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Post by scooter on Nov 19, 2005 0:13:26 GMT -4
Think nozzle...
The whole concept of a rocker nozzle is to take the products of chemical ignition (solid, liquid) and accellerate them, creating a positive thrust. The actual combustion chamber is above the nozzle. The combustion/vast increase in pressure occurs, then is expelled through the narrow area below it. Then it is carefully expanded, according to the chemical reaction happening, and the atmospheric (or lack thereof) conditions below it via a "skirt". Through these various hardware variables, the motor is tailored for it's particular mission. The key is the ability of the engine to accellerate the byproducts of the combustion chamber ignition via the nozzle, and thereafter, the engine skirt.
This is how rockets, and LMs are designed.
Dave
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Post by scooter on Nov 18, 2005 23:55:19 GMT -4
Come on Bob. You gave an opinion and haven't provided facts. While I believe you believe what you say to be true doesn't make it fact. If the propellant ignited on contact, and the pipes were 1 1/2 in diameter, as a lay person I don't believe 11.25 pound entered the chamber in one second. I could be wrong though. However, I also don't believe 11.25 ponds of one chemical mixed with 11.25 pounds of another chemical could lift off the capsule. It was over 10,000 lbs and someone said it was over 3500 pounds in lunar atmosphere weight. Telling me to not question you people is a joke. Is that how you ABers win arguments, ban people who ask questions..? Prove your claim with actual facts like I or any other HBer are required to do. So, it weighed 3500 pounds lunar gravity...now, what does your research tell you was the thrust of the engine?
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Post by scooter on Nov 18, 2005 23:51:48 GMT -4
I fly model rockets, some are kinda big...
My "IRIS" scale sounding rocket model has a motor with a solid propellant weight of about 4 ounces. the rocket, loaded with motor and recovery device, weighs about 3.5 lbs. How can 4 ounces of propellent, burning over about 3 seconds, lift a 3.5 pound rocket...to over 2000 feet???
Dave
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Post by scooter on Nov 18, 2005 22:18:36 GMT -4
The ascent engine was not throttable, it did not increase or decease thrust. It lit, thrust built up almost instanteneously, then it burned at that energy level until shut down. The thrust was plenty adequate to lift it quickly away from the surface (descent module). Any accelleration was due to the velocity vector away from the gravity gradient, and the gradual lightening of the "payload" due to consumed fuel mass. It's rocket science, but it can be understood by a layman...
Dave
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Post by scooter on Nov 18, 2005 21:01:57 GMT -4
OK lets see here...when discussing "explosive bolts", we are not discussing really significant explosions going on here. The bolts are built with small sections of what I will call explosive cord, strategically placed in such a way that, when set off, they vigorously crack the bolt, rendering it "no longer a bolt". It may break in two or three places,depending on how it is engineered and manufactured. It is not accurate to really call it an "explosion"...I hope those more technically knowledgable will help here. The idea of the astronauts decompressing their LM and opening the hatch has been refuted by the Apollo 8 astronauts at least, in wondering if the come home burn didn't happen. The astronaut mindset is to work the problem until you are no longer able, then fall asleep. The mission controllers agree. Meanwhile, engineer it as reliably as possible. And, needless to say, the LM ascent module did have it's own fuel supply for the trip to orbit. You know this now. If you are going to argue, do some real studying...yes, studying. Just browsing and pulling numbers and figures fom a page doesn't do it. You should try to understand how NASA says says they did it before tossing out counter arguements that don't make any sense. Right now you don't seem to fully understand the "NASA story". The ascent stage burned for about 430-some seconds, full thrust, to get it to orbit. Orbit velocity for the Moon is significantly lower that the 17500mph for Earth orbit. Plus, no atmoshere, so they could pitch toward horizontal earlier and gain velocity. Study up, friend, please. Some of your arguments draw ridicule on yourself, which you may not be realizing...unlatching latches for lunar liftoff, exploding batteries...understanding the basics is important to presenting really credible arguments.
