Recommended Posts

Posted (edited)
2 minutes ago, Cheif Operations Director said:

Ok? So put those magnets in a postion where it will help with de-acclerating the fuel.

If you could attach the magnets to the universe rather than the craft, this would be a thing. Otherwise Newton's 3rd law bites your ass.

 

Just now, Cheif Operations Director said:

If those magnets are pushing away from eachother and they are at a 90 angle the magnetic fuel would get slowed and the magents would get push toward the side of the craft or the tail. 

The component of the force that decelerates the reaction mass will be applied to the magnets in the opposite direction. Newton wins again, with the help of force-vectors.

Edited by steve_v

Share this post


Link to post
Share on other sites
Just now, Nothalogh said:

You have a loop of mass, going around in a circle.

Enjoy your gyroscope

I intend to enjoy it. I always likes gyros. :) 

Share this post


Link to post
Share on other sites
3 minutes ago, Cheif Operations Director said:

Ok? So put those magnets in a postion where it will help with de-acclerating the fuel.

If you remove momentum from the fuel, the momentum will go into whatever you slow it down with, in the same direction that the fuel was travelling. So if you decelerate the fuel, you decelerate the craft.

Share this post


Link to post
Share on other sites
Just now, steve_v said:

If you could attach the magnets to the universe rather than the craft, this would be a thing. Otherwise Newton's 3rd law bites your ass.

 

Just now, sevenperforce said:

Equal and opposite reaction, remember?

Im not forgetting it. The magnet has a north and southern field. If you use lets say the southern field from the fuel and the de-accelerator then put the magnets on the back end of the craft the magnet pushs the fuel forward a bit and the magnet pushes toward the side. If you have 4 magnets then it propels the craft equally in the pitch and yaw axis. They cancel each other out.

Just now, Cheif Operations Director said:

Otherwise Newton's 3rd law bites your ass.

yes I know I admit I was being an idiot on the first one and most likely am on this one as well none the less Im not sure what your point is. 

Share this post


Link to post
Share on other sites
Posted (edited)
17 minutes ago, Cheif Operations Director said:

yes I know I admit I was being an idiot on the first one and most likely am on this one as well none the less Im not sure what your point is. 

My point is that this idea is exactly the same as the first, and falls into the same trap. "just use magnets" doesn't change anything.
Magnets are not special and it doesn't matter how you capture the exhaust, just that the net momentum of the system remains the same. Springs, pipes, magnets, condensers, it's all the same to conservation of momentum.

 

17 minutes ago, Cheif Operations Director said:

If you have 4 magnets then it propels the craft equally in the pitch and yaw axis. They cancel each other out.

The magnets pushing fuel forward and the momentum-transfer pushing the craft backwards cancel each other out too.
Closed systems have constant momentum no matter how you move mass around within those systems, unless you have some external thing to push against.

A rocket that doesn't expel any mass is a reactionless-drive, and so far those only work in sci-fi unless you harness an external force, like a solar-sail does.

 

To get back on topic, that thing has to be an NTR, right? I bet cookies that it's an NTR.

Edited by steve_v

Share this post


Link to post
Share on other sites
Just now, steve_v said:

My point is that this idea is exactly the same as the first, and falls into the same trap. "just use magnets" doesn't change anything.
Magnets are not special and it doesn't matter how you capture the exhaust, just that the net momentum of the system remains the same. Springs, pipes, magnets, condensers, it's all the same to conservation of momentum.

 

The magnets pushing fuel forward and the momentum-transfer pushing the craft backwards cancel each other out too.
Closed systems have constant momentum no matter how you move mass around within those systems, unless you have some external thing to push against.

A rocket that doesn't expel any mass is a reactionless-drive, and so far those only work in sci-fi unless you harness an external force, like a solar-sail does.

Is it against the rules to post to a discord server where I can share a diagram? I think you are misinterpreting what I am saying. 

Share this post


Link to post
Share on other sites
Just now, Cheif Operations Director said:

Is it against the rules to post to a discord server where I can share a diagram? I think you are misinterpreting what I am saying. 

I don't see why it would be, but I don't use discord. Why not just embed an image here?

Share this post


Link to post
Share on other sites
Posted (edited)
17 minutes ago, steve_v said:

I don't see why it would be, but I don't use discord. Why not just embed an image here?

How?

@steve_v the arcs are the magnetic fields. If you did this you could slow down the fuel particles while not completely stoping them then it can go into the vaccum back into the condenser. Since the condenser does not need as much energy now it has a new gain. If I figure this right

Edited by Cheif Operations Director

Share this post


Link to post
Share on other sites
Just now, Cheif Operations Director said:

How?

