Rail gun engine the future of space travel?

[Zeiss Ikon]

On 3/7/2018 at 1:55 AM, Vanamonde said:

Moved to Science & Spaceflight, since it's not about KSP. 

Not about science, either.  It violates conservation laws, if it provides any net impulse.

There was a scheme similar to this before WWII -- I've read an article in Popular Mechanics from them; they called it an "impulse-impact" system.  Two weights propelled outward from a center (zero net impulse) strike a spring on one end, a plate on the other; the bounce back from the spring produced twice the impulse as the slap on the plate, moving the whole thing forward.  Once.  If you install a mechanism to reset it, it'll use up the momentum imparted by the spring when it resets the unsprung mass.  Same thing here.  And using enough energy to melt the metal ball means you're also throwing away a lot of radiated heat (and the electric energy required to produce it).

EM drive might still have an EM exhaust of some kind, effectively using something akin to light pressure to produced (minuscule) thrust.  This thing cannot produce any net thrust in any direction (that's not accounted for by wasted heat radiation).

[Vanamonde]

Okay, purists, please stop complaining about whether or not the original idea is science. Replies will certainly contain science whether or not the OP does, so the thread belongs in Science & Spaceflight, mkay?  

[sevenperforce]

1 hour ago, Zeiss Ikon said:

There was a scheme similar to this before WWII -- I've read an article in Popular Mechanics from them; they called it an "impulse-impact" system.  Two weights propelled outward from a center (zero net impulse) strike a spring on one end, a plate on the other; the bounce back from the spring produced twice the impulse as the slap on the plate, moving the whole thing forward.  Once.  If you install a mechanism to reset it, it'll use up the momentum imparted by the spring when it resets the unsprung mass.

It's even simpler than that, actually. The net forward momentum that the assembly has from a single cycle is exactly equal to the net rearward momentum that the spring-bound weight has. 

[Zeiss Ikon]

7 hours ago, Vanamonde said:

Okay, purists, please stop complaining about whether or not the original idea is science. Replies will certainly contain science whether or not the OP does, so the thread belongs in Science & Spaceflight, mkay?  

Mkay.  We shall use science to demonstrate that it's a device for separating potential backers from their money.

7 hours ago, sevenperforce said:

It's even simpler than that, actually. The net forward momentum that the assembly has from a single cycle is exactly equal to the net rearward momentum that the spring-bound weight has. 

Yes, that's correct.  The magazine cover associated with it strongly suggested the magazine's editors didn't know their basic science, however; it showed flying platforms and such in a futuristic city, all supposedly based on this "impulse-impact" drive.

Let's also not forget the (fictional) "skyhook" drive from Lee Corey's Star Driver.  Based on the idea that F=MA only holds if A is small enough, it used a tube full of low pressure neon inside a coil; the neon was ionized and shuffled back and forth by the magnetic fields, turnaround sharp at one end and soft and gentle at the other.  A sort of molecular Dean Drive, if you will.

[p1t1o]

17 minutes ago, Zeiss Ikon said:

A sort of molecular Dean Drive, if you will.

DEAN DRIVE. THATs the thing I have been trying to think of since seeing the OP, thats what it is.

[sevenperforce]

3 hours ago, p1t1o said:

DEAN DRIVE. THATs the thing I have been trying to think of since seeing the OP, thats what it is.

One of the fun things about reactionless drives is that you can ask their inventor to explain how, exactly, net thrust is produced in their desired direction, rather than in the opposite direction.

[p1t1o]

2 minutes ago, sevenperforce said:

One of the fun things about reactionless drives is that you can ask their inventor to explain how, exactly, net thrust is produced in their desired direction, rather than in the opposite direction.

The "inventor" of the dean drive refused to demonstrate or explain it unless he was promised a Nobel Prize first...

The source for this is actually Jerry Pournelle:

https://www.jerrypournelle.com/science/dean.html

[sevenperforce]

9 minutes ago, p1t1o said:

The "inventor" of the dean drive refused to demonstrate or explain it unless he was promised a Nobel Prize first...

