Does Rocketry Work beyond Earth's atmosphere?

If NASA faked the moon landings, does the agency have any credibility at all? Was the Space Shuttle program also a hoax? Is the International Space Station another one? Do not dismiss these hypotheses offhand. Check out our wider NASA research and make up your own mind about it all.
nokidding
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Re: Does Rocketry Work beyond Earth's atmosphere?

Unread post by nokidding » Tue Jul 09, 2019 2:57 am

Just got to the end…may I add something from personal experience? I burnt off lot of gas at high rates from drilling rigs. I was interested in the thread because a few years back I tried to calculate the thrust produced by a horizontal gas flare - someone had angled the flare tip up and I was concerned that the down thrust would exceed the design utilisation for the boom suspension. This was a gas well being flowed full bore for production testing. Like people here I assumed the gas flare itself pushed back.

When you watch a high rate gas stream exiting an open pipe under pressure and burning off you see the ignition point commences a few metres out and appears to race back unstably. The gas needs to draw in Oxygen from the surrounding air to burn. This runs counter to the idea that pressure is built up by resistance of the air. However between the tip and where it starts to burn there is clearly a high pressure jet.

Beyond the ignition point you have what looks much like a rocket launch - imagine 2000 m3 / min shooting out of a 6 inch pipe and igniting (you are perhaps 20 - 30m away – the noise is extreme). The flare is obviously dissipating huge energy but does it push back? Any force has to be pressure in the burning gas stream - and this is only seen at the nozzle / pipe exit. Air pressure may make this greater than in a vacuum but only by 1 bar or 15 psi (at sea level).

What relevance has a gas flare to rockets in space or in air? The rocket engine produces a stream of gas, much like the oil rig flare boom. It may be extremely hot and the product of a chemical reaction, but it is still just gas. The nozzle is an open pipe much like the flare tip, but designed to maximise the velocity of the gas (in speed and direction).

How does pressure build up in a pipe/nozzle with an open end and a void beyond? Because gas is pushing from behind against the inertia of the moving gas forcing it to increase its speed. Force = Mass x Acceleration (not Mass x Velocity as someone stated here). Acceleration is the key to it. I could model the mass flow rate etc using process engineering software so could then put a figure on the thrust.

Both air and vacuum provide a void for the gas to expand into. The pipe/nozzle stays pressurised as long there is sufficient gas supply to accelerate the expanding gas out of the open end into the void. The gas goes one way and the rocket goes the other, or stays put (hopefully) in the case of the flare boom.

To those in doubt just consider - this is the same Law that makes the image of the ‘plane’ going into the WTC so unphysical.

nokidding

Altair
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Re: Does Rocketry Work beyond Earth's atmosphere?

Unread post by Altair » Tue Jul 09, 2019 8:01 am

Very good explanation, nokidding. In fact it's quite puzzling that all pop physics explanations about how rocketry works are centered around Newton's 3rd law, blindly assuming that if you eject a given amount of matter at a given speed from a rocket, it will generate an equal and opposite force upon the later. While from an engineering perspective, if you want to accelerate a body, you must exert a pressure against it, so all calculations should be centered around where and how much of this pressure is applied.

Extrapolating from your rig example, we could say that the rocket would indeed be subject to some force, but this would be only generated by the fuel being accelerated by the pumps (that would apply pressure upon the pumps), but combustion wouldn't add much to this, as pressure in the combustion chamber wouldn't be significantly higher. Amateurs build 'pressure water rockets' (search in YT) that would work in a vacuum, as a liquid would transmit a force to the rocket's body, but of course you cannot store the needed energy in that way.

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Re: Does Rocketry Work beyond Earth's atmosphere?

Unread post by simonshack » Mon Nov 18, 2019 2:25 am

*

Dear friends and valiant Cluesforum contributors,

The time has come for us all to proudly celebrate our...


10TH ANNIVERSARY OF CLUESFORUM'S EXPOSURE OF THE GSTS (the Grand Space-Travel Scam)

Image

...and I think it is appropriate to announce this celebration on this very thread titled "Does Rocketry Work beyond Earth's atmosphere?" - since it represents the logical conclusion of our longstanding investigations which, I dare say, have continuously strived to observe what we may call scientific rationality or, more simply, plain common sense.

