Propellant Recycling

[steve_v]

*crickets*

 

[Cheif Operations Director]

1 minute ago, steve_v said:

*crickets*

 

All I hear is Prussian’s Gloria 

Edited August 10, 2019 by Cheif Operations Director

[Ultimate Steve]

1 minute ago, Cheif Operations Director said:

1. The thrust still reaches 100% at one point though so it would get some speed on that axis (I think) 

2. Sure it will always add up to 100% but as long at one axis has a surplus of energy it will travel in that direction. I juts need the propellant not the energy. 

1. The thrust is 100 percent after the propellant exits the nozzle. 50 percent is taken away by the slow down device and 50 percent is taken away by the redirector (well actually converted from vertical to horizontal force, but that remaining vertical momentum is still transferred to the craft).

2. Yes, if one axis had a non zero energy then it would accelerate along this axis. However, your design has zero net energy in either axis. The y axis energy is all absorbed by the craft/redirected and the x axis nozzles cancel each other out.

[Cheif Operations Director]

1 minute ago, Ultimate Steve said:

1. The thrust is 100 percent after the propellant exits the nozzle. 50 percent is taken away by the slow down device and 50 percent is taken away by the redirector (well actually converted from vertical to horizontal force, but that remaining vertical momentum is still transferred to the craft).

2. Yes, if one axis had a non zero energy then it would accelerate along this axis. However, your design has zero net energy in either axis. The y axis energy is all absorbed by the craft/redirected and the x axis nozzles cancel each other out.

We agree on everything except the part about the axis, how is the forward thrust canceled out since that is the crux of the issue.

[Shpaget]

1 hour ago, kerbiloid said:

If so, then why do they call them magnets?

I always though it was short for magic catch-all for tinfoil crackpots net?

Anyway, somebody needs a lesson in vectors. I actually fired up MS Paint and drew it all out, decided that I'm not going to bother, and then got back to, because I'm an idiot. I then completely redrew it to hopefully make it clearer. I should be getting some sleep instead of doing this.

The big vertical arrow is force of exhaust, the purple arrow is force from the part of the exhaust before it was deflected to the side. Red horizontal arrow is the deflected force of the exhaust.

In order to achieve this deflection, some additional force is needed. That is the diagonal blue arrow. It needs to be angled to cancel axial and induce radial motion. The green arrow is the axial component of the blue one. This green arrow is the one that shows us the force of acceleration in the wrong direction.

 

 

Edited August 10, 2019 by Shpaget

[Cheif Operations Director]

6 minutes ago, KeranoKerman said:

If you want to keep this argument about your tarps and magnets, create another thread. This is about a explosion of a nuclear propulsion mechanism, not other rocket engine designs

It relates to the subject but you have a point. If it is not resolved soon perhaps I will.

4 minutes ago, Shpaget said:

I always though it was short for magic catch-all for tinfoil crackpots net?

Anyway, somebody needs a lesson in vectors. I actually fired up MS Paint and drew it all out, decided that I'm not going to bother, and then got back to, because I'm an idiot. I then completely redrew it to hopefully make it clearer. I should be getting some sleep instead of doing this.

The big vertical arrow is force of exhaust, the purple arrow is force from the part of the exhaust before it was deflected to the side. Red horizontal arrow is the deflected force of the exhaust.

In order to achieve this deflection, some additional force is needed. That is the diagonal blue arrow. It needs to be angled to cancel axial and induce radial motion. The green arrow is the axial component of the blue one. This green arrow is the one that shows us the force of acceleration in the wrong direction.

 

 

Ok but what is your point?

[steve_v]

5 minutes ago, Shpaget said:

somebody needs a lesson in vectors

You might be right, I for one neglected to include on on the basis of "so elementary everyone knows this".

[Cheif Operations Director]

Just now, steve_v said:

You might be right, I for one neglected to include on on the basis of "so elementary everyone knows this".

Good grief

[Ultimate Steve]

25 minutes ago, Cheif Operations Director said:

We agree on everything except the part about the axis, how is the forward thrust canceled out since that is the crux of the issue.

So your design has two parts where forward thrust is cancelled out.

The slow down part is fairly easy to explain. The energy from the propellant goes into the magnets/slow down devices and assuming the magnets are attached to the craft, the energy goes into the craft. If you do not get this I cannot help you.

The second part is a bit more difficult to explain. Say you have 500kn coming into the redirector. Assuming the redirector is perfect, this 500kn will be absorbed by the deflector and into the craft. redirected sideways, 250kn in each direction. You can't get more than 500kn from 500kn. It may seem intuitive that there would still be a 500kn force downwards, but due to deflection it's absorbed by the craft. It involves a bit of vector math that I have forgotten to do, but it works out, and there is zero net vertical thrust.

