HAPPY HOAX ANNIVERSARY!!! (Rockets can't fly in a vacuum)

Clearly you are making things up on the fly when stumped and not paying attention to your own words regarding a 'delve'. Try and keep up.

In your analogy the space underneath the passenger car is a closed containment inside the elevator shaft. You claim that the thrust creates a 'delve' (e.g. a shaft) beneath the rocket that contains the thrust and then propels the rocket upward. However, here's where you really need to pay attention, the atmosphere on all sides of the 'delve' is weaker than the thrust. And there is nothing to contain this 'delve' to make it stronger and more resistant than the thrust from the rocket.

Do you not understand your own 'delve' bit?

Again, please explain what forces create this stronger than thrust atmospheric containment, how, and why. You have failed to do so thus far.

Of course the atmosphere is weaker but the thrust is a direct hit into it and super compresses that atmosphere by the super expansion created by that burn.
It creates a containment because the atmosphere crushes back against that direct hit.
Underneath that direct hit is the delve into the atmosphere and that delve has to lose atmosphere. Where does it go?

Think of the water analogy in the bath to understand what I'm saying.

You people need to pay attention and use your own brains.
Just put your fictional space rocket books down for a minute and pay attention.

Draw a diagram like I asked and explain it.

I did. I drew a diagram, I provided it here, I gave you an explanation of how it works in reality, completely with action-reaction pairs.
It is your turn now, in fact it has been for quite some time. EXPLAIN IT!
If you can't, then see if you can explain what is wrong with my explanation.

If you can't do either you have no basis for your claim that rockets cannot work in space, or that the mainstream explanation is wrong.

Its contained by atmosphere crushing back against the thrust.

If that was the case it wouldn't go far from the rocket. It would all be stuck at the nozzle.
Instead we can easily see it going very far from the rocket.

The atmosphere is not containing the gas.

A rocket will fly as high as its fuel allows, which is not for long.

For a tiny rocket it isn't long. For a much larger rocket, it lasts much longer, several minutes, long enough to get it to space.

The reason why the rocket gains the height it does is due to loss of mass (fuel) whilst still thrusting against ever lessending resistance.

No, the reason why it gains height is because the thrust produced is greater than the weight.
This thrust is produced as part of the action-reaction of expelling the gas at a high velocity.

The atmosphere is only far weaker until it becomes more pressurised. The massive expansion of burning fuel from the rocket sees to that massive pressurisation/compression.

Surely you are capable of understanding that.

Compressed air cannot magically compress the atmosphere to a pressure greater than it. The best you can do is go to a midway point.
That is because at this midway point, the 2 pressures are equal.
That means the compressed air will always be greater (or at best equal to) the pressure of the air (assuming it is higher to begin with). It cannot compress it higher to have it force it back.

But in reality, as there is no containment, then as soon as you compress the atmosphere slightly, it is going to move out of the way by compressing the air around it. It is not going to push back with a greater force.

You can easily see this with something even better than compressed gas, a solid object. If what you are saying is true, objects should not fall. They should compress the air and be pushed back and then just sit on the air.

All that air can do is slow the motion.

Surely you are capable of understanding that.

The rocket sits on the gas fight. What about that can't you understand?

The part where you diagram doesn't have an arrow of force acting on the rocket.
What force is acting on the rocket to move it?

The problem with you and others is, you can't or will not let go of that fictional space vacuum and to admit what I'm telling you will kill it off, so I well understand why you pretend you have no clue.

Again, you are projecting your own inadequcies.
Your problem is that you cannot let go of your FE fantasy, and rockets in space have put satellites in space which have taken pictures of Earth clearly showing it is round. So you need to reject rockets working in space as they kill of your FE fantasy. So we all understand why you pretend you have no clue.

The problem is you are unable to justify any of your claims or refute mainstream science.

Again, if you actually had a clue you would easily provide a diagram showing a force arrow on the rocket clearly explaining what is pushing it. But again, the only option is the gas, like the conventional diagrams, which would then mean it works in space.

Again, if you actually had a clue you would easily be able to refute mainstream explanations by clearly showing what is wrong, rather than pretending they haven't been provided or dismissing them as hogwash.

