The Space Hose


by gutemine
Tags: hose, space
gutemine
gutemine is offline
#37
Sep14-10, 04:52 PM
P: 59
Quote Quote by russ_watters View Post
Before you can say strength is not an issue, you need to actually calculate the pressure required inside the hose at the bottom. Of one thing I can guarantee you without doing the calculation: the pressure will not be trivial. It will matter.
I actually calculated the pressure as good as I could (and included this in the slides). I'm fully aware that the calculation is good only for maybe the first few km at the bottowm (and I'm not even sure about this), but because the airpressure goes down dramatically beyond a few km (50% after 5km) these are the critical ones, so using this formular up to the top should OVER estimate the problem, shouldn't it ?

Quote Quote by russ_watters View Post
The question is so badly conceived as to be unanswerable. If you supply 1 bar of pressure at the bottom of the hose, no air will flow because that's the static pressure of the column of air. You need to provide greater than 1 bar of pressure to make the air flow.
Sorry for the bad wording, but this is a language problem for me (Englis is not my mother language) If the hose would be vertically - one end 1 bar (standard athmosphere) and the other end of the hose open to a huge vacuum chamber, allowing for a reasonable time of stationary flowing would be probably have been a more precise description.

But if I understand you right the pressure gradient should be similar to a hose at 1 bar all the time and 1 bar surpluss at on end (=2bar) , and open to the 1 bar atmosphere at the other end ?

Quote Quote by russ_watters View Post
Without the weight of the hose, you can't calculate the pressure gradient.
This is what the slides do - asuming a minimal size of the hose which would be reaslistically within the N-proze budget (I just googles PE foild prozes and checked what diameter and thickness I could afford)

After getting this weight (300-1000kg for 100km = amazingly low) I checked how fast the flow would need to be to create this weight as friction loss = power on the wall of the hose in the direction of flow.

Quote Quote by russ_watters View Post
So you need to select a possible material first, find its weight, then calculate the required friction force to hold it up. Based on what you said in your second post, it sounds like you deceived him. Did you tell him that it was at 100 km altitude and supported by the hose? Because in your second post, you said "being outside of the launch device" which makes it sound like it isn't still supported by the hose.
This is exactly what I did (but I decided on a payable and available material first - as the slides say - I hate to wait for nano-tubes) Paul is fully aware of this - but other teams which plan to combine balloon with rocket launch also decided first to build and test their ballon for reaching the 30km (and not any real orbital speed there either - even on a very windy day) - and he didn't bann them either - why should he, because they also meet the spirit of the N-priize and have the same unrealistic chance to succeed.

And it should be possible to feed air ONLY with the needed kinetic energy to be eaten up by the friction and not a dramatic pressure surpluss too, but the slides also contain the calculation for the 0,6 bar needed if all pressure loss would have to be feeded. And I checked with the tank strength formular that the pulling strenght of dyneema could hold this not really exciting pressure (unless you are a thin PE foild) even at the bottom. But I'm not even sure if this pressure surpluss strength would be needed. That is the great thing about Bernoully that he shows how easily you can convert pressure and flowspeed (only a diamter change away) - and the friction is going up with the v in case of turbulent flow. You now get ecactly the weakness point in the inflatable space tower approach, and the strength of using the friction force. But the slides also contain a calculation on the wors case (hose closed at the top), then the pressure is only slightly higher even in the worst case of a cyclinder with all the 300km weight on top - simple piston formular what supressure you get - but I' m not sure if this is correct to be overlayed on top of the hydrostatic pressure ?