Yes, we have investigated this sorry scam for more than 10 years now on this forum - and it would seem that, thankfully, many people around the world have been "listening". The viewcounts of our main threads exposing the GSTS may not be sky-high - but since this forum is, basically, my personal effort (supported by a few great souls) to expose the mass deceptions surrounding our lives, I'd say that these viewcounts of our main threads regarding the GSTS are, well... pretty encouraging:

"FAKERY IN ORBIT: THE I$$": 1,421,802 (almost one-and-a-half million views!)
"THE MOON HOAX": 1,386,562 (rather more than 1million views!)
"ENDEAVOUR - the 30-year Space Shuttle hoax" : 1,084,388 (more than 1million views!)
"SATELLITES: GENERAL DISCUSSION AND MUSINGS": 950,210 (almost 1 million views!)
"DOES ROCKETRY WORK BEYOND EARTH'S ATMOSPHERE?": 690,858 (rather more than half-a-million views!)

(There are of course numerous other Cluesforum threads which provide further evidence of the GSTS.)

It was in fact around October/November 2009 that the first thread ("THE MOON HOAX") dedicated to exposing the Grand Space Travel Scam came to life on this forum. I can well remember that, at the time, there were already quite a few websites around the internets debating the fairly large "underground" literature exposing the absurdities of NASA's purported six moon landings (between 1969 and 1972) - i. e. the entire Apollo fable. However, as I started wondering (back in 2009) whether perhaps ALL of NASA's subsequent, purported space travel exploits were similarly faked, I could hardly find ANY websites discussing whether this was the case. This is why I decided to spend several months taking a closer look at NASA's Space Shuttle program which, of course, closely followed the Apollo program and its wondrous exploits - as diffused on TV. It didn't take me too long to realize (and demonstrate) that the Space Shuttle program was every bit as fictitious as the Apollo program - and yet another hoax constructed entirely with the aid of the sort of "Hollywood Special Effects" that movie-goers are all familiar with. My full Space Shuttle research can be found here: "ENDEAVOUR - the 30-year Space Shuttle hoax"

Since then, of course, a lot has happened : many thousands of independent thinkers have now grown an awareness of the sheer inanity of NASA's tales. Yet it would appear that, today, most people still cling to the (rather illogical) idea that ONLY the Apollo program was a Made-for-TV mass deception. In the UK, for instance...

"Coming up is the 50th anniversary of the Apollo 11 moon landing. In 2016, a survey showed that 52 percent of the British public thought that Apollo missions were faked. Skepticism is highest among those who were too young to see it live on TV: 73 percent of aged 25-34 believe we didn’t land on the moon, compared to 38 percent of those aged 55 or more. These numbers seem to be rising every year." http://www.unz.com/article/the-moon-lan ... r-mankind/

Yes, those most encouraging numbers (e.g. 73% of the young and active adults in the UK !) seem to be rising every year - and I think that all the thoughtful Cluesforum contributors to our longstanding, methodical NASA exposure can be righteously proud to have actively facilitated this gradual mass-awakening. This is not saying that we should now discontinue our efforts at picking apart this most "astronomical" hoax hoisted upon humanity. On the contrary: let's keep informing our fellow earthlings about this humongous scam with renewed energy - until no intelligent brain matter on this planet continues to believe that NASA (and its international cohorts) truly sends rockets into outer space - and parachutes probes upon Mars and assorted asteroids... Do not worry about the reactions you will get from many (mostly older?) folks who just LOVE the Space Travel Fables - and just cannot let them go. They will get all twitchy and angry about it - just like the day when you realized, as a kid, that Santa Claus was nothing but a dumb fairy tale sold to you by your very own Mom and Dad! Similarly, to realize that we have all been scammed by our world's largest "Scientific Institutions" is just a phase we adults need to go through - in order to restore some degree of sanity on this planet.

