jon%vector0@sactoh0.SAC.CA.US (Dazed N. Confused) (03/24/91)
Hi. I was talking to a friend about a Rail Gun --- a device that
through magnetic induction is able to fire an object at enormous
speed. I was wondering if I could build a scaled-down model.
This pico-Rail Gun would fire metal washers hopefully 2 feet.
Any ideas? Besides just winding a bunch of wire around a
cardboard tube and hoping for the best, that is.
.----. *-> CONSERVE ENERGY <-*
( ) Jon *-> Kill Yourself <-*
^^::^^ vector0!jon@sactoh0.SAC.CA.US
__;:__ ...PacBell.Com!sactoh0!vector0!jondietz@cs.rochester.edu (Paul Dietz) (03/25/91)
In article <X0PaZ4w163w@vector0> jon%vector0@sactoh0.SAC.CA.US (Dazed N. Confused) writes: > Hi. I was talking to a friend about a Rail Gun --- a device that >through magnetic induction is able to fire an object at enormous >speed. I was wondering if I could build a scaled-down model. Whoa! You are confusing rail guns with electromagnetic launchers in general. A rail gun is a one-turn linear DC motor. Current flows up one rail, across an armature on or behind the projectile, and down the other rail. Rail guns are high current, low voltage devices. Perhaps you are thinking of a coil gun. In one kind of coil gun, a coil in the projectile is energized and accelerated by electromagnetic induction from stator coils. Quite a different concept -- no sliding contact is necessary. The drive coils can have many turns, so coil guns can be higher voltage, lower current devices. You can build a crude toy coil gun by making an iron core solenoid and placing an aluminum ring on one end of the rod. When AC is fed into the solenoid the aluminum ring will shoot several feet into the air. This is a standard high school demonstration of EM induction. You might also try driving the ring with a short current pulse from a large capacitor fed into a planar stator coil. For details on many different kinds of EM launchers, see IEEE Trans. on Magnetics. They occasionally have special issues containing the proceedings of the Electromagnetic Launch Conference. Paul F. Dietz dietz@cs.rochester.edu
will@rins.ryukoku.ac.jp (will) (03/25/91)
Information Unlimited
Box 716 Dept. DIS6
Amherst, N.H. 03031
Send 1.00 dollars for their catalog, I know for a fact that they
have it. Got years ago for a high school project. They even got
kits.
William Dee Rieken
Researcher, Computer Visualization
Faculty of Science and Technology
Ryukoku University
Seta, Otsu 520-21,
Japan
Tel: 0775-43-7418(direct)
Fax: 0775-43-7749
will@rins.ryukoku.ac.jpwill@rins.ryukoku.ac.jp (will) (03/25/91)
I meant electromagnetic launchers. Sorry.
William Dee Rieken
Researcher, Computer Visualization
Faculty of Science and Technology
Ryukoku University
Seta, Otsu 520-21,
Japan
Tel: 0775-43-7418(direct)
Fax: 0775-43-7749
will@rins.ryukoku.ac.jpalleyne@olympus.ics.uci.edu (Brian Derek Alleyne) (03/26/91)
Use the same principle as a linear accelerator. I once shot a bb about
fifty feet using a tube and 8 coils.
c c c c c c c
-=--=--==----===------===----------===---------------===--
-=--=--==----===------===----------===---------------===--
c c c c c c c
1 2 3 4 5 6 7
c = coil wound with thick copper wire
= = Ferrite or soft iron ring around which the coil is wound
to increase the magnetic field.
Each coil from left to right is energized in sequence, and should
be timed to turn off as the projectile reaches it.
ie. coil "1" is turned on first. Just as the projectile reaches it,
it is turned off and coil "2" is turned on. Just as the projectile
reaches coil "2", it is turned off, and coil "3" is turned on etc.
As a result, the projectile (if magnetic) is accellerated (pulled) by the
magnetic field travelling down the tube.
I just used a shift register and a 555 timer to control the switches which
controled the coils, and experimented with the distances between the
coils to get the maximum range.
happy shooting...
