neato! i’m gonna strap one to my bike!

Posted at 8:54 am on Jan 7th, 2009 by grizball

Inb4 gmod jokes.

Posted at 9:47 am on Jan 7th, 2009 by Max

Very cool!

Anyone remember seeing a high school science fair project that demonstrated ion propulsion using I think knitting needles in plastic tubes suspended from a thin wire connected to an automobile ignition coil? Apparently by pulsing the current into the coil one could get this ‘rocket’ to swing like a pendulum. I think I read this in an old encyclopedia my parents had.

Posted at 10:04 am on Jan 7th, 2009 by Alex

This is the same basic principle as a Jacob’s Ladder, right?

Too bad it’s not particularly powerful. I’d have figured out a way to mount it in the trunk of a car for an extra boost of speed. :)

It’d make an awesome cigarette lighter, though. :D

Posted at 10:07 am on Jan 7th, 2009 by Skyler

I have no techno babble to describe this!

Posted at 10:21 am on Jan 7th, 2009 by strider_mt2k

This is both really cool, and no small achievement! If his measurements of 20-40 N of thrust are correct, then this thruster is achieving on the order of the same thrust as some experimental ion engines. Most ion thrusters are measured in terms of milliNewtons, not Newtons! :)

http://en.wikipedia.org/wiki/Ion_engines

That being said, he probably uses more power and much more propellant than those designs, but for a hack attempt, that’s fantastic! :) Well done!!

Posted at 10:48 am on Jan 7th, 2009 by silic0re

This definitely works differently to an ion engine. It seems to be very similar to a jacob’s ladder, although I always thought they worked due to the hot gas rising rather than magnetic effects.

Someone with a jacob’s ladder try it upside-down please!

20-40 N sounded like bollocks, but then I read his current is 30-40 kA!

Posted at 11:09 am on Jan 7th, 2009 by Tim

This thing is amazing to see in person just with the sheer amount of power it expels in just a short amount of time. The EMF it releases when it fires also causes massive amounts of distortion on any electronic recording device attempting to get a shot of it. It was a very impressive piece of work.

Posted at 11:09 am on Jan 7th, 2009 by Pyromancer

Hmm lets combine the last couple days of entries, we get a Van, with an automated grow system, that has an plasma cutter, and and plasma drive and it can parallel park in just 42 seconds in the vacum of space.

Posted at 12:06 pm on Jan 7th, 2009 by James D

Tim

There are instructions for a Jacob’s ladder on here, make and test it yourself.

http://hackaday.com/2008/12/30/jacobs-ladder/

Posted at 12:11 pm on Jan 7th, 2009 by icefox

Really I think this has more in common with a rail gun than a jacob’s ladder.

Posted at 12:58 pm on Jan 7th, 2009 by ex-parrot

Take a look at other MHD drives. quite a few people are working on the opposite of this for super sonic power generators. the incoming air passes past conductor rails while moving into a constricting cylinder the air passing by the conductor generates electricity in the conductor rails
http://www.springerlink.com/content/r3712t8w420v2212/

Posted at 2:01 pm on Jan 7th, 2009 by adam

I wish there was a video of the plasma thruster in action.

Posted at 2:16 pm on Jan 7th, 2009 by Mike c

ex-parrot: not really, no.

Posted at 2:26 pm on Jan 7th, 2009 by aztraph

An upside down jacobs ladder will just arc across the spark gap until it melts. The heat from the plasma is what causes the spark to rise from what I’ve read and seen with my own jacobs ladder. Yes, I melted the hell out of one while not paying attention while it was in a non-vertical mode (it fell over…oops!). Killer hack tho!

Posted at 2:36 pm on Jan 7th, 2009 by chris

so how long does it take to recharge a 28kj capacitor bank in the darkness of interstellar space?

Posted at 2:41 pm on Jan 7th, 2009 by amk

I saw the development of this thing from start until its current state. A video would be awesome except the discharge takes place in 6ms. That is MUCH less that one frame of standard video, so it would need a high speed camera. The further challenge to that would be convincing someone with a high speed camera to allow it so close to such a large EMP. And it actually IS much closer to a rail gun then a Jacobs ladder. The Lorenz forces of the current flowing through the ionized argon accelerates the argon generating the thrust.

Posted at 3:14 pm on Jan 7th, 2009 by mad.hephaestus

The real question is when do we get to see this tested in space?

Posted at 4:17 pm on Jan 7th, 2009 by icefox

Some comments from guy who designed and built that beast:

1) This thruster operated at about 14 Megawatts peak.