So again, it is quite clear who is clinging to fantasy.

Think of the water analogy in the bath to understand what I'm saying.

Why not stick to the trampoline?
Notice how you can easily place an object on the trampoline and have it stay there, rather than fall through?
Again, in order for it to work like you claim, when jumping on the trampoline you would need your feet to pass through it and your torso to go up, without any force acting on it.

Notice how stupid that sounds?

If you really want a water analogy, then do it properly, instead of a pathetic football, try a cannonball thrown at high speed. What happens? It breaks the surface of the water and quickly sinks, with the water just serving to slow it down.

You people need to pay attention and use your own brains.
Just put your fictional space rocket books down for a minute and pay attention.

Again, follow your own advice. We are using our brains, and that is what leads us to conclude your nonsense is nonsense.
Put away your fantasy of a FE, put away your fantasy of rockets not working in space and pay attention.
Actually try dealing with what has been said and address the issues raised, or just rationally think about them, and see what the logical conclusion is.

Again, you have a tube of compressed gas, with one end open (i.e a rocket), in a vacuum.
By simple understanding of forces, the force on the container from the gas is unbalanced and will result in a force towards the closed end, meaning rockets work in space.

Ignoring that and instead just focusing on a few simple questions:
1 - Does the gas leave? If not, then there is absolute no argument against the pressure argument above.
If so, that means the gas has accelerated.
2 - Does accelerating matter require a force? If not, that means no force is needed to accelerate the rocket and thus they work in space..
If so, that means there must be a force acting on the gas.
3 - Does this force need a reactionary force, or as you would say, leverage or something to push off? If not, then the rocket doesn't need one and can work in space.
If so, that means it must be pushing against something.
4 - What is it pushing against? If not the rocket, that means there is something else out there that the rocket can push against and thus work in a vacuum. If the rocket, that means the gas is pushing against the rocket and thus will accelerate the rocket.

No matter what choice is made, rockets work in space.

See, actually using your brain, in an honest, rational manner will inescapably lead to the conclusion that rockets work in space.

So stop telling us to use our brain, pay attention and put aside fictional nonsense.
Do that yourself. Put aside your fictional nonsense of a FE and rockets not working in space.
Pay attention to what has been said, the arguments put forwards and the issues raised.
And then use your brain, honestly and rationally, and see what the honest, rational conclusion is.

Quote from: rabinoz on January 05, 2020, 10:00:33 PM

Quote from: sceptimatic on January 05, 2020, 09:35:54 PM

If the burn from the nozzle is thrusting, it is not exhaust.
A car burning fuel inside a piston is using that burn to push the piston.
The exhaust pipe is the waste gases from that burn.

Burnt propellant/exhaust are just words but if that's the way you want it.

In a rocket engine, and it's just as much an engine as a car engine,

• the fuel and oxidizer is burnt in the combustion chamber,
  
  
• the nozzle (throat and bell) convert that very high pressure (70 to 300 Bar) burnt propellant into low pressure very high velocity gas and thrust
  
  
• and the exit from the nozzle is the exhaust.

The thrust is the force necessary to accelerate that burnt propellant from it's very high pressure, Mach 1 velocity state to the [low pressure, hypersonic velocity state[/i] at the exit.

What's so hard about that?

There's nothing hard about it as long as the truth is told and what you're saying is not the whole truth.

No, I'm telling the the "whole truth" as far as I know it for the part of the thrust produced by the force needed to accelerate the burnt propellant.
There is an extra component when the rocket is in low the pressure environment of space.

That extra thrust is produced when the pressure of the burnt propellant at the exit exceeds the outside pressure.

If you need to include this extra thrust it is (exit area) x (exit pressure - outside pressure). In the vacuum of space that outside pressure is, of course zero!

But I omitted this because of your aversion to equations.

You neglect one very important factor. Can you guess what it is?

No, I don't believe that I did, but do tell!

Show me the chamber.

                     



EDIT: The chamber gas expansion / the internal pressure pushes in all directions.
Left-right components balance themselves out, up-down components don't.
Down component pushes the gas out, up component "carries" the rocket up.
(The directions "up", "down", "left", "right" here are relative to the images.)

