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Post by SeaRat on Nov 26, 2005 22:08:14 GMT -8
Some boy scouts got in trouble launching rockets within three miles of a small airport too, jr. There is a reason the fire marshall is interested in rocket propellants--they cause fires. Before you start working on any of these chemicals, be sure that you are doing it under someone's watchful eyes who knows what he or she is doing. These can be very hazardous, especially if you do them in an enclosed environment (a room, for instance). Each flammable liquid has its own LEL (lower explosive limit) and UEL (upper explosive limit). In that range, there is enough oxygen in the air for the liquid('s vapors in the air--added later) to explode, and that is not a pleasant experience. So be very, very careful about what you are doing, where you are doing it (plenty of ventilation), and under whose supervision you are doing it concerning rocket propellants. This is not something you want to experiment with at home by yourself. I looked up the chemical, nitrous oxide on the National Institute of Occupational Safety and Health (NIOSH) website (Pocket Guide to Hazardous Chemicals), and this is their fact sheet on it: www.cdc.gov/niosh/npg/npgd0465.htmlNote that Nitrous Oxide has no LEL or UEL; it is non-flammable. This is probably why they use it as a propellant in whipped cream (aside from the fact that it won't hurt you in these concentrations. This has nothing to do with diving, other than I want you to continue to be here and interested in diving. Handling rocket propellants inappropriately can cause grevious injury, or worse. John
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Post by jrvancealt on Nov 26, 2005 22:33:00 GMT -8
i completely understand what you are saying and am in no way looking to get hurt or damage property. any way, project pending parental approval there is a reason fire extenguishers were invented,,.. so i dont blow my self up,
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Post by jrvancealt on Nov 26, 2005 22:43:38 GMT -8
about the legality its kind of weird, anyway use common sense and dont launch anything near dry grass and other flammables green is good anyway back to diving uuhh
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Post by Ron Hearn on Nov 27, 2005 7:00:00 GMT -8
Hi
You railroaded my question into a grade 10 rocket class. LOL Thanks for all your input into the use of mixed gas while diving with double hose regulators.
Ron
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Post by SeaRat on Nov 27, 2005 9:04:38 GMT -8
Ron,
I just checked Cousteau's World Without Sun, and he never does state what the gas mixture percentages are, only that their "deep cabin" had a special mixture of oxygen, nitrogen and helium. The oxygen was probably decreased in percentage, rather than increased as we do with nitrox. They were saturation divers, and didn't care whether they saturated in nitrogen, only that the effects were lessoned (nitrogen narcosis).
Concerning Cousteau's deep dives using the submersible chamber, again they probably decreased the oxygen content, rather than increased it. But again, I don't know that Cousteau ever published anything on the technical aspects of his dives.
jr, I may have misled you above with the discussion of flammable liquids. What I was talking about is the evaporation of the solvent into air, and the air around you becoming an explosive atmosphere. The range between the LEL and UEL is the flammable range, and any spark could ignite the air, and cause an explosion. A fire extinguisher would be of limited value in this case (putting out what had already exploded).
John
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Post by mossback on Nov 27, 2005 17:22:29 GMT -8
Jr
Launching near green isn't all that safe.....I, in my youth, did not expect my saucer rocket to catch fire or land in the weeds.........lesson is think of what unexpected things could happen and try to be prepared for them.
Home Rocketry was pretty new when I was a kid, not much concerned about anything but get it into the air. I dare say a few fires, shattered windows etc. caused a lot of changes and new rules. One use to be able to launch from the city park here where I live, new laws prevent that now. Rocketry isn't the same now and I dare say, if one follows the established proceedures one will have a safe and statisfying hobby.
Jr. note that Searat is 100% correct on using of fuels and possible results that he wrote of......and Nemrod as well, suggesting a club where there is a wealth of info to keep your hobby safe...........I might add, a vast majority of this info is based on trials and errors (ie: successes and mistakes made by others before you...myself included)....this goes for diving as well. The lessons learned in the past by divers of what to do or what not to do have accumulated into the basic proceedures we have today.........
Even us OLD divers were doing things a certain way back then based on the experiences of others and it goes forward to today.......unfortunately it seems a lot was lost on the way with the new divers......is why we are here on this forum I suspect.........to preserve the better parts of the past...........
Good luck on your hobbies and stay safe.
PS........making your own fuel now days can get you into trouble......I think it is called basement bombing.....Homeland Security frowns on such activity. Your mom will too if you send her stove vent into the next county.
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Post by jrvancealt on Nov 27, 2005 19:16:53 GMT -8
thats the reason to make the fuel outside
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Post by SeaRat on Nov 27, 2005 21:46:20 GMT -8
For a quick way to get this thread back on track, let me say that rockets and scuba diving do mix, at least in my mind. I was on the recovery team for Apollo 13, as a USAF Pararescueman. We watched the launch of Apollo 13 while on strip alert at McCoy AFB, Florida. If something went wrong during the first 2 minutes of launch, it would be ours for the rescue effort. After that, I think it was passed off to Panama first, then the Azores. As it turned out, the problems with Apollo 13 didn't occur until it was on its way to the moon. As we discussed, they had an explosion on board. It turned out that the Number 2 oxygen tank exploded. You can read a bit more about it here: science.ksc.nasa.gov/history/apollo/apollo-13/apollo-13.htmlThe problem with oxygen is the same, no matter what environment it is in--it can cause fire and explosion. The tie of this to my experience was that we were trained to put the floatation collar onto the capsule when it came back to earth. Unfortunately for me (but fortunately for the astronauts), it came down in the wrong ocean (the Pacific, and I was in the Atlantic), and right next to a US Navy carrier (not quite by accident either). This was the most precise of landings, under the most unusual circumstances. Had it come down somewhere else, we would have parascuba jumped onto the capsule, retrieved the collar. The collar was dropped first, along with a 7 man life raft, both in bundles with a floating line between them. The idea was to drop the two bundles at intervals about 10 seconds apart, so that the line would float between them. Each bundle had a sea anchor on it, and the capsule would be blown between them. The line would then catch on a hook on the capsule, and this would stop the Apollo capsule from being blown by the wind. We would then jump, and put the collar onto the capsule. But it did not come down in our area, and the Navy UDT/Seals had that honor. In our training, we needed to heed the warnings of rocket propellants that may still be coming from the thrusters when it hit the water. One of the components (hydrazine) was very toxic. apollo.spaceborn.dk/index.asp?id=23www.cdc.gov/niosh/npg/npgd0329.htmlWe were told that we were to keep our scuba units in our mouths, and our masks on, while putting the collar onto the Apollo capsule. This was not the first time Apollo had a problem with oxygen. It was a fire in Apollo 1 that killed the three astronauts (Grissom, Young and Chaffee), and led to modifications of the Apollo away from a 100% oxygen environment. Here is a site about the Apollo, block 1, spacecraft: www.apollosaturn.com/block1/blockone.htmSo you see, oxygen is a potential problem, whether it is diving, or in space. We need to be aware of its potentials for damaging equipment, and for fires, to ensure the safety of all. John
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