EDIT: The "chemicals", being hypergolic, don't really "explode", they "ignite. The ignition, in a carefully engineered combustion and thrust chamber, creates thrust. The pressure of the helium tahks, the feed line design and many other details ensure a smoothe thrust build up and a understood "thrust curve" for the durattion of the burn. It is a controlled burn, like any rocket motor, not an explosion. Dave
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Post by scooter on Nov 18, 2005 15:34:03 GMT -4
On a flight not long before Columbia's demise, there was an incident where the primary circuit of one of the 8 holdown posts failed to fire, though the secondary did function, and the liftoff proceeded as normal. This caused a huge stir, IFA reports etc. Redesign here was a part of the shuttle RTF program. If I understand the design, the bolts are secured through the holddown structure at the base of the SRB. Big 3 inch bolts, with explosive "nuts" at the top end, captured in a honeycomed capture device to preclude fragments flying about. The other end goes through the holddown support structure on the MLP and is secured with a fixed bolt. Then the thing is tightened down to many million ft/lbs tension. On release, the main bolt bangs downward into a large capture bucket filled with sand to absorb the enormous release energy. If the bolt (s) failed to fire, not real sure what would transpire... Dave
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Post by scooter on Nov 18, 2005 12:32:25 GMT -4
The conversation log evidences that they did not do so at anytime, thus proving beyond any doubt, and without further showing, that this was all a hoax. This cannot possibly be a serious statement. The frightening thing is that he is serious as a heart attack. He truely believes all this strange stuff. He hasn't yet retracted any of his previous contentions nor has he conceded a single point. I use the word "ignorant" as it is the most accurate, non derogatory term I can come up with, there are plenty less polite terms I could think of. He is, on the other hand, providing plenty of "signature block" material... Dave
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Post by scooter on Jan 25, 2006 20:29:59 GMT -4
The dust (dirt) will be a challenge...how do we keep it from billowing when kicked...or even moving. The flag too...there must be absolutely no air movement inside the set. One tiny, incredibly brilliant light source...well, darn, won't do the shadow anomoly thing, nevermind...how to eliminate dual shadows...hmmmm.
...the set...we're gonna need a really, really big building....bout half mile on a side...
could use some help here Moon Man et al...someone explain the details of how it really was done. Seriously.
Dave
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Post by scooter on Nov 20, 2005 21:34:10 GMT -4
The PLSS pressurized the suit to around 3.5 PSI, and put out 100% O2, whereas the SCUBA units are pressurized with atmosphere. Think of the suit as a mini space capsule, complete with life support, temp control and radiation, micrometeorite, and thermal shielding. The lower pressure, along with the "closed loop" design, allows for much more efficiency than a SCUBA unit. The EVA suits didn't have a "joint" at the waist, just an accordian bellow that allowed a bit more waist flexibility on the longer EVAs. The shuttle EVA suits are actually two piece suits, "torso" and "legs" being seperate pieces. Fascinating technology... Dave
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Post by scooter on Nov 19, 2005 23:01:55 GMT -4
So, we have what appears to be a discrepency in duration, but not in weight. I need to recheck Obviousman's latest post on the suit thread, he may have addressed it there. (you may want to bring this post over there as well, I seem to have diverted this topic, my bad...) Dave
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Post by scooter on Nov 19, 2005 21:17:02 GMT -4
You're changing subjects, back to the suit... Now, where did you get this "long duration" LiH2 canister number, my chart here for the -7 PLSS shows things petering out near 8 hours, dependent on activity level. Dave (go Avs!)
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Post by scooter on Nov 19, 2005 10:38:14 GMT -4
That was 2 burns for a total of 12.5 minutes. okay, my mistake. Long night. Hi Moon, You have seen me use the term "ignorant" from time to time, sometimes in a seemingly harsh manner. This was not my intent. In this case, your "ignorance" (lack of knowledge of the facts) is evident. You speak with an inaccurate authority of a 12.5 second burn for lunar descent and seemingly think the figure makes sense. Very long night indeed! You have acknowledged the error, and this is good. Any straight thinking person would realize such a burn duration would make no sense. I detect a "knee jerk" reaction to snippets of out-of-context data in many of your arguments...you pull out a number found somewhere, and begin making assumptions based on this very limited data which don't make sense. Back to spacesuits... They were designed expecting very small leaks. The acceptable leak rate was 0.0315 lb/hr. This rate was never seen on the lunar missions, though Apollo 12 came close. The effects of the dust on the sealing surfaces and O rings sealing the suit were significant, somewhat mitigated on the later flights. An interesting 2005 article is on my fav link, talks about the dust being a major constraint to extended stays on the Moon. John Young felt that it could be a show stopper unless addressed. The link study also noted that an Apollo 12 third EVA would have been problematic with the effect of the dust on the suit (increased flow leaks), and the severe abrasion suffered to the boots during their two EVAs. The later flight used lubricants to clean the suit attachment rings, and were provided with much tougher overboots and gloves. It will be a significant issue when we go back. There is also a chart there that gives a consumables/EVA curve, based on average metabolic rate of the astronauts out on the surface. O2, LiOH, and cooling feedwater at different leakrates are charted. The "warning" line is around 7.75-8 hours, depending on the variables. Dave
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Post by scooter on Nov 18, 2005 23:20:11 GMT -4
a web link to this, if you please...
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Post by scooter on Nov 18, 2005 23:16:30 GMT -4
You are not a licenced lawyer yet have managed to change Canadian law? nevermind... dave Yes, it was a landmark case which set a Canadian presedence which I believe applies to American law as well. It might even apply to disputes over websites in trademark cases. I could turn ICANN on it's butt as their rules are fatally flawed.
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Post by scooter on Nov 18, 2005 23:02:10 GMT -4
Hey, according to a few people on here, we're the trolls, Scooter.[/quote From an English text, a woman speaking to Winston Churchill... "Winston, you're drunk!" "Madam, you're ugly! Tomorrow, I shall be sober, and you will still be ugly" Gotta love them Brits... Dave]
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