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Carmack's Throatless Rocket Engine
Baldrson writes "John Carmack is working a potentially disruptive technology: A throatless rocket engine. Its made from plain aluminum pipes with few machined fittings. Carmack says: "The great thing about these engines is that it only takes me two nights to machine the parts, so we can test two engines a week if necessary." It scales too: "If this line of tube engine development works out, we can make a 5,000 lbf engine with very little more effort than the test engine." This is what makes disruptive technology development work: Cheap, fast turnaround on on redesign producing technologies that scale. If this works, the NASCAR guys may really start entering space competitions like the X-Cup."
He's going to set his beautiful hair on fire, I just know it. Don't do it john!
NJ Local Music Scene
I thought it was the X-Prize? Or did I miss something?
the Pipedream finally becomes reality.
..is to eventually make a fully working version of the BFG. This is just the first setp.
A morning without coffee is like something without something else.
I mean, why have a genius like Carmack working on shooting rockets into space, when what the world really needs is a better personal rocket launcher... for shooting rockets into other people.
In an effort to propel himself high enough to reach the Quad Damage, John Carmack fragged himself with his own rocket launcher. He will be remembered by a rabid community of gamers. We will all miss you John.
Carmack's UAC Rocket getting ready for its first flight. NASA, Beware!
Not that I'm one to criticize (large liquid-prop rockets built by Skyshadow: 0), but everytime they get an engine together and start encountering difficulties it seems like they scrap it and just go to another design. Assuming that rockets are anything like the mechanical things that I understand (cars), this just isn't how you can go about these things -- you've got to settle on a promising, well thought-out design and then dedicate your efforts towards ironing out the kinks or you'll perpetually be just past "go".
Anyhow, just the impression I get from reading the updates.
Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
If you would have read through armadillo's website you would see that he has been putting a serious effort in. As an aerospace engineer who has been keeping tabs on John for several years I can assure you he's got his design well thought out.
Throatless rockets aren't new... they've been around for awhile. They aren't as efficient as a throated rocket but they offer some operational advantages (namely in throttling, which is nice for a powered reentry).
-everphilski-
"John Carmack is working a potentially disruptive technology: A throatless rocket engine."
So I guess the porn industry will not be funding this?
lbf is pounds-force it is still the international standard for the thrust an engine will produce. Like the trent 900 RR engine will produce upto and including 90,000lb of thrust
The other unit for this is just plain NEWTON or N
... this is the same guy that made a serious bid for the X-Prize. I think he knows how not to blow his nozzles.
s North America really so backwards and stubborn they refuse to use units that the rest of the world is perfectly happy with
yes
This isn't rocket science you know.
When a true genius appears, you can know him by this sign: that all the dunces are in a confederacy against him.
since I'm not a rocket scientist, I fail to understand the importance of what John is doing (or has discovered? surely throatless engines aren't an entirely new concept are they?).
I understand that this *might* impact manufactoring costs, but exactly how is this revolutionary, or going to affect us? Are we going to sport some pocket engines in the future? Are they more environmental friendly? Do they scale well? Will it run Linux?
Seriously, after reading the story and the article a few times I haven't yet understood half of it.
Hack your mind out of its sandbox.
I'm miffed that he didn't express it in stone-furlongs.
Before.....
After.
If this was new rendering technology, I would probably take a second look, but what new innovation can Carmack add to rocket science. I akin this to some guy figuring out a cool new way to launch a potato from a pvc pipe, but not innovative science. He is a brilliant guy, but he doesn't work for NASA... well on second thought maybe he should.
I thought they always measured rocket motor efficiencies in rods/hogshead.
No, we are not "stubborn". And yes, the standard system SUCKS. The reason we haven't moved to metric is that we have too much momentum built up in society for anyone to switch over. What needs to happen in America is a migration. This is slowly being done, but it will take many more generations beyond me.
I was tought the metric system in grade school. However, I only use it personally when working on cars. Most of the time GM will have a mix of standard and metric bolts these days.
Life is not for the lazy.
I think Mr. Carmack has a bit of a Pygmalion complex with Commander Keen. To the heavens!
Well then, that's no problem, as lbf means "pounds-force", not pounds*feet (which would be a measure of torque).
Here's a hint: a serving of beer weighs about a pound. One lbf is how much force you must use to hold it up (assuming you're drinking it somewhere on Earth).
It's also equivalent to about 4.44 newtons, but that unit is too small to provide a satisfactory serving.
So you cant think in Pound-feet? can you think in Newtons? which is the other unit to describe thrust?
I might be a Metric European BUT for THrust I just hate the Newton
Pound-foot, tells you how many pounds can be moved a foot, simple
He reports only an ISP only in the low 200s, this is not efficent enought to get to orbit.
I think that "lbf" here is just for "pound force."
There are two similar versions of the U.S. customary system. The more consistent of the two uses the pound as the unit of force and the slug as the unit of mass. All the equations you know and love work well in this system. In these units, for example, F=mg where g = 32 lbs/slug = 9.81 N/kg
There's also a second system in which the unit of mass is not the slug but the pound -- in which case there needs to be a distinction made between "pounds mass" and "pounds force." So you get two units, "lb" for mass, and "lbf" for force. This is what you're seeing here.
Unfortunately the second system has a way of screwing up equations; you need to throw in extra 1/32 conversion factors to lots of equations that relate forces to masses, and it's generally a pain to work with.
From the site ...
"Too many users... blah blah blah
Probable cause: http://www.slashdot.org/
Try again in a few seconds...
-xian@idsoftware.com"
That has to be the best 'server down' message I've seen in years
"If you would have read through armadillo's website you would see that he has been putting a serious effort in. As an aerospace engineer who has been keeping tabs on John for several years I can assure you he's got his design well thought out." - by everphilski (877346) on Sunday August 07, @11:07AM
:)
That is good to hear, that another pro from that SPECIFIC field is seconding his designs, and as far as thinking things out (when it comes to this guy, Mr. Carmack)?
I believe you.
E.G.=> Ever heard of "Carmack's Reverse"? If not, look it up, & check it out... this showed me this guy can THINK, & "outside of/above & beyond the box"...
Not every computer scientist has things like that to his credit!
IMO, these types of things (engines/algorithms) to overcome limitations ARE the mark of what others called him here:
A genius.
IMO, he is.
After all, his wares from IDSoftware & contributions in the OpenSource world show it. There's little arguing with that & little arguing with success.
*
APK
P.S.=> I wish him the best of luck to be quite blunt & honest about it...
Like he himself has said (not a direct quote):
Once you've accomplished a decent amount in 1 particular field? It's good to take a "hard right turn" into another one that interests you and make a career of it!
In his case it would NOT surprise me one iota if he does not end up becoming a breakthru maker in it as he did in computer science...
People like these, just give them time & experience: They're the types that always come thru!
Yes, this is "intellectual/technical hero worship" & he is one of the few out there I give that much credit to!
He, along with Mr. Anders Hejlsberg (of Borland (TurboPascal/Delphi designer) & Microsoft (C# & Visual Studio improvements) fame)... they're 2 of the 'outstanding' individuals in THIS field (computers) out there now, truly outstanding ones.
There IS a diff. between pretty good, good, great, & absolutely outstanding/in a league of their own.
Never underestimate folks like those, they often surprise... apk
Now "disruptive technology" will become the new buzzword. Suddenly AJAX will be called disruptive technology. Linux will be called disruptive technology. The next P2P file sharing protocol will be called disruptive technology. Fuck!
How much loss of efficiency are we talking? (presumably Isp). Would that pretty much kill any chance if using them for space launch vehicles?
Human genome = 3 billion base pairs = 6 GBit. Windows + Office = 20 Gbit. Which is more impressive?
But... no throat, no supersonic flow... sooooo much energy being lost there...
It doesn't have to be great, it doesn't even have to be good, it only has to be good enough.
The very first internal combusion engines could barely drive a horseless carriage at 10mph just a century ago. Today, Formula 1 are capable of 220+ mph and can go round bends with 5G of lateral acceleration.
Government of the people, by corporate executives, for corporate profits.
rtfa and/or stfu. noob.
What the hell is a lbf? Is North America really so backwards and stubborn they refuse to use units that the rest of the world is perfectly happy with.
;)
Yes. We are able to use non-decimal units because, quite frankly, most applications call for non-decimal units.
Once you've been to the moon and back, THEN maybe we'll consider your ideas on measurement.
Not only was it non-intuitive, it even led you to the wrong conclusion! It stands for pounds of force, which are equal to about 4.45 newtons. The "f" stands for "force" to distinguish it from pounds as a unit of mass.
For anyone having trouble getting used to metric, think of one newton as the amount of force required to lift an apple off the ground.
If this line of tube engine development works out, we can make a 5,000 lbf engine with very little more effort than the test engine."
Interestingly enough, as a kid I made my own alcohol fueled rocket motor, based around a bottle filled with a alcohol/oxygen mix, a small orifice, and an ignition source.
If thing were the way I'd like them to be, I could have scaled it up to be something like twice the power of the Saturn V rocket. But after the first successful test, I was unable to scale the device.
Best of luck to John, may he do better than I did.
Yeah, exactly, there's nothing revolutionary or "disruptive" about it. Its crap. If he were really looking for a useful new design he'd be looking at something like this that automatically adjusts for maximum efficiency as external pressure changes.
