I always use a Pyrodex pellet (more like a little cylinder) in the top
grain. No worry of over pressurization and it always lights. I'll give
you one. They are somewhat hard to get so no need to go thru all the hoops
in trying to locate one. You can also use pyrogen used for making igniters
and swab the upper grain. It won't explode like black powder. Using that
and a dipped e match and you will be good to go.
Also, depending on the output of your electronics, it is usually better to
run multiple igniters in series, not parallel.
Kurt
On Sun, May 13, 2018 at 11:08 AM, Terry McKiernan <terry@xxxxxxxxxxxxx>
wrote:
I have another question about my 2-stage rocket project that I hope some
experienced people can help me with. This is separate from the 3D coupler
/ rail buttons thing, and from the PET2+ vs. altimeter safety question, so
I figured I should start a new thread.
For the airstart of the sustainer, it seems that ignition failures are a
common problem -- after all, consider how many times we burn an igniter in
a rocket on the pad. They just don't work 100% of the time. So, what can
be done to make this more reliable or provide some redundancy?
The obvious solution seems to be to have multiple igniters, so if the
first one fails the second one might get the sustainer started. My
question is, what's the best way to wire this up?
Option 1: Use 2 separate pyro channels on the altimeter, with separate
wires connecting to the igniters. Set the channels to fire, say, 0.5
second apart so that the rocket is still coasting upwards when the second
igniter fires. Pro: complete redudancy. Con: more complex wiring &
altimeter setup, and if the first igniter burns out, it might take out the
2nd igniter with it.
Option 2: Use only 1 pyro channel. Put both igniters on the same channel,
wired in parallel, so they both ignite at the same time. We'll call this
the "big bang" approach :). Pro: simpler wiring and altimeter setup. Con:
less redundancy (igniters but not channels); single pyro channel is a
single point of failure.
Option 3: ???
Any advice?
Also I read that it's a good idea to rough up the sustainer grains to make
them more likely to ignite. Is that true?
I even saw someone saying to spread some Pyrogen on top of the sustainer
grains. I feel unsure about that (and I don't have any Pyrogen anyway).
Seems like that could cause an explosion, like black power, rather than a
controller burn. Is this is valid / recommended idea?
Thanks!
Terry McKiernan
--
ROC-Chat mailing list
roc-chat@xxxxxxxxxxxxx
//www.freelists.org/list/roc-chat