Quote from: Themightykabool on January 05, 2020, 09:41:48 PM

Quote from: sceptimatic on January 05, 2020, 02:03:21 PM

Quote from: Themightykabool on January 05, 2020, 07:28:02 AM

Quote from: sceptimatic on January 05, 2020, 07:17:42 AM

Quote from: Themightykabool on January 05, 2020, 07:15:26 AM

You already played that game for 10s of pg in the ballistic thread.
Answer your own theory with proofs how the "conventional"physics doesnt work.
Your incoherent word vomit of gasongas dossnt explain anything.

Of course it doesn't explain anything to you and your like minded pals. I wouldn't expect it to, when your stance is entirely on the space rocket nonsense and how it supposedly works.

Your game was to deflect the conversation away from you failng to answer your own theory.
Keep failing.

Then stay out of it.

No
Im keeping you on track.
What froce line pushes on the balloon/ rocket?

Show one
In contact
With the rocket

Thats how force diagrams work.

The rocket sits on the gas fight. What about that can't you understand?

A hovercraft sits on a gas fight. I'm sure you can understand that.
The problem with you and others is, you can't or will not let go of that fictional space vacuum and to admit what I'm telling you will kill it off, so I well understand why you pretend you have no clue.

https://cdn4.explainthatstuff.com/how-hovercraft-works.png
https://images.slideplayer.com/23/6642676/slides/slide_5.jpg

see teh arrows pushing the bottom of the hover craft up?
that's what you're missing on your drawing.
the super compressed green bar is NOT a part of the rocket.
it is exhaust fluid that the rocket is sitting ON (as you claim).
so then ther eshould be a force line, from said green bar, to the inside of the rocket.
draw it.

Quote from: MouseWalker on January 05, 2020, 07:52:52 PM

Quote from: sceptimatic on January 05, 2020, 02:06:24 PM

Quote from: Macarios on January 05, 2020, 10:58:09 AM

Several people told you how already:

Fule is burnt in the chamber, creating pressure and exhaust.
Rocket is pushing the exhaust out using pressure.
The exhaust has mass.
You can't push any mass without force.
And since every force has reaction, the reaction to this pushing force is the force that pushes back on the rocket.

You can use any other name while the "exhaust" is not yet outside.
For example, you can name it "exhaust-to-be".
But semantics won't change the operating principle.

Burning fuel is not exhaust.
Burned fuel is exhaust.

Two entirely different things.

Burning fuel creates the exhaust which is directed by the nozzle to the right (action force) : the reaction force is to the left ( moving the rocket ) as the exhaust leaves the nozzle.

If the burn from the nozzle is thrusting, it is not exhaust.
A car burning fuel inside a piston is using that burn to push the piston.
The exhaust pipe is the waste gases from that burn.

This thrusting is the ( action force ) to the right, the ( reaction force ) is to the left against the nozzle moving the rocket to the left. Leaving the exhaust trailing behind.
Internal  combustion is not relevant.

Quote from: Stash on January 05, 2020, 10:23:26 PM

Clearly you are making things up on the fly when stumped and not paying attention to your own words regarding a 'delve'. Try and keep up.

In your analogy the space underneath the passenger car is a closed containment inside the elevator shaft. You claim that the thrust creates a 'delve' (e.g. a shaft) beneath the rocket that contains the thrust and then propels the rocket upward. However, here's where you really need to pay attention, the atmosphere on all sides of the 'delve' is weaker than the thrust. And there is nothing to contain this 'delve' to make it stronger and more resistant than the thrust from the rocket.

Do you not understand your own 'delve' bit?

Again, please explain what forces create this stronger than thrust atmospheric containment, how, and why. You have failed to do so thus far.

Of course the atmosphere is weaker but the thrust is a direct hit into it and super compresses that atmosphere by the super expansion created by that burn.
It creates a containment because the atmosphere crushes back against that direct hit.
Underneath that direct hit is the delve into the atmosphere and that delve has to lose atmosphere. Where does it go?

Think of the water analogy in the bath to understand what I'm saying.