- "Hear that?! The percolations are imminent! Cease your ingress!"
It's spelled amateur.
Does it matter? You aren't gonna get any regardless.
Not really.
1N is defind as lifting 1kg 1m
Were pretty much engines jury rigged on to carriage bodies. That's approximately the state of the art for spacecraft at the moment. To make space travel as accessible as road travel, it has to become cheap.
Government of the people, by corporate executives, for corporate profits.
I know it sounds crazy, but sometimes it is much easier to evolve a nice solution to an engineering problem than to calculate one. For example calculating robustness and reliability is very difficult. It is much easier to simply measure it.
Change the unreliable bits to something else, and see if it breaks. If you kill off the most unreliable part of your design each time, I guess you can work out what happens.
I'm not saying that you shouldn't use simulations or calculate anything at all. Use them as guiding hands, but don't let them alter the process. The problem is many people think that it is easy to create some sort of `breakthrough' design. It isn't; if it was, then everyone would have them.
Per Carmack's writeup, 1.5% ISP loss, which is lost in the noise for their purposes. He also mentions that he thinks he can get about a 15% increase over their initial tested ISP, which was about 190 seconds, and that that would put the ISP very close to the maximum value for the propellant of 220 seconds.
Property law should use #'EQ, not #'EQUAL.
*ahem*
/
http://www.cnn.com/TECH/space/9909/30/mars.metric
Do not trust this signature.
This "throatless" engine seems more useful for testing injectors than actually extracting impluse (propulsion). The narrow throat of engine followed by a expanding nozzle allows for the chamber pressure to be high (good) while the exhaust pressure is lower (also good). This site explains much this and in fact says, "If the pressure ratio (and thus expansion ratio) [like Carmak's design] is 1, then F = 0. The only thrust produced by such a nozzle is the pressure thrust, or Ftotal = (Pe-Pa)Ae. Such a nozzle, of course, would have no divergent portion, since A*/Ae=1, and would be a badly designed rocket nozzle!"
;)
Simon
Ok, first, you don't get shockwaves in nozzles- not unless you've got a rough nozzle surface, which is a bad idea, because the hot gas comes to a screaming halt ("stagnates") and the local temperature goes way up, and then the nozzle melts. And yeah, Carmack knows that a nozzle and throat needs to be smooth, this isn't the first bipropellent engine he's built, and he's widely known not to be stupid. :-).
Oh yeah and actually, even these 'throatless' engines has a throat, but it's kinda hard to spot :-), the gas makes up its own mind where to put the throat, in realtime- the throat is defined to be where the gas goes sonic, and this always happens when the combustion pressure is more than 2.7 times the ambient.
You mainly get shockwaves in air inlets in jet engines, not in the nozzle. You also get shockwaves in the exhaust plume of rocket engines where the exhaust kinda bounces of the external atmosphere, but that's harmless (actually kinda pretty google on "mach diamonds"), and they form wayyy downstream of the exit. Oh yeah, and a rocket launching, once it passes about mach 0.85 gives transonic shockwave around its nosecone, and then later supersonic shockwaves there, those can cause damage, but they rarely do.
So, these non existent shockwaves can't damage any equipment, or waste any energy. Oh yeah, and did I mention there aren't any shockwaves? :-)
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Well, considering that HE is the one building this thing YOU don't need I don't see what your gripe is...
Would someone please be kind enough to copy-n-paste it?
Take the 90-Day Challenge! http://rwmurker.bodybyvi.com/
Didn't someone once say "Release early, release often"?
~~~~~ BigLig2? You mean there's another one of me?
OMG you're a retard. A unit of force doesn't describe WORK, numbnuts.
The only industry that has made a full switch is the drug industry, both legal (mg=Miligrams) and illegal (Grams and kilos).
Obama's legacy: (N)othing (S)ecure (A)nywhere and (T)error (S)imulation (A)dministration
Damn that's funny. Wish I had mods today.
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
From Mirror:
http://www.mirrordot.org/stories/8f5373b24e35f5c45 3edf914cc953eff/index.html
Armadillo Aerospace News Archive
>
Servo regulator, Throatless engines, Hold down test
Aug 4, 2005 notes
Despite not having time to do an update for a while, we have been steadily working...
Servo regulator
When we last worked with it, the setup showed what seemed to be a valve lash problem - flow would begin when the high pressure ball valve reached 15% open, but it wouldn't shut off until it was closed all the way back to 5%. Since we had fabricated our own actuator to valve adapter, we thought we might have allowed too much lash into the coupling. We built a new mount using helical beam couplers with zero lash, but that turned out not to help. The coupling seems tighter, with the valve following every little jitter of the actuator, but the flow behavior seems to be an aspect of the seals in the ball valve, not the linkage between the actuator and the valve.
This cracking problem is only really an issue at very low flow rates, so we were able to do some flow tests at roughly the performance levels that our single-man space shot vehicle will use. With a single large nitrogen bottle feeding the servo regulator, we did the following test:
2700 psi initial bottle pressure
60 gallons of water at 230 psi and 215 gpm flow rate
1800 psi final bottle pressure
2" plumbing, 1" valve
The small fittings at the bottle valve became the limiting factor as the pressure dropped below about 2200 psi, with the servo valve eventually going wide open and still not quite being able to keep up. Our flight vehicle pressurant tanks will manifold directly out of bottle necks with a -10 fitting, so they won't become flow limited at all. When our new 36" hemispheres arrive, we will be welding up the full tankage and pressurization system for the big vehicle and doing water flow tests in preparation for testing a 5,000 lbf class engine.
Speaking of spheres, here are a couple pictures of the tear area on the burst one:
http://media.armadilloaerospace.com/2005_08_03/tor nSphere.jpg
http://media.armadilloaerospace.com/2005_08_03/tor nSphere2.jpg
Throatless engine
I was recently looking at the table in Sutton regarding losses due to small chamber to throat contraction ratios, and they weren't as significant as I had remembered them. A chamber with no contraction ratio at all will lose 20% of its thrust due to pressure losses from accelerating gasses in the straight section, but the Isp loss is only 1.5%. The text mentions "throatless rockets" being used in some missile applications to minimize chamber length and dry mass at the expense of Isp. The text doesn't say if these were liquids or solids, but I assume they were solids.
However, this does open up the question of building liquid engines like that. If L* remained constant, you would have an extremely long engine that would probably be impossible to cool, but I could imagine the accelerating, high speed flow could reduce required combustion stay times significantly. A 1.5% Isp loss is utterly meaningless for our purposes, so a configuration that traded that for fabrication benefits could be quite useful.
We fired a few crude throatless lox / ethanol chambers, and the results were surprisingly encouraging. With a very crude injector (a spray nozzle for the lox and four straight horizontal jets for the ethanol), we measured a 190 Isp from a 12" long straight pipe combustion chamber. It melted in a couple seconds, but this was still very impressive. With a 3:1 expansion cone added, performance should increase about 15% to around 220 Isp. That would be right at theoretical va
"If all the world's a stage, I want to operate the trap door." - Paul Beatty
Is North America really so backwards and stubborn they refuse to use units that the rest of the world is perfectly happy with.
Ok, it's a 5klbf engine. Happy?
If I have been able to see further than others, it is because I bought a pair of binoculars.
Unfortunately, no. Chemically fueled rockets are just barely capable of making it to orbit. They're mostly fuel tankage. Single stage to orbit craft must have at least a 90% fuel fraction. At least. Any serious inefficiency or weight growth kills the design, as happened for Rotary Rocket.
Staging helps. Two stages will get you to low earth orbit. Beyond low orbit usually requires three. This reduces the fuel fraction, but by less than one would hope. The Shuttle's fuel fraction is around 89%.
So space flight is all about weight reduction. Which is why everything is so fragile and unreliable. If you could build a launch system with a fuel fraction of 50%, which is roughly where most aircraft live, it would be a straightforward job.
Maybe IBM will step in and straighten some of it out for Carmack. Outside experts 'stepping in' has certainly salvaged Linux. . .
I'm just pissed that the French Revolutionaries didn't also succeed in imposing the decimal calendar.
I mean, WTF? Why can't there be 100 days in a year? It's as arbitrary as any other aspect of the Metric system.
How come Europe has been able to switch over to metric? We did use some backward measuring systems in the past, and I'm sure we had problems converting.
Escher was the first MC and Giger invented the HR department.
lbf is "pounds-force", a slightly more specific unit than "lb", which could refer to a mass (0.454 kg) or a force (4.54 N).
As a scientist I think in SI these days though it took years to unlearn the training of my youth, and I still vascillate between F and C for my preferred temperature unit.
Nobody uses perfect units. Why aren't you measuring your car's efficiency in inverse square millimeters?
There are times when the physics points to previously unimagined possibilities--think Einsteins equations and the atomic bomb--and there are other times when actual results contradict our understanding of the physics involved--think ceramic high-temperature superconductors...most 1980s era physicists would have dismissed the idea out of hand....but they worked and the physics had to be revisited to try and explain why.
http://redcone.net
No. Canada's official system of measurement is metric.
lbf is "pounds of force", not pound-feet, which would be typically be shown as lb-ft or lb*ft.