THE FLAT EARTH DAMAGE-CONTROL PSYOP
Of course, NASA's Propaganda Department hasn't been sitting on its ass this last decade - as public awareness of the GSTS slowly started sky-rocketing (just like their slow-starting rockets...): around mid-2014 or so (i.e. around the time when Cluesforum enjoyed its historical peak of daily visitors), the NASA Propaganda Department launched their "FLAT EARTH Programme" : this propaganda gimmick is, I must admit, a quite clever psychological operation designed to associate anyone who questions NASA with those who claim that Earth is as flat as a French pancake. The net result being that, if you now try telling to someone that NASA is a total scam, this person will most likely say: "Oh, so you must be a Flat Earther, eh?" - and thus dismiss you as a raving crackpot. I really must concede - even though it hurts - that NASA's Flat Earth Psyop has to be one of the smartest (and evidently highly successful - internationally!) "damage-control" operation of all times. One must (reluctantly) "admire" their skills at fooling the world - much as one may "admire" David Copperfield for making the Statue of Liberty disappear in front of a large audience... The question is: HOW LONG will these magicians get away with it?

NASA: HOLLYWOOD'S SCI-FI DEPARTMENT
Few people will know that the first administrator of NASA (founded in 1958), T. Keith Glennan, was a former studio director for the Paramount and Goldwyn Mayer movie giants around which Hollywood was founded. In hindsight (and knowing what we now know), it is no wonder that he was chosen to be NASA's first administrator - since NASA has never been anything else than an ongoing, multi-trillion-grossing movie production sold to the world as reality. Fortunately, every seam of this massive cinematic hoax is now starting to crackle - as most people are now aware of the sort of advanced movie special effects such as those used to produce the 2013 movie "GRAVITY" (starring Sandra Bollocks and George Clowney). However, probably very few people know of (or remember) the techniques already available back in the 1950's - such as those featured in the old Russian movie "The ROAD TO THE STARS": in this vintage 1956 movie, we can see apparently weightless "actornauts" hovering and bobbing around their spaceships (rather realistically) - much like those modern-day "ISS Space Station" actornauts featured in NASA's numerous Youtube videos. I would say - very solemnly - that the most urgent realization for any living person today is that practically ANYTHING can be faked with movie technology (and has been so for a long, long time). We ALL need to start thinking for ourselves. Television - and the entire mainstream media - has been selling to our world's population a bunch of idiotic lies for many decades and, unfortunately, most people have bought them. It is now high time to realize this disgraceful state of affairs - and start organizing ourselves so as to reclaim reality.

SPUTNIK (1957) - THE START OF THE GSTS SCAM:
When Sputnik - the "first man-made satellite" - was aired on TV back in 1957 (the year before NASA was founded), the hapless TV-viewers had no way of imagining - let alone suspecting - that it could possibly be a hoax: Television ITSELF was still a fresh novelty for the world's population - and people had little or no idea of what sort of deranged psychopaths are running (or, if you will, "holding the reins of") this planet. At the time, the frightful so-called "Cold War" between Russia and America was on everyone's lips; we now know that the "Cold War" was just a farcical tale designed to keep this world's population in constant fear of an impending nuclear holocaust. Amazingly however, there are - still today - many people who simply cannot see the blatant farce that Sputnik was: you can show them this comical (or pathetic) 1957 CBS "News Report" - but they will still believe that the Sputnik satellite narrative (which, at the time, scared the wits out of the American populace, since they were told that it might carry an atomic weapon) was absolutely real !


full link: http://www.youtube.com/watch?v=dO33bvFbUCU

Of course, no man-made satellites could possibly survive the constant bombardment of (millions? billions? trillions?) of meteors which enter our atmosphere every day - which thankfully burn up / get vaporized by sheer molecular friction (...unlike NASA's wondrous space machines which somehow are able to re-enter our atmosphere without barbecuing the human flesh of the alleged ass-true-nots on board!). It's a silly joke - and the joke is on us, the gullible populace. One fine day, our children will all laugh hysterically about our incredible gullibility - and with good reason. We may however remain hopeful that this fine day will come soon - since 75% of the young & active adult Brits (God bless'em!) refuse to believe in NASA's flawless six moon landings between 1969 and 1972...