You people need to pay attention and use your own brains.
Just put your fictional space rocket books down for a minute and pay attention.

This has nothing to do with books of knowledge and you are not paying attention and simply not using your brain. Apply some logic, it will take you a long way.

First, to super compress the atmosphere it would need to be contained. It it is not. There is no mechanism for the atmosphere to 'crush back'. How would it know to do that? What is the atmosphere pushing against to 'crush back'?

Second, the atmosphere gets thinner (weaker) as the rocket ascends. How does an even weaker atmosphere at higher elevations provide the same super compressed 'crush' as with lower elevations?

Third, you ask where does the atmosphere go below the rocket. Equally, where does the atmosphere go above the rocket?

Lastly, your water analogy has to do with buoyancy in a tub, not a rocket in the atmosphere. So it it is incorrect, illogical, and wildly irrelevant.

Quote from: sceptimatic on January 05, 2020, 10:18:54 PM

Show me the chamber.

                     



EDIT: The chamber gas expansion / the internal pressure pushes in all directions.
Left-right components balance themselves out, up-down components don't.
Down component pushes the gas out, up component "carries" the rocket up.
(The directions "up", "down", "left", "right" here are relative to the images.)

can't you see that at the bottom of this picture that the bell is going to build up pressure directly under the rocket to provide the lift. BECAUSE of the atmosphere resistance around the edge of the bell. If the were a vacuum around the bell the exhaust pressure would just dissipate instantly. Why do you even need the nozzle if the power of the exhaust is what is moving the rocket?

Because of atmosphere?

Hops is making the drag effects to overcomplicate the diagram and introduce more elements in an attempt to distract that sceptis diagram fails to show what specifically is touching the rocket to lift it.

The stack of sponges. How many times does he have to tell that!

The stack of sponges. How many times does he have to tell that!

How do stacked sponges explain the opposite of lift off?

For example:  A rocket that is fired straight down toward earth from a high altitude.  What is causing the rocket to accelerate beyond terminal velocity compared to the same just free-falling?  How does this stacking work then?

Additionally, why wouldn't the stacked sponges that are underneath the rocket compress to the point where they would resist the rocket?  When a rocket lifts off there is little atmospheric stack underneath it, yet it resists the rocket allowing it to gain altitude..  A much large stack should easily resist the rocket that comes from above.

Hops is making the drag effects to overcomplicate the diagram and introduce more elements in an attempt to distract that sceptis diagram fails to show what specifically is touching the rocket to lift it.

if it was just exhaust shooting out the back that moves a rocket, then you would not need the bell nozzle. The nozzle collects the exhaust force to "stack" it under the rocket. You wouldn't need a nozzle if it was just exhaust shooting out the bottom of the rocket to produce lift.

Quote from: Themightykabool on January 07, 2020, 07:53:33 AM

Hops is making the drag effects to overcomplicate the diagram and introduce more elements in an attempt to distract that sceptis diagram fails to show what specifically is touching the rocket to lift it.

if it was just exhaust shooting out the back that moves a rocket, then you would not need the bell nozzle.

Yes, you certainly do need the bell nozzle. It is not just the mass of burnt propellant but it's velocity is just as important.

The bell nozzle, as has been explained numerous times, converts the high-pressure gas moving at the speed of sound in the throat into a much higher velocity but lower pressure gas at the exit.

The major part of a rocket's thrust is simply (mass flow rate) x (exit velocity).

can't you see that at the bottom of this picture that the bell is going to build up pressure directly under the rocket to provide the lift.

No, because there is no way for it to transfer it back.
Can't you see from this the gas is already pushing the rocket upwards.

In fact, if the nozzle is shaped perfectly, the pressure at the end of the nozzle will be the same as the atmosphere.

If the were a vacuum around the bell the exhaust pressure would just dissipate instantly.

How?
How do you plan on having the gas magically accelerate to faster than the speed of light instantly?

Gas can only dissipate at a finite speed, even in a vacuum, so even in a vacuum, you still have that exhaust pressure pushing on the rocket.

Why do you even need the nozzle if the power of the exhaust is what is moving the rocket?

