Re: Need help with igniter

<< I need a reliable igniter for cluster ignition of AT motors in the F and G class.>>
http://www.quickburst.net /
Send them an email if you're not sure which of their igniters to use.
<<(I know AT is defunct but I was hoping for a NOS supply). >>
AT isn't defunct. They're still in business as RCS.
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snipped-for-privacy@aol.com (Mfreptiles) wrote in

What about using low-watt, low-resistance resistors (say 10 ohm 1/8W) and dip those? A lot easier than trying to get commercial e-matches. I've used this method to make squibs for theatrical stuff when we couldn't get/afford the real thing.
--
Sooner dot boomer at gbronline dot com

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10 ohms is fairly high resistance. I wouldn't use them in a cluster unless you use a discharge unit.
Mike F.
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Just to be sure we're talking 'ematches', and not 'squibs' which are regulated.
One of the hybrid pages had performed testing on resistor ignitors and found them reliable. I believe the whole site was pulled after 9/11 and haven't found it in yahoo cache.
If you're having difficulty finding emaches, they're quite simple to make. Review Skyligher's #15 bulletin. The chips are rather large but could be trimmed down for igniters for these smaller motors. Whether or not you can see 51g nichrome wire across the edge will determine if that's a possibility.
Joel.phx

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wrote:

Have you tried http://www.waybackmachine.org/ ?
--
Darren J Longhorn http://www.geocities.com/darrenlonghorn /
NSRG #005 http://www.northstarrocketry.org.uk /
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found
haven't
:) http://www.privatedata.com/byb/rocketry/Ignitor/pk_smd_cached / They didn't archive the page from Paul's old site. :(
I also found: http://www.privatedata.com/byb/rocketry/Ignitor/dahlquist_papers/igniter2.htm

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I would recommend using dipped commercial electric matches but they are too large to fit in the slots of some (most?) F and G C-slot composite motors.
Try measuring the igniter resistance and only using closely matched igniters in a cluster. This should limit the variability of ignition times. You will need to be able to measure low resistances on the order of one ohm with resolution better than a tenth of an ohm (more is better of course) to do this. You will also want to use an ohm meter that does four wire measurements.
I have the design for such a beast at:
http://home.earthlink.net/~david.schultz/meter/meter.html
This page is still "unpublished" in that there are no links to it on any of my web pages. I still need to go over it and correct some typing errors and tweek a few things. One of those things is that the amplifier gain set resistor is pretty sensitive. So sensitive that I decided not to use a range select switch in mine because just moving my hand around the wires to it caused the output to change.
Commercial electric matches are the best choice for clusters of larger motors because they require a low and well characterized amount of energy to fire. I have some data from a recent altimeter flight test that shows an action time (time from pyro output commanded on to first detected acceleration from ejection charge) of less than about 5 milliseconds. And that was with a power source of a 1000uF capacitor charged to 9 volts.
But getting the igniter to function is just the first part of the problem. The second part is just how long will the igniter take to light the motor?
There is a lot of variability here. As an example, I used several igniterman kit igniters this weekend. The F39T and G80FWL (stored in a sealed box along with a bunch of other reload kits and composite motors) lit quickly. But one F25W that had been stored in non-ideal conditions (stuck in the back end of a rocket for a couple years after a Copperhead failed to light it) chuffed, spit, and generally took a long time before deciding to go.
Reece Talley wrote:

--
David W. Schultz
http://home.earthlink.net/~david.schultz
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supply).
know
all
As Ray stated QucikBurst.
I have used their Poppers for air staring clusters of F20 and G40 motors so far. So if they can cluster off a 9 volt ni-cad battery in the airstarter, they will cluster fire on your 12 volt automotive battery system no problem.

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Quickburst will handle all your needs. His stuff works well. He provides on-site service at Texas launches and has developed most of his products from customer requests. Get in touch with him and he will help you with anything needed. He also has Top Flight parachutes and electronics along with Loc components. He has been expanding beyond the igniter market. Amazing that a rocketry dealer is adding on with all of the doom and gloom on RMR.
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