THE PSYCHOPATHS BEHIND THE NASA SCAM
To illustrate the sort of clowns who get recruited to perpetuate the ongoing GSTS, I have chosen just two of them - so as to exemplify the kind of individuals who make a living out of lying. I trust that anyone graced with a sound and astute cognitive disposition will sense the untrustworthy nature of these two bizarre individuals:

Would you buy a used car from ROBERT ZUBRIN? https://en.wikipedia.org/wiki/Robert_Zubrin

full link: http://www.youtube.com/watch?v=PKZW61IXvsc

Would you buy a used car from DON PETTIT? https://en.wikipedia.org/wiki/Donald_Pettit

full link: http://www.youtube.com/watch?v=BK-uatwOOeA

MY TYCHOS RESEARCH
I would now like to underline the fact that my TYCHOS research would never have seen the light of day - if it wasn't for my realization that NASA (and ALL space travel) is a massive / worldwide scam - unwittingly financed by the taxpayers of the USA, Europe, Israel, India, China... and even Ecuador! In other words, the GSTS is run by a multi-national "mafia" cartel - all of which are happy to defraud millions of taxpayers by exploiting the seductive "excitement" of Space Travel. I, for one, will have none of it, thank you very much. What about YOU? Are you, as a taxpayer, happy to keep supporting this massive, ongoing scam?

heniek1812
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Re: Does Rocketry Work beyond Earth's atmosphere?

Unread post by heniek1812 » Tue Nov 19, 2019 3:31 pm

Congrats Simon for a Herculean job you are doing on this forum !!!

Zubrin gives off such negative body signals that I would put an ankle bracelet on him lest he got too close to a grade school. Pettit on the other hand just looks and behaves like an idiot. Amazing circus idiocy. :lol:

heniek1812
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Re: Does Rocketry Work beyond Earth's atmosphere?

Unread post by heniek1812 » Wed Dec 04, 2019 11:56 am

Well I finally read all the pages of this discussion. It took a while as it was not done at one sitting.

Personally I'm in the camp that NASA did not land on the Moon and that they are playing games with us. What I don't know is to what extent they are doing this. What happens in Space is an open question for me as there is sufficient information available to us today to give us a sense of how easy it is to lie about just about anything. I would think that anyone who thinks critically would have to admit that we know what we are told to know. So we have basically two options, believe it or not. To not believe would entail doing work to show that it is not so. Now that may not be all that easy or in some case simply impossible for us little creatures.

Here is an example of how knowledge may look,
Science has lost its way, at a big cost to humanity
By Michael Hiltzik
Oct. 27, 2013

In today’s world, brimful as it is with opinion and falsehoods masquerading as facts, you’d think the one place you can depend on for verifiable facts is science.

You’d be wrong. Many billions of dollars’ worth of wrong.

A few years ago, scientists at the Thousand Oaks biotech firm Amgen set out to double-check the results of 53 landmark papers in their fields of cancer research and blood biology.
I once observed a discussion on a forum regarding the lack of dust on the Lunar Module during those Moon Landings. This discussion eventually touched on the subject of the waving US flag when apparently nothing was going on around it. The "explanation" (NASA) was that it was the depressurization of the cabin that caused it. So we are to believe that a tiny vent valve and 14 psi air in the cabin released into the vacuum directed its streamlined air molecules to hit a flag 30 ft. away and cause it to move (work). Huuummm, I don't think so. Here we most certainly have a situation where Joule's Free Expansion is applicable!!!

While reading those 55 pages of discussion I started to look for literature on testing of rockets in vacuum. Using Google gave me the impression that published work on this topic is very sparse. Mention was made of vacuum chambers being used but I did not see anything discussing those tests. I have access to a fairly good source of scientific literature online but I found only one paper that clearly stated that they were testing a rocket IN VACUUM. It was this paper from 1968,
First results of ignition tests on rocket engines in high vacuum: E Matt and J Bach,Vakuum-Technik, 17 (6), June 1968, 141–145 (in German)
As luck would have it access to the paper was not available except the information that it existed.

I'm not saying there may not be literature out there on such tests being made but only that I did not see any. This surprised me as I would think that knowing how an engine behaves in vacuum while working would be of utmost importance hence leading to a lot of papers addressing this situation. Going to the Moon is not driving to LA from NYC. Thinking as an engineer, just because I have everything under control in atmospheric conditions does not imply that I will not hit a discontinuity when I get my rocket into the vastness of Open Space. Faith based engineering is a dangerous profession leading to Boeing 737 MAX like situations.

