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Post by sts60 on Jun 16, 2006 10:18:24 GMT -4
the whole argument my friend was making semmed too basic anyways .. it literally was "they used x ammount of fuel to leave earth so they should have used 1/6 of x on the moon" ... not considering any other factors, the first one being that the object being lifted is no longer a massive rocket full of fuel .. but JayUtah explained it in great detail !
Did you point out to your friend that vastly different masses were involved, different propellants, different engines, etc., in addition to the fact that you cannot simply divide by some ratio, as Jay explained so well?
Did he say anything? Why not invite him over here?
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Post by mndwrp on Jun 16, 2006 12:31:46 GMT -4
Did he say anything? Why not invite him over here?
i sent him the explaination .. if he's gonna be bothered to actually read it and understand even the basics of it is another story ..
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Post by JayUtah on Jun 16, 2006 12:58:39 GMT -4
...it literally was "they used x ammount of fuel to leave earth so they should have used 1/6 of x on the moon"
Yeah, that's not rocket science. Just because he can express his error in an equation doesn't make it the right idea.
It just isn't that simple. The Saturn V used RP-1 (a kind of kerosene), hydrogen, and liquid oxygen. The lunar module used a kind of hydrazine and nitrogen tetroxide. Pound for pound, those propellants behave differently.
And gallon for gallon they behave differently too. This is a perennial discussion between myself (with a liquid-fuel rocketry background) and my clients ATK (major players in the solid-fuel rocketry field). Pound-for-pound solid fuel isn't as powerful as most liquid fuel, but a pound of their fuel will fit handily in your glove compartment while a pound of liquid hydrogen takes up a lot of space. Hydrogen as a liquid still isn't especially dense.
So then the problem becomes creating a tank to hold the fuel. Solid-fuel rockets achieve better performance from weaker fuel by requiring less rocket structure to hold an equivalent propellant mass and propulsive capacity. That means less dead weight.
No matter what form your fuel takes, the rocket fuselage for an Earth launch has to be aerodynamic. That means a long thin cylinder. When the shape of your fuel tank is dictated to you as a requirement, you can't necessarily optimize in other ways.
If someone told you, "I need a tank that can hold ten gallons of fuel, and it has to be as light as it can possibly be," you could experiment with different shapes and discover that a sphere shape holds the most volume with the least surface area and thus the least material. So by minimizing the amount of the material you need to make the tank, you can keep the weight down.
(Now of course an engineer will examine tradeoffs. We know 10 gallons equates to a certain volume. But we might discover a certain exotic material that has absurdly high yield strength and absurdly low density, but can only be manufactured in flat plates. So if we cement flat plates together in a tetrahedron or cube or dodecahedron, we can get overall less mass to the tank for an equivalent enclosed volume, even if the shape is not optimal.)
But then the customer says, "Oh by the way, I also need that tank to have favorable aerodynamic properties in at least one dimension."
Grr. To enclose a certain volume in a tank that also has good aerodynamic properties means a tank with a small cross-section. A long, thin cylinder with an appropriate fairing presented end-on to the airflow will create far less drag than a sphere of the same volume. But the tank also has to be stiff enough to retain its shape. That's easy for a sphere, but harder to do for a cylinder. The cylinder will want to bend in the middle, so it means you have to add material to build a thicker, stiffer structure. If you had a more geometrically favorable shape you could use less material and keep the tank lighter.
What this means is that designing the lunar module and designing the Delta II involve lots of different design criteria that affect how efficient each vehicle will be in different ways. It makes the resulting vehicles not directly comparable.
If your wife tells you to go build a swingset for Junior and to get it done this morning and for less than $100, you'd go out to Home Depot and buy a bunch of stock lumber and nail it together. Structurally it would be overbuilt by a factor of about 5, and it would look like crap. But if instead she tells you to take your time and do it right, make it as light a structure as possible, and make it something fun to look at, you could retain an engineer who would charge you $10,000 to do a minimal catenary arch made of vermiculite concrete. Both products fit the definition of "swingset", but beyond that they don't compare in terms of cost, construction, appearance, or performance under different circumstances.
