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Registered Member #1634
Joined: Tue Aug 12 2008, 06:36PM
Location: Germany
Posts: 1
Dear Gentlemen, i am 16 years old and studend in Germany. Yesterday i found this forum and i am really glad about this. 2 Friends and me will start in September to work on a Coil gun, especially a mass driver. This Science Contest is named "Jugend Forscht" (12 to 21 years old work on theme and are hopefully rewarded for it). The last time time we were regarded for our Project called "The aerodynamic attributes of paper planes." Among other things we build a wind tunnel to explore the attributes.
So, my question is, what do i have to pay attention to building a mass driver? The purpose of this prototype is, to get values, through which we can compute how much it cost to bring one kilogramm material in a stable orbit.
Registered Member #1633
Joined: Tue Aug 12 2008, 04:21AM
Location:
Posts: 45
You might want to check out Barrys coilgun site first. Though Coilguns are scaleable, they quickly increase their power demand as they get bigger. Also, adding multiple stages would increase the velocity of the "projectile," but each subsequent stage adds a suprisingly small amount of energy to the projectile. Thus the "cost for orbit" would depend on the total amount of energy used, the cost of said energy, the cost of building the actual devise, and the number of times it is used to launch.
If you want to build one, I suggest you obtain some magnet wire, a couple of used flash cameras (you can obtain these freely at any 1 hr photo shop) some wire, a pushbutton switch, a straw, super glue, sodder and other stuff that you need for quick and dirty electronics projects.
The problem with getting into coilgun design is that they are inherintly inneficcient. my own latest design got a maximum efficiency of about .26%, obtaining efficiencies greater than 2% are the realm of experienced and well funded coilgunners, though who knows? you may get lucky
Registered Member #90
Joined: Thu Feb 09 2006, 02:44PM
Location: Seattle, Washington
Posts: 301
Here's a link to a feasibility study that includes a coilgun that can launch-to-L1-point. It's part of a larger study for putting lenses into space but you may find useful coilgun sizing techniques in some sections. For example, it has a good treatment of atmospheric drag and heating, and a comparative study of electromagnetic launches.
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
young, when you say wellfunded people for achieving higher effeciancy, what do you mean by this (as in what would you buy to make it more effeciant) do you think its feasable for 3% with a 3 stage coilgun at 1Kj at each stage.
Registered Member #1633
Joined: Tue Aug 12 2008, 04:21AM
Location:
Posts: 45
Lol, well i mean by those ppl who actually have a job. I dont have a job and as such my budget is under $100, so I cant afford to do that much testing, thought the occasional allowance does seem to help. Sure I think its feasable, I am not quite sure what you would need to get 3%, but 1KJ each stage is alot of energy; the scr's to handle that would cost at least $10-$50 bucks a pop. To increase efficiency, you can do alot of tuning and calibration, or you can use v-switches (doubles the amount of scr's you'll need, hence a twofold increase in price) + lots of cirucuitry. if your trying for that much energy, make sure it comes in the form of higher voltages, because using larger capacitances can become a problem especially if your coil resistance is too high, or your scr's are not of behemoth size.
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Science Project in Germany
