Hoax? - Lunar Launches - Too Fast

[JayUtah]

I know his tactic, as we just saw again -- I answer, and he responds with a dozen pedantic questions, trying to paint the picture (which all here will believe) that he's smarter than me...

My "tactic" is called the Socratic method of teaching. I can just tell you what's what, but history has shown that you will just sidestep it, ignore it, and move on to the next knee-jerk claim. Instead I'm helping you teach yourself.

[najak]

#1: That's how most engines work.
#2: The contribution of the pressure term increases in vacuum.
#3: What if the mechanical arrangement of rocket and surroundings briefly created a kind of cylinder with the spacecraft as a kind of piston?

Perfect, thank you for actually saying stuff.  It gives me something to work with here.  I believe I am following all that you say here.

#1: Yes, gas combustion engines work entirely (or almost) off of Gas Expansion from heat, that pushes on the pistons which in turn does "work".

#2: Thank you for this exposition on this topic.  I found it enlightening, and I trust your explanation as it seems to match with what I've read.  At least now we can establish that we're on the same page here.   Rocketry's term "Pressure Thrust" isn't apples-to-apples on how "Pressure Thrust" is treated in other contexts, such as inside of a gas engine's piston, correct? (to ensure I understand the difference, I'm asking for clarification or correct)    I do not believe the "confusion" here is not in concept (i.e. how they apply thrust) but rather only in the terminology usage itself.


#3: You are suggesting that we need to examine this "added concept" of Pressure Thrust, which is built-up/supported by "Heat" as Heat tries to Expand, which then applies Force and does Work.  This work is similar to what we see working inside of a gas engine's pistons, right?  (or a bomb that is sealed up when you ignite something inside it that blows it apart)

Please confirm/clarify my understanding of where you are headed with this particular concept, in relation to Launch Thrust.

Before we proceed, can you answer:
1. Do you have any OTHER measurable contributors to Thrust that you'd like to consider in this proof?

Then let's proceed with your proof of how this fuel combustion can induce Piston-like thrust for the rocket... (or however you want to term it)

[Mag40]

Then let's proceed with your proof of how this fuel combustion can induce Piston-like thrust for the rocket... (or however you want to term it)

Piston like? Exhaust bell is within an enclosed area. The thrust of the rocket is impacting the upper deck of the descent stage and the enclosed area for the bell. Newton's third law.

[najak]

Piston like? Exhaust bell is within an enclosed area. The thrust of the rocket is impacting the upper deck of the descent stage and the enclosed area for the bell. Newton's third law.

Well Pistons are enclosed inside of a tube, so not "the same" in that way... but the analogy was drawn above to combustion engines.  So am just going with this analogy..   I'm not nick-picking it.  Does it seem like I am?

And I think we're all in agreement that Newton's 3rd law is one of the prime concepts at work in this context.

[Mag40]

Well Pistons are enclosed inside of a tube, so not "the same" in that way... but the analogy was drawn above to combustion engines.  So am just going with this analogy..   I'm not nick-picking it.  Does it seem like I am?

I don't want to interrupt the flow of this thread. Piston "like" - the piston being the exhaust bell inside its enclosed area. Newton's 3rd law being not just what happens with the rocket but what expanding into an enclosed place does.

[najak]

I don't want to interrupt the flow of this thread. Piston "like" - the piston being the exhaust bell inside its enclosed area. Newton's 3rd law being not just what happens with the rocket but what expanding into an enclosed place does.

It sounds like we're all in agreement here about Pistons and Newtons 3rd law, and that a similar effect would also apply to the rocket bell, in the case of "obstructing the nozzle exit" (either partial or complete).

[najak]

...

@JayUTAH:  I'm trying to find the "energy released per mass unit" for Aerozine-50.   I'm seeing a Google AI answer, but without any source links that confirm it.  Where do you find this reference/info?

[Mag40]

https://ntrs.nasa.gov/api/citations/19690006888/downloads/19690006888.pdf

That any assistance?

[najak]

That any assistance?

Thanks for trying.  I found that one, and the word Joule/MJ/KJ exists nowhere..  Lots of equations but no quantities that I could find.

For now, so that I have SOME number, I'm using Hydrazine's 19.5 MJ/kg.

[smartcooky]

I know his tactic, as we just saw again -- I answer, and he responds with a dozen pedantic questions, trying to paint the picture (which all here will believe) that he's smarter than me...

