Author Topic: So, who wants to win 1 million Euro?  (Read 588269 times)

Offline Glom

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Re: So, who wants to win 1 million Euro?
« Reply #510 on: January 02, 2013, 11:36:48 AM »
Same applies to fuel used during travel at sea? Compare a car running out of fuel, etc, etc.

The concept of energy balance is indeed the same, but the application is not. In a car or a ship the fuel is burned on board and energy transferred to moving components which then transmit it to other moving parts to drive the vehicle forward. That's the system in that case. In a rocket the fuel is burned and blasted out the back at high speed. It's the 'blasted out the back at high speed' you seem to be having trouble with. It's the reaction of that mass being thrown out in one direction pushing the ship in the other that makes your attempt at balancing the energy wrong. That mass of exhaust is still part of the system that needs to be accounted for. You can't ignore it just because it is no longer aboard the spacecraft when it is the very act of dumping it overboard that gives you the change in momentum you are trying to describe! If you applied your energy balance equations to ANY rocket, even the ones used just to put things into orbit (which you say is evidently possible), you would find the same problem of apparent impossibility because you just are not doing the right equations.

Would be part of Heiwa's demonstrated incomprehension thus far.  He even seems incredulous about a spacecraft flying "backwards" in space.

Offline ka9q

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Re: So, who wants to win 1 million Euro?
« Reply #511 on: January 02, 2013, 11:42:12 AM »
I happen to know that because I worked out the same problem yesterday.  I'm interested in seeing what you come up with.
Okay, here you go. Remember, this is for a stoichiometric mixture of Aerozine 50 with N2O4, so my numbers will be higher than yours.

Assuming the reaction products are gaseous N2, liquid H2O and gaseous CO2 at STP, 1 kg of Aerozine 50 requires 2.249 kg of N2O4, for a sum of 3.249 kg of propellants, and the enthalpy change is 8.124 MJ/kg. This looks quite reasonable, don't you think?

Strictly speaking the reaction products should all be gases under ~0 pressure since the engine is operating in a vacuum, but again I was only looking for a bound. What we have done here is to estimate the thermodynamic efficiency of a rocket engine at turning chemical energy into kinetic energy, and the result is surprisingly high. But maybe it shouldn't be so surprising as chemical rockets probably have the highest combustion temperatures of any heat engine.

 

« Last Edit: January 02, 2013, 11:47:01 AM by ka9q »

Offline JayUtah

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Re: So, who wants to win 1 million Euro?
« Reply #512 on: January 02, 2013, 11:53:28 AM »
...liquid H2O

Jay raises a finger but then...

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Strictly speaking the reaction products should all be gases under ~0 pressure since the engine is operating in a vacuum, but again I was only looking for a bound.

...which answers my question.

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What we have done here is to estimate the thermodynamic efficiency of a rocket engine at turning chemical energy into kinetic energy, and the result is surprisingly high.

The upper bound is surprisingly high.  Most of the work in the field these days is toward identifying and eliminating sources of inefficiency that make actual performance rather less.  We're just now getting to the point where fine-grained FEM simulations give us useful data in that regard.

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But maybe it shouldn't be so surprising as chemical rockets probably have the highest combustion temperatures of any heat engine.

Really no "probably" about it.  And we tend to look toward LOX/LH2 as the "1.0" against which most other processes are normalized.
"Facts are stubborn things." --John Adams

Offline Heiwa

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Re: So, who wants to win 1 million Euro?
« Reply #513 on: January 02, 2013, 12:04:19 PM »
The energy (fuel mass) used up to brake the space craft (the mass of the fuel 'burnt') is evidently not part of the space craft after braking but has been transmitted to the surrounding space through the rocket exhaust and cannot be used by the space craft. It is gone. For ever.

Yes, and you have to account for that in your calculations. You have not. The mass of exhaust, and the kinetic energy it has, are not things you can simply ignore. You don't find it remotely odd that when you include it suddenly all the numbers balance out OK? You don't think that maybe you're the one who misunderstands the whole issue rather than the thousands of qualified people around the world who have had access to this data all the time? Conservation of momentum is an alien concept to you?

