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#11
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Peroxide biprop ignition
Thanks Henry, John.
All else being equal, would you not prefer your 98% peroxide stabilized? After all, stabilizers are not added by manufacturers to make life harder for rocket builders. They are supposed to make peroxide safer. You've explained why all else is not exactly equal but the bottom line is a tradeoff between complexity perceived safety. Such perceptions are not an exact science and are liable to change quickly on certain circumstances. Oren |
#12
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Peroxide biprop ignition
In article ,
Oren Tirosh wrote: All else being equal, would you not prefer your 98% peroxide stabilized? After all, stabilizers are not added by manufacturers to make life harder for rocket builders. They are supposed to make peroxide safer. It's actually more a matter of making it less prone to deteriorate due to contamination, and giving it a longer shelf life. I can't speak for John, but if I were doing peroxide rocketry, I'd be willing to accept constraints like a short shelf life and a need to be fussy about cleanliness, in return for less hassle with catalyst poisoning etc. All else being equal, yes, I'd be happier with *lightly* stabilized peroxide using stabilizers compatible with my catalysts. (There is some choice about just which stabilizers are used, and if you're buying in bulk, you should have some voice in that decision.) The less fussy I have to be about procedural details like cleaning and shelf life, the more time and effort I can spend on design and development problems. But there are a lot of assumptions in that (e.g, *are* there such stabilizers?) and just getting it unstabilized might well be less hassle all around. -- MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer pointing, 10 Sept; first science, early Oct; all well. | |
#13
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Peroxide biprop ignition
In article ,
Oren Tirosh wrote: All else being equal, would you not prefer your 98% peroxide stabilized? After all, stabilizers are not added by manufacturers to make life harder for rocket builders. They are supposed to make peroxide safer. It's actually more a matter of making it less prone to deteriorate due to contamination, and giving it a longer shelf life. I can't speak for John, but if I were doing peroxide rocketry, I'd be willing to accept constraints like a short shelf life and a need to be fussy about cleanliness, in return for less hassle with catalyst poisoning etc. All else being equal, yes, I'd be happier with *lightly* stabilized peroxide using stabilizers compatible with my catalysts. (There is some choice about just which stabilizers are used, and if you're buying in bulk, you should have some voice in that decision.) The less fussy I have to be about procedural details like cleaning and shelf life, the more time and effort I can spend on design and development problems. But there are a lot of assumptions in that (e.g, *are* there such stabilizers?) and just getting it unstabilized might well be less hassle all around. -- MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer pointing, 10 Sept; first science, early Oct; all well. | |
#14
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Peroxide biprop ignition
In article ,
Julian Bordas wrote: I have real doubts about that part of the idea. Catalystic decomposition will not be slow with high-concentration peroxide and an effective liquid catalyst mixed well together. Mixing *in* the chamber sounds both better and safer. Once the rocket is firing, is it possible to use non catalysed HTP? Yes, definitely. As with any propellant combination, once it's lit it will generally stay lit, modulo combustion-stability issues. People have built rocket engines using peroxide as oxidizer with no catalyst at all, just a conventional ignition system. -- MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer pointing, 10 Sept; first science, early Oct; all well. | |
#15
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Peroxide biprop ignition
In article ,
Julian Bordas wrote: I have real doubts about that part of the idea. Catalystic decomposition will not be slow with high-concentration peroxide and an effective liquid catalyst mixed well together. Mixing *in* the chamber sounds both better and safer. Once the rocket is firing, is it possible to use non catalysed HTP? Yes, definitely. As with any propellant combination, once it's lit it will generally stay lit, modulo combustion-stability issues. People have built rocket engines using peroxide as oxidizer with no catalyst at all, just a conventional ignition system. -- MOST launched 30 June; first light, 29 July; 5arcsec | Henry Spencer pointing, 10 Sept; first science, early Oct; all well. | |
#16
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Peroxide biprop ignition
Henry Spencer wrote:
Restartable and reusable. Subject to the need for yet another fluid system, with the added complexity that entails. The catalyst is mixed into the peroxide just before injection into the chamber. This cannot be done safely with a fuel but catalytic decomposition is slow enought to give some time for mixing. I have real doubts about that part of the idea. Catalystic decomposition will not be slow with high-concentration peroxide and an effective liquid catalyst mixed well together. Mixing *in* the chamber sounds both better and safer. Once the rocket is firing, is it possible to use non catalysed HTP? |
#17
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Peroxide biprop ignition
Henry Spencer wrote:
Restartable and reusable. Subject to the need for yet another fluid system, with the added complexity that entails. The catalyst is mixed into the peroxide just before injection into the chamber. This cannot be done safely with a fuel but catalytic decomposition is slow enought to give some time for mixing. I have real doubts about that part of the idea. Catalystic decomposition will not be slow with high-concentration peroxide and an effective liquid catalyst mixed well together. Mixing *in* the chamber sounds both better and safer. Once the rocket is firing, is it possible to use non catalysed HTP? |
#18
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Peroxide biprop ignition
Henry Spencer wrote:
In article , Julian Bordas wrote: I have real doubts about that part of the idea. Catalystic decomposition will not be slow with high-concentration peroxide and an effective liquid catalyst mixed well together. Mixing *in* the chamber sounds both better and safer. Once the rocket is firing, is it possible to use non catalysed HTP? Yes, definitely. As with any propellant combination, once it's lit it will generally stay lit, modulo combustion-stability issues. People have built rocket engines using peroxide as oxidizer with no catalyst at all, just a conventional ignition system. Thanks Henry. I'm one step closer :-) Julian |
#19
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Peroxide biprop ignition
Henry Spencer wrote:
In article , Julian Bordas wrote: I have real doubts about that part of the idea. Catalystic decomposition will not be slow with high-concentration peroxide and an effective liquid catalyst mixed well together. Mixing *in* the chamber sounds both better and safer. Once the rocket is firing, is it possible to use non catalysed HTP? Yes, definitely. As with any propellant combination, once it's lit it will generally stay lit, modulo combustion-stability issues. People have built rocket engines using peroxide as oxidizer with no catalyst at all, just a conventional ignition system. Thanks Henry. I'm one step closer :-) Julian |
#20
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Peroxide biprop ignition
Catalystic decomposition
will not be slow with high-concentration peroxide and an effective liquid catalyst mixed well together. I've only heard of solid catalyst beds. What's a [non-exotic] liquid catalyst for HTP, [High Test Peroxide over 85% pure]? ^ //^\\ ~~~ near space elevator ~~~~ ~~~members.aol.com/beanstalkr/~~~ |
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