That is akin to asking why a gun has a barrel. It has one to harness the pressurised gas.
To harness the power of the rocket.
If you just had the gas behind the rocket and expand, only a small portion would push the rocket.
Likewise, if you just had highly compressed gas pushed out the back of the rocket, then only a small portion of that pressure is going towards pushing the rocket.
The point of the bell is to expand the gas and harness that pressure, so the rocket gets the most force out of it.

The easier way to understand it is based upon momentum and Bernoulli's principle.
Momentum must be conserved.
Thus the faster the gas is expelled, the more force must act on the rocket.
By expanding the gas, you lower the pressure and increase the velocity, and thus increase the force on the rocket.

It changes it from high pressure gas leaking out of the rocket to a low pressure gas shooting out at a very high velocity.

What is clear by watching rockets is that it clearly has nothing at all to do with collecting the atmosphere as the exhaust very quickly leaves the rocket.

Now as I said before, perhaps you can address the problem that has plagued jamas, Tom and Skepti?
You have a tube of compressed air in a vacuum with one end open (i.e. a rocket with a cold gas thruster). What happens?

Rational thought dictates the following:
1 - The gas leaves the rocket.
2 - This means it needs to accelerate.
3 - This means it must have a force act on it.
4 - This means it must have a reactionary force with it acting on another object.
5 - The only other object is the rocket.
6 - This means the gas must apply a force to the rocket.
7 - This means the rocket must work in a vacuum.

Quote from: Themightykabool on January 07, 2020, 07:53:33 AM

Hops is making the drag effects to overcomplicate the diagram and introduce more elements in an attempt to distract that sceptis diagram fails to show what specifically is touching the rocket to lift it.

if it was just exhaust shooting out the back that moves a rocket, then you would not need the bell nozzle. The nozzle collects the exhaust force to "stack" it under the rocket. You wouldn't need a nozzle if it was just exhaust shooting out the bottom of the rocket to produce lift.

A nozzle is very important:

Quote from: Macarios on January 06, 2020, 01:16:19 AM

Quote from: sceptimatic on January 05, 2020, 10:18:54 PM

Show me the chamber.

                     



EDIT: The chamber gas expansion / the internal pressure pushes in all directions.
Left-right components balance themselves out, up-down components don't.
Down component pushes the gas out, up component "carries" the rocket up.
(The directions "up", "down", "left", "right" here are relative to the images.)

can't you see that at the bottom of this picture that the bell is going to build up pressure directly under the rocket to provide the lift. BECAUSE of the atmosphere resistance around the edge of the bell.

It doesn't "build up pressure". In an optimally designed rocket engine the exit pressure is almost equal to the outside pressure though this "optimally designed rocket engine" is impractical in a vacuum.

If the were a vacuum around the bell the exhaust pressure would just dissipate instantly. Why do you even need the nozzle if the power of the exhaust is what is moving the rocket?

• It cannot "just dissipate instantly" because a vacuum cannot accelerate anything but in a near-vacuum, the exhaust gas does spread out and dissipate very rapidly.
  
  See in the first photo where at near sea-level the air pressure keeps the high-velocity exhaust stream confined but in the second at a very high altitude the exhaust gas spreads out very rapidly.
  
  Quote from: rabinoz on January 05, 2020, 01:28:37 PM

  Look at the exhaust stream of a real rocket and note that at sea-level it does not expand greatly into the atmosphere because the pressure in that exhaust stream in very little if any above atmospheric pressure.
  Look at this when near sea-level:
  
  Note how narrow the exhaust trail is, hardly wider than the rocket's width.
  
  Then, at high altitude and very low air-pressure:
  
  Here the rocket is seen edge-on but see how wide the exhaust trail has expanded in the much lower pressure air.
  

  
  
  
• Even if "the exhaust pressure" did "just dissipate instantly" it would not be relevant because the burnt propellant has already "done its work" inside the bell of the rocket engine.

I agree, the nozzle is important for atmospheric travel. It helps produce the stacking effect that skeppy talks about. In a vacuum it wouldn't help.

I agree, the nozzle is important for atmospheric travel. It helps produce the stacking effect that skeppy talks about. In a vacuum it wouldn't help.

