It's 2015 and you aren't even close to owning a Spaceship

Quote from: Papa Legba on November 19, 2015, 12:13:45 PM

Quote from: markjo on November 19, 2015, 08:35:46 AM

Secondly, the coolant running through the tubes is a cryogenic liquid, not a gas. 

Apprently, the LOX will only be liquid when under the extreme high pressure found within the fuel tank.

As soon as it is released from the high-pressure tank it will immediately revert to gaseous form.

Yup, LOX is only ever a liquid when under pressure.
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It seems like your welder buddy is an idiot too.

Beat me to it.

Markjo: how does your unpressurised & cryogenically frozen LOX get out of the cylinder for use in welding?

Who cares?  The J2 rocket engine burns liquid oxygen and liquid hydrogen.  How a oxy/hydrogen torch works is completely irrelevant.

As for how the cryogenic liquid hydrogen and liquid oxygen get from the pressurized tanks to the engine...  Turbopumps.

Oh, look.  You started a new page.  All of your arguments are invalid.

Quote from: Papa Legba on November 19, 2015, 02:39:29 PM

Markjo: how does your unpressurised & cryogenically frozen LOX get out of the cylinder for use in welding?

\

Welding gases aren't usually in cryogenic state. You need an insulated dewar for that. Regular gas cylinders just contain the gas phase and are also much higher pressure than dewars. An oxygen cylinder could be 3,000 psi or more whereas a dewar would have a safety vent valve at more like 350 psi. Liquid dewars come in handy because they hold so much more than a gas cylinder since the element is stored as a liquid. Dewars do need some pressure to move the liquid out if you wanted it. They have a pressure building valve you an turn and they will then slowly pressurize to the set pressure.

Little trivia, liquid helium dewars vent off so much they don't even have a way to close them tightly.

You finished your little shitpost rampage?

Feeling pretty pleased with the sheer amount of manure you spread all over everything?

Good.

Now; back to the matter at hand.

Focusing an oxy-acetylene torch creates a tip with a temperature of 3,500C; exactly the same temp as in a 'spayze-rokkit' combustion chamber.

The tip also needs to be Oxygen-rich; a mix of about 6:1 LOX to Fuel.

& funnily enough, the mix the J2 engine uses is 5.5:1 LOX to Fuel... near enough identical again.

All of which is allegedly being blasted at hypersonic speed & enormous pressure against a steel tube with a melting point of 1600C max, one third of a millimetre thick & filled with highly combustible pressurised gas, for 8 solid minutes.

Now; you can tell me that flimsy little tube would not melt like butter as long, loud & often as you like; but I am used to your brainwashing ways by now so will simply ignore you.

Because it is Physically Impossible; there is no 'cooling system' imaginable that could protect it from such extreme temperatures.

Okay?

Unlike all of you Raown Derfer desk-jockeys & wiki-spammers, I have actually used an OA cutter; I know what that kind of gas mix at those kind of temperatures does to metals & it is not pretty.

Feel free to spam some more youtubes of water-filled cups, bowls of LOX & anything you like; it will not change a thing...

So; Carry On Lying!

I have actually used an OA cutter; I know what that kind of gas mix at those kind of temperatures does to metals & it is not pretty.

So, why doesn't the torch head melt?  As you said, the flame gets to 3500 degrees.  Brass, the main metal used in the head, melts below 2000 degrees.  How would the torch head survive the 3500 degree flame?  According to your logic, the torch head should melt fairly quickly.  And as you just stated, you have seen what the flame does to metals.

LOL!!!

The Derfers must be getting desperate if they gotta rope an old nag like you in ain't they?

If the combustion of the gases was occurring within the torch head then it would be problematic.

But it is not.

Unlike a shpayze-rokkit combustion chamber, where it most decidedly is.

What's more, the internal pressure is enormous, & it is being forced through the nozzle throat at supersonic velocity.

Of course, a mere One Third of a millimetre of steel tubing can easily withstand all this colossal heat & pressure...

Why?

Because it is Shpayze-Shteeel Toobinng, made by Rokkit Scintistses & is orl shpeshal & stuf!

LOL

What a fwaderfer!!!

Torch burns 3500 brass melts 2000

Torch melted in hand

Derpderderp

LOL

Focusing an oxy-acetylene torch creates a tip with a temperature of 3,500C; exactly the same temp as in a 'spayze-rokkit' combustion chamber.

The tip also needs to be Oxygen-rich; a mix of about 6:1 LOX to Fuel.

& funnily enough, the mix the J2 engine uses is 5.5:1 LOX to Fuel... near enough identical again.