However, you still have 500kn of thrust to work with as you are expelling the exhaust rather than capturing it, the same amount you would have had if you didn't deflect it at all. You have decided, for some reason, to deflect it in a way that has no net thrust (the two nozzles opposite each other).

 

Edited August 10, 2019 by Ultimate Steve

[Cheif Operations Director]

4 minutes ago, Ultimate Steve said:

The slow down part is fairly easy to explain. The energy from the propellant goes into the magnets/slow down devices and assuming the magnets are attached to the craft, the energy goes into the craft. If you do not get this I cannot help you.

Yes it goes into the craft, but along which axis of the craft? It just does not disappear or get equally distributed, if I push a table from the center the pressure is “distributed” but it still goes in one direction.  Same thing goes for a space station. When Progress collided with MIR it still had a major effect in one part of the space station in terms of attitude control.

Sorry for the long reply had to confirm the thing about mir before posting 

15 minutes ago, Ultimate Steve said:

The second part is a bit more difficult to explain. Say you have 500kn coming into the redirector. Assuming the redirector is perfect, this 500kn will be absorbed by the deflector and into the craft. redirected sideways, 250kn in each direction. You can't get more than 500kn from 500kn. It may seem intuitive that there would still be a 500kn force downwards, but due to deflection it's absorbed by the craft. It involves a bit of vector math that I have forgotten to do, but it works out, and there is zero net vertical thrust.

However, you still have 500kn of thrust to work with as you are expelled the exhaust rather than capturing it, the same amount you would have had if you didn't deflect it at all. You have decided, for some reason, to deflect it in a way that has no net thrust (the two nozzles opposite each other).

That nozzle thing was just an example to explain how the magnetic forces would effectively cancel each other out. 

[Shpaget]

45 minutes ago, Cheif Operations Director said:

Ok but what is your point?

The point is: no matter how and what you use to redirect exhaust, the only result is loss of usefull thrust. The redirected portion is wasted. Nothing good will come of it.

As for the topic, yes, spike in radiation is quite telling. Some sort of excursion deffinitely happened.

Edited August 10, 2019 by Shpaget

[Cheif Operations Director]

Just now, Shpaget said:

The poit is: no matter how and what you use to redirect exhaust, the only result is loss of usefull thrust. The refirected portion is wasted. Nothing good will come of it.

As for the topic, yes, spike in radiation is quite telling. Some sort of excursion deffinitely happened.

Creating as much friction as possible would most likely help this design if I think is done in the right areas. Again I’m trying to recycle the propellant not the energy, this is not a free energy machine. 

[Ultimate Steve]

9 minutes ago, Cheif Operations Director said:

Yes it goes into the craft, but along which axis of the craft? It just does not disappear or get equally distributed, if I push a table from the center the pressure is “distributed” but it still goes in one direction.  Same thing goes for a space station. When Progress collided with MIR it still had a major effect in one part of the space station in terms of attitude control.

Sorry for the long reply had to confirm the thing about mir before posting 

If you push down on the center of a table the force goes downwards into the legs. However, assume you are stuck in space with just a table. If you hold on to the table, pushing against it isn't going to do anything. Replace table with spaceship and push with fire engine at.

The force would go into the y axis of the craft.

And yes, if you send a Progress crashing into Mir, Mir would have altered velocity. However, in your engine, Mir launched Progresszt itself, and the energy spent to accelerate Progress (accelerating Mir in the opposite direction) went straight back into decelerating Progress (and decelerating Mir in the opposite direction).

Basically, we have a gun shooting a bullet, but the end of the barrel is blocked, and to simplify we have a spring instead of gunpowder. The spring, attached to the gun, accelerates the bullet down the barrel, and also accelerates the gun in the opposite direction. When the bullet hits the blocked barrel it transfers it's energy back into the gun. No net change in velocity.

3 minutes ago, Cheif Operations Director said:

Again I’m trying to recycle the propellant not the energy, this is not a free energy machine. 

If you don't permanently expel something backwards, or push off of something in the environment, you will not gain velocity. If you recapture what you expel, you are by definition not expelling it permanently.

[steve_v]

13 minutes ago, NiL said:

Wait, is this thread now THAT dank? That guy with magnets is proposing to capture expelled fuel, lol?

That's exactly how it started, way back on page-two. LoL indeed.