WRT discord, no idea. Does it provide direct links to images? If you can get a URL that points to an image file and you put that URL in your post, the forum should embed the image.

'https://www.foo/bar/image.png' , when pasted into the editor becomes [pretty picture].

Share this post


Link to post
Share on other sites
2 minutes ago, steve_v said:

WRT discord, no idea. Does it provide direct links to images? If you can get a URL that points to an image file and you put that URL in your post, the forum should embed the image.

'https://www.foo/bar/image.png' , when pasted into the editor becomes [pretty picture].

fuel-nuclearstuff.png

There @steve_v

excuse the awful sketch

Share this post


Link to post
Share on other sites

preview

If you're just slowing the exhaust down rather than trying to reuse it (and it still escapes the system), you will indeed get forward thrust. It'll just be reduced thrust because you're wasting energy counteracting the engine.

My sketching is worse than yours. :P

Share this post


Link to post
Share on other sites
4 minutes ago, steve_v said:

preview

If you're just slowing the exhaust down rather than trying to reuse it (and it still escapes the system), you will indeed get forward thrust. It'll just be reduced thrust because you're wasting energy counteracting the engine.

My sketching is worse than yours. :P

If the gases are allowed to escape all I have done is slow down the thrust after it left the internal nozzle. We agree on that right?

Share this post


Link to post
Share on other sites
Just now, Cheif Operations Director said:

If the gases are allowed to escape all I have done is slow down the thrust after it left the internal nozzle. We agree on that right?

Sure. Why would you want to do that?

Share this post


Link to post
Share on other sites
Posted (edited)
5 minutes ago, steve_v said:

Sure. Why would you want to do that?

Ok stand by making a new diagram

 

nuclearfuel_two.png

@steve_v ok now that the thrust has been reduced on the other side the thrust goes into the tubes. Now this causes an opposite reaction BUT NOT EQUAL since the thrust has been slowed. The return thrust my be 10 Kilo Newtons while the output at 11 Kn but it is still +1 Kn. Thus forward thrust

Do you get my point now? You can get a net positive thrust. Off of this contraption. While it is in-efficient you can have 30 years or so of constant thrust. This would be great for space probes. 

Edited by Cheif Operations Director

Share this post


Link to post
Share on other sites
Posted (edited)
21 minutes ago, Cheif Operations Director said:

ok now that the thrust has been reduced on the other side the thrust goes into the tubes. Now this causes an opposite reaction BUT NOT EQUAL since the thrust has been slowed. The return thrust my be 10 Kilo Newtons while the output at 11 Kn but it is still +1 Kn. Thus forward thrust

If you have a cylinder in space containing a vacuum and a super-bouncy ball, and that ball bounces from one end to the other, do you get forward thrust?
If you pump liquid mass backwards and forwards inside a vehicle, do you get forward thrust?
If you use magnets for some of that pumping, does it change anything?

This is still essentially what you're doing. That "NOT EQUAL" doesn't account for the change in craft momentum produced by slowing the exhaust to begin with.

21 minutes ago, Cheif Operations Director said:

since the thrust has been slowed.

Slowing the exhaust creates a force on the vehicle.

11KN from engine -1KN transferred to magnets -10KN from reversed flow == 0
Not likely numbers, but whatever. Conservation of momentum still holds.

Nobody has been able to find a system that breaks this rule, despite the EMdrive controversy.

Edited by steve_v

Share this post


Link to post
Share on other sites
Just now, steve_v said:

If you have a cylinder in space containing a vacuum and a super-bouncy ball, and that ball bounces from one end to the other, do you get forward thrust?
If you pump liquid mass backwards and forwards inside a vehicle, do you get forward thrust?
If you use magnets for some of that pumping, does it change anything?

This is still essentially what you're doing. That "NOT EQUAL" doesn't account for the change in craft momentum produced by slowing the exhaust to begin with.

Slowing the exhaust creates a force on the vehicle.

11KN from engine -1KN transferred to magnets -10KN from reversed flow == 0
Not likely numbers, but whatever. Conservation of momentum still holds.

Nobody has been able to find a system that breaks this rule, despite the EM controversy.

I gtg I will finish this tommorow

Share this post


Link to post
Share on other sites
Just now, Cheif Operations Director said:

I gtg I will finish this tommorow

I'm supposed to be fixing my car right now, but it's raining outside. :(
So here I am.