The source for this is actually Jerry Pournelle:

https://www.jerrypournelle.com/science/dean.html

The course of true love never did run smooth.

[p1t1o]

@sevenperforce

Dang, that blog is gold. Here's one line: "A former Peenemunde rocket scientist associate of mine..."

[KSK]

18 hours ago, sevenperforce said:

One of the fun things about reactionless drives is that you can ask their inventor to explain how, exactly, net thrust is produced in their desired direction, rather than in the opposite direction.

Depends which way the invisible unicorns are pointing. Duh.

[Zeiss Ikon]

On 3/9/2018 at 9:21 AM, p1t1o said:

The "inventor" of the dean drive refused to demonstrate or explain it unless he was promised a Nobel Prize first...

The source for this is actually Jerry Pournelle:

https://www.jerrypournelle.com/science/dean.html

Yeah.  On the patent application (according to an article I read in Analog magazine in the 1970s), the drawings make it clear that the original Dean Drive was in fact a tape drive -- not anything to do with reactionless thrust.  Dean always claimed that he falsified the patent docs to prevent making his invention public; the Analog article pointed out that this would actually invalidate any protection his invention might have gained from the patent.

I met a man at a convention in the early 1980s who claimed he'd built a "skyhook" drive based on the one described in Star Driver -- after talking to G. Harry Stine (Lee Correy was his peudonym for SF stories and novels).  Mind you, he never reappeared as a billionaire, so I'm inclined to believe it didn't work.  The principle here was that no one had tested that the third derivative of displacement (i.e. "rate of change of acceleration") was in fact zero relative to F=MA, and the "skyhook" drive assumed that if you changed the acceleration rapidly enough, you'd get more or less acceleration relative to the power applied, resulting in a net thrust from a system that accelerated particles with a high "jolt" in one direction, and very low "jolt" in the other.

The principle is still generally untested -- from what I understand (I'm no physicist) it's fairly hard to set up an apparatus to actually measure this particular condition.

On 3/9/2018 at 9:52 AM, p1t1o said:

@sevenperforce

Dang, that blog is gold. Here's one line: "A former Peenemunde rocket scientist associate of mine..."

Heh.  "Speaking almost inaudibly from his nursing home bed..."  Edit: Oh, that's quoting from Pournelle's 1950s perspective.  The rocket scientist might have been in his 50s then.

Edited March 10, 2018 by Zeiss Ikon

[p1t1o]

2 hours ago, Zeiss Ikon said:

Yeah.  On the patent application (according to an article I read in Analog magazine in the 1970s), the drawings make it clear that the original Dean Drive was in fact a tape drive -- not anything to do with reactionless thrust.  Dean always claimed that he falsified the patent docs to prevent making his invention public; the Analog article pointed out that this would actually invalidate any protection his invention might have gained from the patent.

I met a man at a convention in the early 1980s who claimed he'd built a "skyhook" drive based on the one described in Star Driver -- after talking to G. Harry Stine (Lee Correy was his peudonym for SF stories and novels).  Mind you, he never reappeared as a billionaire, so I'm inclined to believe it didn't work.  The principle here was that no one had tested that the third derivative of displacement (i.e. "rate of change of acceleration") was in fact zero relative to F=MA, and the "skyhook" drive assumed that if you changed the acceleration rapidly enough, you'd get more or less acceleration relative to the power applied, resulting in a net thrust from a system that accelerated particles with a high "jolt" in one direction, and very low "jolt" in the other.

The principle is still generally untested -- from what I understand (I'm no physicist) it's fairly hard to set up an apparatus to actually measure this particular condition.

Heh.  "Speaking almost inaudibly from his nursing home bed..."  Edit: Oh, that's quoting from Pournelle's 1950s perspective.  The rocket scientist might have been in his 50s then.

Apparently, the patent application did not describe the actual dean drive. Only a couple of people actually claim to have seen it aside from Dean himself, and they claim what was described in the patent was not what they saw.