And yes, we are that backwards and stubborn. Jet and rocket engines are usually measured in pounds of thrust, not in newtons. Although they are the same class of unit (measures of force).
Random and weird software I've written.
We all know what this administration does to people who purchase large numbers of aluminum tubes.
That, and he makes video games! Ones that might possibly have boobie-enabling mods!
I am no longer wasting my time with slashdot
Why are scientists still determined to use rockets?
Why not just move the universe around the craft? It works for Professor Hubert Farnsworth! Nothing's impossible; not if you can imagine it!
</obligatory groening reference>
I always thought one of the more interesting things about Carmack wasn't his original work (which is impressive) but his ability to mine academic papers for techniques useful to him. Most of the really cool things he introduced to the gaming world came from research in CGI and such (BSP's, etc). The point is, while everyone else was writing what they know, John was learning what he needed to know to make his vision.
"A language that doesn't affect the way you think about programming, is not worth knowing" - Alan Perlis
Very little of anything that has to do with the Metric system defines real work, for that matter.
Just diddling around with test tubes, and 32-hour-week bloated loafers in the provinces of France.
You can't think very well.
It's pounds of force, which you could have discovered by doing a minimal amount of research. All praise the consistency of the metric system, it gives you so many choices (CGS, ESU, EMU, Gaussian, MKS, MKSA, SI) for systems of units.
We've been long-needing another faulty, nonfunctional technology to replace the "lie detector".
Finally an opportunity to promote my website!
Piiiiipppesss! [Bill Cosby]
can it run doom3?
I mean, hundreds of years years of rocket nozzle development is just thrown out the window. Remember, fireworks were developed in China a long time ago, and they had tapered nozzles. Oh, and all that research by Goddard and Von Braun et al, was just a waste of time I guess. I couldn't read the article because it tanked, but it sounds as though he is trying to make an easy to manufacture engine work, instead of making a better design easy to manufacture. CNC? Robotic welding? Sure they are expensive, but it looks as though his "disruptive" technology may just be disruptive to Armadillo Aerospace. How high a price can you put on failure? I guess the sky is the limit. Maybe it is time to hire some more (or better) engineers. Best of luck with your tubular nozzle. Maybe he should look into spike rocket nozzles. They look to be easier to manufacture.
Actually the correct units would be stone.furlongs/(fortnight.fortnight) grandparent got his dimensions wrong.
Gentlemen, you can't fight in here, this is the War Room!
I myself try to stay with DD-cup or smaller.
Erm, maybe because our calendar units are based on the Solar year?
Sleep is futile.
What we need is government conversion. I guarantee that if speed limits, mile markers, taxes (gas, property, everything), etc were calculated in metric, and government forms had to be filled out in metric, we would be 90% switched in a few years, and completely switched in a single generation.
Romero wanted to make an RPG, but he decided to make a throatless rocket engine.
Screw that! Rocket-jump, baby!
Freedom: "I won't!"
Confuding? Yes.
"Glory is fleeting, but obscurity is forever." --Napoleon Bonaparte
Just to clarify, 1N is the force required to accelerate 1kg by 1m/s/s. Hence to lift an apple (approx 100g) from the ground (approx 10m/s/s).
---- Den ene knappen er powerknapp, den andre er Bender voice knapp "Bite My Shiny Metal Ass"
When you figure out how to change the rate of spin of the earth or the orbit around the sun to accommodate 100 days a year, let us know, and the progressive metric countries will surely follow suit.
The hardest part is to learn what you need to know and be lucky enough to have it non-patented.
The creatures outside looked from Alt-Right to Antifa; but already it was impossible to say which was which.
We tried that in the 70's. They put up speed limit signs in metric and people shot holes in them. I guess they decided it was "too hard". And now, thanks to the inbred rednecks in this country, I have to convert units whenever I try to do science.
Yes. We are able to use non-decimal units because, quite frankly, most applications call for non-decimal units.
Which is the standard, utterly nonsensical, argument. These are only measurement systems. You can use either to express anything. However, one of them (and I'll let you figure out which) makes it MUCH easier to do conversions and allows useful equations (like e=mc^2) to actually work without inventing new units to fit. So yes, something which is an inch today may be 2.54cm, which isn't as convenient to write. But guess what, that same thing in a metric country would be 2.5cm, or maybe even 3cm. Which is 1.18110236. I'll let you work out what fraction that is....
---- Den ene knappen er powerknapp, den andre er Bender voice knapp "Bite My Shiny Metal Ass"
Agreed, 110%, on your posting reply to mine man...
:)
(by jericho4.0 (565125) on Sunday August 07, @12:25PM #13264177... etc./et all)
*
Imo, after all, your brain/mind/consciousness, whatever you wanna call it, is just a GIANT relational database engine in a way.
(The more you learn, on varied & diff. fields, the more you can relate & apply them... hopefully, for the betterment of the "human condition")
APK
P.S.=> And, Mr. Carmack's obviously got the "balls" to go out & give it a shot... indicative of courage to me @ least, above all else, because he runs the risk of alot of (imo, jealous & less competent individuals) naysayers saying "Yea, you did well repeatedly @ computers, but not so well @ rocketry"...
I say, patience, & let's see what the man can come up with!
Again - judging by what he accomplished in this field (ala/e.g.-> "Carmack's Reverse" which again, imo, is the TRUE MARK of genius in this field... engines/algorithms that bypass limitations & are completely "above & beyond" outta the box thinking)?
Wouldn't surprise me 1 iota if he did some 'breakthru' stuff in this arena as well...
Like I state earlier, which you replied to:
Just give a mind like his time & experience along with learning (standing on the shoulders of other giants before him, which is what we ALL do, because of what I call the greatest invention of all time: The written word - imo, our "racial memory") to build upon it even moreso...
There are VERY few "Tesla-like" minds out there, & imo Mr. Carmack &/or Anders Hejlsberg are 2 of them imo... they come along 1 or 2 for every generation only it seems like! apk
When the Quake 3 engine will be available under GPL?
We have at least 10x the highway structure for one. Imagine changing millions of highway signs that have lifetimes of a decade or more. Ain't going to happen.
An Education is the Font of All Liberty
oh?
is that so?
keep in mind that the US had to "borrow" german scientists like and Werner von Braun from the third reich nazi regime in order to develop the technology.
no need to tank me for reminding...
Right... he should spend his meager 6 or 7 digit budget on researching something that 9 digits have already been spent on, without enough success to see them in use.
You know, maybe he's not just spending money for the sake of spending, but actually wants to be able to fly on something?
Property law should use #'EQ, not #'EQUAL.
... but it seems like a fair portion of their problems are heat-related and melting parts. Is this just because they don't care about breaking things now and are only interested in taking measurements pre-breakage?
Anyway, I'm curious how/if this type of thing would benefit from the use of ceramics rather than metals. If I'm understanding right it's just a matter of finding the perfect shape to tune the exhaust output. If they can come up with that perfect, static shape, then I would think that shape could be made out of anything, high temperature ceramics not excluded. Then perhaps they could do away with these pesky cooling systems.
The Russian approach to rocket science was along the lines of "let's see how it blows up and make sure it blows up in a different way next time". Eventually, they ran out of ways for the engine to blow up and they had a working rocket engine. It seemed to work just fine for them.
sigs are hazardous to your health
I call them Ph.Ds. I don't know what Carmack's education is, and it does't matter, because he is obviously successful (by most measures, maybe not in the big time rocketry department), but researching academic papers are one of the major things that Ph.D students do as part of getting their doctorate. That is how the system works. So yes, hats off to him for mining academic papers. There is a lot of good research there, and that helps society as a whole get further along with regards to knowledge.
wrong - i buy my weed in good old Ounces...the only time I have to use grams as a measurement is when it's exceptionally good hydro or hash and i'm not buying very much.
otherwise it's still Ounces all the way
How come Europe has been able to switch over to metric? We did use some backward measuring systems in the past, and I'm sure we had problems converting. :-)
We had one measurement system per local lord, which meant that the foot in this valley would be different from the foot in the next valley. We had no concept of a common measurement system so that when the French invented one, it would start as "just one more measurement system" without meeting much resistance. Since people were used to dealing with different measurements anyway, eventually adopting this new system as the One True System wasn't much of a problem for them.
Besides, for much of Europe, the system is Invented Here whileas in the US, it is Not. Furthermore, in the bargain that gave the British the Meridian and the French the Measurements, the US got nothing, so there may have been some sour grapes over the decades
sigs are hazardous to your health
I'd love to put my old ISP into space...
Why not just have split signs? One half can be in MPH and the other KPH. Think of it as a training mode. People can look at the two readings and get a general idea of scale. Also, as we are weaned off of the standard system, we can eventually use signs that are just KPH.
Life is not for the lazy.
Its strange how positive experimentation such as this is dubbed distruptive.
The very quote you post is regarding the work he does on his Sharnoa CNC mill. So even CNC won't necessarily prevent walking.
As to hiring a good machinist, Armadillo doesn't hire anyone - they're all volunteers.
According to the X Cup Schedule, Armadillo will be conducting a demo flight out in New Mexico. (Check out Oct 9th activities).
I wonder if he'll be showing off the BFG as well... =p
More information on the current usage of imperial units can be found here: http://en.wikipedia.org/wiki/Imperial_units#Curren t_use_of_Imperial_units/, but you knew that, right? Canada appears to be even more on board with metric usage than, say, the U.K.
