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Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
I recently put together my railgun, all ready to fire. Someone brought up insulating some of the begining of the rail's, so there is a magnetic field behind the projectile. I forgot about this, and closed it up (extremely hard to open). How much will this affect it? My hope is that the injection will be strong enough to force it in the rail's. Any comment's?
EDIT: you can see the location here: The copper to right is where the powered rails are.
Registered Member #222
Joined: Mon Feb 20 2006, 05:49PM
Location:
Posts: 96
It depends on how fast your injection speed is in relation to how fast the current can rise. I think it will still work, but not as well as it could. All I can say is to try and see if it works.
What you can do is bend back the cables to act as the rails. You could also use a saturable reactor. This will help out a lil bit. What are you using for a projectile?
Your setup looks strikingly similar to another railgun on the web... hahhaha
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
Pfft... i was planning this long before i saw that one =) Plus, mine is custom machined to .001" tolerance, and only 2 pieces.
After much bending wedging, and bolt's, i finally got it separated. I put 2 mill packing tape on the first 1.5" of the rails. Good idea on the rails, i will also do that.
Projectile is a .5" aluminum square. I know its big, but i was to keep projectile speed low for ease of chrono. I made it easily configurable into .25" bore.
Injection is only 60 PSI, but the valve is the best you can get. It is all ready to fire, expect a post by sunday next week.
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
meh =) Originally i planned one with GP03 fiberglass (after browsing mcmaster) due to its low cost. It would look much like badastronauts, but a smaller cross section and 3 feet long. If i used that, the enclosure would only cost 26$. After i was offered free machined parts, I asked for fiberglass, but they suggested that I use garolite.
I uploaded a video of the injection:
Speaking of sam, i just found out he sold the railgun to plans and kits unlimited... I have a feeling he is only doing this stuff for free stuff, money, and his resume =p
Registered Member #222
Joined: Mon Feb 20 2006, 05:49PM
Location:
Posts: 96
That is interesting that he sold it... I wonder how much money he made off of it. Someone email him and ask :)
Plans/kits mentions that it fires at 1kmps :P lulz Mine fires at 1.6kmps with 2.5kJ of KE starting from rest. 12% efficiency isn't so bad. I wonder if they will buy mine for a substantial price.
For what it's worth, I don't think you'll be able to get an optical chronograph to work with a railgun, at least not very easily. I would suggest wire break velocimetry, though that will require a decent oscilloscope.
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railgun mistake