Quote

Anyway, nothing came of it all. If it worked I never saw it work, and neither did the 3M team. The original device as described by Campbell and Stine was never found after Dean died, and the thing described in the patent doesn't work and isn't, according to Stine, what Dean showed as a working device.

 

[Zeiss Ikon]

7 minutes ago, p1t1o said:

Apparently, the patent application did not describe the actual dean drive. Only a couple of people actually claim to have seen it aside from Dean himself, and they claim what was described in the patent was not what they saw.

That's what I said.  My opinion -- Dean never had a working drive; he had something that, via resonance, fooled a scale, as well as fooling Campbell and Stine (because of their limited ability to observe the device).  Furthermore, he knew it; he used the fact it could spoof a scale to try to get a bunch of money (out of 3M and presumably Boeing -- "large aerospace company in the Northwest") that he could then use to vanish.

[p1t1o]

3 minutes ago, Zeiss Ikon said:

That's what I said.  My opinion -- Dean never had a working drive; he had something that, via resonance, fooled a scale, as well as fooling Campbell and Stine (because of their limited ability to observe the device).  Furthermore, he knew it; he used the fact it could spoof a scale to try to get a bunch of money (out of 3M and presumably Boeing -- "large aerospace company in the Northwest") that he could then use to vanish.

Ah sorry, my mind must have skipped a beat there

Yeah I dont think anyone is in doubt that the whole thing was hokum.

I mean...

Quote

Oh. He also wanted a promise of a Nobel Prize.

...thats one hack of a red flag! Right?

[sevenperforce]

4 hours ago, Zeiss Ikon said:

I met a man at a convention in the early 1980s who claimed he'd built a "skyhook" drive based on the one described in Star Driver -- after talking to G. Harry Stine (Lee Correy was his peudonym for SF stories and novels).  Mind you, he never reappeared as a billionaire, so I'm inclined to believe it didn't work.  The principle here was that no one had tested that the third derivative of displacement (i.e. "rate of change of acceleration") was in fact zero relative to F=MA, and the "skyhook" drive assumed that if you changed the acceleration rapidly enough, you'd get more or less acceleration relative to the power applied, resulting in a net thrust from a system that accelerated particles with a high "jolt" in one direction, and very low "jolt" in the other.

The principle is still generally untested -- from what I understand (I'm no physicist) it's fairly hard to set up an apparatus to actually measure this particular condition.

As a physicist, I can say that this is approximately equivalent to saying, "No one has yet tested whether cupcakes are spontaneously generated on the moon when Donald Trump hums Waltzing Matilda while dangling upside-down from the third ray on the Statue of Liberty's crown." Technically it is true, but that doesn't make the spontaneous generation of cupcakes any less a violation of the laws of physics. Likewise, no amount of yet-untested manipulation of jerk in an inertial system is going to create momentum from nothing.

1 hour ago, p1t1o said:

Yeah I dont think anyone is in doubt that the whole thing was hokum.

I mean...

Quote

He also wanted a promise of a Nobel Prize.

...thats one hack of a red flag! Right?

Like the guy said -- he'd happily promise a Nobel Prize, despite having no capability to generate one, simply because if you can overturn the basic laws of physics, you are guaranteed to get a Nobel.

[kerbiloid]

Spoiler

Fizzix-schmizzix, who cares. Laws are created to be violated.

13 hours ago, sevenperforce said:

Technically it is true, but that doesn't make the spontaneous generation of cupcakes any less a violation of the laws of physics.

Unless the pairs of cupcake-anticupcake virtually appear from the vacuum fluctuations.
So, as we aren't observing megaton explosions o the Moon, we can suppose that possibility of such event is below our current observation abilities, and this problem requires additional funding.

[Green Baron]

Funny how fascinating this stuff consistently is.

Perpetual machines, reactionless drives, telekinesis, energy for nothing, youth brought back, simple things that nobody has thought of before, ...

Those who want to believe do so and rarely can be convinced of their error.