I am just interested in the kinetic energy B (J) Before braking and kinetic energy A (J) After braking of the space ship and the difference B - A, that is the energy used for braking. Evidently the space ship mass differs between before/after braking because fuel aboard with a mass is used to produce a brake force F (N)  that is applied to the space ship, while braking distance/displacement L (m). B-A = F*L .

The mass of exhaust, type of fuel, etc. have nothing to do with my basic energy calculations that only involves force and distance/displacement.

The momentum before braking is evidently much bigger than after braking because masses and velocities are reduced during braking due to a force F being applied when space ship displaces distance L. No momentum is conserved as a force is applied to the space ship system - to brake.

I have a feeling Willy had problems getting it right 1969 too.  :'( :'(

Offline Daggerstab

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Re: So, who wants to win 1 million Euro?
« Reply #514 on: January 02, 2013, 12:14:09 PM »
Hey, Heiwa, do rocket engines work in vacuum? :P

Offline ipearse

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Re: So, who wants to win 1 million Euro?
« Reply #515 on: January 02, 2013, 12:31:19 PM »
But before I'll send you a cheque, you have to master the basic space ship 3-D driving course, e.g. how to accelerate and stop in space, how to change direction in space, how to get into the orbit of a planet/moon in space, etc, etc. all with a basic, space craft with big drive/brake engine at one end and small ones to rotate your craft in 3-D.

Are you seriously trying to say that you can't understand that firing a large rocket is going to change your speed, one way or another? And that you can utilise gravitational attraction to help you with course changes? And you call yourself an engineer? I have no engineering training, just some physics knowledge, and I can see immediately that that would work. And, by the way, they invented computers some time ago.. you know, to help with the calculus and stuff in plotting orbits, accelerations, and so on?
"The Earth is the cradle of the mind, but we cannot live in the cradle forever" - Konstantin Tsiolkovski

Offline JayUtah

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Re: So, who wants to win 1 million Euro?
« Reply #516 on: January 02, 2013, 12:41:34 PM »
The energy (fuel mass) used up to brake the space craft (the mass of the fuel 'burnt') is evidently not part of the space craft after braking...

Not as mass, of course.  You failed to account for this both in a momentum-conservation formation and in an energy-conservation formulation.  Not only did you fail to account for it, you admitted it was a significant factor that you intentionally omitted from your model.  The excuse you gave for the omission was the factually-incorrect accusation that NASA had failed to provide you with appropriate values.  You never did suggest or prove that the factor you omitted was irrelevant or inconsequential.  Hence you knew from the start that your model was wrong, yet you had the audacity to set it up as the yardstick against which to judge the work of thousands of qualified professionals whose credentials and prior success are well established.

Hence it is highly dishonest of you to present a model you knew to be incomplete, assert that it proves someone else wrong who used the proper methods, and then challenge others to show you the error of your ways.  When you promise a reward for meeting that challenge, then ignore the many subsequent refutations, you cross the line to criminal fraud.

But that's not even half the problem.  As has been belabored, while the expended propellant mass is no longer combined with the spacecraft dry mass to arrive at the combined mass of the spacecraft for the purpose of computing momentum and energy, the propellant mass is still part of the system you defined when you set up the energy balance equation.  If you don't understand what constitutes a system for the purposes of energy computations, then you need remedial training.

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...but has been transmitted to the surrounding space through the rocket exhaust and cannot be used by the space craft. It is gone.

No.  While it was previously convenient to consider the propellant as a constituent of the spacecraft mass, that is an improper formulation.  If you consider the mass of the propellant as part of the system for initial conditions, you must consider it as part of the system for final conditions, even if the overall system mass is a set of disjoint particles.  You suggest that the relevant properties of the propellant, in the form of exhaust gases, are released to the environment.  This leads you to compute incorrectly the required change in kinetic energy, and thus the required fuel mass.  The propellant properties, in terms of residual heat and of mechanical energy, remain part of the system.  That is how energy-balance checks work.

