either directly for a projectile switched launcher, or via a high current switching device like a SCR or ignitron.

Having a switching device is neat because it allows you to load the projectile into the rails by hand, charge your capacitor up, and then close the switch to launch your projectile from a standstill using only EM energy. Leaving the switch out saves a lot of money and hassle, but the projectile has to be fired into the rails at high speed by an injector mechanism, so it's not nearly so cool, since you don't get a clear demo of a projectile being launched by electricity.

One thing that sometimes catches people is that the busbars and wiring of the launcher feel much the same magnetic pressure that the projectile does. So they need to be mechanically strong and firmly fixed in place if you're planning to use high energy.

Re: Railgun
J.Lanum, Sat Mar 04 2006, 02:14AM

That exlplains it perfectly thanks guys. Now where can I find a 4k resistor and a voltage doubler?

Re: Railgun
Hazmatt_(The Underdog), Sat Mar 04 2006, 04:49AM

This is what I would do:

1. Single high current pulse coil at the tail just like my ring tosser causes Vi to be about 22 f.p.s. AND you already have a charging source! So you have 3 extra small caps, who cares!
Okay, that thing is SCR pulsed, the projectile flys down the barrel into the conducting bars and BANG gets accelerated a second time!

All electrical. AND YOU KNOW WHAT! If you increase Vi by increasing your 1st stage repulsive accelerator, you could theoretically get more Vf.

>>>waits for applause<<<

Re: Railgun
..., Sat Mar 04 2006, 06:22AM

um, are you sure you put that in the right thread?

In any case, JL check your pm's I just sent an offer for a 4k resistor and a doubler

Re: Railgun
Steve Conner, Sat Mar 04 2006, 03:00PM

I think hazmatt is suggesting using a coilgun as the injector stage for your railgun. That might be tricky, since a good railgun projectile (a piece of teflon with thick wads of copper strands shoved through holes in it) is not at all the same thing as a good coilgun projectile (a piece of iron)

You could make it work- one sensible idea might be to use an induction coilgun and an aluminium projectile, since an aluminium block makes an OK railgun slug- but suddenly the swinging rubber mallet injector proposed by a previous poster seems attractive

Re: Railgun
J.Lanum, Mon Mar 06 2006, 03:18PM

I already asked about usinga coilgun as an injector in a previous post but was told that ferrous materials doesn't work well w/ the railgun.

Are there any good Electricity books you guys have read. I need one for basic electricity.

Re: Railgun
Hazmatt_(The Underdog), Mon Mar 06 2006, 11:37PM

What's the problem with it being non-ferrous if its in a railgun?
Accelerating Al magnetically in the first injector stage is not a problem, then after that, blasting down the high current rails doesn't really necesitate being ferrous either.

I see the problem in a coilgun yes, but not railgun. And I thought discussion was allowed since I saw a picture of a railgun. Sorry if I got confused.

Re: Railgun
Steve Conner, Tue Mar 07 2006, 12:33AM

Non-ferrous is fine in a railgun. The problem is with non-ferrous in a coilgun, or ferrous in a railgun. Hazmatt's ring tosser only works well because the projectile is in the shape of a ring and gets very high coupling to the launching coil. A railgun projectile needs to be more of a slug shape that makes it hard to launch by induction. A ferrous metal projectile in a reluctance coilgun would work better, but then ferrous metal doesn't play well in the rails.

If you really wanted to do it, I guess the best route would be a toaster-bored railgun (with its slice-of-bread-shaped projectile) and an induction launcher that pops the projectile sideways like a toaster, such as Chris's "Lateral disc cannon" from the old board.

Re: Railgun
Quantum Singularity, Wed Mar 08 2006, 06:01PM

Seems like I read somewhere a few years ago the problem with ferrous materials in a railgun is that ferrous material has 'poles' in it and might either oppose the direction of the magnetic field and would have to align themselves with it wich introduces a lag and inefficiency. I guess when you think about the core theory of how a railgun works its simply passing a current perpindicular through a magnetic field. If the projectile has any magnetic poles in it would interfere. But you could make it multi-stage like a ferrous sabot in a injector then aluminum slug continues into the rails? Or you could just use aluminum for the whole thing and use an inductance type coilgun to inject it but probably wouldnt be as efficient as the projectile probably wouldnt be optomized for such a coil gun.