All of which is allegedly being blasted at hypersonic speed & enormous pressure against a steel tube with a melting point of 1600C max, one third of a millimetre thick & filled with highly combustible pressurised gas, for 8 solid minutes.

Now; you can tell me that flimsy little tube would not melt like butter as long, loud & often as you like; but I am used to your brainwashing ways by now so will simply ignore you.

Because it is Physically Impossible; there is no 'cooling system' imaginable that could protect it from such extreme temperatures.

Okay?

So, not only are you saying that rocket engines can't work in a vacuum, now you're saying that rocket engines can't even work in the atmosphere?  What about all of those test videos showing the rocket engines not melting?

Firstly when the LOX tanks are opened the system as a whole is still under pressure so there is no reason why the oxygen would vaporise.

Secondly to find out if the stainless steel melts you need to calculate the net amount of energy that the stainless steel absorbs. This means the amount added by the combusting fuel and oxidiser in the combustion chamber and the amount taken away by the cryogenic coolant. To calculate this (even approximately) you need mass flow rates, heat capacities inlet temperatures, heat transfer coefficient and an idea of the Reynolds numbers of the two fluids. Given you are so confident that the chamber will melt presumably you can provide these figures easily....?

Thirdly whilst LOX is highly reactive, it must be in the presence of a reactant and at a sufficient temperature to undergo a reaction. What temperature does the LOX reach when it exits the cooling circuit.

Fourth the ratios you quote aren't some magic number it is simply the mass ratio of oxygen to hydrogen to get the correct reaction stoichiometry so that the reaction is as efficient as possible ie 2H₂ + O₂ = 2H₂O . Twice as many hydrogen atoms but oxygen weighs about 16 times more. 

What a fwaderfer!!!

Yeah; knew you'd be too dumb to get it.

Too dumb to know I'm not a flat earther too, as well as too dumb to think up your own insults...

So, not only are you saying that rocket engines can't work in a vacuum, now you're saying that rocket engines can't even work in the atmosphere?  What about all of those test videos showing the rocket engines not melting?

God, you're dumb too...

I am saying that the figures we are quoted for 'shpayze-rokkit enjinnz' are all bullshit; the temps, the speeds, the thrust, the burn-time - everything.

And your beloved 'test videos' are of crappy pimped-up flamethrowers that look impressive but are in fact useless.

Fake engines; Fake data; Fake footage; Fake Rokkitz, ALL Fake, right the way back to the gimcrack German V2 that started this whole woeful business off...

Military. Propaganda.

Speaking of which, don't you claim to be ex-military, markjo?

LOL!!!

Secondly to find out if the stainless steel melts you need to calculate the net amount of energy that the stainless steel absorbs.

What a mighty shitpost from you; been beavering away at the wiki in an attempt to convince us you really ARE a pwoper scientist, have we?

But no; to find out if a paper-thin steel tube will melt when blasted by 3500C gas I don't need to calculate a damn thing.

I just need to rely on my own experience.

Have fun with your mathematical masturbation & verbal diahrrea though; maybe some sucker'll fall for it?

'Stoichiometry' - LOL!!!

Here's a tip; if you really want to stink the place out try just filling a post with Navier-Stokes equations...

Easily copy-pasta'd from wiki & no-one will know.

Toodle-pip, dingbats!

yep, u're just ignoring hundreds of liters per second of fluid at -200° c on the other side of the wall.

just out of curiosity, where did u find the figure of 0.3mm? i'm not saying that, without a proper cooling system, the thickness will make difference, but i'm really curious about the desing of the nozzle but could find anything satisfactory on the internet.

yep, u're just ignoring hundreds of liters per second of fluid at -200° c on the other side of the wall.

just out of curiosity, where did u find the figure of 0.3mm? i'm not saying that, without a proper cooling system, the thickness will make difference, but i'm really curious about the desing of the nozzle but could find anything satisfactory on the internet.

To be fair the figure of 0.3mm is correct. It is the wall thickness of the tubing used to construct the combustion chamber.

'Stoichiometry' - LOL!!!

Aw. Did the nasty man use a big word that you didn't understand....?

That's what happens when you go to University and learn how things work instead of being an uneducated cretin like yourself.

yeah yeah, not doubting that, i just want a reference cause i wanna know how the chamber is desing. the colling pipes are of that thickness but the rest of the nozzle? i know the principle but i'm iterested about the detailed desing

If you are interested in the F-1 rocket engine nozzle construction ...



Here we see the tubes open, before "the other end" was placed to close the circulation.

It consists of 178 primary tubes and 356 secondary tubes, for a total length of over 3000 feet - not all, but about 70% of the total fuel was first directed through these tubes to cool the thrust chamber and nozzle.

Here we see a close look at the primary tubes splitting into the secondary ones.



