- This topic has 21 replies, 11 voices, and was last updated 14 years, 5 months ago by
SCOTT EVANS.
SCOTT EVANS.-
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Jeffrey Joe Hinton
Be aware that the Quest Q2G2 ignitors, depending on the launch system, will ignite on a continuity check. This has not occurred with the NCR system but ask Tim about a launch at Springfest that filled his shorts. I particularly like the fact that Quest will sell a 24 pack of ignitors in the short size and 6 packs of the long. Great replacements for Copperheads in most instances.
Steve Jensen
Joe,
Will they go off when we power up our altimeters? I’d like to see if they work for e-match deployment charges.
Bruce R. Schaefer
Will they go off when we power up our altimeters? I’d like to see if they work for e-match deployment charges.
No. E-matches are used for deployment and altimeters are always “e-match safe.” Otherwise, just about all of us would have gone ka-bloey by now, technically speaking. As well as any launcher I’ve ever built, since e-matches came out anyway. Simple circuitry. I have an old FSI e-match for igniting a Mach 1 Dart (which I still have on an old FSI launcher in my office downstairs :)… These are very good questions, L_S.
Jeffrey Joe Hinton
The standard answer would be NO, but then it might depend on the altimeter. One of the electronic geeks could answer this better than I can but NO. The Q2G2 ignitors should be safe to be used for deployment charges unless your avionics are powered by a 12 volt battery. FWIW, the specs on the J-Tek’s – Bridge Wire Resistance – 1ohm plus or minus .2 ohms, Maximum No-Fire Current .30 amp. Minimum All-Fire Current .75 amp, Recommended Min. Firing Current 1.00 amp, Recommended Nominal Firing Current 1.25 amp, Maximum Test Current .04 amps. I don”t have the specs on the Q2G2’s.
Bruce R. Schaefer
Nicely said, Joe. “Normal” e-matches won’t ignite, BUT if you find out differently, as with the Apogee ones, PLEASE let us know. Most, if not all of us, don’t use more that 9 volts to set off the charge. A resistor is all that’s needed. But… just let us know…
Steve Jensen
I checked them and they’re all around 2 ohms +/- .5 (my meter isn’t that great).
So far so good. I am ground testing tomorrow and will tell you how they work.
I’m going to use the latex tubing two ties per end method.
Steve Jensen
I have used these now for the main charge on 5 dual deploy rockets and in about 12 ground tests. I plan to use them with my Raven in tandem with commercial e-matches.
I use the surgical tubing technique.
Every one has worked.
I have been warned by several more experienced rocketry enthusiasts about the dangers of roll your own e-matches.
If nothing else is available (or you have a rocket you’re not fond of) I do think these matches work.
Of note, I ohm checked each one. All but one fell within spec. It worked too, but I used it on a ground test.
The price savings is not there. Commercial e-matches are about the same cost.
bryans
Steve, your previous post, to which e-matches are you referring, just to be clear, since four or 5 types have gone by in the thread here…
Adrian
The standard answer would be NO, but then it might depend on the altimeter. One of the electronic geeks could answer this better than I can but NO. The Q2G2 ignitors should be safe to be used for deployment charges unless your avionics are powered by a 12 volt battery. FWIW, the specs on the J-Tek’s – Bridge Wire Resistance – 1ohm plus or minus .2 ohms, Maximum No-Fire Current .30 amp. Minimum All-Fire Current .75 amp, Recommended Min. Firing Current 1.00 amp, Recommended Nominal Firing Current 1.25 amp, Maximum Test Current .04 amps. I don”t have the specs on the Q2G2’s.
After testing a small sample size, the all-fire current for the Q2G2s is about 0.3 Amps, which makes it the most sensitive ematch I know of. The nominal resistance is about 2.5 +/- 1 Ohm.
Featherweight altimeters have a current-limiting resistor for the continuity check that’s big enough that you can use whatever battery you want. Even at 100 V you would still only have about 1/500 the current needed to fire a Q2G2.
The Estes electron beam launcher runs enough current for its continuity check to power its incandescent flashlight bulb when you put the key in, which is why it will always set off a Q2G2. You can replace the incandescent bulb with an LED bulb from a pinball machine supplier for < $5, which reduces the current to where it's not a problem. Plus it's brighter and more durable.
Steve Jensen
http://ncrocketry.org/modules.php?name=Forums&file=viewtopic&t=1741&highlight=burst
It’s in the above forum. Hope this helps!
Jeffrey Joe Hinton
Steve Jensen
Bruce R. Schaefer
bryans
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