Quote Quote by russ_watters View Post
In the rules, it says the satellite cannot be attached to the launch vehicle. So it is clear to me that just sitting on top of a tower - at any altitude - does not qualify. You're missing the point: just achieving 100km of altitude and sitting on a tower doesn't solve the problem they are trying to solve. Getting into orbit is a big problem and solving it is the goal of the N-Prize. Just sitting on a 100km tower - as daunting a challenge as that is - is much easier than getting into orbit. Once you are clear with the N-Prize organizers about the concept, they will realize that your device does not meet their criteria.
Yes, but if somebody would be able to build a canaon on ground which creates orbital speed on its outlet (but no height at all - the inverse problem of the space hose) he would also qualify if he at least has an idea how to solve the height problem (maybe by pointing it upwards, double the speed and overcome the air resistance by using a big buble gum ball shield conitinuously bringing as isolation for protecting the N-SAT inside -- why not let him participate and have fun trying ? And yes, I'm aware that his N-SAT would be smashed when leaving a normal cannon (unless maybe it would be just rolled alluminium foil and not expensive electronics - sorry for the joke)
gutemine
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#38
Sep14-10, 04:58 PM
P: 59
Quote Quote by jarednjames View Post
Gutemine, I see little point in you replying to anything else regarding your entry into the N-Prize unless you can explain how you will get around rule 11 as I have pointed out above.

Anything???

In the rules it say's you have to prove it completes 9 orbits and that they have to be satisfied with the evidence. The "I broadcast, so I am here" business let's you know exactly what it is you are tracking, a simple radar reflection does not.

Besides, how would you deploy 1m^2 of foil with less than 19.99 grams to work with? A simple transmitter and battery would take far less than any device for constructing a foil sheet.
Sorry, I'm still not finishing answering the old questions and you have already a new one :-)

The aluminium foil N-SAT was just an illustrative example to overcome another problem.

If I would decide not to put the N-SAT on top (see the slides for details - for example because I need to blow it out) I could for example make it go up inside the hose with a balloon or a parachute (remember I have air flowing up to 100km with a pressure of at least 200PA and pretty fast too - meaning a ballon is not only relying on buoyancy) - and the later would maybe already have all the Aluminium foild I need.

Just another example of creative thinking: Cut a circular 1m piece of Aluminium foil, then cut stripes to the center of let's say 5cm (yes, you will loose a lot of triangualr foil pieces due to the diameter loss). If you then roll the aliminium foil arms by your fingers to the center and would take this device to space - the arms would unroll without any problem or extra energy on relief and if you would release it from your hand with only a minimum spinn it would form a nice christmas star in space.

But you are asking already for the propellor - could we discuss/finish the wings first ?

PS: But don't be discouraged, input and ideas are welcome - I just share mine with you and asked for help - remember the beginnign of the thread?
JaredJames
JaredJames is offline
#39
Sep14-10, 05:05 PM
P: 3,390
Quote Quote by gutemine View Post
Just anotehr example of creative thinking: Cut a circular 1m piece of Aluminium foil, then cut stripes to the center of let's say 5cm (yes, you will loose a lot of triangualr foil pieces due to the diameter loss). If you then roll the aliminium foil arms by your fingers tpo the center and would take this device to space - the arms would unroll without any problem on relief and if you would release it from your hand with only a minimum spinn it would form a nice christmas star in space.
Can anyone verify this unrolling of the aluminium foil in space? Based on the foil I have, when I roll it up with my fingers it shows no sign unrolling when released, it just holds its shape. Even if I give it a 'nudge'. I don't see why this would be different in space.

I know I sound really discouraging right now, but I prefer to see solid proof any of what you propose is possible.
gutemine
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#40
Sep14-10, 05:28 PM
P: 59
Quote Quote by jarednjames View Post
So by the logic I'm seeing here, everything is orbiting the planet earth, plants, animals, pebbles, the ocean.... (you get the idea).

Anyway, if my understanding of what Gutemine is saying, if you were to build a skyscraper 100km high, he (and apparently the N-Prize judges) would consider anyone on the top floor to be in orbit. And if they were to fly a kite that would be considered a successful satellite launch and orbit (despite still being attached). Am I correct?
Which means they must also consider a person in a 1km skyscraper (or any of the above examples) to be in orbit. The only reason they can't win is because of the "must be above 100km" rule. I think that's a fair assessment of the situation here. This 'space hose' is simply an extension of the earth in the same way as Mount Everest, in fact, why not just deploy from atop such a mountain so you don't need such a long pipe.