Share this post


Link to post
Share on other sites
5 hours ago, steve_v said:

If you have a cylinder in space containing a vacuum and a super-bouncy ball, and that ball bounces from one end to the other, do you get forward thrust?
If you pump liquid mass backwards and forwards inside a vehicle, do you get forward thrust?
If you use magnets for some of that pumping, does it change anything?

This is still essentially what you're doing. That "NOT EQUAL" doesn't account for the change in craft momentum produced by slowing the exhaust to begin with.

Slowing the exhaust creates a force on the vehicle.

11KN from engine -1KN transferred to magnets -10KN from reversed flow == 0
Not likely numbers, but whatever. Conservation of momentum still holds.

Nobody has been able to find a system that breaks this rule, despite the EMdrive controversy.

Here is what this does. Imagine in KSP if I fired an engine at 100 percent throttle. Then I had another back to back at 90% thrust. That has a +10% net thrust? That is what we need to achieve in the rocket. Now imagine if I I have  rcs thurst on the side of a tank in a + configuration. If all of the RCS Thrusters move it would be a NET movement of 0. Right? 

Now if I slow down the exhaust via the magnets (remember it is still goin gat extremely high speeds) and I thrust that energy toward the side of the rocket the NET thrust in the pitch and Yaw is 0 (think about this like KSP RCS) Still the fuel is slowed down. Since I slowed down the fuel as long as it does not re-accelerate I am can re-direct it and still get a net positive thrust. 

When you say " This is still essentially what you're doing. That "NOT EQUAL" doesn't account for the change in craft momentum produced by slowing the exhaust to begin with.

Slowing the exhaust creates a force on the vehicle." I agree with you BUT that force is not being exerted on the bow or aft of the rocket, but rather on the pitch and yaw (IN RCS TERMS) of the rocket. Since there are four of these magnets and they are in a good configuration the forces do not cause the craft to tumble out of control but rather just cause the forces to cancel each other out in the NET movement since. (Although the movement is still happening)

Share this post


Link to post
Share on other sites
13 minutes ago, Cheif Operations Director said:

Here is what this does. Imagine in KSP if I fired an engine at 100 percent throttle. Then I had another back to back at 90% thrust. That has a +10% net thrust?

Sure, both rockets are expelling propellant. Adding the thrust vectors gives you a net force on the craft.
 

15 minutes ago, Cheif Operations Director said:

Now if I slow down the exhaust via the magnets (remember it is still goin gat extremely high speeds) and I thrust that energy toward the side of the rocket the NET thrust in the pitch and Yaw is 0 (think about this like KSP RCS) Still the fuel is slowed down. Since I slowed down the fuel as long as it does not re-accelerate I am can re-direct it and still get a net positive thrust. 
...
Slowing the exhaust creates a force on the vehicle." I agree with you BUT that force is not being exerted on the bow or aft of the rocket, but rather on the pitch and yaw (IN RCS TERMS) of the rocket.

Redirecting a gas stream is accelerating it. By turning the exhaust stream 90°, you cancel it's velocity along the axis of the craft.
Centripetal force and all that jazz comes into play, but because engine and deflector/magnet are part of the same system, the axial forces generated by the engine-deflector system are simply absorbed by the connecting structure.
Making the exhaust go sideways with magnets is exactly the same as slowing it down with magnets, so far as forward thrust is concerned - you just stopped the exhaust moving in the opposite direction to the one you want to go, so you don't go.

You'll get some miniscule thrust from the propellant moving rearward in relation to the craft, but once that propellant is jettisoned out the side it's gone - what you have is just an incredibly inefficient rocket.

This is all irrelevant to your "30 year burn time" proposal anyway, you were talking about recovering propellant, not expelling it as a super-inefficient craft-squeezing device.
Whatever you do to the exhaust stream, if it's being done by something physically connected to the craft then it can't move the craft - it's happening in the same frame of reference, in a closed system.
That's the fundamental problem - if the reaction mass is not decoupled from the engine system, you get no thrust. If you add velocity/momentum to your propellant opposite your direction of travel, it needs to stay that way.

The only way to get something to move in space is to apply a force relative to something else - i.e. the application of the laws of motion on your reaction mass. A reactionless drive is like lifting yourself by pulling on your own bootlaces.

One of these works, the other has been shown over and over to not work:

preview

Your recirculating propellant is just shifting mass around inside the craft, in the same way the "mechanical rocket" does. It goes against all the fundamental principles of rocketry, and it Does. Not. Work.
If getting free propellant and infinite ΔV was as easy as redirecting the exhaust with magnets, details be damned, we'd all be living on Mars right now.