The lunar module and a Delta II rocket differ in so many important ways that it's just not possible to compare them as directly as saying one should be a simple integer factor of the other.
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Post by Jason Thompson on Jun 16, 2006 18:46:46 GMT -4
Hasn't the LM been described as 'the most pure flying machine design ever devised' or something like that, precisely because it doesn't have to account for drag, aerodynamics, creating lift using aerofoils etc.? It's basically (purely in flight terms) just a big engine with stabilisers.
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Post by JayUtah on Jun 16, 2006 19:19:23 GMT -4
Yes, the LM has been described that way, but it's not entirely true. Every machine is a product of its requirements and constraints, and every successful machine is a more or less pure creation within those constraints.
But because the LM was not required also to be an aircraft, it could optimize toward other requirements. Its shape and configuration was an outgrowth mostly of the requirements of Newtonian dynamics. The engines are high in their respective frames, with the mass concentrations of fuel tanks cantilevered to the side rather than placed in line.
That's why it really irks me when conspiracy theorists say the LM was unstable compared to launch vehicles, or obviously incapable of stable flight. That's so unbelievably ignorant. The LM is an example of how you should arrange mass concentrations in a spacecraft when aerodynamics does not require them to be arranged differently.
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Post by SpitfireIX on Jun 16, 2006 20:55:02 GMT -4
Skim this article. www.clavius.org/bibvoron.html
I wrote it for a similar situation.That's very good, Jay, and I don't remember ever having read it (though I recall your posting some of this information on badastronomy a while back). How long has it been on Clavius? Also, I assume that "Der Voron" is a pseudonym, so is your use of "Mr. Voron" intended as a somewhat tongue-in-cheek dig at DV? ;D
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Post by JayUtah on Jun 17, 2006 0:31:45 GMT -4
Der Voron is not, to my knowledge, a pseudonym or nom du plume. He has written UFO-related books under that name. He does not speak English natively, so I suspect his name is real but foreign.
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Post by SpitfireIX on Jun 18, 2006 13:28:22 GMT -4
Der Voron is not, to my knowledge, a pseudonym or nom du plume. He has written UFO-related books under that name. He does not speak English natively, so I suspect his name is real but foreign.You've obviously spent a lot more time dealing with him and his material than I, but the first time I ever saw the name, I assumed that "Der Voron" was a pseudonym, as "der" is the [edit: nominative] masculine definite article in German. I did some googling and developed the following information: - "Voron" is the Russian word for raven.
- "Voronin" is a Russian surname. According to a genealogy web site I found, it "originates from the term voron ('raven') or vorona ('crow'). This term may have been given as a nickname to someone who possessed some quality characteristic of a raven or crow, perhaps a harsh-voiced or black-haired individual. English spelling variants include: Voronen, Varonan, Varonin, Veronin, Johnson...."
- "Voron" is an American surname, but it is extremely rare (23 death notices in the US Social Security Administration database, against several hundred thousand each for "Smith," "Jones," and "Davis").
- "Der" does not appear to be an established first name, male or female, in any major language (see here), although I did find it listed as a possible short form of "Derek" in one English-language database of baby names (I checked several).
- The Russian language does not use articles, either definite or indefinite (thus the translated Russian title of Edgar Allan Poe's famous poem "The Raven" is simply "Voron," but in German it is "Der Rabe").
