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Model Forum / General / Rockets / August 2007Helium
Has anyone used it in rocket? If so how? Donald A. Laskey > Has anyone used it in rocket? If so how? > > Donald A. Laskey Hi Donald, it was sometimes(?) used as a neutral gas in charging liquid rocket engine pump lines. Even in an Estes Big Dude, it will not do any good for model rocket flights. > Even in an Estes Big Dude, it will not do any good for model rocket flights. So nobody has used it instead of nose weight Donald A. Laskey A rocket with a nose that is too light... which will fly backwards in circles, not good.  SignatureTAI FU > > Even in an Estes Big Dude, it will not do any good for model rocket > flights. > > So nobody has used it instead of nose weight > > Donald A. Laskey > - Show quoted text - Sorry what I meant was tail light (for lack of a better term) as a posed to nose weight. Donald A. Laskey > > Even in an Estes Big Dude, it will not do any good for model rocket > flights. > > So nobody has used it instead of nose weight > > Donald A. Laskey I think you'd run into one of two problems (which hare really the same problem) If you're using helium to lighten the aft end of a small rocket (LPR/MPR) the volume just isn't there to lighten it significantly(unless you go to higher pressures which would require thicker materials....which makes it heavier...). If you're using it in a HPR rocket which has the volume and could withstand higher pressures, you're now dealing with materials that are thicker and therefore heavier which would require move volume and higher pressures of helium. (viscous circle ensues) You also have the problem of containment. If you wanted to fill and purge the container for each flight, you have to allow for plumbing (connectors, etc) which weight would offset the benefit of the helium. If it isn't refillable, then you have to engineer your rocket to be filled once and then sealed in such a way that the helium doesn't escape.(not an easy task, also would be heavier than no containment at all) I like the thinking outside the box, but I don't see how this use of helium in rocketry would work. -Aaron > > > Even in an Estes Big Dude, it will not do any good for model rocket > > flights. [quoted text clipped - 10 lines] > in a HPR rocket which has the volume and could withstand higher > pressures, you're now dealing with materials that are thicker and Ahh, adding He by pressurizing a volume does not make the volume lighter. Even He has mass (therefore weight) and the more you add to a volume, the heavier that volume gets. > > > > Even in an Estes Big Dude, it will not do any good for model rocket > > > flights. [quoted text clipped - 14 lines] > lighter. Even He has mass (therefore weight) and the more you add to a > volume, the heavier that volume gets. So, the limit you'd want to fill the volume would be up to 14.7 PSI (1 ATM), correct? At that point, you're replacing the air with He and He is definitely lighter than air, thus making the overall volume lighter, correct? You still have to worry about containing the He or filling/purging the He and all of those things will add weight which would offset any gains made by using He. What I was thinking was a balloon, (you know the type that you use to make animals out of) this would mean you would not need to make the rocket to withstand any abnormal pressure leaves. The only thing that I have not come with is how to close it but still being able to top it off. Also since I am talking about rockets that fly with in the atmosphere as long as I keep the amount of He under the weight of air in the same space the He will still have mass but negative weight (since weight is not a constant but mass is). Donald A. Laskey > What I was thinking was a balloon, (you know the type that you use to > make animals out of) this would mean you would not need to make the [quoted text clipped - 4 lines] > in the same space the He will still have mass but negative weight > (since weight is not a constant but mass is). The Estes big dude was a rocket made from a silver ballon. here is one for sale: http://tinyurl.com/23yrqf A good price since it comes with the estes E pad and controller. Many tried seeing if using He in it instead of air would make it float away. it didn't > What I was thinking was a balloon, (you know the type that you use to > make animals out of) this would mean you would not need to make the [quoted text clipped - 4 lines] > in the same space the He will still have mass but negative weight > (since weight is not a constant but mass is). "...negative weight..." I don't know whether to laugh or cry. At least our junior space cadet can only legally fly Estes stuff. Watch out if he gets older without getting smarter. > "...negative weight..." > > I don't know whether to laugh or cry. > > At least our junior space cadet can only legally fly Estes stuff. He may not be eloquent, but his understanding of weight vs. mass appears to exceed your own. A rocket that has its enclosed air replaced with helium WILL have mass, although it will be less than an air-filled rocket; and conceivably, it could weigh less than zero (i.e. "negative weight") if it was basically just a balloon or gasbag like the "Dude". >>"...negative weight..." >> [quoted text clipped - 7 lines] > and conceivably, it could weigh less than zero (i.e. "negative weight") if it > was basically just a balloon or gasbag like the "Dude". Sigh. "....weigh less than zero..." Dear lord, there are at least *two* of them out there. Here's a hint. It will *never* weigh "less than zero". It might weigh less than the volume of air it displaces, which is why a helium or hydrogen filled balloon will "float" in an oxygen / nitrogen atmosphere, but neither your hypothetical balloon nor the helium or hydrogen it contains will weigh "less than zero". The only way something will "...weigh less than zero..." is if you repeal the physical Law of Gravity. And neith you, nor NASA boy, are capable of that, though you are each so full of hot air that you could each, independantly, lift a balloon. Does no one learn physics any longer? > >>"...negative weight..." > >> [quoted text clipped - 17 lines] > > It will *never* weigh "less than zero". Pish. I remember on this Star Trek episode where... ;-) SignatureTweak Some people fill a balloon up with helium and breathe the gas in and talk like certain rocket scientist... Or else fill a balloon and dont tie it, and just let it go, it will go off like a rocket. SignatureTAI FU > Has anyone used it in rocket? If so how? > > Donald A. Laskey > Has anyone used it in rocket? If so how? > > Donald A. Laskey As far as I know, it has only been used as a pressurant(pressurizes your fuel or oxidizer) and not as either fuel or oxidizer. -Aaron > Has anyone used it in rocket? If so how? It makes the LCOs voice sound really funny. SignatureBob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)! <<< Kaplow Klips & Baffle: http://nira-rocketry.org/Document/MayJun00.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org Sir, if I was building a weapon of mass destruction, you wouldn't be able to find it. |
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