Ok, I understand, you post was really just an occassion to whing...
John it seems like to me one of your games is becoming reality. Look at you these days you're slightly older than 8 but you're building a Bean With Bacon in the back yard and searching the universe for the right part. You've found the throat less engine now you need the car battery and the XX Vodka. :o)
-VERN
A concise explanation of shock diamonds(mach diamonds) here.
What's neat is, despite the process sounding horribly dangerous, this ultimately results in a much safer design.
"ISP loss"? "maximum propelleant value"?
Sheesh, what do you guys think this is, rocket science?
It is a pound-force, as distinguished from the pound-mass, which weighs 1 pound-force when sitting in 1 normal g acceleartion at Earth's surface.
It is true, this is a hard to learn and obsolete system of units. But since some of the most advanced machinery in the history of the world was developed in it, and we have a whole industrial base that can crank out devices and gadgets practically on demand that revolve around it, we are loathe to give it up just so we can be like the French.
By the way, Pound-feet is abbreviated lb-ft and indicates a torque as opposed to ft-lbs, which would be an energy. Probably. You need to actually Understand what you are doing over here.
ps. 1 pound (lbf) is equal to 4.448 Newtons. Which most metric people would call 2.205 kilos anyway, because they don't know a force from a mass.
Behold, this dreamer cometh. Come now, and let us slay him... and we shall see what will become of his dreams.
He should have just used the jump pads.
---
PS - This is what part of the alphabet would look like if Q and R were eliminated.
Generated by SlashdotRndSig via GreaseMonkey
Why is it that when you believe something it's an opinion, but when I believe something it's a manifesto?
Damn, I really wish I had mod points... great post.
You're joking. Right? When Canada converted back in the 70's we used a hitherto undreamed of high-tech device called a "Sticker". We then "stuck" these "stickers" over the old numbers and units on the signs. Truly not a big deal.
pound-force, as contrasted to pound-mass.
-everphilski-
"The reason we haven't moved to metric is that we have too much momentum built up in society for anyone to switch over. " ...well we switched over in the UK without too much trouble. Change the law, and dont teach the old system in schools. Worked for us. Was in europe when they changed the currency, that went pretty smoothly too. People are quite adaptable.
You just change the lbf to newtons. Sometimes, it is even a 1-1 conversion. At least it was on several missions going to mars.
I prefer the "u" in honour as it seems to be missing these days.
Canadian raises his hand.
We've been...
you're stupid.
The problem was hydrogen peroxide. His first engines were built around the stuff. The way hydrogen peroxide works is you catalyze it - that is run it through a mesh of material that reacts with it to liberate steam and hot oxygen, which you then combust with a fuel. Hydrogen Peroxide is a nasty beast. It's hard to find vendors to sell to you (at rocket grade concentrations, 90-98%), and combustion is tricky. After a lot of experimenting (and he himself will tell you - a lot of valuable data gained; he was able to test at rates higher than using other fuel combos) they gave up on it.
Now they are using liquid oxygen as an oxidizer. They aren't stalled. They are exploring their options. If you look at NASA they have really only done things one way, the convergent-divergent regeneratively cooled nozzle, using O2 and H2, occasionally kero. He's sticking his neck out trying something new, it just takes awhile with limited funds. He's not stalled now.
-everphilski-
He meant real drugs. Not weed.
Throatless Rocket Engine powered Rocket-Launcher, perhaps? Think of the possibilities!
Nobody's gay for Mole-Man.
http://eazar.pepix.net/quake3/arsenal/IMAG0014.JPG maybe?
Nobody's gay for Mole-Man.
How much *design* is actually going into these if they are expecting to build 2-3 a week???
What does it matter? Rapid turnaround means he can develop a lot of them, and pick the best performers.
Maybe John, as brilliant as he is, should go to school for awhile to learn a bit about fluid dynamics and thermal dynamics and the equations that govern those sciences.
Why would you assume that he doesn't already know a great deal about these subjects?
I really don't get the knee-jerk reaction around here. Whenever someone does something interesting and potentially significant, there's always this chorus of people looking for something to bitch about to try to look cleverer than the guy who's acually doing something.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
"So space flight is all about weight reduction."
All fine if you're only planning to make half a dozen very expensive rockets. To make spaceflight cheap you have to be planning to make a thousand or ten thousand vehicles. Then the materials or fuel are not the expensive step, the manufacture is.
I have absolutely no idea whether this thing'll work at all but I do know that the cost structure is completely different for low volume vs high volume items and it's high volume low cost space flight that is being aimed at.
Deleted
Just compromise and settle on K
Academic papers...
Most of that stuff isn't patented.
Dude,
You can fake computer science on Slashdot. It's not frequent that something is posted where I say "oh, I'm a kind of specialist in that," but trust me, when it is, about 95% of the posts are wrong. I even had posts where I put in accurate information, that got modded up.
And for the French, Pound Sand.
Plus it gives people something to bitch about and blame pretty much everything that goes wrong on. They always appreciate that.
Switch back to Slashdot's D1 system.
Indeed. I can't stand it when people say something "weighs" some amount of kilograms. Mass is not weight.
They put up speed limit signs in metric and people shot holes in them.
I've got news for you: people have been shooting holes in all kinds of road signs since before there were automobiles in this country. The metric signs didn't get any special treatment.
thanks to the inbred rednecks in this country,
What a nasty, bigoted thing to say.
I have to convert units whenever I try to do science.
No you don't. Just work with whichever system you like from the beginning. Make all your measurements in the metric system if that floats your boat.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
So the problem is, that we don't any possible fuel source that has a high enough energy density? I guess we can't really have any thing like on star trek until we find technology to move beyond chemical rockets. Wasn't there research into nuclear propulsion for use at lift-off at one time?
NASA did things based on previous research by Goddard, Von Braun, and others. H2/LOX fueled engines didn't materialize until the Apollo program. Kero/LOX was the status quo for big liquid fueled boosters before that. And it is still used by the Russians. Is your argument that NASA has only done things one way, and hasn't explored other options? What about the Soviet space program, did they steal the design from NASA, or did the also come up with it through research? If alien cultures ever made cars, do you think they would have round wheels? Some times the optimum solution is the same, no matter where it is invented. I don't think that chemical rockets are the end all be all of rocketry, but they are a mature technology, and everyone who has achived orbit has used convergent-divergent nozzles. The revolutionary step is mass production, to bring the cost down. Making parts from aerospace alloys is difficult. Tubular shapes are easy because tubing is mass produced. If you want to bring the cost down, one needs to find cheaper ways of making rockets. Liquid fueled rockets are complex and require turbo machinery. Maybe he should look to solid fueled rockets. There isn't as much complexity in them.
That'd just make summer that much the worse, though... I mean, looking at the thermometer outside and seeing that it's 105 in the shade is bad enough. Can you imagine looking outside and seeing the temperature at 314 in the shade?
If you believe everything you read, you'd better not read. - Japanese proverb
Will that be anything like disccussing the tactical importance of Jessica Linden's uterus to national security?
(curse you theOnion for taking your archives offline)
Can you be Even More Awesome?!
The Russian approach to rocket science was along the lines of "let's see how it blows up and make sure it blows up in a different way next time".
That's a complete crock. The Russians, just like the USA, started from the V2s they captured, and applied the best engineering practices that were known at the time. They blew up a lot of rockets, and so did anyone else who every tried to build a rocket.
The fact that they got Sputnik into orbit first, and got Gagarin into space before anyone else is a testament to their skill.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
What's even worse is that it many industries there are multiple English units for the same measurement. Everyday where I work, depending on the context, we use PSI, inH2O, inHg, and ftH2O.
It's frustrating to say the least.
>It is rocket science, not rocket trial and error.
A lot of rocket science IS trial and error and that is exactly what he is doing. Even modern rocket engines go through a build and test phase simply because rocket science isn't exact. There are many complications that you can only work out through practical experience. Combustion in a rocket engine is highly complex and I am sure he doesn't have the computing power to model it to any great degree.
And reinvention is not necessarily a bad thing. He is approaching it from the point of view of an amateur learning as he goes. In my opinion he is going about it in the exact right way.
You're saying that America has more roads than Europe? I very much doubt that, most of America is open wasteland.
arbitrary you say? odd that. what temperate does water freeze/melt at? (at sea level) what temperature does water boil/condense at? (at sea level) what does 1 cubic metre of water weigh? (at sea level, at its maximum density temperature)
Hmm... just found this on WikiQuote:
"The idea that I can be presented with a problem, set out to logically solve it with the tools at hand, and wind up with a program that could not be legally used because someone else followed the same logical steps some years ago and filed for a patent on it is horrifying." -- John Carmack
So obviously he already got burned by patents on at least one occasion.
The creatures outside looked from Alt-Right to Antifa; but already it was impossible to say which was which.
A more serious effort for SSTO was DC-X. The full size version probably wouldn't quite have made it to orbit, but it would have been close enough to know if it was possible to do it with a reasonable payload. Unfortunately, after two successful Air Force flights, NASA took over and the craft was destroyed because a technician didn't hook up a hydraulic line to one of the landing "legs". Then NASA cancelled it in favor of X-33, a project with no hope of success. X-33 allowed NASA to say, with a straight face, "SSTO doesn't work", when what they proved was X-33 doesn't work.