Sceptis stack analogy fails to show what part is pushing the rocket up.
The green bar he drew shows force acting on it frpm both sides.
But shows exerts no force on the rocket.

I agree, the nozzle is important for atmospheric travel. It helps produce the stacking effect that skeppy talks about. In a vacuum it wouldn't help.

Then why do rockets work better in a vacuum than at sea-level?

Quote from: hoppy on January 07, 2020, 03:00:25 PM

I agree, the nozzle is important for atmospheric travel. It helps produce the stacking effect that skeppy talks about. In a vacuum it wouldn't help.

Sceptis stack analogy fails to show what part is pushing the rocket up.
The green bar he drew shows force acting on it frpm both sides.
But shows exerts no force on the rocket.

The force is exerted through the nozzle, that is why the nozzle is there. It keeps the force from spreading out sideway, and sends the force down only to produce the stacking effect.

Quote from: hoppy on January 07, 2020, 03:00:25 PM

I agree, the nozzle is important for atmospheric travel. It helps produce the stacking effect that skeppy talks about. In a vacuum it wouldn't help.

Then why do rockets work better in a vacuum than at sea-level?

To keep with skeppy's kind of language. You have been super about rockets traveling in a vacuum.

I agree, the nozzle is important for atmospheric travel. It helps produce the stacking effect that skeppy talks about. In a vacuum it wouldn't help.

Then you have to ask yourself, does the stack extend all the way to the ground no matter the altitude of the rocket? If not, what is supporting the stack? What is the containment that is allowing a stack to form and build a greater resistance to the thrust from the rocket?

Quote from: hoppy on January 07, 2020, 11:31:08 AM

Quote from: Themightykabool on January 07, 2020, 07:53:33 AM

Hops is making the drag effects to overcomplicate the diagram and introduce more elements in an attempt to distract that sceptis diagram fails to show what specifically is touching the rocket to lift it.

if it was just exhaust shooting out the back that moves a rocket, then you would not need the bell nozzle.

Yes, you certainly do need the bell nozzle. It is not just the mass of burnt propellant but it's velocity is just as important.

The bell nozzle, as has been explained numerous times, converts the high-pressure gas moving at the speed of sound in the throat into a much higher velocity but lower pressure gas at the exit.

The major part of a rocket's thrust is simply (mass flow rate) x (exit velocity).

the nozzle can also be used for steering if equipped with a gimbal.

By the way, air to air missiles have a higher speed and longer range when shot at high altitudes than at sea level. Yet another thing that doesn't fit with skeppy's version.

Quote from: Themightykabool on January 07, 2020, 03:07:23 PM

Quote from: hoppy on January 07, 2020, 03:00:25 PM

I agree, the nozzle is important for atmospheric travel. It helps produce the stacking effect that skeppy talks about. In a vacuum it wouldn't help.

Sceptis stack analogy fails to show what part is pushing the rocket up.
The green bar he drew shows force acting on it frpm both sides.
But shows exerts no force on the rocket.

The force is exerted through the nozzle, that is why the nozzle is there. It keeps the force from spreading out sideway, and sends the force down only to produce the stacking effect.

Does the force push against the nozzle as it spreads out?  Have Newton's 3 laws been repealed?

Quote from: Macarios on January 06, 2020, 01:16:19 AM

Quote from: sceptimatic on January 05, 2020, 10:18:54 PM

Show me the chamber.

                     



EDIT: The chamber gas expansion / the internal pressure pushes in all directions.
Left-right components balance themselves out, up-down components don't.
Down component pushes the gas out, up component "carries" the rocket up.
(The directions "up", "down", "left", "right" here are relative to the images.)

can't you see that at the bottom of this picture that the bell is going to build up pressure directly under the rocket to provide the lift. BECAUSE of the atmosphere resistance around the edge of the bell. If the were a vacuum around the bell the exhaust pressure would just dissipate instantly. Why do you even need the nozzle if the power of the exhaust is what is moving the rocket?