[Cheif Operations Director]

17 minutes ago, Ultimate Steve said:

If you push down on the center of a table the force goes downwards into the legs. However, assume you are stuck in space with just a table. If you hold on to the table, pushing against it isn't going to do anything. Replace table with spaceship and push with fire engine at.

The force would go into the y axis of the craft.

And yes, if you send a Progress crashing into Mir, Mir would have altered velocity. However, in your engine, Mir launched Progresszt itself, and the energy spent to accelerate Progress (accelerating Mir in the opposite direction) went straight back into decelerating Progress (and decelerating Mir in the opposite direction).

Basically, we have a gun shooting a bullet, but the end of the barrel is blocked, and to simplify we have a spring instead of gunpowder. The spring, attached to the gun, accelerates the bullet down the barrel, and also accelerates the gun in the opposite direction. When the bullet hits the blocked barrel it transfers it's energy back into the gun. No net change in velocity.

If you don't permanently expel something backwards, or push off of something in the environment, you will not gain velocity. If you recapture what you expel, you are by definition not expelling it permanently.

Ok I think we may be at a bit of an impasse. If you push off of a table in space you will go backward as will the table. Your gun analogy is interesting but it has the problem that the bullet is not slowed down with another system. Other than the impact. The end goal of all of this is too convert the heat of a nuclear reactor into a rocket propellant. The propellant will need to last longer than the nuclear reactor for it to be effective.

1 minute ago, NiL said:

I don't think that drinking alcohol solution of iodin from pharmcy can help a lot, but thanks for information, i didn't know that

I think it is potassium iodide that helps so yea that would most likely not work as effectively.

4 minutes ago, steve_v said:

That's exactly how it started, way back on page-two. LoL indeed.

I will ignore that

[Ultimate Steve]

Just now, Cheif Operations Director said:

Ok I think we may be at a bit of an impasse. If you push off of a table in space you will go backward as will the table.

Correct. But if you hold on to the table, or grab the table right after pushing off if it, eg recapturing the propellant, you and the table will be slowed back down to whatever velocity they started with.

1 minute ago, Cheif Operations Director said:

Your gun analogy is interesting but it has the problem that the bullet is not slowed down with another system. Other than the impact.

Exactly. The impact slows the bullet down, transferring it's energy to the gun. How it is slowed down doesn't matter, only the fact that it is slowed down completely by the thing that launched it or something attached to it.

3 minutes ago, Cheif Operations Director said:

The end goal of all of this is too convert the heat of a nuclear reactor into a rocket propellant. The propellant will need to last longer than the nuclear reactor for it to be effective.

Converting heat into usable propulsive energy without expelling any matter you started with, or directly converting heat I to matter to then expel is what you appear to be proposing, no?

 

[Cheif Operations Director]

1 minute ago, Ultimate Steve said:

Converting heat into usable propulsive energy without expelling any matter you started with, or directly converting heat I to matter to then expel is what you appear to be proposing, no?

I want to take the heat from a nuclear reactor and allow that heat to be used as propellant, however you need matter for propellant and heat in general. Thus I need a way of using matter as thrust without running out of it before the nuclear reactor expires. The only way I think that is possible is it re-capture propellant. 

4 minutes ago, Ultimate Steve said:

Exactly. The impact slows the bullet down, transferring it's energy to the gun. How it is slowed down doesn't matter, only the fact that it is slowed down completely by the thing that launched it or something attached to it.

I guess a better way of thinking about this is spreading the energy unevenly onto one specific access to allow for thrust in a particular direction

5 minutes ago, Ultimate Steve said:

Correct. But if you hold on to the table, or grab the table right after pushing off if it, eg recapturing the propellant, you and the table will be slowed back down to whatever velocity they started with.

Now suppose that you never let go but transferred some of your heat energy into The kinetic energy of the table.

10 minutes ago, Dragon01 said:

careful about it, because kooks  latch onto inconsistencies like this and try to invalidate one argument on the basis of a poorly chosen example.  I've seen that happen way too often. If winning such an argument is at all possible (it often isn't), your own arguments need to be ironclad.

I do not like when people do that either, I try not to do that

[Guest]

2 minutes ago, Cheif Operations Director said:

Now suppose that you never let go but transferred some of your heat energy into The kinetic energy of the table.

Your entire problem is that you're always thinking in terms of energy. But it's not a matter of energy. It's a matter of momentum. This is different from kinetic energy, is also conserved, and it's a rule as fundamental as conservation of energy. You can change heat into kinetic energy, but you need to account for momentum. Heat has no momentum, so you need to throw away mass.