Staging helps. Two stages will get you to low earth orbit. Beyond low orbit usually requires three. This reduces the fuel fraction, but by less than one would hope. The Shuttle's fuel fraction is around 89%.
Yes, and staging also complicates the design, making it more expensive. You get those one-shot parts you throw away, which means doing lots of extra work (ie spending $$) to make sure they work the first and only time. I suppose you could have some kind of flyback reuseable stage, but that's complicated enough that it won't save you any money.
So space flight is all about weight reduction. Which is why everything is so fragile and unreliable. If you could build a launch system with a fuel fraction of 50%, which is roughly where most aircraft live, it would be a straightforward job.
Everything is fragile and unreliable because the design philosophy is wrong. It's a question of designing for perfomance when we should be designing for operational efficiency. In the end the mass fraction doesn't matter - what matters is reliability and $/lb. to orbit. There will always be a market for heavy lift launchers, but for manned flight you'd rather have frequency and reliability.
The benefit to VTVL SSTO is you can launch it more frequently, since all you have to do for the next flight is inspect it and fill up the tanks. The reentry is powered, so you don't have thermal problems, and since you don't need a runway you can land it on the same spot you launched it.
Look at it this way - the amount of fuel it takes to get to orbit will get you from the US to Australia in a 747. The reason it's cheaper to go to Australia is they don't throw away the plane when you get there (expendables) or take it apart and rebuild it (the shuttle) before the next flight.
This also has implications for safety. Would you rather fly a 747 for its maiden flight or its 100th? If you fly the same craft more than once you're much less likely to be bitten by manufacturing defects.
We've been using staged rockets for fifty years now, and the price is still a huge multiple of fuel costs. Time to try something different.
Why not just have split signs? One half can be in MPH and the other KPH. Think of it as a training mode. People can look at the two readings and get a general idea of scale. Also, as we are weaned off of the standard system, we can eventually use signs that are just KPH.
As an added bonus, you'll find that Canadian drivers who don't have markings on their speedometers in miles per hour don't drive slowly and back up traffic....
The rest of the world uses metric, it's time for the US to join the 20th century. After all, the rest of us are in the 21st century, don't you think it's about time?
If you believe everything you read, you'd better not read. - Japanese proverb
This idiot should stick to games.
Well, thank you for that well-reasoned critique of his efforts.
I have to wonder, what is it about achievement, or even effort, that brings people like you out of the woodwork? Why are you so jealous of him?
'Disruptive' is one of those buzzwords that business school types throw around when they are trying to deceive investors.
It's also a term that describes any number of scientific and technological advances that came from private effort like John's. In any case, he's doing this with his own money, so what's it to you?
What is the advantage of this engine design? What are the reactants, ISP?
Hey, here's a wild idea: why not RTFA and find out?
Meaningful details like that don't get you posted on slashdot I guess.
The same could be said for meaningful critiques. Better luck next time.
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Thats fine.
All I'm saying is that there are a vast number of technologies that are covered in academic papers that are not patented.
This number is in the majority.
The spaceship was lost because someone didn't know how to convert units.
All that means is either use one set of units or know how to convert between them. It doesn't argue for the metric system over the imperial system.
Psst....
The Metric calendar was 365 or 366 days per year, depending on leap years, not 100 days per year. It consisted of 10 months, each consisting of 3 10-day weeks, and 5 (or 6) leap days at the end of the year which were holiday.
It actually made a whole lot of sense, and the main reason it flopped wasn't because it was needlessly arbitrary, it was because the church considered it an affront to the whole 7-day thing that they're so fond of.
If you believe everything you read, you'd better not read. - Japanese proverb
Science in general has a lot of trial and error. But what makes it science is the building of a body of research and moving on from there, not chucking good ideas and starting over again. Is Armadillo's problem getting a good working design, or is it manufacturing a working design. Ok, I don't have any problems with what Armadillo is doing. The person who posted the original article, and did the write up, in my opinion, blew it way out of proportion with the "disruptive" technology bit. It was his perspective that Armadillo (and Carmack) was going to revolutionize rocket design by going with a throatless nozzle. I call bullshit, and will continue to point out that the convergant-divergent nozzle is the product of a huge body of research, not just some good idea. Convergant-divergent nozzles are hard to manufacture, but they seem to be one optimal solution for a liquid fueled rocket. Tubular nozzles aren't as efficient and it seems that Armadillo is using it as a trade off from a manufacturability standpoint. Ok, fine, but energy efficiency is important when you are trying to send a rocket up.
The ideal system would be a metric system in base-12, (using base-12 numerals), because it would be as convenient as the current metric system for multiplying by the base, but also evenly divisble by 2, 3, 4, and 6 like the English system.
On a personal note, the thing I find annoying about the metric system is the lack of a standard unit of measurement between centimeters and meters.
If you don't know where you are going, you will wind up somewhere else.
Does this mean if I'm living in USA and have some salt with me, I can destroy mass and convert into energy easily? Coool!
There was never suppose to be a fleet of shuttles. They were supposed to have such a fast turnaround that the capital cost of each shuttle would be amortized over zillions of launches. It was originally sold to Congress as having a turnaround of a week. It was never sold as being cheap to mass produce a fleet of them. You wouldn't need a fleet if they had a one week turnaround.
Infuriate left and right
It's called an elephant's trunk whereas it is in fact, an elephant's nose, a nose by any other name would smell as sweet
Yes! For the slight inconvenience of having to work with four different length units (inch, foot, yard, mile) with easily remembered conversion factors, we can finally express lengths of 1/3 or 1/6 inch as umm... 10.667/32 in, or... 0.3333 mill. Better example: Highway exit signs. The Englisch system is obviously superior, since we can easily say 1/4 mile, where you only need to divide 1760 by 4 to get yards. Easy! Converting something like 1/4 kilometer to meters would involve dividing 1000 by 4: Totally ARBITRARY!
You win, I'm switching over to Imperial today.
chl
PS: Is 543 yards plus 1563 yards longer than 1-1/4 mile? I lost my calculator.
PPS: Sarcasm is not funny. Mod this insightful.
WTF? He should spend more time on his GAME engines rather than his rocket engines, and maybe the next ID release wouldn't suck as bad as the last ;)
we are not "stubborn"
Yes, you are.
The reason we haven't moved to metric is that we have too much momentum built up in society for anyone to switch over.
Bull-fucking-shit.
The rest of the world had the exact same amount of momentum, and they changed over decades ago.
You don't do it because you're stubborn, lazy americans.
And you call yourself a scientist, 1 pound (mass) is 0.454 kg. One pound (force) is 4.45 Newtons!
My god. You have _completely_ missed the point.
What Carmack is doing is making a solid, robust, easy-to-maufacture, _simple_ engine. The kind of engine that is provably reliable. The kind of engine people can _afford_.
The engine you linked to is exotic to the extreme. Nice as a research project, but it would need big defense contractor type manufacturing capabilities. It would be rediculously expensive. Yes, in fact, it would be something a big government agency would dream up. Do you happen to work for a big space-oriented government agency?
On the moon, maybe.
chl
The problem is, Carmack has been working on underpowered rockets for a long time now (and switching fuels constantly, and hitting one many-times-hit brick wall after another after ignoring the lessons of history). His ISP is already lousy, as is his thrust. If he loses much more thrust, he'll hardly be making up for gravity losses; it'll just hover.
I've followed Carmack's logs, and they're almost embarassing. He keeps chosing long-rejected rocketry paths, and then getting stuck by the physics that led those paths to get rejected. It's good to see that he learns from his mistakes, at least, even if he's unwilling to learn from the mistakes of others.
There's a reason why Rutan won the X-prize and not Carmack.
I wish people would stop comparing JÃnsi to God. He's good, but he's no JÃnsi.
It certainly seems to me (IANARS) that powered re-entry is the answer to the most problematic architectural problems of spaceflight. The biggest problem with powered re-entry is that you have to take the fuel up with you to slow during re-entry. I see many stories about Mars missions and the like making the fuel at the destination for the return journey. Is it possible to do the same for orbital flight? What mechanisms could we use for an "orbital" fuel manufacturing station.
"The first thing to do when you find yourself in a hole is stop digging."
That's certainly how it looks from a plane! Flying from London to LAX you get some farms around Winnipeg, but from then on its wilderness (with only the occasional, empty, road) until you hit San Bernadino.
May be i don't get it .. Anyway, between centimeters and meters units, you've got decimeters. Wich is 10 Cm, or 1/10 meter.
Ok, next to nobody use it...
Parent: No. Canada's official system of measurement is metric.
I believe that Mexico also uses S.I. units.
.. paranoid crackpot leftover from the days of Amiga.
Nope, GM and the rest of the carmakers have been designing for 10 years exclusively in metric. They still have a few older designs(read Chevy V-8 and some V-6's derived from them)that are based in imperial units that are reaching their end of life. Everything new for the last 10 years has been metric.
Hmmm...
Talk about prior art, this design is at least 2200 years old. It may have been disruptive technology during the Early Han dynasty, but now all it is is a waste of propellant.