I'm pretty much done here TBH, your posts are extremely difficult to make sense of and arguing around in circles about force-vectors doesn't change conservation of momentum, no matter how you twist it.

Share this post


Link to post
Share on other sites

@steve_v

Ok fine I can end of the conversation if you would like, I’m still going to post my response however.

37 minutes ago, steve_v said:

turning the exhaust stream 90°, you cancel it's velocity along the axis of the craft.

Ok? Why is this a bad thing assuming it has already done its intended job, that intended job is to accelerate the craft via going through the nozzle. It still has its 0* angle at some point giving forward velocity a long that axis. 

 

“Making the exhaust go forward —> you don't go.” 

 

Suppose I have a centaur upper stage. I in tow have a small tarp above 200 feet away from the craft. Excluding the fact the propellant is hot and will melt the tarp and the fact that propellant will building up on the tarp. Do you agree that you can still have forward thrust? With the same exclusions if I close the connecting wires to make it into an faring like structure do you still agree I can have thrust? If so the idea of a closed rocket could work (with those restrictions)

 

“You'll get some miniscule thrust from the propellant moving rearward in relation to the craft, but once that propellant is jettisoned out the side it's gone - what you have is just an incredibly inefficient rocket.” Like I said the propellant will not be jettisoned out the side. 

 

I have to go I will reply to the rest later

 

 

 

 

Share this post


Link to post
Share on other sites

You are willfully considering the forces on only a portion of the vehicle and not the sum of all forces.

Share this post


Link to post
Share on other sites

No, if you don't let any exhaust escape, you won't get any net thrust. Like what was said earlier, pulling up on your own shoe laces doesn't lift you off the ground, in the same way that blowing into a balloon doesn't move you forward because none of the air escapes to produce thrust. You effectively must lose something to gain something, in this case it's propellant for thrust. Nothing is ever free according to physics.

Share this post


Link to post
Share on other sites
9 hours ago, magnemoe said:

Closed cycle was on the table for nuclear planes, the idea is pretty pointless for rocket engines unless you use the reactor as an power source to run high isp electrical powered engine like vasmir or ion. 

It could be something exotic like this. A subcritical reactor or a critically-boosted RTG that uses the propellant as a heat sink to generate power and then ionizes and accelerates it. 

29 minutes ago, Cheif Operations Director said:

Suppose I have a centaur upper stage. I in tow have a small tarp above 200 feet away from the craft. Excluding the fact the propellant is hot and will melt the tarp and the fact that propellant will building up on the tarp. Do you agree that you can still have forward thrust?

No.

The force from the exhaust gases collecting on the tarp is equal and opposite to the force from the exhaust gases pushing against the nozzle on their way out of the engine. There would be zero forward thrust in this situation. There would be 220.2 kN of tension on the ropes towing the tarp, but that is beside the point.

31 minutes ago, Cheif Operations Director said:
1 hour ago, steve_v said:

turning the exhaust stream 90°, you cancel it's velocity along the axis of the craft.

Ok? Why is this a bad thing assuming it has already done its intended job, that intended job is to accelerate the craft via going through the nozzle

That's the problem -- if you don't "let go" of it, it hasn't done its "intended job" at all.

32 minutes ago, Cheif Operations Director said:

“You'll get some miniscule thrust from the propellant moving rearward in relation to the craft, but once that propellant is jettisoned out the side it's gone - what you have is just an incredibly inefficient rocket.” Like I said the propellant will not be jettisoned out the side. 

If you do not lose the propellant you do not have any thrust at all. There can be no reactionless thruster.

Imagine that you are inside a sealed boxcar on a frictionless railway. You have a collection of tennis balls and you have a few other friends inside the boxcar with you.

There is NOTHING you can do with those tennis balls inside that boxcar to make the boxcar accelerate down the track. Whether you throw them, bounce them, roll them, or spin them around with magnetic butterfly nets, moving the tennis balls around inside the boxcar does nothing whatsoever to actually accelerate the boxcar with respect to the track.

2 minutes ago, RCgothic said:

You are willfully considering the forces on only a portion of the vehicle and not the sum of all forces.

I would urge gentility. Newton's laws are harsh mistresses and it can take time to appreciate the extent of their dominance.