On a more serious note, where would you get 100km of such a hose within the budget? What would you use to pressurise it? I've never heard of any systems that could apply a suitable pressure over 100km, especially not vertically into space.
The hose material and its cost are in the slides and also a very basic energy calculation for the blowing power needed - and because the blower would be only supporting the launche device it doesn't could for the budget - only the fuel cost.

But off course such thin PE foil would probably not really work beyond a few km even on a windless day, even if you add a pendular stabilized diffusor o top pulling it upwards by finally blowing the air downwards.

But as a POC within the budget this is not more or less then what others spending thousands of dollars on prototypes or reasearch (also not counting for the budget) before their first test flight would do.

And achieving 1km with such a weird approach (a model air plane motor and propeller could support in this case the 8kg of weight if you use PE foild that you can buy from the next grocery literally speaking) is a similar archivement then a 30km weatcher ballon launch to test the nice N-SAT that you might have built.

And as I already said at the half bakery - if somebody is willing to try it I will bring the beer !
gutemine
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#41
Sep14-10, 05:36 PM
P: 59
Quote Quote by jarednjames View Post
Can anyone verify this unrolling of the aluminium foil in space? Based on the foil I have, when I roll it up with my fingers it shows no sign unrolling when released, it just holds its shape. Even if I give it a 'nudge'. I don't see why this would be different in space.

I know I sound really discouraging right now, but I prefer to see solid proof any of what you propose is possible.
Thanks for trying - you are now subcontracted to find a way to MAKE it unrolling (which should be a solvable task - but not sure about the easiness) :-)

But you now get the idea - Congratulation !

You think/make up a possible solution, check/calc/try it - and maybe have to come up with the next/better one.

Even the space hose is just a creative combination of existing ideas when I tried to figure out their problems and tried to overcome them (and created new ones which I'm pleased to hear from you, and maybe even solve with you together)

PS: That's why I included the parachute or the aluminium ballon in the slides (and not the Chistmas star) - they would work much better (actually the ballon on ground would be very similar to the parachute anyway - because you can hardly fill it to allow for the expansion on top (if it is not an hyper-ellastic weather ballon), but with 3.5m/sec you can already blow a lot upwards if it is only 9,9 gram). And some aluminium foil on the outside of the hose every few 100m would work definitely and form a nice dotted line to space on radar and also reflect the sun compared to the black foil hose - no need for expensive monitoring devices there either.

So sorry for misleading you - it was only for educational purpose (and hopefully you will not charge me for the foil).
JaredJames
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#42
Sep14-10, 05:40 PM
P: 3,390
Please can you answer regarding rule 11, with point A I still don't see how you achieve orbital velocity? Point B speaks for itself.
gutemine
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#43
Sep14-10, 06:02 PM
P: 59
Quote Quote by jarednjames View Post
Please can you answer regarding rule 11, with point A I still don't see how you achieve orbital velocity? Point B speaks for itself.
Now you are getting to an interesting point - remember I asked for advice and did some calculation already :-)

What really amazed me was when I did the ideal gas formular between top and bottom - due to the huge pressure difference (approximatel 1:1000) the expansion would be also HUGE (but less then the 1:1000 due to the temperature drop)

If the hose diameter would be fixed the speed of the air in the hose without any diffusion or diameter change would be already pretty close to orbital speed (aprox 5400m/s in my assumed example, and orbital speed is about 7400m/s if I remember right - it is late already, and the excact number is in the slides).