Tell that to my 97 Saturn SC2. I often find a mix. Most of the time it's metric. For example, the brake system uses metric bolts as does the oil drain plug. However, the top engine mount was not metric. I double checked my sockets and made sure the nut wasn't "rounded off". Sure enough, it was standard.
Interestingly, when I replaced the mount, I was given two new studs and bolts to go with the new thread design. Difference: They were metric. Strange...maybe it was cheaper to use up the standard bolts due to over-stock in the supply chain. I dunno other then that.
Life is not for the lazy.
Members of the Rifle Association has very good sight. They can put a bullet in the metric part of the "new" highway sign half a mile away, plus more.
You can't just go changing all this stuff willy-nilly. Any change has to have the benefits provided measured against the downside. The downside of changing to metric in the USA is significant. That is why the change hasn't been made. Not because metric is inferior; but because we're not willing to knock back progress and annoy everyone for decades to come.
Personally, I keep this magic thing called a "calculator" around, and convert as required. Mine does unit conversion easily and reliably (HP-48), among many other useful things. Get one for your Mac desktop here or one for your windows desktop here.
I've fallen off your lawn, and I can't get up.
I've fallen off your lawn, and I can't get up.
Just a thought if you could Magnetohydrodynamics to dynamically build a throat to optimally fit operating conditions.
Having said that, I don't dispute any of the facts you've given (except I'd just like to ask if by "sonic" you mean "transsonic" or "supersonic", as it is airspeeds BELOW that which would be "sonic").
In the same way that we have Sourceforge for software and OpenCores for Open Source microelectronics, I'm wondering if it might be an idea to set up a site for Open Source Rocketry, or even Open Source Engineering in general. Any thoughts?
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Yes, that's all well and great, but have you ever actually driven in the US? The US has quite a few more road mileage signs than Canada. Also, it's probably a bit easier to get 30million people to switch over at once with fewer signs than it is to get almost 300million to switch over at once with more signs.
http://www.xcor.com/engines.html X-cor has been making "throatless" motors for some time. Very nice and simple.
People are quite adaptable. ... when they want to be. When they don't want to be adaptable, they are stubborn and obstinant to no end.
Convincing the US to be willing to change measurement systems would require strong leadership, which we haven't seen in a while. Our "leaders" are too busy bickering and infighting and trying to please the specific groups that are going to vote for them. Until we have 10M people who demand a change, no politician is going to risk pissing anybody off on a long-term investment. Switching systems just isn't going to make anybody happy in time for the next election.
Use decimeters for your measuring pleasure. You don't have to make it hard for yourself you know...
True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.
The UK has changed, and that's where the imperial system came from. Still not?
Those sheets of plywood you speak of are not made to the exact sizes specified in imperial units by precision equipment, they're rounded. Same rounding happens with metric. And do you think all doors are the same height? Or all sheets of plywood?
Road signs are always corrected with stickers. No-one in any coutry would ever change millions of signs at once for a small change. Not even just a few signs.
Furniture is no problem, I have a 210x190 bed, which happens to be slightly larger than the most common size in Finland. Note that other countries thend to have different common sizes for beds. Some like them wide, some like more floor space. Anything else is a non-issue since you don't by furniture by the measurement, you buy the shelf that fits in the space.
Speeds is like changing currency unit (which has been tried successfully), except hell of a lot easier. Takes some getting used to, and after a year, no-one will remember the old system.
Land is not dependent on units. You look at cornerstones, find out the borders, and calculate the area in whatever unit. Which unit doesn't matter because the numbers won't be rounded, they have to be precise.
Of course there's changes, but look, you take a few years to prepare and then change. It isn't rocket science, man!
Take this roadmap as a service from me:
2008 Q1- change distances
2008 Q2 - change speeds
2008 Q3 - change the loose ends, tidbits
True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.
You do know the best way to learn is to screw up dont you? How do you know what the 'right' way is if you do not know what the wrong way is? For example Tomas Edison once said "I have not failed. I've just found 10,000 ways that won't work"
Everyone at work says 'oh your so smart' blah blah blah. I tell them 'I am not smart I just screw up faster than you and figured it out before you got to it.'
He has basically said 'hey I have found a way I can learn a bunch really fast and not cost me as much.'
That is probably a good idea when a rig can cost you 100k or more.
Also Rutan has been doing this *SINCE* the mid 70's. Carmak has since the mid 90's. Who should be ahead?
http://en.wikipedia.org/wiki/Project_Orion
DRM 'manages access' in the same way that a prison 'manages freedom'
Stalin tried a 5 day week, with rotating days off for different people, too. It was meant to keep all the capital in factories busy all the time, instead of a 1-2 day lull each week.
It failed dismally. People hated it.
Things that 'make a lot of sense' for a board of intellectuals often fail in the real world. You're rather short-sighted in just blaming it on 'the church.' Regular people almost certainly thought it really, really sucked.
The rest of the world uses metric, it's time for the US to join the 20th century. After all, the rest of us are in the 21st century, don't you think it's about time?
The only people who get any say at all in this are Americans, and the vast majority have spoken in favor of keeping the current system.
Really, I don't know that all the spineless whining is about. Learn both systems and do the extremely simple conversions when necessary. Unlike the general topic, this isn't rocket science!
Max
My god carries a hammer. Your god died nailed to a tree. Any questions?
So space flight is all about weight reduction.
That's the NASA myth, and why they build crappy spacecraft.
Certainly weight reduction is important, but if you don't keep looking at the overall system, and the trade-offs, you'll fuck up the design. The focus on Isp is a symptom of that. The Shuttle is a prime example of it.
Sure, high Isp means you need less weight of propellant per unit of impulse (thrust * time), which sounds great. So the propulsion guys start focusing on Isp and design exotic high-pressure engines that use fuels like LH2 which is really light and gives you an engine with a 400-range Isp. Never mind that you have to practically rebuild the thing after every flight. (It also gives you a relatively low thrust to weight ratio, so you end up having to augment it at launch with something with high thrust even if crappy Isp, like SRBs)
The propellant guys figure LH2 is cool too -- highest energy per unit weight, and all that.
And the airframe guys just build the lightest structure they can to hold what the propulsion and propulsion guys give them.
All of which leads to a suboptimal design.
LH2 is about the lowest density liquid around. High density urethane foam would sink in the stuff, it's about the same density as lighter weight foams. Which means you need a bloody big tank to put the stuff in. The Shuttle uses 8 times, by weight, as much LOX as LH2, but the LH2 tank is about three times bigger than the LOX tank.
Tankage is heavy. The portion of airframe weight devoted to tankage scales as the volume of the propellant, not the weight.
Replace LH2 with something like liquid methane and your tankage -- and its weight -- becomes much less, which ends up improving your fuel fraction, even with the slightly lower Isp of methane-LOX.
The original Atlas launch vehicle, which used LOX and kerosene and stainless steel tankage, could reach orbit without shedding any stages. (Although it did shed two of its three engines.) It also couldn't carry much payload that way, but we're talking late 1950s technology.
NASA technology is fragile and unreliable because they're more interested in engineering projects for the sake of engineering projects, and then have to hack it back because of budget limitations. Anyone in software development who has seen a project get designed with all sorts of bells and whistles and the designers' favorite new technlogies, only to be turned into some ugly hacks toward the end when deadlines are looming and the budget has run out, will understand this.
-- Alastair
reducing the cost of icbms hmmmmmmm
Roger Gregory, for those who don't know, was a large part of the Xanadu project. I found the Armadillo project interesting, but the engine design described in the url below, blew my mind.
Rotary Rocket Engine
The problem with the nuclear engine isn't that it's too advanced to build (it isn't) but that the spacecraft essentially sits on top of a huge curved plate and rides a series of nuclear fireballs into orbit.
While this is highly efficient at getting a payload into space, it tends to be rather bad for anything within a few miles of the craft when it launches. If you're using a 'dirty' engine (e.g., spitting plutonium pellets out the back and igniting them with a laser) you'll also leave a nice poisonous trail of radioactive fallout on the way up.
Nuclear engines would only be of real value for interplanetary travel, or for lifting from a non-Earth world (no ecology or population to damage).
Max
My god carries a hammer. Your god died nailed to a tree. Any questions?
Two words: Thomas Edison
- The race is not [always] to the swift, nor the battle to the strong. -
Or better yet, use eV. THAT would make life a lot simpler for doing calculations.
The DC-X saw a lot more than two successful flights. At one point in its SDIO (not just Air Force) operated test series, it did two flights with a 24 hour turnaround.
I had the privilege of attending the first public flight, which was the second real flight. Seeing a rocket climb out and then just stop in mid-air is quite something. Then it flew sideways a hundred yards or so and descended tail first to a perfect landing.
Later flights went higher and faster, and one demonstrated its survivability when an at-launch explosion of vented hydrogen blew off part of the aeroshell, and the thing was dropping bits and pieces as it climbed out. The remote pilot (Pete Conrad) just clicked the emergency autoland button and the thing hovered until it had burned off enough fuel to land (the landing gear wasn't designed to support fully fueled weight, it sat on a "milk stool" for launch).
Then NASA took it over and, as you mention, fucked up their first flight. The unconnected leg folded up on landing and the thing fell over, broke apart and burned.