The special X-750 tubing high-nickel, stainless steel alloy allowed for thinner walls and thereby greater inner diameter of the tubes (outside diameter of the secondary tubes was 1 inch).

Much more detail and many more pictures are found here ... http://heroicrelics.org/info/f-1/f-1-thrust-chamber.html

Here is a 112 page public NASA document about Liquid rocket engine nozzles (including the F-1 one) ... http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770009165.pdf

And a 35 page document from 1965 about the material (X-750) and generally the flow and temperature  properties of that F-1 nozzle ... http://agentdc.uah.edu/homepages/dcfiles/UAHDC/Furnbrazf1thrucham_082007094528.pdf

Is that enough for now?

thanks

Aw. Did the nasty man use a big word that you didn't understand....?

That's what happens when you go to University and learn how things work instead of being an uneducated cretin like yourself.

LULZ!!!

You are totally delusional & never went to any kind of University, anywhere, ever...

Have you forgotten you wrote this?

It was only a day ago, Walter Mittty...

Have you ever tries welding a piece of metal that has the other end stuck in a bucket of ice cold water? Try it. I guarantee that the acetylene torch will not cut the metal as too much heat will be drawn away into the water. Once the water has boiled off then the acetylene will cut the metal.

Two of my mates read it & wouldn't believe that it wasn't YOU who was the flat earther; THAT'S how utterly insane you come over to normal people.

So just stop Pretending that you have any Intellectual authority here, okay?

Lunatic...

Oh, & soulblood/twelve steps; we're talking about the J2 engine, not the F1.

Drunk again?

Not that it matters, cos they're both so fake a child could see through them...

The Saturn V: a 3,000-tonne rokkit-szhypp to teh munn!!!

Yeah; 3,000 tonnes; that's the same as two WW2 destroyers; why not send a couple of them to teh munn too?

Or a third of the Eiffel Tower?

Or 4,500 VW Beetles?

Christ, what a bunch of clowns you all are...

LOL

What a fwaderfer!!!

Torch burns 3500 brass melts 2000

Torch melted in hand

Derpderderp

LOL

It doesn't burn inside the tube. It ignites and burns OUTSIDE of that tube and nozzle just like a rocket does but we are told to believe a rocket has an internal combustion chamber.

Hey, I am sure PL is right, it's not like it's rocket science ...

I always wanted to say this

Hey, I am sure PL is right, it's not like it's rocket science ...

Yes; I am.

Thanks for noting that, even in your sozzled state!

Because what we are Told is 'rocket science' is complete bullshit.

Just understanding how a De Laval nozzle functions completely destroys all notions of 'space flight'...

Try finding out; wise yourselves up a bit, maybe?

Quote from: Soulblood on November 20, 2015, 03:16:15 AM

Hey, I am sure PL is right, it's not like it's rocket science ...

Yes; I am.

Thanks for noting that, even in your sozzled state!

Because what we are Told is 'rocket science' is complete bullshit.

Just understanding how a De Laval nozzle functions completely destroys all notions of 'space flight'...

Try finding out; wise yourselves up a bit, maybe?

How about you post some links to sites that you believe are incorrect of manufacturers, universities etc.

How about you post some links to sites that you believe are incorrect of manufacturers, universities etc.

Sorry, could you repeat that in English please?

I'm not as fluent in Gibberish as you Raown Derfer Trolls...

Quote from: inquisitive on November 20, 2015, 03:29:37 AM

How about you post some links to sites that you believe are incorrect of manufacturers, universities etc.

Sorry, could you repeat that in English please?

I'm not as fluent in Gibberish as you Raown Derfer Trolls...

You believe space flight is not possible.  Post some links of organisations that claim to be involved.

Test-firing of the Saturn V stage one F-1 rocket engines ... especially interesting the slow-motion close-up of one F-1 firing starting at 10:35 ...

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You believe space flight is not possible.  Post some links of organisations that claim to be involved.

1: I do not 'believe' anything; I KNOW 'space flight' is not possible.

2: Don't tell me what to do, Thought-Cop.

Note to neutrals; research De Laval nozzles; note how nozzle design has to be tuned to specific ambient pressure outside nozzle in order to function efficiently; note that ambient pressure will drop to only 30% that of sea level at just 5 miles in altitude; understand why 'shpayze-rokkits' are impossible.

& Twelve steps; that's just a big flamethrower.

Grow up & lay off the booze.

Quote from: inquisitive on November 20, 2015, 03:51:03 AM

You believe space flight is not possible.  Post some links of organisations that claim to be involved.

1: I do not 'believe' anything; I KNOW 'space flight' is not possible.

2: Don't tell me what to do, Thought-Cop.