When the fuel burns in the chamber it creates high pressure.
That pressure pushes the gas out.
That gas has the mass.
When the rocket pushes the mass of the gas it is force.
Reaction to that force pushes the rocket back.
Thefinal result: the rocket pushes itself off the exhaust.
What would the atmosphere be needed for in all that?

Compressed air cannot magically compress the atmosphere to a pressure greater than it. The best you can do is go to a midway point.

It only has to compress the atmosphere enough to create a barrier in the stack. A delve directly in the path of it and that compression cannot be compressed any more than what the object compressing it, offers, as you mention.

But that's just the point. It doesn't need to.
The energy is stored in the actual object releasing the pressure.
The atmosphere merely acts as the resistance to compression, to then, as you mention again, to be equally compressed. It's a stacked compression.

I keep saying time and time and time again for people to pay attention but too many are hell bent on merely creating their own resistance to understanding it from my side because of fear it destroys their side. You included.

Quote from: sceptimatic on January 05, 2020, 10:06:20 PM

Quote from: rabinoz on January 05, 2020, 10:00:33 PM

Quote from: sceptimatic on January 05, 2020, 09:35:54 PM

If the burn from the nozzle is thrusting, it is not exhaust.
A car burning fuel inside a piston is using that burn to push the piston.
The exhaust pipe is the waste gases from that burn.

Burnt propellant/exhaust are just words but if that's the way you want it.

In a rocket engine, and it's just as much an engine as a car engine,

• the fuel and oxidizer is burnt in the combustion chamber,
  
  
• the nozzle (throat and bell) convert that very high pressure (70 to 300 Bar) burnt propellant into low pressure very high velocity gas and thrust
  
  
• and the exit from the nozzle is the exhaust.

The thrust is the force necessary to accelerate that burnt propellant from it's very high pressure, Mach 1 velocity state to the [low pressure, hypersonic velocity state[/i] at the exit.

What's so hard about that?

There's nothing hard about it as long as the truth is told and what you're saying is not the whole truth.

No, I'm telling the the "whole truth" as far as I know it for the part of the thrust produced by the force needed to accelerate the burnt propellant.
There is an extra component when the rocket is in low the pressure environment of space.

That extra thrust is produced when the pressure of the burnt propellant at the exit exceeds the outside pressure.

If you need to include this extra thrust it is (exit area) x (exit pressure - outside pressure). In the vacuum of space that outside pressure is, of course zero!

But I omitted this because of your aversion to equations.

Quote from: sceptimatic

You neglect one very important factor. Can you guess what it is?

No, I don't believe that I did, but do tell!

Let me try and help you out.

Picture a massive water tank.
Put a nozzle underneath that water tank and open it up.

Tell me where the forces are acting in that flow of water in terms up pushing the water tank up.
You can clearly see the water being expelled from the tank to the ground but where is the opposite push, vertically up into the tank?

If there is none then how in  the hell do you expect your rocket to produce the same opposing force?

Quote from: sceptimatic on January 05, 2020, 10:18:54 PM

Show me the chamber.

                     



EDIT: The chamber gas expansion / the internal pressure pushes in all directions.
Left-right components balance themselves out, up-down components don't.
Down component pushes the gas out, up component "carries" the rocket up.
(The directions "up", "down", "left", "right" here are relative to the images.)

If it did that it would cancel everything out.
Come on for crying out loud, surely you can see this.
The only way it could possibly work is if it has an opposing resistance to the mass expansion of that burning fuel.
It does....it's called atmospheric resistance.

That diagram is a big con.
It may look ok to those who don't care to challenge it but it's clearly utter nonsense in the way it's put out when you omit external resistance to what that nozzle puts out.

https://cdn4.explainthatstuff.com/how-hovercraft-works.png
https://images.slideplayer.com/23/6642676/slides/slide_5.jpg

see teh arrows pushing the bottom of the hover craft up?
that's what you're missing on your drawing.
the super compressed green bar is NOT a part of the rocket.
it is exhaust fluid that the rocket is sitting ON (as you claim).
so then there should be a force line, from said green bar, to the inside of the rocket.
draw it.

It perfectly explains what I'm talking about. It just needs to be applied to the rocket in a different form, in terms of a burn....but in essence it is the exact same end product of a gas on gas fight.