[Cheif Operations Director]

5 minutes ago, Dragon01 said:

Your entire problem is that you're always thinking in terms of energy. But it's not a matter of energy. It's a matter of momentum. This is different from kinetic energy, is also conserved, and it's a rule as fundamental as conservation of energy. You can change heat into kinetic energy, but you need to account for momentum. Heat has no momentum, so you need to throw away mass.

Let me go over the design again. 

[NiL]

7 minutes ago, Cheif Operations Director said:

I want to take the heat from a nuclear reactor and allow that heat to be used as propellant, however you need matter for propellant and heat in general. Thus I need a way of using matter as thrust without running out of it before the nuclear reactor expires. 

If you capturing expelled propellant, you are creating a fuel loop. Just like if you took a hose and connected it to both sides of the pump. You can pump fuel around the loop as fast as you like (can connect a nuclear reactor to your pump), but you will not move. 

12 minutes ago, Cheif Operations Director said:

The only way I think that is possible is it re-capture propellant.

You can use energy to generate photons and expel them from the back of your rocket. It's called "photon rocket" and it doesn't need propellant, just energy. Thrust is non-existent (your engine is a lightbulb), but it doesn't violate the laws of physics.

[Guest]

Just now, NiL said:

You can use energy to generate photons and expel them from the back of your rocket. It's called "photon rocket" and it doesn't need propellant, just energy. Thrust is non-existent (your engine is a lightbulb), but it doesn't violate the laws of physics.

Actually, it is more like a laser, and it uses propellant, this being photons, which have mass and thus momentum. Mass that is expelled does come directly from energy, on the basis of Einstein's famous relation. On the basis of the same relation, mass of the ship does decrease, and as a result you get a system that acts like a normal rocket with Isp of c. I find this impressive, considering the calculations you'd likely have to go through to get that result out of SR. 

You can, in theory, use far IR radiation as a photon rocket (not really worse than any other kind), but it's probably easier to use a laser.

[Ultimate Steve]

2 minutes ago, Cheif Operations Director said:

Thus I need a way of using matter as thrust without running out of it before the nuclear reactor expires. The only way I think that is possible is it re-capture propellant. 

And the act of recapturing the propellant would negate the thrust gained.

4 minutes ago, Cheif Operations Director said:

I guess a better way of thinking about this is spreading the energy unevenly onto one specific access to allow for thrust in a particular direction

So you want a way to recapture the propellant and slow it down enough to be reused without negating all of the thrust.

So you want to give something a certain amount of momentum and then slow it down so it has zero momentum so you can reuse it, and still have momentum left to push the craft forward.

So you want to, in effect, get more momentum out than you put in.

If you can do that, congratulations, you have a free energy machine.

[Cheif Operations Director]

2 minutes ago, Dragon01 said:

Actually, it is more like a laser, and it uses propellant, this being photons, which have mass and thus momentum. Mass that is expelled does come directly from energy, on the basis of Einstein's famous relation. On the basis of the same relation, mass of the ship does decrease, and as a result you get a system that acts like a normal rocket with Isp of c. I find this impressive, considering the calculations you'd likely have to go through to get that result out of SR. 

You can, in theory, use far IR radiation as a photon rocket (not really worse than any other kind), but it's probably easier to use a laser.

Why has this not been done yet?

2 minutes ago, Ultimate Steve said:

So you want to give something a certain amount of momentum and then slow it down so it has zero momentum so you can reuse it, and still have momentum left to push the craft forward.

So you want to, in effect, get more momentum out than you put in.

If you can do that, congratulations, you have a free energy machine.

I mean yes but I get new momentum by putting the liquid propellant into a chamber and turning it into a gas where it is these expelled like a normal chemical rocket, at least that was the idea.

So not really free energy

[ThatGuyWithALongUsername]

3 minutes ago, Cheif Operations Director said:

Why has this not been done yet?

Thrust is way, way too small. Much easier to use larger sources of energy, even in the form of photons- now we're getting into solar sail territory.

 

Or, it you want more concentrated power, lasers from the ground (so you don't have to carry their tremendous weight). See project Starshot. Still hard, though.

Edited August 10, 2019 by ThatGuyWithALongUsername

[NiL]

2 minutes ago, Dragon01 said:

On the basis of the same relation, mass of the ship does decrease

0_o

I agree about photons being a propellant, of cource, but they are generated from pure energy. If i will use a non-expendable light source (like heating a metal plate to produce IR radiation) and a ~non expendable energy source (solar panels), how would ship's mass decrease? I mean a metal plate can lose some matter due to outgassing and stuff, but it is not part of the ship's propulsion process.