Your inability to properly maintain the consistency of system formulation and your incorrect assertion that propellant kinetic energy (or mass, since it's unclear to what you refer) is somehow transmitted across the system boundary into the environment and thus exempt for consideration is simply wrong.  You have attempted to style these errors as mere refinements or improvements to your model, but they are not refinements.  You have failed the first step of energy-balance formulation, which is to define the system.  This is a glaring, fundamental error, not some minute detail you can safely sidestep.

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Pls return to topic So, who wants to win 1 million Euro?

First, do not attempt to moderate the thread.  You are neither the thread author nor the forum moderator, and you have been warned by the moderator not to attempt to control what can and cannot be posted.  It is a hallmark of the most dishonest conspiracy theorists to attempt to avoid refutations by declaring them irrelevant or off-topic.  I assure you our moderator will not fall for such cheap tricks.

Second, no one here is attempting to win the money.  They are simply trying to set the record straight on the basis of their devotion to historical truth in general, and out of their enjoyment of the field of rocketry.  I've lost count of the number of times you've tried to force a discussion of the money instead of a discussion of your claims to which the money refers.

Third, no one believes you have the money and would pay it out if you did.  An ordinary person claiming to have a very large sum of money and announcing he is willing to pay it to someone for performing a task constitutes an extraordinary claim.  You have the burden to prove that claim, which in this case means proving that the money exists and is available under the conditions you specify.  I have described to you the means by which monetary rewards are commonly offered and escrowed for collection.  I have invited you to prove by those means that your reward is winnable.  You have ignored that invitation.  I have asked you why you are unwilling to submit to customary means of offering prizes, and you have similarly ignored that.  I have no alternative but to conclude that the money does not exist and you have no intention of ever paying it.  Hence I infer from that conclusion that your obsession over the non-existent prize is an intentional distraction.

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In order to win you have to understand basic space travel physics...

You have to realize that there are literally thousands of people in the world who understand not only basic space travel physics but also advanced space travel physics, that these people practice it professionally, and that practically none of them work for NASA.  Space engineering is a decades-old commercial endeavor, of which I and others here are active practitioners.  We are not the "fat NASA PhDs" of your straw-man fantasy, but engineers who work for a living and whose success is determined solely by whether our machines succeed in their assigned tasks.

The bottom line is that you cannot write a bunch of impressive-looking gobbledy-gook and fool everyone into thinking you have knowledge that you do not have.  Rocket science is not such an esoteric or priestly field that egregious errors cannot be quickly discovered.  Your ego-centric fantasy of being some genius engineer and exposing the imagined sins of the actual practitioners in the field simply does not hold up in the real world.

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...that a mass of fuel transformed into a force to brake the space ship in the voyage is gone.

Gone, but not forgotten.  It must be included in the final-condition expression of the system, even though it is no longer physically contained within the spacecraft.  Your inability to properly formulate an energy-balance problem for spacecraft dynamics is one of the many signs that you are not sufficiently versed in the appropriate field of engineering.  This makes you an improper judge for whether you model is correct, and an improper judge of whether thousands of professionals did their jobs correctly.

The fact that you refuse to be corrected on this point (and indeed few others), tells us you are no engineer, and that your alleged million-euro reward is nothing more than irrelevant chest-thumping designed to inflate your substantial ego.

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Same applies to fuel used during travel at sea?

No.

A properly formulated energy-balance equation would be relevant in each case, but that's entirely irrelevant from the notion that the model for one case applies to the dynamics of another case.  Some equation E1 may apply to a ship at sea under conditions of straight-line travel at constant speed.  Some other equation E2 may apply to a spacecraft in accelerated flight in an orbital environment.  To say that some equation may be written in each case is not the same as believing that E1 ≡ E2.