Open Space changes things completely in how gases will behave (I'm not thinking of Newton's Laws) which can not be resolved through slide ruler and pencil methods (I'm thinking of the 50's and 60's). You need to test in condition as close to vacuum of space as possible to see what is going on. What one derives on paper may be completely off the wall. Seeing little literature about this put doubt in my mind. But again, I must qualify this thought with the fact that I do not have complete access to what is out there.

Here is one paper which hints at the potential of finding “discontinuities” in ones knowledge,
Highly resolved numerical simulation of combustion downstream of a rocket engine igniter
1. 1.Institut Pprime UPR3346 CNRS, Téléport 2FuturoscopeFrance
2. 2.Airbus Safran LaunchersVernonFrance
Original Article
First Online: 28 February 2017

Abstract
We study ignition processes in the turbulent reactive flow established downstream of highly under-expanded coflowing jets. The corresponding configuration is typical of a rocket engine igniter, and to the best knowledge of the authors, this study is the first that documents highly resolved numerical simulations of such a reactive flowfield. Considering the discharge of axisymmetric coaxial under-expanded jets, various morphologies are expected, depending on the value of the nozzle pressure ratio, a key parameter used to classify them. The present computations are conducted with a value of this ratio set to fifteen. The simulations are performed with the massively parallel CREAMS solver on a grid featuring approximately 440,000,000 computational nodes. In the main zone of interest, the level of spatial resolution is D/74, with D the central inlet stream diameter. The computational results reveal the complex topology of the compressible flowfield. The obtained results also bring new and useful insights into the development of ignition processes. In particular, ignition is found to take place rather far downstream of the shock barrel, a conclusion that contrasts with early computational studies conducted within the unsteady RANS computational framework. Consideration of detailed chemistry confirms the essential role of hydroperoxyl radicals, while the analysis of the Takeno index reveals the predominance of a non-premixed combustion mode.
But lets be cognizant of the fact that the people who wrote the above paper may not be right. Why? They are numerically modeling the given situation. If the model and the simulator are not representing Reality correctly then it is "Garbage In Garbage Out”. Reality is not a Numerical Simulation.

Now let’s take a look at the cross-section of a rocket motor. In the liquid fuel rockets we basically have 2 tanks, pumps, a mixer, combustion chamber and the nozzle housing.

Image

Assuming everything is mechanically designed to withstand zero pressure environment the first place that the rocket “sees” vacuum when started is inside the mixing chamber. In reading the comments here I get the impression that some people think that vacuum could simply suck away anything that is comes into the rocket's combustion chamber nullifying a chance to fire the rocket. Yes, the pressure gradient (chamber-Space) would be huge when the fluid mixture would be allowed to flow into the combustion chamber thus driving the gas toward Space. However the nozzle of the rocket has a throat constriction (converging-diverging nozzle) which has the following characteristic. With decreasing downstream pressure P_b the mass flow rate reaches a max and then stays constant at some design value know as choked flow.


Image


Thus vacuum can not suck everything out instantaneously if choked flow condition holds. I found this description of what is going on to be quite clear.

“A typical nozzle used in rocket application usually has a fixed converging section, a throat and a fixed diverging section. In this design, the hot gases leave the combustion chamber to the converging duct at subsonic velocities where they are accelerated due to the decreasing area until they reach the throat section of minimal area where they reach supersonic velocities due to flow choke, M = 1, since the flow is now supersonic, to further increase its velocity the area of the diverging duct is increasing, the flow is expanded isentropically. The expansion of the supersonic flow cause the static pressure and temperature to decrease from the throat to the exhaust, hence, the amount of expansion determines the exhaust pressure and temperature. The exit velocity of the gases, its pressure and mass flow rate through the nozzle, are the key variables that determine the amount of thrust produced by the engine. Nozzle Design (2019) “

Now at conditions different than choked flow we have a different story.

So let’s assume we can reach choked flow and this is not an issue. What could go wrong? This is where FervidGus's info comes into play when discussing PVT behavior. In particular this plot,

Image

Now I don't know if this the Phase Behavior of the fuel, LOX, or perhaps the mixture but just looking at this diagram we see some intriguing information. We know that inside that combustion chamber we are going to be at very very low Temperature and Pressure (Open Space). So what does the diagram tell us? For the substance that it represents if it was to be found in space the substance would be a SOLID!!!! [I know, I did not consider the effect of changing Volume and how that would affect phase change. Well, I leave it to you to figure that out.]

