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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."
Ugh. This isn't a sexual euphemism of some sort, is it?
oh great, just what we need: more amatures building shit we dont need :/
this sig no verb
GO LINUX!
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.
5,000 lbf engine
But on Vista it will only be 2,500lbf - that crap
..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!
...than building it. How about the nozzle designs? Unless Carmack is properly matching a nozzle to the back pressure generated by his engine such that the shock wave is optimal (at the nozzle exit), I'm not impressed. 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.
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.
PS. Miles don't count. I can think in miles. I can't think in pounds, and I especially can't think in pound-feet, which is what this author expects me to do.
PocketGamer.org - For the gamer on the go!
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.
"John Carmack is working a potentially disruptive technology: A throatless rocket engine."
So I guess the porn industry will not be funding this?
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.
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 think Mr. Carmack has a bit of a Pygmalion complex with Commander Keen. To the heavens!
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
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!
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.
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.
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.
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
Would someone please be kind enough to copy-n-paste it?
Take the 90-Day Challenge! http://rwmurker.bodybyvi.com/
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
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.
Carmack says: NOTHING you idiot Carmack is dead he's locked in my basement.
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
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>
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.
I myself try to stay with DD-cup or smaller.
Romero wanted to make an RPG, but he decided to make a throatless rocket engine.
Screw that! Rocket-jump, baby!
Freedom: "I won't!"
When the Quake 3 engine will be available under GPL?
... 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.
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.
This idiot should stick to games. 'Disruptive' is one of those buzzwords that business school types throw around when they are trying to deceive investors. What is the advantage of this engine design? What are the reactants, ISP? Meaningful details like that don't get you posted on slashdot I guess.
an ill wind that blows no good
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
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
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?
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.
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-
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.
"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
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.
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?!
>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.
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.
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.
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.
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
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 ;)
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."
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.
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)
Yeah, ASSCAR in Space. How fucking boring. Let's watch a bunch of ignorant rednecks fly around in circles in space. The only bonus would be that once they crash into each other, maybe some other them would actually get jettisoned out into space forever never to be seen again.
Of course, ignorant rednecks making it into Space is highly unlikely anyways. They will be too busy trying to convince people in Kansas that creationism is real.
Of course, by the time Space racing becomes a reality, IRL (Indy) be have replaced ASSCAR anyways, since Indy is what ASSCAR always wishing it could be. And Formula One will still have a cloned version of Michael Shumacher racing to a win every time.
In the future of space racing, my heart will still be with the one true motorsport...Rally. Except, instead of WRC, it will be SSRC or GRC. That would kick ass.
http://www.xcor.com/engines.html X-cor has been making "throatless" motors for some time. Very nice and simple.
http://en.wikipedia.org/wiki/Project_Orion
DRM 'manages access' in the same way that a prison 'manages freedom'
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?
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
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.
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.
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.
"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.
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.
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?
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. --
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.
" 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.
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.
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My penis just went flaccid.