Note to neutrals; research De Laval nozzles; note how nozzle design has to be tuned to specific ambient pressure outside nozzle in order to function efficiently; note that ambient pressure will drop to only 30% that of sea level at just 5 miles in altitude; understand why 'shpayze-rokkits' are impossible.

& Twelve steps; that's just a big flamethrower.

Grow up & lay off the booze.

De laval nozzles are optimized for a specific altitude... So what? At other altitudes they are less efficient but they still produce a lot of thrust, 50% or more than the altitude for which they're designed. For example the j2, meant to be used in the second and third stage of the Saturn 5 though optimized for maximum thrust in vacuum(cause by the time u ignite the second stage u're definitely at very high altitude) they still produce half of their thrust at sea level.
Designs of engines that can change the geometry in order to be optimized at every altitude do exist and are being developed but in the 60's they were heavier more complicated and potential more unreliable. It's a trade-off (normal practice in engineering) they chose light and reliable but less efficient instead of efficient but heavy and unreliable, I would say a sane choice considering that Saturn V  were used for manned missions

De laval nozzles are optimized for a specific altitude... So what?

Sloppy researcher ain't you?

What's your Imaginary Qualification in?

De Laval nozzles will only accelerate gases above mach 1 at the specific back-pressure they are designed for.

See the problem here?

So if they're designed to work best at sea level they will stop accelerating gases above mach 1 within a couple of thousand feet.

By the time they're up to, say, 50,000 feet they'll be practically useless.

And good luck getting to teh munn at subsonic velocity!

Like Twelve Steps said; it's not rocket science...

I am saying that the figures we are quoted for 'shpayze-rokkit enjinnz' are all bullshit; the temps, the speeds, the thrust, the burn-time - everything.

You know this for a fact because you've done the math to prove it, right?

And your beloved 'test videos' are of crappy pimped-up flamethrowers that look impressive but are in fact useless.

I don't know about that.  They look pretty useful on launch day.

Fake engines; Fake data; Fake footage; Fake Rokkitz, ALL Fake, right the way back to the gimcrack German V2 that started this whole woeful business off...

The V2 didn't use regenerative cooling.  It used an alcohol/water and LOX mix to keep the chamber temperature at a manageable level.

Military. Propaganda.

Speaking of which, don't you claim to be ex-military, markjo?

LOL!!!

Once a Marine, always a Marine.  Ooh rah.

What have you done for your country?

De Laval nozzles will only accelerate gases above mach 1 at the specific back-pressure they are designed for.

Obviously, PL's thoughts have nothing to do with rocket science ...

Mass flow and dimensions of the nozzle must make sure that the achieved pressure is above the ambient pressure to reach supersonic exhaust speeds ... if this is achieved at ground level this is of course also achieved at higher level, against lower ambient pressure (or even vacuum).

There is an ideal ambient pressure value for each nozzle shape (expansion factor), operating above or below that height means a loss in efficiency ... first stage rockets are generally designed so they are over-expanding at sea level and under-expanding in vacuum, reaching optimal efficiency somewhere in between. Later stage rockets can be optimized for vacuum use.

Here is a document (from the university of Rome) explaining this in a little more detail, including formulas and even values and charts for different rocket engines (including the F-1).

http://www.ingaero.uniroma1.it/attachments/617_PSP%20Lez.%2007%20SUMMARY%20OF%20ROCKET%20NOZZLE%20RELATIONSHIPS.pdf

BTW, did I read that right and PL is claiming that Nazi Germany did not fire 3.200 V-2 rockets at targets in England, France, Belgium, Netherlands and even 11 at their own city of Remagen, late in WW2, killing around 8.000 people?

No need to do Math; Yes need to Observe & Experiment.

The substitution of Geometrical Abstractions for Empirical Evidence is how we all got into this sordid sci-fi mess in the first place.

Once a Marine, always a Marine.

You said it.

Thus, as NASA is a Military organisation promoting Military Propaganda, I am quite justified in believing you are here to uphold that Propaganda at all costs.

Anyhow; De Laval nozzles can only accelerate gases beyond supersonic velocity at the specific back-pressure they are designed for.

This has rather grave implications for NASA's 'shpayze-fllyte' claims, do you not think?

LOL!!!

Of COURSE you 'do not think'; that's your purpose here ain't it?

Semper Fi, Sister!

Oh, & Twelve Step's post is b.s; this part is just a massive, desperate lie:

if this is achieved at ground level this is of course also achieved at higher level, against lower ambient pressure (or even vacuum)

LULZ!!!

Research the subject yourselves, neutrals; you'll see I'm correct.

Toodle-pip, Liars & Propagandists!