Your error at the highest level is presuming that because you think you understand the dynamics of maritime propulsion, you can apply the same dynamic formulations to all propulsion.  You evidently do not understand as much as you think about maritime propulsion, because part of any such understanding is realizing how one particular expression fits into the overarching science that supports it -- specifically, what factors exist in the science, but which may be safely ignored in some expression.  You are dumbly applying one expression to a dissimilar system, ignorantly omitting in the final result the simplifications that removed terms in the source.

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Compare a car running out of fuel

Why do you think that directly compares?
"Facts are stubborn things." --John Adams

Offline Andromeda

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Re: So, who wants to win 1 million Euro?
« Reply #517 on: January 02, 2013, 12:43:04 PM »
But before I'll send you a cheque, you have to master the basic space ship 3-D driving course, e.g. how to accelerate and stop in space, how to change direction in space, how to get into the orbit of a planet/moon in space, etc, etc. all with a basic, space craft with big drive/brake engine at one end and small ones to rotate your craft in 3-D.

Are you seriously trying to say that you can't understand that firing a large rocket is going to change your speed, one way or another? And that you can utilise gravitational attraction to help you with course changes? And you call yourself an engineer? I have no engineering training, just some physics knowledge, and I can see immediately that that would work. And, by the way, they invented computers some time ago.. you know, to help with the calculus and stuff in plotting orbits, accelerations, and so on?

He demanded to see such a thing in post 393, I gave him an image in post 398 and he didnt even acknowledge it.  That's his modus operandi so don't expect any response from him to your post.
"The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...'" - Isaac Asimov.

Offline Glom

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Re: So, who wants to win 1 million Euro?
« Reply #518 on: January 02, 2013, 12:44:48 PM »

I am just interested in the kinetic energy B (J) Before braking and kinetic energy A (J)

Then your area of interest is wrong.  If you want to do energy balance, you need to consider the whole system, not just pick the parts you're interested in.

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After braking of the space ship and the difference B - A, that is the energy used for braking.

No.  The energy goes into the exhaust along with the energy derived from the combustion.  It is that total energy you need to consider when doing energy balance.

I'll say it again more loudly.

YOUR EQUATIONS ARE WRONG!!

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Evidently the space ship mass differs between before/after braking because fuel aboard with a mass is used to produce a brake force F (N)  that is applied to the space ship, while braking distance/displacement L (m). B-A = F*L .

You're applying the formula for work done in the wrong frame of reference.

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The mass of exhaust, type of fuel, etc. have nothing to do with my basic energy calculations that only involves force and distance/displacement.

We know that.  It's why your calculations keep coming up with the wrong answer.

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The momentum before braking is evidently much bigger than after braking because masses and velocities are reduced during braking due to a force F being applied when space ship displaces distance L.

You think sticking algebra in your qualitative sentences is supposed to make you look smart?  You're like a Star Trek writer sticking nonsense made up of buzzwords to make it look like the characters know what they're talking about.

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No momentum is conserved as a force is applied to the space ship system - to brake.

Momentum is always conserved.  You're questioning Newton's Laws now?

Offline JayUtah

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Re: So, who wants to win 1 million Euro?
« Reply #519 on: January 02, 2013, 12:50:00 PM »
I am just interested in the kinetic energy B (J) Before braking and kinetic energy A (J) After braking of the space ship and the difference B - A, that is the energy used for braking.

But your problem is that the system you use to compute the conditions of A is not the same system you use to compute the conditions of B.  Because you compare two dissimilar systems, your energy values are not directly comparable.

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The mass of exhaust, type of fuel, etc. have nothing to do with my basic energy calculations...

Yes they do.  Your problem is exactly that you don't know how to properly incorporate the mass and energy properties of the propellant in any of your computations.  The deficits you identify as evidence of fraud are the deficits arising in your computations from your inability to consider all the relevant factors.  You wrongly believe that your "basic" computations that omit these factors accurately describe the behavior of the mechanical world.  They do not, hence they are inappropriate yardsticks.

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The momentum before braking is evidently much bigger than after braking because masses and velocities are reduced during braking due to a force F being applied when space ship displaces distance L. No momentum is conserved as a force is applied to the space ship system - to brake.