He doesn't have to paint that picture... we already know he's smarter than you... way smarter, and its not even a high hurdle to clear. You have proved that with your posturing, your arrogance, and your blanket refusal to learn!

The questions Jay asks you are NOT pedantic, they are styled to get YOU to to figure out where YOU are going wrong. There is no learning that sticks better than when the student comes to the right conclusion with guidance and inquiry rather than instruction.

https://tilt.colostate.edu/the-socratic-method/

If you DO want to learn (which I seriously doubt anyway) you need to put aside ALL of your preconceived conclusions and pay close attention to what Jay is telling you. I am a certified and degreed Aeronautical Engineer; I understand jet engines a lot better than I understand rocket engines (even though some of the principles and terminology are similar).... yet I am learning NEW stuff about rocket engines from Jay's interactions with you.

Sadly, you do not appear to be learning anything!!

[najak]

...

My preliminary conclusion here is that for this context, "Conservation of Energy Law" is not easy to prove because there is an IMMENSE amount of energy in Combustion, and at Launch, < 0.2% of this energy is being transferred into the AM mechanical energy, we'd just need to increase this to 0.3% -- so there's simply far too much Combustion energy here to be concerned with "Did we create any new energy?"

@Jay - you could have easily said this in 5 seconds, and I would have learned it just as well with 100x less time.   I suspect your goal is to "school me", not "teach me".

So I am withdrawing my claim of "Apollo can't break the Law of Conservation of Energy".

We still have more work to do though...  Fluid dynamics, flow rates, pressure stuff.

[najak]

Sadly, you do not appear to be learning anything!!

Socratic method has it's place.  This is not one of them, at least not for "pure Socratic method" - because I'd learn a hell of a lot faster from him just stating what he knows and thinks.  We could be through it in MINUTES, instead of DAYS.

His goal in doing this publicly is not to "teach" but rather to "school" and "posture".  I know he knows the Rocket Science concepts better - so share them.  For my "Conservation of Energy" suspicion, he should have just said outright - "there's 40 MJ/sec of combustion energy, but only 0.12% of it being transferred into AM Mechanical energy" from the onset.

I was making a rookie mistake - simply from being a rookie.  His method now allows him to "rub my nose in it".... i.e. "school me" -- establish "superiority/posture".

Now watch -- this will be held against me forever...  as though it's meaningful and can be used to discredit me.   This will confirm my suspicion -- "schooling" not "teaching".

[najak]

...

My learning here, no thanks to Jay (as he could have simply said this in 5 seconds and it would have stuck)  is that when a rocket engine is claimed to be about 60% efficient...  this means "steady state" and indicates the amount of "Mechanical energy transferred into BOTH the Rocket and the Fuel"... not just the rocket.

In hindsight, this is obvious.  A rookie mistake, and would have been simple and quick to correct, assuming Jay noticed my wrongful understanding.

When I saw 60% efficient, I assumed this meant "60% of combustion translates into AM mechanical energy" -- this is simply not the case.  And if I saw someone making this mistake, I don't let them "linger in their mistake", I correct it.   It's when they DON'T CATCH ON TO THE CORRECTION - that I start to make judgements about aptitude.

But this one will be used against me -- even though it should have been corrected by Jay when I first brought it up... and saved time.

Stalling, Schooling and posturing - is his goal.  Or he's a terribly inefficient teacher.  I had to discover this on my own, which took hours instead of 5 seconds.  And this time waste didn't make me learn it any better.   It just provided the Apollogists on this site, more fuel for discrediting me -- which was the obvious goal.

[najak]

Example - @Mag40 calculated "Work Energy" as "Force * Time"...  Did I let him "linger in being wrong" so that he might go on and on about it -- so that I could maximize his embarrassment and my posturing??

Nope - I corrected him IMMEDIATELY and kindly.  I didn't rub his nose in it, and I won't bring it up again - because it's an easy mistake, and easy correction.   I'm only bringing it up now - as an example of "how to teach and treat people" if you care about them, rather than are trying to set up for posturing and discrediting them.

Jay isn't dumb enough to be this "bad of a teacher"...   it's a clear posturing maneuver.

[najak]

To put things back on track, the issue of "Conservation of Energy" isn't a factor here.  There is PLENTY of energy to go around.

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The proof that Jay needs to make now is regarding fluid dynamics, heat/expansion/pressure, etc... whatever he deems fit.