I don't do 29mm...not worth it. I like 4" or larger but often do 38mm for
students wanting to launch their level one or two rockets 'cheaply' before
doing their cert testing. I found thin wall PVC pipe makes nice lining for the
38mm cases. Like Jimmy, I don't like to go over 1,000 psi and normally do even
less (get a little longer burn time and less risk of CATO if there is a problem
with the grains. Plus, with the new change in Tripoli allowing steel nozzles
for sugar at TRA research launches, I don't want a lot of steel nozzles being
ejected because the pressure is too high. If you think about it, the nozzle
should be landing near the launch pad where no one is located. A much different
story is when chutes fail to deploy and rockets come in ballistic whether they
have steel or graphite of phenolic nozzles. The steel nozzle prohibition just
never made sense to me.
Rick
On Saturday, June 8, 2019 05:54:30 PM PDT,
<jyawn@xxxxxxxx> wrote:
Max pressure of 1000psi is my rule of thumb. They should be able to
handle more, but I like to have a good safety margin.
I've never burst one of these casings, when overpressured, it's usually
the nozzle end that lets go, in my experience.
Jimmy
Good news because I just purchased a large lot of various 38mm hardware.
Should be a great starting point. Some are not anodized. Was told it was
the last of hardware when production was discontinued.
What should I be modeling for max chamber pressure?
I don't want to discover this limit by trial and error for obvious
reasons.
On Fri, Jun 7, 2019, 7:05 AM <jyawn@xxxxxxxx> wrote:
I've used Gorilla casings quite a lot, and they have worked well for me.
(Except for when I did something stupid, of course. I've CATO-ed
several
brands.)
I vaguely recall Jim Harris telling me that Mike Fisher (Binder Design)
made the hardware for him.
Jimmy Yawn
jyawn@xxxxxxxx
I've used both Ellis Mountain and Loki that are similar and workedout
ok.
Even machined a 38mm steel nozzle but now I mostly fly 3 and 4" that I
made myself.
On Wednesday, June 5, 2019, 11:24:35 AM PDT, William Schmiedlin
<wschmiedlin@xxxxxxxxx> wrote:
Has anyone used Gorilla hardware for EX sugar motors? Looking at
purchasing some 38mm cases, and was thinking this would be a good
starting point, vs. machining my own.