Given the huge workforce that NASA keeps employed to fly the Shuttle (or rather, to act like they're keeping it flying while keeping the actual number of launches to a minimum -- reduces the career risk for NASA managers), it's not surprising that they don't like anything that might threaten that turf. Not that, as you point out, the ridiculous design of X-33 ever remotely threatened it, and gave NASA engineers (and their LockMart, etc, buddies) something else to spend money on.
-- Alastair
I have no reason to believe that Soviet rocket scientists were unskilled. In fact, the engines they ended up with were (arguable I am sure) better than their US counterparts. It's just a different way of doing engineering.
Nukes are (perhaps) a more modern example. The US used to blow up real nukes in order to learn how to design them. Now they use computers to simulate them in stead. While this may be better in terms of pollution, it is not given that the results produced will necessary be better.
sigs are hazardous to your health
What is this "whing"? Did you mean "whine"?
On a personal note, the thing I find annoying about the metric system is the lack of a standard unit of measurement between centimeters and meters.
Like the decimeter? Hint: There is only ONE standard unit of length in the metric system. The meter. That's it. Everything else is a fraction or multiple of that. So just use whatever prefix suits - milli, nano, centi, deci, kilo - take your pick. Each is ten times bigger (or smaller) than the last. Makes life easy, no?
Frankly, base-10 is a crappy number base and we only use it because that's what everyone knows.
And that's a damn good reason to use it. Virtually every currency in the world is base 10, the only counting system 99% of the population ever use is base 10. While base 12 might be great, it's not going to happen (ever tried to teach someone non-techincal hex?). So of the two choices (base 10 or base-something-different-every-time) I'd pick metric.
---- Den ene knappen er powerknapp, den andre er Bender voice knapp "Bite My Shiny Metal Ass"
It's a force equivalent to that of Earth's gravity (at the surface) exerted on a roughly half-kilogram mass (0.454 kg, to be precise). About four and a half newtons.
(lbf = pounds force, not pounds feet)
-- Alastair
Which was originally an ICBM because it had "balloon" tanks which get their structural rigidity from being pressurized within. Granted, NASA did use the Atlas for some manned missions, but it was felt that structures that could support themselves without pressurization were safer. The Atlas would collapse under its own weight if not under pressure. I'm not saying that NASA's position is better, but they had their reasons.
Your example of construction materials still being produced in US customary units is technically wrong. The nominal sizes are still expressed in feet, inches, whatever.
The vast majority of construction materials are actually produced using metric measurements. Your 4'x8' sheet of plywood is no longer 4'x8'. It's 1220 x 2440 mm.
Just cuz you ain't paranoid, doesn't mean they're not after you.
Other countries of the world have accomplished this seemingly insurmountable task - why can't the US? If you answer is "we don't want to" then fine, so be it, it's not really any of my business. But saying "we'd like to but we just can't" is absurd.
Building materials -- they're made in inches and feet.
So you change that.
How are you going to make unit metric parts for the millions of homes that are already in units of inches and feet?
You're not. You provide both for as long as needed. If I go into a hardware store in NYC I can already buy all the tools, screws, nails etc I might need in either metric or imperial. Already. See? It wasn't hard.
Personally, I keep this magic thing called a "calculator" around, and convert as required. Mine does unit conversion easily and reliably (HP-48), among many other useful things.
You should tell NASA, they could use some. Personally I prefer using a sensible unit system so I can easily do it all in my head.
---- Den ene knappen er powerknapp, den andre er Bender voice knapp "Bite My Shiny Metal Ass"
You know, there was an incident when it actually was more complicated that rocket science. And that was a Bad Thing.
True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.
For anyone having trouble getting used to metric, think of one newton as the amount of force required to lift an apple off the ground.
Or a Quarter-Pounder* to your mouth.
(* pre-cooked weight)
-- Alastair
As a scientist I think in SI these days though it took years to unlearn the training of my youth, and I still vascillate between F and C for my preferred temperature unit.
Just compromise and settle on K
Well, we're talking rocket science here. The traditional unit would be R.
-- Alastair
Didn't Mr Edison make over 100 prototype of lightbulbs before finding the successful version?
With Carmack is trying many different technologies, I presume that he is learning from each problem/difficulty with each model he works with. This shall eventually result in him having a broad and deep knowledge of the technologies involved, and give him the ability to achieve his goal, given enough time.
See my art -> http://herbevore.deviantart.com
XCOR engines have throats. Some of the engines look like a straight tube from the outside, but that's just the profile of the cooling jacket. Inside that jacket, between the chamber and atmosphere, there is a throat.
I have "burned" on patent law myself -
:(
Especially by those outside the United States. They don't hold up well outside U.S. borders especially, @ least in my case, which I do NOT feel like going into here.
(That is, unless you have the power of a Microsoft OR the RIAA & their "fleet of legal attack dogs" etc. (which, I personally, don't))...
*
APK
P.S.=> Besides, there is truly very little original thought... BUT, there is very many similar problems scenarios out there, especially in THIS field...
AND, like Mr. Carmack said & I requote from KiloByte (825081) on Sunday August 07, @02:50PM, from WikiPedia:
"The idea that I can be presented with a problem, set out to logically solve it with the tools at hand, and wind up with a program that could not be legally used because someone else followed the same logical steps some years ago and filed for a patent on it is horrifying." -- John Carmack
I agree, in MOST cases.
Unless your idea is ABSOLUTELY original, & never had been done before (e.g.-> A program type of which I created the first of in GUI form, which had happened to me, & I was WARNED I would be copied no less eventually), I agree w/ him 100%... apk
TFA Coralized (original is ./ed)
Pragmatic Semantic Web Log
parent is not a trolll... sounds like an actual rocket scientist who realizes how stupid a 'throatless' rocket engine is.
You do know the best way to learn is to screw up don't you
The best way to learn is to first read about what essentially the entire world, often in groups working apart from each other, decided was a Bad Idea in rocketry (for example, H2O2 monoprop rockets and vaned thrust deflection for rockets (it's hard enough on jet engines, and saps your power - that's why people use gimballing). Otherwise, you're "screwing up" for no good reason.
when a rig can cost you 100k or more
A book will cost you 10-100$.
I wish people would stop comparing JÃnsi to God. He's good, but he's no JÃnsi.
If everyone accepted as truth the popular beliefs of their peers we would yet be living in a flat world assaulted by mythical gods.
It is typically those who do not accept the findings of others as substitute for their own findings that change the face of human knowledge. The others at best make significant logical progressions.
Ok, first, you don't get shockwaves in nozzles- not unless you've got a rough nozzle surface, which is a bad idea, because the hot gas comes to a screaming halt ("stagnates") and the local temperature goes way up, and then the nozzle melts.
huh? There's a shockwave in the throat of the standard converging / diverging nozzel. It's where the gas is accelerated supersonic. The shockwave is at what's called the choke point.
You sir, are the one who's full of shit. There is always a shock where flow goes from subsonic to supersonic.
There are 10 types of people in this world, those who can count in binary and those who can't.
If everyone accepted as truth the popular beliefs of their peers we would yet be living in a flat world assaulted by mythical gods.
There is no reason to rpeat every experiment ever done in physics... you just read about the ones that were done and repeat them if you see an error in their methodology... to do otherwise is to waste your time.
We're not talking about metters of opinion here... we're talking about things that were tested, failed, and then the failures were explained by a better understanding of the physics.
It is typically those who do not accept the findings of others as substitute for their own findings that change the face of human knowledge. The others at best make significant logical progressions.
No it is typical for such people to never do anything useful. A human life is finite, and you have to manage your time to get anything done.
Sure you can't accept everything at face value... but you also have to admit you're wrong when confronted with the evidence.
There are 10 types of people in this world, those who can count in binary and those who can't.
"We're not talking about metters of opinion here... we're talking about things that were tested, failed, and then the failures were explained by a better understanding of the physics."
There is almost no fact in modern physics. Therefore everything is a matter of opinion. Of course one should not reinvent the wheel, but the person who invents a truely revolutionary wheel replacement will be someone who came up with their own solution without knowledge of the wheel. Those who know of the wheel will be closed minded toward matters relating to wheels because they believe the subject has already been covered.
"If you have shock waves inside the nozzle or if you blow the shock out the end, you are losing energy, and potentially wrecking equipment." :-)
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Nope. The flow in a converging/diverging nozzle is isentropic, which means that there are no shocks. The fluid is smoothly accelerated past sonic velocity because of the nozzle's smoothly changing area. Shocks occur at discontinuities, like a sharp change in pressure at the exit or the nose cone of a rocket.
NO, North America is not backwards. Just the United States is backwards.
Hey, here's a wild idea: why not RTFA and find out?
I tried but all I could find was TFP. There is no caption. It looks like a cheezy science project. Do you know something about it? What is disruptive about it?
an ill wind that blows no good
"The DC-X saw a lot more than two successful flights. At one point in its SDIO (not just Air Force) operated test series, it did two flights with a 24 hour turnaround."
So if we're going with the conspiracy theory. Then it stands to reason that John could take the existing design and work on that. Instead of trying to create something new. I'll leave it as a readership exercise as to why he's not doing that.
There is almost no fact in modern physics. Therefore everything is a matter of opinion.
Are you a troll or just an idiot? If physics were a matter of opinion, I'd be able to fly by flapping my arms. Modern physics is every bit based on facts that have been experimentally verified.