 

Moar evidence based thinking !

Edited March 11, 2018 by Green Baron

[mikegarrison]

People try to sell stuff like this to Boeing all the time. I knew a guy who had been in the defense group who was tasked with writing up a paper explaining why the FTL communication system somebody was trying to sell based on quantum entanglement wouldn't be useful, because it wasn't actually possible to pass any information that way.

[kerbiloid]

Spoiler

6 minutes ago, mikegarrison said:

a guy who had been in the defense group who was tasked with writing up a paper explaining why the FTL communication system somebody was trying to sell based on quantum entanglement wouldn't be useful, because it wasn't actually possible to pass any information that way.

Now there are two guys trying to sell a FTL communication system based on quantum entanglement...

 

Edited March 11, 2018 by kerbiloid

[sevenperforce]

3 hours ago, Green Baron said:

Funny how fascinating this stuff consistently is.

Perpetual machines, reactionless drives, telekinesis, energy for nothing, youth brought back, simple things that nobody has thought of before, ...

Those who want to believe do so and rarely can be convinced of their error.

Moar evidence based thinking !

"But it would be so cool if we lived in a world where free energy and telekinesis and extreme longevity were real!"

Or we could just look around at this world. The fastest animal alive today is a small carnivorous dinosaur, Falco peregrinus, which preys mainly on other dinosaurs, striking and killing them in midair with its powerful hind claws. Our species successfully completed a campaign to utterly annihilate a deadly microbe called Variola major that threatened to destroy us, and we did it by hijacking our own bodies with science. We landed humans on the largest relative moon in our solar system and brought them back. Our only natural satellite is precisely the right size and in precisely the right orbit that we are able to directly observe the corona of our star with surprising regularity. We figured out how to collect subatomic particles produced only during the dying breath of a collapsing supergiant star billions of years ago, and split them apart to get power for our homes.

We just sent a freaking car to another planet on a giant missile, which we powered by releasing sunlight that had been trapped underground for hundreds of millions of years.

This is a pretty cool world.

I'd much rather live in a world where vaccines, dinosaurs, and the moon landing are real and free energy is a deceitful conspiracy than a world where free energy is real but vaccines, dinosaurs, and the moon landing are conspiracies.

Edited March 11, 2018 by sevenperforce

[kerbiloid]

7 minutes ago, sevenperforce said:

We figured out how to collect subatomic particles produced only during the dying breath of a collapsing supergiant star billions of years ago

It's frightening to think HOW old are the atoms of our bodies. (Well, at least their cores).
And probably some of them (gold , etc) came here from neutron stars collision billions years ago.

Spoiler

And all those space cataclysmes were just to make somebody who will put paper into the office printer to get random numbers.

 

Edited March 11, 2018 by kerbiloid

[Lordmaddog]

A revised version of the Rail gun engine.

A spherical lump of metal starts in the loading chamber (dark blue) and is injected on to the rail (brown) using electromagnets.

The rail speeds the projectile up to impossible speeds and melts it into liquid due to the extreme heat generated from the arcing electricity, at the same time generating thousands of newtons of thrust.

At the end of the rail the liquid projectile slams into the splitter (bright red) cutting the projectile in half and sadly reducing the total thrust generated by 20 to 35%.

The divided projectile flies down the redirecting tubes (purple) once again sadly reducing the total thrust generated further by another 15 to 20%. as their momentum and kinetic force are turned 90*.

Once redirected the two projectiles enter the stopping chamber (black) and slamming into the plungers (red) exactly opposite of each other at the exact same time. Thus canceling out each others remaining momentum and kinetic energy and leaving at least 40% of the thrust the engine generated by launching them. 

Now as more liquid metal comes into the stopping chamber the projectile reforming valve ( small orange thing) lets precisely measured amounts of the liquid metal  into  the cooling chamber (ice blue) were it once again thanks to zero G forms into perfectly spherical projectiles.