Share this post


Link to post
Share on other sites
Posted (edited)
1 hour ago, .50calBMG said:

No, if you don't let any exhaust escape, you won't get any net thrust. Like what was said earlier, pulling up on your own shoe laces doesn't lift you off the ground, in the same way that blowing into a balloon doesn't move you forward because none of the air escapes to produce thrust. You effectively must lose something to gain something, in this case it's propellant for thrust. Nothing is ever free according to physics.

I never said it’s free, I’m saying you convert the energy from the nuclear reactor into force that a rocket can use, that is the whole point of it. The Problem is that the fuel you expel with be used up before the nuclear reactor has used its fuel. I’m not trying to create a free energy machine. 

1 hour ago, sevenperforce said:

The force from the exhaust gases collecting on the tarp is equal and opposite to the force from the exhaust gases pushing against the nozzle on their way out of the engine. There would be zero forward thrust in this situation. There would be 220.2 kN of tension on the ropes towing the tarp, but that is beside the point.

My example excluded that part. My point is supposing you could create a tarp that would reduce the force hitting the tarp  (again not possible in this scenario) you would still go slower than without the tarp but it would still be a net gain. This all supposes that the force hitting the tarp can be reduced. If it can not be reduced I agree with you. From Wikipedia

 

First law: In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force
   
Third law:

When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.

 

If the tarp uses the first law to close the constant velocity of the equal Andy opposite reaction you get a net positive thrust

1 hour ago, sevenperforce said:

If you do not lose the propellant you do not have any thrust at all. There can be no reactionless thruster.

Imagine that you are inside a sealed boxcar on a frictionless railway. You have a collection of tennis balls and you have a few other friends inside the boxcar with you.

There is NOTHING you can do with those tennis balls inside that boxcar to make the boxcar accelerate down the track. Whether you throw them, bounce them, roll them, or spin them around with magnetic butterfly nets, moving the tennis balls around inside the boxcar does nothing whatsoever to actually accelerate the boxcar with respect to the track.

You would gain force if the tennis ball did not touch the box car again, ie if you lost propellant. You would also gain speed if the equal and opposite reaction could be turn in equal via the 1st law.

Second law:

In an inertial frame of reference, the vector sum of the forces F on an object is equal to the mass  m of that object multiplied by the acceleration  a of the object: F = ma. (It is assumed here that the mass m is constant. 

 

If the reduce the acceleration of the equal and opposite reaction the force it less.

Edited by Cheif Operations Director

Share this post


Link to post
Share on other sites
Posted (edited)
3 hours ago, Cheif Operations Director said:

Why is this a bad thing assuming it has already done its intended job, that intended job is to accelerate the craft via going through the nozzle. It still has its 0* angle at some point giving forward velocity a long that axis.

This has already been answered, but I can't resist a little:
startrek-picard-facepalm-700x341.jpg

You're still not getting the basic laws of motion, this stuff was written down over 300 years ago.

 

3 hours ago, Cheif Operations Director said:

I in tow have a small tarp above 200 feet away from the craft
... Do you agree that you can still have forward thrust?
...faring like structure do you still agree I can have thrust?
...the idea of a closed rocket could work (with those restrictions)

No, no, and definitely not. Absolutely, utterly, and unequivocally no.
 

1 hour ago, Cheif Operations Director said:

My point is supposing you could create a tarp that would reduce the force hitting the tarp  (again not possible in this scenario)

Not possible at all, anywhere anytime. This is not a case of inventing some magic material (or putting magnets on it), it is, to the best of humanity's cumulative knowledge, a basic property of the universe.
If you catch a moving something and bring it to rest relative to you, you must absorb it's kinetic energy somehow. That will impart a force on the catcher. No ifs buts or maybes, will. Anything else is pure fantasy.
Force is energy, and energy does not simply go away when you find it convenient.
 

1 hour ago, Cheif Operations Director said:

If the tarp uses the first law to close the constant velocity of the equal Andy opposite reaction you get a net positive thrust

I'm not at all sure that sentence makes any sense. Who's Andy?

 

1 hour ago, Cheif Operations Director said:

You would gain force if the tennis ball did not touch the box car again, ie if you lost propellant.

Yay! If the tennis ball is expelled from the system at speed, it will move the car. Just like a rocket, and just like I've been trying to explain for hours.

 

1 hour ago, Cheif Operations Director said:

If the reduce the acceleration of the equal and opposite reaction the force it less.

Sentence sense make not does. :confused:
Are you talking about cheating at physics again? Trying to dodge the "equal" part of Newton's third law? Not going to happen.
 

Edited by steve_v

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.