There are 10 types of people in this world, those who can count in binary and those who can't.
NASA is a sham, a front, a cover for the real space program. The real U.S. space program exists in military black-projects and that is where 2000s level technology is being developed and used. You think UFOs are alien? Ha!
Do your own research, but I will present you with the basic idea that ZPE and antigravity are a reality within military black-ops and has been for decades.
It is your personal duty to fight for what is right on a daily basis. Ignoring injustice is identical to approving
Where were you 7 years ago? We have been there already, it is a very common term.
A disruptive technology is any new development that renders portions of the economy obsolete by it's introduction.
It is your personal duty to fight for what is right on a daily basis. Ignoring injustice is identical to approving
Screw shooting rockets AT people; that's too quick and painless. What I want is a personal rocket launcher for launching people I don't like into space. It should preferably be adaptable for different environments- office chair, easy chair, etc.
Pretty easy, too. I don't give a crap about the survivability of anything- especially the passenger. Simplifies the design process ;-)
Please help metamoderate.
Why aren't you measuring your car's efficiency in inverse square millimeters?
Because it's hard to see the little buggers, especially when they are upside-down.
-
- - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
I was going to reply, but realized that without my tinfoil hat, the NSA may pick up my brainwaves as I type my response and I can't have that while responding to a post about black projects involving antigravity and free energy.
He was talking about the high-power high-rpm torsion magneto-gravitic field effects first pioneered by the Nazis with the Nazi-bell experiments. They tended to use mercury because it was easy to accellerate to high speeds and pass current through. Today, the most common experimental forms use torroidal plasma confinement, accellerating the plasma while super-charging it to get the desired effects. Other variations exist.
What did you think he was talking about?
I'm with you. From now on, days are the equivelant of 3.6525 current days, and there are 100 days in a year. Months are now ten days long, and we'll just get rid of February and May, because February sucks, and May already has its own day.
Ah, the ideas.. my mind feels like it's running at 5,280 ft. per minute!
https://www.eff.org/https-everywhere
US congress first adopted the Metric system in 1866. You would think that 139 years has been a long enough transition time. No?
Maybe rockets would go into space cheaper if something superheated/eliminated the air in front of them like the way lightning bolts start and the way Lance Armstrong follows his teamates.
-- Each tock of the Planck clock is a new world and here we are still life. --
Dude, try the other link in the article.
Patrick Doyle
I mod down every jackass who puts his moderation policy in his sig. Oh, wait a sec....
I want my railgun where the hell is my railgun for the dashboard of my car?? These are the important things :)
A computer once beat me at chess, but it was no match for me at kick boxing. Emo Philips
"Look at it this way - the amount of fuel it takes to get to orbit will get you from the US to Australia in a 747. The reason it's cheaper to go to Australia is they don't throw away the plane when you get there (expendables) or take it apart and rebuild it (the shuttle) before the next flight."
I do love this old chestnut: it's perfectly true, and yet so misleading.
Helpful Hint #1: How long does it take to fly the 747 to Australia? What would happen if you took that long getting to orbit?
Helpful Hint #2: What is the difference between energy and power? If two machines release the same total energy, but machine #2 must release it much more quickly with equal or greater precision, which is likely to be more complex and expensive?
Ah, that works out to about 22,000 N.
In most other fields, coming up with something patent-worthy is a matter of five years of research.
On the other hand, most software patents are on the level with things a non-drone programmer invents several times per day. Sure, there is a good chunk of insight involved, but if you can implement your idea in half an hour as opposed to years, patenting these is simply a murder on the idea for everyone else.
The creatures outside looked from Alt-Right to Antifa; but already it was impossible to say which was which.
Okay, so there's 12 inces in a foot. But how many feet are there in a mile then? Or the other way, what's the next smaller step than an inch ? Generally half, quarter and so on are used, which means it's base 2 and so for example 1/12 inch is *not* easily expressed.
The US system means like 3 different measures for length, none of which related in a straigthforward way, and none of which are related to other measures like volume in any sensible way whatsoever. (quick now how many gallons is 1 cubic foot ?)
Or to put it short: The US "system" is no system at all but rather a historical accident.
" Slashdotters are generally more tech-aware, are more likely to read and understand tech journals"
:0
I think you meant to say "read and misunderstand", as the comment thread clearly denotes.
1/6 of 37.25 feet is 74.5 inches. That's what's usefull. .0001 feet or .0012 inches is the same so you don't need to do the convertions. But you can use them to do more mental math with things like 1/6 of 10 feet is 20 inches or 1 foot 8 inches.
Now what's 5/6th of 10 meters?
Granted when comparing different units can be a pain but when working with units in your head it can be vary usefull.
Personaly I would be happy to drop metric units for most things but the inches > feet converiton is usefull. I could see finding even with your example to be ok if i used the units enough though.
1,760 yards + 440
Anyway, things are about as bad as doing 5/3 km vs 726 m +938m.
I don't know what you're trying to say here. The point was you could get to orbit with the same amout of fuel. I didn't say you'd do it in a 747.
Helpful Hint #2: What is the difference between energy and power? If two machines release the same total energy, but machine #2 must release it much more quickly with equal or greater precision, which is likely to be more complex and expensive?
Actually, jet engines are far more complicated than rocket engines. There's a reason rockets predated jets by, what, 40 years? I have no doubt Carmack and his folks at Armadillo will be successful building a rocket engine that will get them to orbit, but if you told me they were building a jet engine from scratch I'd roll on the floor laughing.
The reason flights to orbit are excessively expensive is either 1) You throw away most of the craft and have to build it again for the next flight and/or 2) You built the craft to be reusable but you designed it for maximum performance, which made everything complex (and thus expensive).
No Throat Singing for this rocket motor!
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
Well, you can use nuclear energy to heat a reaction mass and use the extreme temp/pressure created to eject the reaction mass (non-radioactive) from the engine.
Awesome furniture, accessories and cabinetry in Santa Rosa, CA: http://humanity-home.com/
You also say: Anyway, things are about as bad as doing 5/3 km vs 726 m +938m.
The point I want to make is that noone in metric-land ever wants to give distances in fractions of a unit (other than decimal fractions), so you always just add the decimal fractions. You don't have to calculate (or remember) if 107in is more or less than 9ft. You just look at the numbers and immediately know it. In extreme cases, you may have to move a decimal point by three digits. I also posit that in practice, it is easily remembered that 1000/3 = 333 and a bit. This also teaches you about measurement tolerances and the need to restrict yourself to a reasonable number significant digits;-) By way of compensation, dividing by 5 or 10 is really easy in the metric, or rather, the decimal system.
As an aside: I occasionally do machining in a non-metric shop and I especially hate the coexistence of mills and 1/64th of inches. The latter has all the disadvantages of having to do fractions in your head and all the disadvantages of having few (i.e. one) prime divisors.
chl
If you ask any physics professor he will tell you that modern physics is based upon theory yet to be disproven; not upon already proven facts.
Of course. My point was that you can say the exact same thing about base-10 numbers. It's totally arbitrary and decidedly non-optimal.
If you don't know where you are going, you will wind up somewhere else.
My penis just went flaccid.
Mathemathically it's arbitrary ofcourse, non-optimal I don't know, atleast there's no large advantages with any base.
The Durham Freeway (I think.. some major thoroughfare around here...and that's Durham, North Carolina, USA; not County Durham, UK) near the Research Triangle Park does have split signs, but only for the distances (i.e. Raleigh ... 5mi ... 8km); not for speeds.
.5 mi, even .1 mi) on most, if not all, major thoroughfares denoting your position from an arbitrary zero point (often a state boundary). This is helpful for emergency crews to pinpoint locations of accidents, etc. All the mile markers would have to be pulled up and respaced; I doubt drivers would be as happy with "1.6km markers"....just as functional, yes, but lazy Americans (yes, I count myself among the lazy!) would dislike all the decimal places.
The problem with the sticker idea is that does nothing for mile-markers. I don't know if Canada uses a similar idea, but we have small signs every mile (more frequently in some places,
Yes, conversion is possible and might even be a change for the better, but would encounter such inertia as to be incredibly prohibitive.
http://undecidedgames.blogspot.com
Not on the moon, but I did get it backwards.
1 kilogram of mass, at the earth's surface, would weight 9.81 Newtons, which would equal about 2.205 pounds (lbf). On the moon it would be about 1/6th less (force).
Behold, this dreamer cometh. Come now, and let us slay him... and we shall see what will become of his dreams.
So one of your arguments is that 1/6 of some length in feet will still give an integral number of inches. Is that *really* worth all the hassle that I humourously illustrated in my previous post?
/6 = 2Pi inches. The reason why this is usefull is you can do the same thing when dealing with feet when deviding by 5 you move the decimal point over one place and multiply by 2. So it's easy to find out that 27 feet / (2,3,5,6,10,12) is. vs 27m/(2,5,10) Granted I use metric most of the time, but if you are taking all the mesurments then using metric is less usefull. I think doing the convertion is a good idea now, but if you where going to say build a house from a bunch of trees then metric much less usefull.
Ok now that the tread is "over" I am going to admit I was messing with you but the idea is you can change deviding by 6 to multiplying by 2 when going to inches even when dealing with not integer numbers. Pi feet