The newly formed sphere then floats around the cooling chamber until it has cooled enough to once again become magnetic.  At this point it is pull down into the loading line (grey) by electromagnets and using a electromagnetic systme similar to a gauss rifle it is shuttled back into the loading chamber where it can be shot once again.

_______

DISCLAIMER 

I realize that this it what is called a reactionless drive and many believe such a thing brakes the laws of physics, however I am a firm believer that we haven't even began to scratch the surface of science and what we THINK we know is often WRONG. I also believe that for every law there is another that counters that law IE: Law of gravity witch for thousands of years was thought impossible to get around yet a few hundred years  ago the law of aerodynamics was discovered for ever changing what we as humans are capable of.

______

Now to testing.

As was pointed out my last experiment was flawed in that it did not take into account friction so this time the experiment is done on water or hanging from a string to minimize friction.

To test you forum two rails out of paper clips glued on your base side by side. Then using long strawls ( the longer the better) you bend them so they gradually curve into a ninety degree turn exactly opposite of each other and glue them on your base. Now cork the end of the strawls 

Then just shoot (BBs are good) and see the out come.

Using two 100w capacitor (one for each rail) you should be able to get about 2 to 3 inches of movement tho if you don't get the timing/placement exactly right all your ship will do is spin.

 

[magnemoe]

11 hours ago, kerbiloid said:

It's frightening to think HOW old are the atoms of our bodies. (Well, at least their cores).
And probably some of them (gold , etc) came here from neutron stars collision billions years ago.

  Reveal hidden contents

And all those space cataclysmes were just to make somebody who will put paper into the office printer to get random numbers.

 

You only want old atoms in your body, the young ones are probably radioactive. 
Predating the sun is nice
 

[Hypercosmic]

Looks like that mad dog made another thread for this railgun bull[censored]...

EDIT:

To magnemoe: Recoilless? I wonder...

To sevenperforce and Vanamonde: I guess I was just too liquided... oh good two more reports

Edited March 14, 2018 by Hypercosmic

[magnemoe]

12 hours ago, sevenperforce said:

"But it would be so cool if we lived in a world where free energy and telekinesis and extreme longevity were real!"

Or we could just look around at this world. The fastest animal alive today is a small carnivorous dinosaur, Falco peregrinus, which preys mainly on other dinosaurs, striking and killing them in midair with its powerful hind claws. Our species successfully completed a campaign to utterly annihilate a deadly microbe called Variola major that threatened to destroy us, and we did it by hijacking our own bodies with science. We landed humans on the largest relative moon in our solar system and brought them back. Our only natural satellite is precisely the right size and in precisely the right orbit that we are able to directly observe the corona of our star with surprising regularity. We figured out how to collect subatomic particles produced only during the dying breath of a collapsing supergiant star billions of years ago, and split them apart to get power for our homes.

We just sent a freaking car to another planet on a giant missile, which we powered by releasing sunlight that had been trapped underground for hundreds of millions of years.

This is a pretty cool world.

I'd much rather live in a world where vaccines, dinosaurs, and the moon landing are real and free energy is a deceitful conspiracy than a world where free energy is real but vaccines, dinosaurs, and the moon landing are conspiracies.

Free energy has issues as with anything free, you don't care if you use 1000 MW making your Alaska land an tropical environment simply as you prefer it, it don't cost anything. 
Moving south would be easier
Somewhat related its various political projects who is free for the one driving them, same with cooperate ones for balance. Windows 8 is an good example of an insanely expensive fail. 
It did not result in replacing the upper leadership Stalin style who I would required as an major stockholder, that is outside of the killing part
Loads of other examples like Indian army giving out free condoms and found soldiers ran trough multiple each day, yes they used them to protector phones and other electronic and gun barrels. 

Extreme longevity is plausible, yes it would require a lot of GM, you would not be human anymore so pointed ears is part of the package

18 minutes ago, Hypercosmic said:

Looks like that mad dog made another thread for this railgun bull[censored]...

Now perhaps he come up with an recoil-less railgun, that would be useful