2) As shown, this device is actually an arcjet thruster. The operation is similar to a chemical rocket where hot gases are expanded in a nozzle to get thrust – except here the gas is heated by an electric arc.

3) In order for magnetoplasmadynamic effects to generate the bulk of the thrust, the device must be operated in a near vacuum. I couldn’t get a hold of a large vacuum chamber so I went with arcjet operation instead.

4) Total thrust of 20-40 N is respectable, but not a good performance measure. You could probably get 20 N by throwing a few bowling balls. A much more useful measure is thrust per unit of propellant mass. This is know as the specific impulse (measured in seconds. Yes, seconds. That’s just how the math works out.) The space shuttle’s main engines operate at about 450s. Arcjets operate around 2-3,000s. MPD thrusters operate upwards of 30,000s. My thruster was probably somewhere around 2,000s, which puts it at the low range of an arcjet. Not too shabby. Results probably would have been much better with a proper nozzle.

Posted at 4:31 pm on Jan 7th, 2009 by Matthew Krolak

aztraph: it really is very similar, insofar as I can see. this is essentially a rail gun with the metal projectile replaced by a conductive cloud of plasma.

Posted at 4:57 pm on Jan 7th, 2009 by ex-parrot

Thanks, Matt. That’s a sweet bit of kit there. I’ve got a megawatt stack I could try, but previous experiments found tungsten melting like butter on a hot griddle. How’d the nozzle hold out?

Posted at 9:24 pm on Jan 7th, 2009 by K.

So you need 14 MW for 40 N thrust- or 350 KW for 1 N. Hm… If we suppose you are using solar cells with 350 W/m2, and 1 m2 of cells is only 0.1 kg mass, you need 1000 m2 of cells to produce 1 N thrust, and weight of cells is 100 kg. Then your acceleration is a=F/m=0.01 m/s. Not bad at all for an electric thruster, and with solar cells, working time is unlimited. In ~1 day you would achieve 1 km/s speed, in 100 days 100 km/s. That’s excellent! Even with solar cells weighing 1000 kg, design is still very good and useful, for example for asteroid belt exploration.

Posted at 7:34 am on Jan 8th, 2009 by MC screwdriver

@james d
don’t forget, it would be controlled using a wii and everyone has to complain about how it’s not a real hack

Posted at 11:22 am on Jan 8th, 2009 by Sol

simply said, let F-Zero projects commence

Posted at 7:27 pm on Jan 9th, 2009 by sora

Hey! speaking of space engines, I’ve got a
doosie. I thought this up when thinking about
the plausibility of using the equivelant of
the electrons spinning around an atom (at the
speed of light) but if you could get the atoms
to go foreward and around, you wouldn’t be limited
by rocket engines. (E=mc2 just use another
source of controlled energy to stimulate the
atoms) I warn you that he who tries this WILL
die and be atomically disentegrated (not to mention BECOMING A NUKE!!!). But, I was thinking
about the ability to control the stimuli and
accelerate to any speed, not limited by any other
internal force (except gravity and friction)
but hey, what happens in space stays in space.

Posted at 6:57 am on Jan 13th, 2009 by Phive

* Using the electrons spinning around an atom
for a method of invincible shielding (I was
thinking that if everybody got those, people
would get tired of shooting at each other
and I would get the nobel piece prize for
world piece) — Started saying that, but I
accidentally skipped ahead (I was thinking
about the lightspeed thingie) And, guess what
(this is kick-ass, because nobody my age would
probably have these ideas) I am 17.)

Posted at 7:01 am on Jan 13th, 2009 by Phive

@Phive

That would be amazing if you didn’t use words like thingie…

And if it wasn’t complete BS.

Prove me wrong, anyone can say ‘I was thinking about using a microwave oven to make plasma particles to use in my superluminal propulsion system’

Posted at 2:34 pm on Jan 14th, 2009 by Andar

Matthew,
Have you gotten a chance to test this out in a vacuum chamber yet?
If you were operating the device as an MPD as opposed to an arcjet, will there be a decrease in total thrust in exchange for greater specific impulse? (as I understand it, MPD operation requires low injected propellant pressures as well as near-vacuum operation)
Lastly, how much Isp/thrust variability wiggle room do you have to match mission constraints along the lines of the VASIMIR concept, within reasonable limits of electrode lifetime?
Cool build, hope to pursue something similar for my senior design.

Posted at 2:56 pm on Mar 29th, 2009 by Quintin Davis