The real kicker, however, was when I discovered, quite by accident, that a book called Russian Experiences was published at about the same time as DV's first UFO book. Russian Experiences is a supposedly at least semi-autobiographical account of the early life of one of the co-authors, who was born and raised in Soviet Russia. The co-author uses the pseudonym "The Raven." Both books have been reviewed together on several web sites (including this one). The connection is that both books were reviewed by Denise M. Clark, and those were the o nly two books she reviewed. This strikes me as extremely unlikely to be a coincidence. Presumably Ms. Clark might shed some light on the issue. In view of the foregoing, I feel that "Der Voron" is most likely a pseudonym. DV probably decided for whatever reason to use the Russian word for Raven (possibly because his real name is Voronin) as a pen name; perhaps he felt the need to add a definite article to make it sound more like a real name (first and last), and, as Russian lacks a suitable word, he chose the German definite article "der" (masculine, correct for the German word for raven, and possibly more Russian-sounding than "il," "le," or "el"). [edited to add: I also just made another very interesting discovery. The other co-author of Russian Experiences is named Marie Clair. "Marie Clair" is also one of the nine people (to date) who has reviewed DV's book on Amazon.com. The review is clearly a shill--brief, five-star, and the only one she's ever written. The plot thickens.]
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Post by JayUtah on Jun 19, 2006 0:37:04 GMT -4
I have talked to Ms. Clark. She is real. She exists. www.denisemclark.com/And she is so mad at Der Voron that she is considering legal action against him. She is a free-lance writer and reviewer, and she honestly did write a view of Der Voron's books. The problem is that Der Voron appropriated her identity and sent that review under her name literally to hundreds of publishers. My first contact with Der Voron was to send a message to the e-mail address associated with an article he wrote for an online tabloid. Within about two hours of having sent that message, I got several solicitations from "Denise M. Clark" requesting that Clavius publish reviews for Der Voron's UFO-related books. The solicitations continued. Finally I contacted Denise via her web site and asked her politely to stop sending me articles. I received a message (from a different address than the solicitations) that was the paragon of humility, apology, and exasperation. This is all on my page: www.clavius.org/bibvoron.htmlI then had a lengthy correspondence with Der Voron about his rocket science claims. Finally he admitted he didn't have any scientific or engineering training, but that he had a 165 I.Q. (presumably from one of those online tests). The clincher came when he begged me not to reveal to anyone that he was unqualified to make his claims. So naturally I published that fact as far and wide as I was able. I don't really care what his name is. If he's impersonating real people and trashing their reputations, and deliberately withholding admissions of ignorance from his audience, then to me he represents the absolute worst in conspiracism: someone who is lying, who knows he's lying, and who brazenly defrauds his audience. I think Der Voron belongs in jail, personally.
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Post by PhantomWolf on Jun 19, 2006 6:47:06 GMT -4
In a cell right beside Sibrel.
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Post by mndwrp on Jun 19, 2006 11:43:48 GMT -4
thats the unfortunate downside of having a society with freedom of speech .. even crazy nutters get a voice .. i think the best thing is to not give them attention and never ever buy their crap books .. it's what theyre in it for .. attention and a quick buck on the imagination of the public
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Post by JayUtah on Jun 19, 2006 12:57:52 GMT -4
Back in the Olden Days everyone had free speech, but in order to have a wide audience you had to convince a publisher or a producer that your idea had enough merit to warrant the cost of distributing copies of it. Nowadays anyone with the price of a junker car burning a hole in his pocket can buy a decent camera, a computer, and a copy of Final Cut Pro and make a movie.
Oh sure, Bart Sibrel claims it cost between $500,000 and $1 million to make his first movie. (The former claim is made on his website, the latter made to people I've talked to who have tried to do business with him.) He claims it cost tens of thousands of dollars to have licensed Dinah Washington's "Fly Me To the Moon" -- a claim I've run past several filmmakers from small-time operators to guys with offices on Sunset Blvd. in Hollywood and generated vast peals of laughter. Sibrel's either lying or he got royally ripped off.
The Internet and associated digital revolution has given everyone's desktop write-access to mass media, which of course gives undue attention and credibility to the uninformed opinion and the unscrupulous business plan.
No, of course we shouldn't buy their books or videos. That is exactly why they do what they do. Ideologically it's not a good idea to prevent people we think are crazy nutters from having a voice. But as consumer advocates in the marketplace of ideas we can surely provide something better. The cure to bad speech is generally better speech, not censorship. But there is a difference between censorship and fraud, and I think some of the conspiracy theorists have crossed the line.
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