No, once again you omit relevant energies and momentums because you redefined your system between computations.  Your initial-condition system includes the propellant.  Your final-condition system excludes the propellant.  You wrongly believe you can do this because the propellant, in the form of exhaust products, has exited the vehicle.  You do not realize that "system" for the purposes of your computations must continue to include the propellant's properties (whether mass, energy, or momentum) in order for your computations to be consistent from initial to final state.

Your persistent failure to realize this illustrates just how little you know about rocket propulsion and about physics in general.

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I have a feeling Willy had problems getting it right 1969 too.  :'( :'(

No.  You're the only one making errors here.  You have deftly attempted to blame NASA for your ignorance, but it is yours.
"Facts are stubborn things." --John Adams

Offline Glom

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Re: So, who wants to win 1 million Euro?
« Reply #520 on: January 02, 2013, 12:50:38 PM »
But before I'll send you a cheque, you have to master the basic space ship 3-D driving course, e.g. how to accelerate and stop in space, how to change direction in space, how to get into the orbit of a planet/moon in space, etc, etc. all with a basic, space craft with big drive/brake engine at one end and small ones to rotate your craft in 3-D.

Are you seriously trying to say that you can't understand that firing a large rocket is going to change your speed, one way or another? And that you can utilise gravitational attraction to help you with course changes? And you call yourself an engineer? I have no engineering training, just some physics knowledge, and I can see immediately that that would work. And, by the way, they invented computers some time ago.. you know, to help with the calculus and stuff in plotting orbits, accelerations, and so on?

He demanded to see such a thing in post 393, I gave him an image in post 398 and he didnt even acknowledge it.  That's his modus operandi so don't expect any response from him to your post.

And he still has yet to acknowledge that he got the fuel wrong, the engine wrong, the propellant load wrong and other things wrong too.

He just keeps restating his original incorrect work, laden with algebraic terms and improper jargon to make it look like it's intelligent.  It actually looks like the homework of a 14 year old, a 14 year old well on his way to failing his Physics exam.

Offline Andromeda

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Re: So, who wants to win 1 million Euro?
« Reply #521 on: January 02, 2013, 12:54:09 PM »
Damn, Jay - post 516 might just be the finest thing I've ever read here.
« Last Edit: January 02, 2013, 12:57:03 PM by Andromeda »
"The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...'" - Isaac Asimov.

Offline Glom

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Re: So, who wants to win 1 million Euro?
« Reply #522 on: January 02, 2013, 12:55:44 PM »


This has got to be the worst case of Dunning-Kruger I've seen.

It is explained in minute detail what he did wrong and he still thinks he's right.

Offline JayUtah

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Re: So, who wants to win 1 million Euro?
« Reply #523 on: January 02, 2013, 12:56:07 PM »
He demanded to see such a thing in post 393, I gave him an image in post 398 and he didnt even acknowledge it.  That's his modus operandi so don't expect any response from him to your post.

Indeed, other people are watching this thread and are well aware that the exact information has been supplied that Anders claims was unavailable or being hidden, and they are further well aware that the numbers are absolutely damning to Anders' claims.  He is clearly aware of and uninterested in the truth.

Instead his constant references to some alleged statement by one Apollo functionary, George Low (whom he continues impolitely to identify only by a nickname), as the sole source of information on Apollo dynamics leads me to conclude that he's really just interesting in slinging mud at his designated enemy, regardless of the facts.  He is only out to show how much more clever he is than those "fat lazy NASA PhDs" by whatever illusory means present themselves.  Anything that requires him to admit error violates his little ego-reinforcement construct.
"Facts are stubborn things." --John Adams

Offline Andromeda

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Re: So, who wants to win 1 million Euro?
« Reply #524 on: January 02, 2013, 12:58:34 PM »
Heiwa

You are extremely aggressive and abusive towards NASA in particular and I am curious as to why.  Did NASA run over your dog or something?
"The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...'" - Isaac Asimov.