In this simplistic scenario I'd say there is going to be a slight problem with flow rate when this happens. Perhaps a pre-heater is used???? Very well, then what happens when the fuel and LOX is mixed? How does the phase diagram look like then? To pre-heat a fluid moving at a high mass flow rate is going to be an engineering challenge.

[Edited by inserting the following]
Another way to understand the operating pressure range of industrial vacuum systems is to consider gas density or the number of gas molecules that reside in a given volume. There are roughly 2.65 x 1019 or 26,500,000,000,000,000,000 molecules in a cubic centimeter of gas at 103 mbar, which is atmospheric pressure at sea level (Table 2). Under lower and lower pressure, the molecules spread out further and further, until, at ultra-high vacuum (10-12 mbar), there are only 2.65 x 104 or 26,500 molecules per cubic centimeter. At this density, there is only one molecule roughly every 0.33 mm in space. Since the diameter of each gas molecule is much less than this (4 x 10-8 cm for air, for example), there is a great deal of space between molecules. To put it into proportion, if gas molecules were grains of sand, at ultra-high vacuum they would be 1,650 meters apart. At these extremely low pressures, the collisions between molecules, which normally dictate the properties of gases, become very infrequent and a different theoretical model is required to explain their properties (the so-called Kinetic Theory of Gases).

The Continuum Theory and The Kinetic Theory of Gases

At or near atmospheric pressure, and in non-vacuum systems, the so-called continuum theory accurately describes the properties of gases. In simple terms, it tells us that collisions between gas molecules dictate the properties of a gas. The continuum theory is what we call macroscopic in nature, and governed by the gas laws such as The Ideal Gas Law, Boyles Law, and Daltons Law.

Ideal Gas Law: In a perfect or ideal gas the change in density is directly related to the change of both temperature and pressure
Boyles Law: The pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies, at constant temperature
Dalton’s Law of partial pressures: In a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases

After vacuum pump technology developed to the extent that fewer and fewer gas molecules were possible in a given volume, the governing principles affecting the properties of these gases changed, and molecular considerations became primary. Namely, the gas molecules become so spread out that intermolecular collisions between gas molecules no longer dominated, but rather collisions with the chamber walls were the determining factor affecting the gas properties. This led to the Kinetic Theory of Gases, which applies not only at low pressures (high vacuum) but is also accurate over the entire range of pressures seen in industrial vacuum systems.
These are just some of the things that came to my mind while reading this thread. I am clear on one thing, without physical testing in vacuum conditions you will not be able to tune this to such an extent that you will bet your Life and venture out there into Open Space. I ASSUME they studied this doing physical experiments in a vacuum chamber able to simulate conditions of Open Space because if that rocket doesn't ignite you are in deep dooodooo. My suspicion is that in the 1960's behavior of those rocket motors in Open Space were on the level of their TI calculator using wound wire coil memory. I repeat, IN OPEN SPACE not in the atmosphere. Lets recall how the astronauts learned to fly the LEM. First wobbling on wires and then quickly into the latest model SIMULATOR!!! :-)

I don't buy the story that going from one environment into a wholly different one is no big deal. Knowledge in one does not automatically transfer into the other. In engineering anyone who would be willing to make such assumptions better stick to working in a sandbox building sand castles. And it seems that there is such an army of people willing to do just that.

https://www.quora.com/How-do-rockets-wo ... atmosphere

In my next post I will share some ideas of potential test that I think could be done in a garage. Ciau ;-)

patrix
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Re: Does Rocketry Work beyond Earth's atmosphere?

Unread post by patrix » Fri Dec 06, 2019 11:18 am

In my next post I will share some ideas of potential test that I think could be done in a garage.
Looking forward to that heniek and great post. It’s amazing how many people that when asked what will happen if you stand inside a vacuum chamber and releases a balloon, believes the balloon will fly away. I will of course drop straight to the floor since the gas will exit freely and this is a demonstrable fact. But I must humbly remind me that I was myself not many years ago in similar lines of thoughts. I could not see why it is not possible for a gas expansion to create work in vacuum. Very odd feeling to know that things I regarded self-evident a few years ago are in fact physically impossible. :o

heniek1812
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Re: Does Rocketry Work beyond Earth's atmosphere?

