Fast MHz has made another EM rocket. You might remember their other EM projects from a few months ago.
“Hi all…after seeing my gauss gun appreciated here, I figure I’ll share my latest gadget: EM Rockets! That’s right, “rockets” launched with nothing more than electricity. Unlike gauss guns/coilguns, which are reluctance based, these are induction based…electricity goes through a coil, which imparts a current into aluminum, which then itself becomes magnetic…the repulsion of the coil and aluminum launch the rocket itself. ”
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June 19th, 2006
Because the impulse from the EM coil is so short, part of the launch energy is lost destroying the
cardboard tube. It needs a way of storing the energy, so reducing the acceleration of the tube
i.e. Kicker (aluminium)> spring > Body (cardboard)
See Project Orion http://en.wikipedia.org/wiki/Project_Orion
June 19th, 2006
That’s a fantastic idea, to use a spring…I’ll give that a shot on future designs!
June 19th, 2006
How is the induction part of it built?
June 19th, 2006
re: spring
Since you need something light and safe for low flying aircraft, try one or two ping-pong balls.
pneumatic springs can be a little ‘lossy’ but that shouldn’t be a problem in this case.
June 20th, 2006
Thanks for the additional feedback! I’ll try the ping pong balls and see what happens…I suspect they’d last 1 launch, but if it saves the rocket, that’s better! I have extensive information on how I built the coils for the induction part at FastMHz.com, under Projects, and then “Induction Launchers & EM Rocketry”.
June 20th, 2006
I’ve just been looking at your bbs; The rocket is larger than I thought, so you’re right, a ping-pong ball will not be up to the job. The spring has to survive the launch or will just waste power. What about a few of those super-bouncy rubber balls?
June 21st, 2006
I was thinking of those superballs myself, but they do weigh a few grams…it’s a catch-22 of sorts, more weight, maybe it survives, but it wouldn’t go as high. I’m in the process of building my first 3 layer launching coil…this should make the pulse a little longer and allow me to fire at 3.5kj instead of just 2.1kj. It may or may not work better, but I’m thinking the pulse is too short. I plan to take video of me making one of the coil layers so that everyone that’s asked me “how do you make those coils” will know
June 22nd, 2006
this is too totaly kool would you please share the build plans for this project i would realy like to see them and mabe make a mock up my self and test out a few ideas of my own
June 23rd, 2006
I just made a video of how to make the coils which are the hardest part to make. It’s on HackedGadgets and FastMHz.com. As for the capacitor bank, you’ll have to get some large capacitors first, and I got mine on eBay. There are 16 in my bank, each one is 350v @ 3600uf, wired into a bank for 1400v @ 3600uf (~3.5kj) Just ONE of these things can be FATAL, much less 16 of them!! I’d advise you to visit the 4hv.org forum, where I happen to frequent, to get advice from plenty of other folks doing EM experiments. Feel free to post to my FastMHz.com BBS as well if you have a Q specific to something I did. You’ll also need magnet wire, SCRs, charging unit, huge resistors, diodes and some very thick wire.