Electromagnetic Propulsion

[nacnud]

That is to do with friction.<br /><br />There are two types of friction, static and dynamic. On your skateboard you can move forward with both feet on the board by exploiting the difference between them. You are actually pushing the earth back to go forward in this case.<br /><br />I’ll explain more in a minute, (at work can’t post)<br /><br />There is no friction (to speak of) in space so this won’t work there. And you would need to push off something anyway.<br /><br />

 

[cuddlyrocket]

Newton's Laws of Motion have never been shown to be violated ever. His Theory of Gravitation was superseded by General Relativity, but that didn't affect the Laws of Motion.<br /><br />The skateboard works because you are applying a force to the ground when you push off. The skateboard and you go forward and the Earth goes back (although not by much because it is so much more massive). When you return your leg to the starting position, you're simply rearranging the layout of the skateboard/you system, so this doesn't involve any slowing down of the centre of mass.<br /><br />With your original magnet idea, the magnet is propelled into the back of the probe by something that is attached to the probe itself. Then it is returned to its original system by something else attached to the probe. The probe/magnet is a self-contained system (unlike the skateboard/you which is interacting with the Earth). Such a system will not accelerate unless there is an net external force (or you throw bits out the back).

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p>A problem with Newton theories is that they were the fundamental once, explaining very simple systems. His theories were made 250 years ago. <p><hr /></p></p></blockquote><br />I guess its pointless to try to explain from here on . And i think this thread should go to wherever basic physics is taught.

 

[vidar]

That would be like starting the engine without setting it in gear. <br /><br />There might be need for some tuning. It can be done electrically. The frequency should not start at 1000 Hz but increase from 1 to 1000. Maybe some dc should be added at first, so the beating won’t be that hard in the beginning. Furthermore, the backwards elmag movement should be less than the forwards, for compensation to the forwards acceleration.<br />

 

[larper]

Sit on a skateboard with a sandbag. You are tied to the sand bag with a long cord. The sand bag is mounted on a wheeled platform.<br /><br />Throw the sandbag as hard as you can. The sandbag always lands on its wheels.<br /><br />Reel in the sandbag with the cord.<br /><br />Wash, rinse repeat. Tell me how long it takes to get to the corner store. <div class="Discussion_UserSignature"> <p><strong><font color="#ff0000">Vote </font><font color="#3366ff">Libertarian</font></strong></p> </div>

 

[vidar]

That is something I will not do in public.

 

[mrmorris]

<font color="yellow">"That is something I will not do in public. "</font><br /><br />Why not? It won't make you look any sillier than this thread has.

 

[tap_sa]

On earth these 'concepts' sometimes seem work, but just because friction at the wheels doesn't remain uniform while you are throwing around your sandbags.

 

[vidar]

In reply to:<br />The skateboard and you go forward and the Earth goes back <br />--------------<br />Well, yes. Then let’s imagine the elmag ship pushes the sun a little too. <br />

 

[nacnud]

Ok so how are you going to push the sun? A barge pole would catch fire...

 

[vidar]

‘The unpublished work of Isaac Newton included much that would now be classified as occult studies. He worked extensively outside the strict bounds of science and mathematics, particularly on chronology, alchemy, and Biblical interpretation (especially of the Apocalypse). Much of his writing on alchemy may have been lost in a fire in his laboratory, so the true extent of his work in this area may have been larger than is currently known. He also suffered a 'nervous breakdown' during his period of alchemical work, which is thought by some due to the psychological transformation that alchemy originally was designed to induce, though there is also speculation it may have been some form of chemical poisoning.’ <br />Ref. http://en.wikipedia.org/wiki/Isaac_Newton%27s_occult_studies <br />------------<br /><br />Imagine Newton after some alchemy experiments trying to move a vessel that he is in. He can’t, and believed it should be put down in a law. He did not live to see trains, cars, jets or rockets, though.<br />

 

[drwayne]

"Newton’s laws might say I can not, but anyone can do it themselves if they try."<br /><br />Actually Newton's laws, applied properly *do* allow, and explain this. In particular, the shift in the center of mass of the person/skateboard combination can result in displacement because of the effects of friction. In particular, in the case of the "forward" motion, it the impulse is high enough, friction can be overcome and the skateboard shifts foward. When the skater returns to the original position, if this motion is slow enough, friction is not overcome.<br /><br />If there is no friction in the wheels, (similar to space conditions), this does not work, i.e. the center of mass does not shift.<br /><br />The hardest problem for introductory statics and dynamics students is to identify and account for all of the forces acting in a problem.<br /><br />Wayne <div class="Discussion_UserSignature"> <p>"1) Give no quarter; 2) Take no prisoners; 3) Sink everything."  Admiral Jackie Fisher</p> </div>

 

[larper]

<blockquote><font class="small">In reply to:</font><hr /><p>He did not live to see trains, cars, jets or rockets, though.<p><hr /></p></p></blockquote><br />Huh? What????<br /><br />Cannons. Guns. Chinese Rockets. Greek steam engines. DaVinci spring wound toys. <br /><br />Newton realized not only how orbits work, but how you could GET to orbit.<br /><br />Time to end this waste of time.<br /><br />*plonk* <div class="Discussion_UserSignature"> <p><strong><font color="#ff0000">Vote </font><font color="#3366ff">Libertarian</font></strong></p> </div>

 

[tomnackid]

Of course Vidar's hammer concept (and all of the other "reactionless drive" schemes so far proposed) is unworkable, but there is one thing that bothers me about Newton. He assumes that reaction is instantaneous. Is it even possible for a reaction force to act instantaneously in a relativisitic universe? And if not is there some way to take advantage of the delay?