I know that this is by far hypersonic even at the low 100Pa pressure in 100km height. So you have 2 ways - try to find out if such a hose can withstand that (I think in the slides I asked 2x if this hose would work like a kind of upright standing de La Valle nozzle with fixed diameter by using not the diameter change to accelerate but the decreasing hydrostaic pressure of the medium)

And don't say instantly no - we still can do the Dnymeema strengthening as on the bottom, and still outside pressure and inside pressure should not differer that much on a hose (0 without friction I think - but not sure about this). So maybe you already have air at orbital speed in the hose without knowing ???

Actually this would be pretty logic in my understanding - because of the expansion into vacuum after leaving the hose this air is more likely to mix with the sorrounding air at very low but similar pressure, instead of dropping like a stone because of the not orbital velocity argument (Paul was pretty clever by stating some loose particles in orbit don't qualify).

But even if you keep the speed down in the hose by increasing/decreasing hose diameter (depending if flow is above or below sound speed) or by a diffusor recovering some of the flow energy and pressure loss you still have 620m/hour going to 100km height and you could convert this to amazing speed as the ideal gas law would suggest (that's how the de Laval nozzle blowout made it into the slides - because it can work also as a diffusor to recover some pressure).

This means we should first check the math for the gasflow (then for the friction) and if we know which calculation is right (pressure drop due to friction is pressure surpluss, or only speed surpluss because of hose not pipe) hypersonic or not.
Just do some simple math with fixed temperature - if you start with 3,5m/sec flowspeed if you had isothermic flow after dropping the pressure approximately 1:100 you would be beyond the 340m/sec of the speed of sound - actually this 1000Pa is present approximately at the height of 45-50km - If I remeber right my physics lesson this is one of the reason why there the temperature recovers to almost 0 degree of celsius (so it is actually almost isothermic - but not on the way in between) after having dropped to -60 degree of celsius between 10.20km. And don't be too afraid of the sound barrier - remember we are expaindig here very slow over multiple km - this is as smooth as a turbulent flow probably can get.

So half of the hose could be flowing below and half above the speed of sound (up to orbital speed) ? Not very likely - but input/critics is welcome ?

Finally you would still have all the remaining classical options like rocket start from top too if you feel more comfortable with that - remember you 'only' need to add 30,5MJ of kinetic energy for 1kg, which means peanuts for the 9,9 gram - and yes, I know that it is not that easy, that's why I would prefere to use what we already have (see previous paragraph)

And I already pointed out, even standing on the top of such a structure and still not leaving it on the 99th testflight would be quite an achievment and would give an ant or a cockroach astronaute wings at the NASA :-)



gutemine
JaredJames
JaredJames is offline
#44
Sep14-10, 06:11 PM
P: 3,390
30.5 MJ - that's 30.5 Mega Joules

Are you sure, that's a huge amount of energy?

EDIT:
Quote Quote by gutemine View Post
even standing on the top of such a structure and still not leaving it on the 99th testflight would be quite an achievment and would give an ant or a cockroach astronaute wings at the NASA
gutemine
Why would standing on top of a 100km structure cause you to leave it? You wouldn't be travelling at orbital velocity to overcome earths gravity. The only time you would 'take off' from a structure would be when you are past the 36,000km mark. Or am I misreading it?
gutemine
gutemine is offline
#45
Sep14-10, 06:31 PM
P: 59
32MJ is amazingly small - it is the burning energy of 730g of jet fuel and is the quivalent of 1km in orbit (pure cinetic and height energy needed)

I didn't say that standing there would make you leave - but I actually would enjoy the view (and the lack of sickness due to freefall). I just came back to the point of climbing that height is also nothing you should not feel proud of.

Could somebody please comment on the cas dynamics and speed question, because the real answer on getting (or having already) the needed orbital speed lies there in my opinion.

PS: If you use flowing air as 'fuel' to get there containing all the needed energy it would be idiotic to use something else for the final step to orbit anyway.
Just think about your gardening hose - inside the hose the water flows pretty slow, but after it goes trough the nozzle you can entertain the neighbour with it :-)

but I have to get some rest know - n8
mugaliens
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#46
Sep14-10, 07:41 PM
P: 594
Quote Quote by jarednjames View Post
So by the logic I'm seeing here, everything is orbiting the planet earth, plants, animals, pebbles, the ocean.... (you get the idea).
No, as there remains the 99.9 km height ruling.

