WarezWally Posted October 10, 2007 Posted October 10, 2007 After finally making a rocket on my new tooling and after having a second look at the nozzle it seems to small for 3/4" rockets. http://img405.imageshack.us/img405/7048/nozzlevz0.jpg
Pretty green flame Posted October 10, 2007 Posted October 10, 2007 That does seem a bit small. Is this a core burner or end burner? Such a nozzle in a core burner will result in a CATO, no question about that. But an end burner might work. I've seen some pretty small nozzle on some commercial end burners (3mm nozzle in a 14mm ID rocket) and they fly very well. Best and easiest way is to fire it, if it CATO's, more luck next time, if it fles, good job.
WarezWally Posted October 10, 2007 Author Posted October 10, 2007 Core burner yea not good, i rammed some really slow fuel and ill go shoot it withing a few hours. If it catos ill be sending a email to supremepyro.
WarezWally Posted October 10, 2007 Author Posted October 10, 2007 Just be sure ill make one now with a handrolled tube with 5mm walls. Will fire both.
Pretty green flame Posted October 10, 2007 Posted October 10, 2007 Just be sure ill make one now with a handrolled tube with 5mm walls. Will fire both. So this is chinese tooling? I've taken apart a few rocket motors in the past (they were as yours, about 20mm ID, the nozzle was DAMN small, kinda like yours), anyway, the fule that was inside burned like total and utter shit. Hardly burned, I had to hold a naked flame to it and the only thing i got out of it was a couple of sparks. But when packed in in tube this stuff works wonderfully. Hope it works for you, good luck.
WarezWally Posted October 10, 2007 Author Posted October 10, 2007 Both cato'd on launch, the one with the 5mm tube reached maybe 5m before exploding. The thinner tubed one just blew on launch. Fuel for both was 65:25:10 +5 charcoal.http://pyrobin.com/files/cato.avi To pissed to edit the other one (and my face is in it), maybe i can arrange some sort of partial refund.
Pretty green flame Posted October 10, 2007 Posted October 10, 2007 Try something even slower. Maybe something like Chrysanthemum 8 or chrysanthemum of mistery, these two have an enormous charcoal content so they should burn slowly and not CATO these rockets, plus, if it works you've got the most pretty charcoal tail to go with the shell.
WarezWally Posted October 10, 2007 Author Posted October 10, 2007 Ill see what response i get, i would rather have tooling that works well instead of having to resort to using star comp as fuel.
moonshot Posted October 10, 2007 Posted October 10, 2007 I have had this problem with my homemade tooling. I made the spindle of my 15mm ID 130mm long tooling 3mm at the base of the taper and the nozzle ID was too small. I solved my CATO problems by using a 5mm drill bit to just ream out the nozzle ID. You may even have to go 6mm. Try it out and see if it works for you.Good luck!
cplmac Posted October 10, 2007 Posted October 10, 2007 You could alway ram a couple tiny increments of BP down the core to shorten it up. That looks just like an end burn motor though.
Aquarius Posted October 10, 2007 Posted October 10, 2007 My 15 mm ID coreburners has a a 6 mm nozzle, and its not to long, about 70 mm. Even tried with a 5 mm spindle with slow fuel and it worked. With a longer spindle it CATOS, even with fairly slow fuel, 7:2:1 and 10 % coarse charcoal.If your tooling for a 20 mm ID has a 3 mm nozzle, it's probably made for the crappy standard Chinese fuel, 6:1:1 it think it is. And it's often not very well made, just fairly coarse stuff screened in. What is the length of the spindle, and does it come with any kind of recommendations on the fuel? My best guess is that your BP is way too hot for that tooling, as other here have pointed out. What part of the motor blows, nozzle, endplug, tube or all of them?It could tell something about where the fault lies.
psyco_1322 Posted October 10, 2007 Posted October 10, 2007 dont use a nozzle, leave it out and try that. Use hot bp though. Itll fly.
invisibleworld Posted October 13, 2007 Posted October 13, 2007 Drill it out the choke to 3/8th inch about two inches deep. I have solved some CATO that way. If it still CATO's try adding about 15% more charcoal, 80 mesh if you have it.
WarezWally Posted October 13, 2007 Author Posted October 13, 2007 Bit on update: Rammed 2 more rockets with same fuel but another +5 charcoal, the first rocket had the normal sized core and nozzle while the second one i drilled out the nozzle and core by another 3mm. The first rocket reached a height of about 6m and cato'd while the second one performed flawlessly. Ive have emailed Greg Boyd and have a set of 1lb tooling en route. Im awaiting a quote from hobbyhorse for some NEPT tubes so if thats works out ill be set. http://img181.imageshack.us/img181/594/rckettu1.jpg Final photo of the larger nozzle'd rocket with a 2g flash header. Plenty of fuse so i can get the fuck away from it
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