|
|
||||
|
||||
| 1 | General Discussion (registration required to post) / Hybrid Motors / Re: where to get paraffin? on: Jan 28th, 2010, 1:36pm |
| Started by kuzimm | Post by b_centaurus | |
| Presence as a part of a fuel grain of a component with a high melting point impoverishes the best idea of use of low-melting hydrocarbonic combustible (paraffin). For increase of a mechanical durability without essential change of internal ballistics of solid fuel I would recommend use paper as filler (the toilet paper milled on a coffe grinder) or a skeleton, for example from the goffered filters (poliestеr) for industrial extractors. |
|
  
|
|
| 2 | General Discussion (registration required to post) / Your Hybrid motor / Re: so i want to build a rocket engine... on: Jan 19th, 2010, 5:47am |
| Started by r2k_in_the_vortex | Post by r2k_in_the_vortex | |
| okey, status update, got my nylon tubing will make ignition tests asap also got a high speed cam(up to 510fps) to record the results |
|
|
|
|
| 3 | General Discussion (registration required to post) / Your Hybrid motor / Re: so i want to build a rocket engine... on: Jan 12th, 2010, 9:55am |
| Started by r2k_in_the_vortex | Post by r2k_in_the_vortex | |
| okay, got my 8g n2o cartridges and did some pressure testing, i have plenty polyurethane tubing lying around so i tried using that, 3mm OD, didn't work so well, blew with a bang in 3 seconds, looks like it has to be nylon tubing after all - that i don't have lying around, gotta go and buy some. at least i know a place where i can buy it by the meter not a whole 50m roll in once | |
|
|
|
| 4 | General Discussion (registration required to post) / Your Hybrid motor / Re: so i want to build a rocket engine... on: Jan 5th, 2010, 10:27am |
| Started by r2k_in_the_vortex | Post by r2k_in_the_vortex | |
| sure will, atm just went and got some teflon lube, first i thought vaseline would work just the same, but fortunately someone was kind enough to put some sense into me before i tried, i will be more careful with oxidizers from now on will get some nylon pneumatic tubing and 8g n2o canisters next, so then i can try ignition. don't have proper gse yet, have to order the nitrous bottle and valve from the internet, because locally these things cost 5X more than say in usa this week i'll also try out one place where i might get access to lathe |
|
|
|
|
| 5 | General Discussion (registration required to post) / Upcoming Experimental Hybrid Launches / Re: FAR sponsored Static and Flight tests, Mojave on: Jan 4th, 2010, 2:48am |
| Started by rocketdev | Post by rocketdev | |
| Sorry to hear. If you come by NorCal, please call or visit. Contact me at my e mail address for telecontact inf0. | |
|
|
|
| 6 | General Discussion (registration required to post) / Please read- spamming information / Re: Spamming on this forum- on: Jan 4th, 2010, 2:43am |
| Started by rocketdev | Post by rocketdev | |
| An unfortunate event. I am forwarding this complaint to our webmaster. | |
|
|
|
| 7 | General Discussion (registration required to post) / Your Hybrid motor / Re: so i want to build a rocket engine... on: Jan 2nd, 2010, 11:47am |
| Started by r2k_in_the_vortex | Post by boo | |
| Good to see you're still working on your project. Commercial HPR hybrid motor designs are indeed useful as starting points because they're straightforward and have been shown to be workable and reasonably safe in normal/as-designed use. They rarely incorporate pre- and postcombustion volumes as deliberate design elements (though you will see short grains with spacers used in some motor/grain combinations, but this is generally sinply to add more grain options for a given motor tube length rather than to incorporate pre/postcombustion volumes per se). You, on the other hand, have the option of designing your motor and grain lengths and using spacers to deliberately create appropriate pre/postcombustion "chambers". The usefulness of these is well recognized and would be a good advance over standard commercial HPR designs. Best of luck in your efforts and keep us posted  |
|
|
|
|
| 8 | General Discussion (registration required to post) / Hybrid Motors / Re: where to get paraffin? on: Jan 2nd, 2010, 8:39am |
| Started by kuzimm | Post by r2k_in_the_vortex | |
| http://www.alphahybrids.com/Media/Wax Based Fuels.pdf hi, here's a paraffin recipe alfahybrids developed 80% paraffin 18% hot glue 2% carbon black pure paraffin tends to crack, break pieces loose, glog your nozzle and kaboom hot glue fixes that, i guess they must have worked that specific ratio out with many tests carbon black is there as an opacifier, so the infrared radiation from burning wouldn't melt up all your grain in one go also wax based grains apparently need to be spin cast, because wax deforms when cooling making mandrel casting difficult take care not to spin it too fast tho, otherwise carbon will separate out |
|
|
|
|
| 9 | General Discussion (registration required to post) / Hybrid Motors / Re: computational fluid dynamics on: Jan 2nd, 2010, 8:14am |
| Started by r2k_in_the_vortex | Post by r2k_in_the_vortex | |
| okey this was a dead end i can live with flow simulations for eg nozzle simulation but phase change/combustion is where the horror starts, definitely not practical to start your first ex motor off with cfd study unless you already know what you are doing so for anyone who gets the same bright idea of using cfd for rocket motor design i recommend to fire the engine first, simulate later and make design improvements as needed in general hybrids seem too caprice for simulation to have any meaning in the first place, you cant really control oxidizer flow in real time so your performance will be greatly influenced by ambient temperature, pressure, state of moon and whatever else(also simulating burning fuel grain will be more than difficult) im sure cfd would be much more useful in liquid bi-propellant engine designs(in hybrid design only if you really know what exactly you are doing) |
|
|
|
|
| 10 | General Discussion (registration required to post) / Your Hybrid motor / Re: so i want to build a rocket engine... on: Dec 31st, 2009, 2:54pm |
| Started by r2k_in_the_vortex | Post by r2k_in_the_vortex | |
| hi nearly a year has passed and now im back with vengeance. lets see what comes out of this project this time, about next week i'll start acquiring various components&materials for my engine. have changed my concept a bit to make it easier to build, i think it will be more like the commercial variations of hybrid motors. there's an added bonus to that - easier to build a rocket around. |
|
|
|
|