Anyway, if my understanding of what Gutemine is saying, if you were to build a skyscraper 100km high, he (and apparently the N-Prize judges) would consider anyone on the top floor to be in orbit. And if they were to fly a kite that would be considered a successful satellite launch and orbit (despite still being attached). Am I correct?
That's what I read in the rules.

On a more serious note, where would you get 100km of such a hose within the budget?
It's pretty inexpensive stuff, about $6 for 100 m, which means 100 km of it would cost $6,000.

What would you use to pressurise it?
A fan.

I've never heard of any systems that could apply a suitable pressure over 100km, especially not vertically into space.
Ok, then - the bleed air from a turbofan engine.

My primary concern is how does one get the column to rise? I would imagine it could be laid out on a straight, 100 km stretch of road somewhere, but once it's pressurized, it will not magically rise into the air, nor would an articulated exhaust "lift" nozzle at the end be able to lift it's entire length. In fact, you'd need many such computer-controlled and articulating nozzles along its length, which would require a tapering design to manage the airflow properly.

There are some huge challanges with this approach, no doubt.
DaveC426913
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#47
Sep14-10, 07:45 PM
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Quote Quote by mugaliens View Post
That's what I read in the rules.
How could you continually misread it? The word 'orbit' is used numerous times.
JaredJames
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#48
Sep14-10, 07:58 PM
P: 3,390
Ok, I was going for sarcasm with the first two paragraphs about "the ocean being in orbit".

I understand the whole orbit situation, I was simply asking for clarification on what gutemines understanding of the rules where by using those examples.

Regarding the 99.9km rule, I did mention that later on to say why someone couldn't win it by standing on the ground.

I'm still waiting for an explanation of how he would pass rule 11. Again, scenario a) requires the satellite to be at orbital velocity, I don't see how he will achieve this. Scenario b) is clearly breaches the rules.

$6000 is not cheap when the budget is supposed to be under 999.99 (about $1500).
mugaliens
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#49
Sep14-10, 08:01 PM
P: 594
Quote Quote by DaveC426913 View Post
Yes. Their use of the term orbit.
No, that's your definition, Dave. That's not what's specified in the rules.

If he updated his proposal such that it claimed to do nothing more than sit at the top of the tower, I guarantee...
Unless you're one of the N-prize judges, you can make no such guarantee.

Please re-read. It's up to them, not you.

"These rules may be amended at any time without prior notice. Such amendments will normally (but not necessarily) be made in order to clarify points, to close loopholes in order to ensure that all entrants remain within the spirit of the N-Prize, or for unavoidable legal reasons. Therefore, all entrants are strongly advised to contact the organisers before and during the preparation of their entry."

Gutemine did so. They (the N-prize judges) confirmed his design meets the rules. You're trying to second-guess their decision, which has already been made, according to gutamine.

If you don't like their ruling for some reason, talk to them.

Quote Quote by jarednjames View Post
I'm still waiting for an explanation of how he would pass rule 11. Again, scenario a) requires the satellite to be at orbital velocity...
Actually, this is a misnomer. All the rules state is "but orbits will not count toward the 9 orbit target until such over-weight items have been jettisoned or consumed. As noted, other items (spent rockets; shielding etc) may enter orbit with the satellite, but must not remain attached to it."

Therefore, he could meet the rules with a 15 gram ball balancing on the column of expended air, like a ball balancing in the breeze of an upturned fan.

Let's get back to the spirit of the N-Prize itself, something many here keep forgetting: "it is possible that loopholes in these rules may make it possible to complete the challenge in a spirit not intended by the N-Prize organisers." However, what is that "spirit?" Is it to think inside the box like we always have? Or is it to put a small object 100 km or higher and keep it there for 9 days?