Brian
-------------------------------------------------------------
Je ne pense pas donc "poof"... alleyne@ics.uci.edu
-------------------------------------------------------------
--
-------------------------------------------------------------
Je ne pense pas donc "poof"... alleyne@ics.uci.edu
-------------------------------------------------------------rainer@boulder.Colorado.EDU (Rainer Malzbender) (03/26/91)
In article <27EE910A.10011@ics.uci.edu> alleyne@ics.uci.edu (Brian Derek Alleyne) writes: > > c c c c c c c >-=--=--==----===------===----------===---------------===-- >-=--=--==----===------===----------===---------------===-- > c c c c c c c > 1 2 3 4 5 6 7 > The astute reader will no doubt recognize this as a mass driver, not a rail gun. A rail gun is much simpler in that it doesn't need position sensors, it's just a big cannon. A bit of useless history: I worked on one of the early mass driver projects with Gerry O'Neill, for potential lunar applications. His counterpart at MIT, Henry Kolm, headed the Magneplane project (a little levitated train), and was also into mass drivers. I lost of track of what happened after 1980 or so, but I know Kolm became more involved with rail guns. I think the government did, too, I suppose because of the sheer simplicity and brute force of the things. Mass drivers are trickier. FYI, we used optical triggers to sense the approach of the projectile, which in turn dumped huge amounts of current through the coils using SCR's. The above non-linear spacing of the coils makes it easy to have fixed-frequency pulses energize the coils, but you lose the power (for a given length) of regularly spaced coils. -- Rainer Malzbender, PhD "It's not the bullet that kills you, it's the hole." Dept. of Physics (303)492-6829 -Laurie Anderson U. of Colorado, Boulder rainer@boulder.colorado.edu 128.138.240.246
henry@zoo.toronto.edu (Henry Spencer) (03/27/91)
In article <1991Mar26.094649.28010@colorado.edu> rainer@boulder.Colorado.EDU (Rainer Malzbender) writes: >The astute reader will no doubt recognize this as a mass driver, not >a rail gun... No, the astute reader will recognize it as a coilgun. The mass driver, Gerry O'Neill's invention, uses recirculating payload carriers ("buckets") so that it does not need to throw away a magnetic element with each shot. If it doesn't decelerate and re-use buckets, it is not a mass driver. (Although the early O'Neill/SSI/MIT prototypes were called that, based on their intent as proof-of-principle experiments for a true mass driver.) -- "[Some people] positively *wish* to | Henry Spencer @ U of Toronto Zoology believe ill of the modern world."-R.Peto| henry@zoo.toronto.edu utzoo!henry
dietz@cs.rochester.edu (Paul Dietz) (03/27/91)
In article <1991Mar26.165529.28754@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >In article <1991Mar26.094649.28010@colorado.edu> rainer@boulder.Colorado.EDU (Rainer Malzbender) writes: >>The astute reader will no doubt recognize this as a mass driver, not >>a rail gun... > >No, the astute reader will recognize it as a coilgun. The mass driver, >Gerry O'Neill's invention, uses recirculating payload carriers ("buckets") >so that it does not need to throw away a magnetic element with each shot. Moreover, the mass driver buckets used coils, not solid pieces of iron. Saturation of iron projectiles limits their performance. High performance coil guns or mass drivers would use aluminum, beryllium or superconducting bucket coils. Paul F. Dietz dietz@cs.rochester.edu
yaadmin@levels.sait.edu.au (03/28/91)
In article <27EE910A.10011@ics.uci.edu>, alleyne@olympus.ics.uci.edu (Brian Derek Alleyne) writes: > Use the same principle as a linear accelerator. I once shot a bb about > fifty feet using a tube and 8 coils. > > > > c c c c c c c > -=--=--==----===------===----------===---------------===-- > -=--=--==----===------===----------===---------------===-- > c c c c c c c > 1 2 3 4 5 6 7 > > c = coil wound with thick copper wire > > = = Ferrite or soft iron ring around which the coil is wound > to increase the magnetic field. > > Each coil from left to right is energized in sequence, and should > be timed to turn off as the projectile reaches it. > > (Rest of article deleted) This looks like it'd be fun to make...:-) How about some dimensions? i.e Tube diameter/length Coil diameter/#turns Voltages/currents Driving circuitry Muchos Gracias in advance ============================================================================= Robert Lacina yaadmin@levels.sait.edu.au ============================================================================= DISCLAIMER: Insert your favourite disclaimer here ->[] Please write legibly.
will@rins.ryukoku.ac.jp (will) (04/01/91)
How about filling in the blanks. I'm not an expert in elec. but it would help to spend idle time. Will.