 

[dragon04]

Read this link explaining how a maglev train works. Then think about what would stop the principle being applied to a spaceship.<br /><br />HINT : Look at the entire system. Not just the electromagentics involved.<br /><br />http://travel.howstuffworks.com/maglev-train1.htm <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[cyrostir]

the same type of technology that the maglev train uses, should be useful on places such as the moon....<br /><br />how was the moon buggy powered? electronic motors?<br />

 

[vidar]

In the very first post I wrote.<br />“That is done quite effective by the electromotor and in the magnetic levitation train, Maglev, which can reach over 400 km/h. Similar system could be interesting for launching rockets.”<br /><br />It means that I do not propose maglev as propulsion for spaceships. It means that I think it is a good idea to use maglev for launching rockets. It is no point for me to argue about something I do not propose. <br /><br />At the moon, a maglev launcher will have the advantages of zero air friction and 1/6 G. The disadvantage is to the amount of electricity it requires. There are several options, but I think nukes are best for mainpower and solar power is good for backup. (Another use of the generator could be to power some scopes, disks and a transmitter, for space surveillance.)<br />

 

[starfhury]

Suprisingly, I see what you are trying to say. How about that? Let me explain it this way. You have your plunger for lack of a better word attach to you spaceship with by a line. Crude but, >---->>> something like that. You would slowly unreal the second stage then electromaginetically accelerated it into the back of the first section. Since the first part is heavier than the second, the second would be accelerated and impact into the first providing a supposed net acceleration in the this --> direction. This is sort of a reverse of tossing stuff away. IE, a faster smaller object impacting into a larger slower moving object imparts it's velocity and heat to both objects. The smaller one slows drammatically while the larger object speeds up somewhat. Actually it's pretty interesting. Can some one else confirm if this is reasonable? Imagine if we had two of these impactors, they could be cycled provided they are not fused after impact. If they are not a second impact would jar the first one lose and it'd have net space velocity less than the new impactor plus larger body. So it would fall behind only to be accelerated again for another impact. As an example of what this would be like, imagine an object getting hit by a bullet. The bullet imparts it's energy into the object it hits accelerating it. In this case, the bullet is attached by a string an magnetically accellerated for repeated impacts. The enegry difference coming for say the fuel expended to create the magnetic field to accelerate the bullet in the first place.<br /><br />It seems plausible to me, but I think there must be some violation of momentum in there somewhere. Can anyone else confirms if this makes sense. Vidar is that what you were implying? <div class="Discussion_UserSignature"> </div>

 

[vidar]

Thank you for trying to see the idea. It is hard to explain and I know I challenge fundamental theories of physics. <br /><br />In brief, there is added kinetic energy to the ship. The challenge is to direct a little more of the energy in one direction, than the other.<br /><br />Some main points are: <br />The rocket is much more massive than the hammer. Let’s say 1/100.<br />The hammer will be pulled towards the ship, and not visa versa, because of the mass difference and the speed of the hammer’s beat.<br />The hammer is pulled back by switching the polarity of the elmag (like your string). The pullback should not be as forceful as the beat.

 

[vidar]

I think it is ’gauche’ to discredit anyone, even me.<br />And I strongly suggest that such is not started in the first place.<br /><br />I know I challenge fundamental laws of physics, and I also strongly agree to Newton’s laws of motion. I am, however, trying to find a way to make a small deviation, that could mean much for space propulsion.<br />

 

[nacnud]

Guys it won’t work.<br /><br />Your trying to break the conservation of momentum. <br />

 

[vidar]

Looking back with Mirrorshades.

 

[tap_sa]

Your hammer-ship will be as succesful as sailboat which has a propeller to blow air to the sails. The sooner you realize this the less you waste your own time. Newton has pretty much everything macroscopic covered by his laws.<br /><br />I know only one credible theory that appears to create thrust <i>seemingly</i> without throwing reaction mass, it used some hairy physics to tap into vacuum inertia ie. it sort of used vacuum as reaction mass. Extremely strong magnetic fields and whatnot were involved. Unfortunately I've forgotten link to the article but it was credible peer-review scientific site, not for crackpot science.

 

[vidar]

I am not trying to break the conservation of momentum, energy or mass.<br /><br />There will be some loss of energy, but no loss of mass. Couldn’t the energy difference cause difference in momentum?<br />

 

[no_way]

<blockquote><font class="small">In reply to:</font><hr /><p> You would slowly unreal the second stage then electromaginetically accelerated it into the back of the first section<p><hr /></p></p></blockquote><br /><br />One last time, try to get this now. For strarters, lets assume two equal-sized "impactors" or electomangets or whatever.<br /><br />Lets say they are a hundred meters apart. Turn on the magnets. What happens ? They both move 50 meters towards eachother and slam, standstill if they arent elastic. Reverse the polarity ( TM ) and they move away from eachother again, equal speeds.<br /><br />Now lets take one small "impactor" and another big one. Say ten times as massive as the other. 100 m apart again. Turn on the magnet. What happens ? The small object will accelerate as hell towards the other one .. but the large object _will accelerate too_, slower, but it will. <br />Result at the impact = zero total speed if the "impactors" arent elastic or they will bounce off eachother if they are.<br /><br />In the end, it doesnt matter how elastic or how big each of the impactors will be, or if you will use magnets for pulling/pushing or something else . The net speed of a total system will be standstill. <br /><br />For chrissake its basic physics, not that hard to get.<br /><br /><br />Or to illustrate even further .. You are familiar with a mass driver concept. Small slugs are shot out of the back end of your spacecraft with "magnetic cannon", each imparting a small velocity increase to the spacecraft. What would happen if you had a string attached to a slug you shot out and want to reel it back in ? <b><i>your spacecraft would lose all the speed it gained while you are decelerating and reeling in the slug again and stand still at the end of the cycle</i>/<b>. Get it ?</b></b>