Let's go back to the rules: "The N-Prize is aimed at amateurs, enthusiasts, would-be boffins and foolhardy optimists." and "Any method of attaining orbit is acceptable, provided it does not breach the rules or spirit of the N-Prize Challenge. Examples might include (but are by no means limited to) conventional rockets; balloon-launched rockets (rockoons); gun-launched projectiles; or combinations of these or other methods."

The organizers have already stated that a 100 km geostationary orbit meets both the spirit and the rules of the N-Prize. It's a matter of altitude and duration, not orbital velocity.

$6000 is not cheap when the budget is supposed to be under 999.99 (about $1500).
You are absolutely correct! I think one might be able to find it for less. How much less I haven't a clue, but possibly a lot less, as the small amount I found is retail quantity, and I have no idea what the diameter was. I just did a couple of quick searches.
DaveC426913
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#50
Sep14-10, 08:04 PM
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Quote Quote by mugaliens View Post
No, as there remains the 99.9 km height ruling.
Let's just be clear; that is a separate criteria, independent of achieving orbit.

Achieving orbit can be done without achieving 100km altitude.
Achieving 100km altitude can be achieved without acheivng orbit.
The N-prize requires both.

That being said, this chair and the oceans are not in orbit by any criteria, let alone the rules of the N-prize.

Like the chair and coean, the satellite on top of the tower is also not in orbit.
DaveC426913
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#51
Sep14-10, 08:05 PM
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Quote Quote by mugaliens View Post
No, that's your definition, Dave.
No it isn't.
Quote Quote by mugaliens View Post
That's not what's specified in the rules.
It is. By their use of the word.
JaredJames
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#52
Sep14-10, 08:23 PM
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Quote Quote by DaveC426913 View Post
That being said, this chair and the oceans are not in orbit by any criteria, let alone the rules of the N-prize.

Like the chair and coean, the satellite on top of the tower is also not in orbit.
Ok, really clarifying now, I was not saying the oceans etc are in orbit, I was simply pointing out that under the terms they have granted gutemine for the n-prize challenge, all could be considered it. (The fan + hose + item on top of tower would still be resting on the ground, in the same way a chair or the oceans are). But they can't win because they are below the 100km rule.

I completely agree that unless the satellite leaves the tower, it is not in orbit. The moment it leaves the tower, if it is not at orbital velocity, it will fall back to earth. Period.

As for "balanced on a column of air" I'd like to see you do that. What you are proposing is firstly erecting a 100km tower and then expecting the atmosphere to have no effect what-so-ever (wind etc) and then being able to keep it so steady a 9 to 19 gram satellite could balance on it. Yeah, good luck with that.
mugaliens
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#53
Sep14-10, 08:26 PM
P: 594
The spirit of the N-Prize is well-expressed in the rules. They're looking for out-of-box thinking and innovation, which I think gutemine is clearly doing.

Some appear to be troubled by this and are making every attempt to cram the ideas and concepts back into their version of in-the-box thinking, which is contrary to the N-Prize intent.

Again, for the nth time, the N-Prize organizers have clearly and repeatedly stated their interest is one of achieving altitude and duration by means of out-of-the-box thinking.

If you can't tolerate this for some reason, I respectfully suggest to reexamine the goals, pupose, and spirit of the N-prize as clearly stated in their rules before revisiting this thread.
DaveC426913
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#54
Sep14-10, 08:27 PM
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Quote Quote by jarednjames View Post
Ok, really clarifying now, I was not saying the oceans etc are in orbit, I was simply pointing out that under the terms they have granted gutemine for the n-prize challenge, all could be considered it. (The fan + hose + item on top of tower would still be resting on the ground, in the same way a chair or the oceans are). But they can't win because they are below the 100km rule.
You get it and I get it. Mug and glutamine don't.

But neither do I think they have been granted this. I think glutamine is misunderstanding.


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