I use MJG initiators that are dipped into igniter pyrogen. Specifically:
https://www.rocketflite.com/products_ml.htm
Allen
Terseness and mis-spelling courtesy of my iPhone
On May 23, 2018, at 10:16 PM, Terry McKiernan <terry@xxxxxxxxxxxxx> wrote:
Hello all,
Still trying to get my 2-stage high-power rocket project ready for the June
launch. I have a question about igniters I hope you can all help me with.
Basically I am looking for a recommendation: should I use the igniter that
comes with the motor, or buy an igniter more suitable for airstarts, if there
is such a thing?
My design uses two 3" rockets which are outfitted with Aerotech motor
retainers, and I have Aerotech casings, so I've only used Aerotech motors
with them. These are 38mm motor mounts and I'll be using class H or I motors
for the sustainer stage.
I am concerned that the Aerotech motors will be hard to start with a small
battery that can fit in a payload bay. I found a few posting online
indicating that Aerotech's igniters require 12V and can pull 15A+ momentarily
when they short & burn. This is OK I guess for a ground control system with
a big fat car battery or marine battery attached. But, it seems like an
awful lot for an altimeter battery.
The airstart will be controlled an a Raven altimeter, and it does support
having a small 1S LiPo for the altimeter and a second battery up to 20V for
the pyro channel. And, yes, I can get a 2S 30C 12V LiPo on Amazon. So,
theoretically it should be able to start the motor using the Aerotech igniter.
Alternatively I could buy some other igniter, or ematch, or make my own. Any
recommendations?
I am tempted by this ClusterFire kit, which promises 1 second burn at 5400F,
using 6V and 2.3A:
https://www.rocketflite.com/store/index.php?route=product/category&path=61
Or maybe H-3 Compound?
https://www.apogeerockets.com/Rocket-Motors/Motor-Starters/H3-Igniter-Dip
Or MJG?
https://electricmatch.com/pyrotechnics/see/6/5/mjg-firewire-initiator
Note that at the March launch my Aerotech igniter on one launch failed, and I
tried an MJG ematch I had bought from buyrocketmotors.com as a replacement
and it failed, and then I bought a FirstFire and it worked. But, that was a
ground launch not an airstart. In any case my only experience with MJG was
not good.
Or Slim Gem?
https://www.apogeerockets.com/Rocket_Motors/Motor_Starters/Slim_Gem_Starters
One thing i note about Slim Gem is they also require 12V just like Aerotech.
Also according to the Apogee site they burn at 1400F, vs. the 5400F claimed
for ClusterFire. Quite a difference...
Or Quest Q2G2?
http://www.buyrocketmotors.com/quest-q2g2-3-initiators-6-pack/
Or ... probably lots of other choices out there?
Thanks for any suggestions!
Terry McKiernan
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