Unread post by heniek1812 » Fri Dec 06, 2019 3:44 pm

patrix wrote:
Fri Dec 06, 2019 11:18 am
In my next post I will share some ideas of potential test that I think could be done in a garage.
Looking forward to that heniek and great post. It’s amazing how many people that when asked what will happen if you stand inside a vacuum chamber and releases a balloon, believes the balloon will fly away.
Hi patrix, glad you enjoyed this.

I was raised on a booked titled "Transport Phenomena" by Bird,Stewart and Lightfoot. In the case of "what is going on in vacuum" I can't quite throw everything out of the bathtub WITHOUT having done some testing/experimenting. Thought experiments are good but physical experiments are even better.

1) In the case of the water jet pack that was suggested by Simon
Image
I see one way to do a test to see if the water surface/ground is needed to support the flyer. Have the flyer fly over a surface discontinuity, a water fall or a deep ditch where the water surface suddenly disappears . Then see what happens to the flyer when he finds himself over this. We have two possibilities not much or drops lower down toward the new horizontal surface.

Alternately we (where I am it is freezing) can take a garden hose and start the water at such a rate that if we hold the hose some distance from the water spray we will have the same situation as the water jet pack.
Image
Water jet keeps the end at a constant height.

I have played this game in my younger days, a sort of "walk the dog" trick. Now do this except now over something that is around the house that rapidly goes below the ground level. Where I am we have small windows to the basement below the ground surface level and there is an opening area made of concrete (oil drum would also do the trick). Hence we could walk this "water dog" first on the ground then move the hose so as to locate it over the opening. If the flow rate is constant we should see one of two possibilities, nothing happens or it drops lower :-)

2) Rockets in Open Space. I am in the camp that what I know I know it because I have been told so. We on Earth (the little people) have no contact with this environment. Everything I have learned has been related to things working in our atmosphere. Did something go into Deep deep Space? I have no clue. I was told it did and that is it. Faith Baby Faith.
The experiments with rockets in vacuum on YT are BS. It looks nice but it misses on one fundamental aspect, Scaling Law. If you want to see how and actual rocket (potentially) will work in Open Space you need to scale everything such that the experimental environment will scale-wise come close to (I'm going to get hit here) Open Space. What I would do,
1) Make a tiny rocket
2) Lay it within a glass tube (little friction) with jet sticking out just outside of this tube.
3) Place this inside of a tank the size XXX. XXX would need to be calculated based on rocket size, jet/plume size, etc. so that boundary problems in the first ms of firing would not be an issue. This is where Scaling Law would come into play.
4 Evacuate to ... well as best a vacuum as you can get.
5) High speed cameras
6) Ignite it and observe the first ms of the burn. The rocket has one degree of freedom.

Moving or Not Moving?

3) Now a few words about the discontinuity air-vacuum. I will refer again to this article,
https://vacaero.com/information-resourc ... heory.html
This is not a trivial situation as some people in the Internet would like us to believe. Hell, just reading this should give anyone familiar with thermodynamics, fluid dynamic, mechanics and space communication a pause and a thought "will what I know work there?". Many without blinking say YES they believe that between 1960 and 1969 all issues with traveling to the Moon and back were figured out??? Wow, that is a lot to swallow. I don't buy it.

Now for an experiment. Back again to our water hose. Get a large oil drum and fill it with water. Set a table like surface next to the drum so that water level and the table surface are the same. Now get that hose and do as I said above, "walk the dog". Make sure the "dog" maintains a constant height for the given flow rate. Now walk it from the table to be above the water and then slowly push it toward water surface. What happens?

As I recall the "dog" will get sucked underwater. Like I said I can not do this experiment today but I recall doing this when filling a bucket. I recall always feeling a distinct pulling sensation when doing this. Hence, when in the air the thrust is enough to keep the "dog" at constant height but when contacting water the forces change. I would have to do this again as my memory could be wrong on this. But the experiment would be a good one to see if surface comes into play in the dynamics of the water jet.

Behavior at a "discontinuity" is often very abrupt. That's how ships disappear off the surface of the oceans. How abrupt is this when you are dealing with air-vacuum????

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