E-Match Question

Is my understanding correct that in order to obtain/possess e-matches (such as Davyfires, Oxrals, M-TEK's, etc.) that you must have a LEUP? If so, what
are most of the non-LEUP holders using for ejection charge firing? I'm aware of flash-bulbs but would care not to go that route. Any input would be greatly appreciated. Thanks!
Chuck Neff TRA #7915 L3 NAR 74595 L3
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Why won't anyone respond? I realize that I'm not a regular poster, but I do frequently visit the group. There can be good info. found here at times (as long as you can read between everything else). Please?

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Chuck Neff wrote:

Didn't see your post until now, odd ;/
Well, I'm still working on my last box of Daveyfire 28B's so I'm pretty set. That being said I used to use flash bulbs but those are VERY hard to come by now-a-days.
Once my supply of 28B's are gone I'm going to give xmas bulbs a shot. $1.99 gets you a whole string of them at Target. That's about the price for one ematch, total bargain.
Ted Novak TRA#5512 IEAS#75
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Do you take the glass of Xmas bulbs - or how do you get enough heat?
H
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Halam Rose wrote:

The way I've seen it done is to crush the tip of the bulb exposing the insides, hot glue bulb in a crdbrd tube and fill with BP. I'm sure google could come up with some sites.
Ted Novak TRA#5512 IEAS#75
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Halam Rose wrote:

http://www.perfectflite.com/Downloads/Ejection.pdf
I used this method once for dual deploy and it worked 50%. I had continuity on the altimeter when the rocket launched, but during flight, the bulb in the drogue section wound up coming loose and didn't fire. The bulb with the main deployed perfectly though.
I haven't taken the time to really think of other ways to make this work, but I am sure there are many ways to do so. Plus they are SUPER cheap, so if you figure out a reliable way to use them, then great!
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I was on vacation recently and stopped by a fireworks showroom. They had refill fuse "e-matches" for an inexpensive fireworks firing console they also sold. After seeing them, I went ahead and bought two boxes (25 e-matches ea.) for $9.95 each thinking I may be able to use them. They're basically a little plastic closepin with a filament inside notched to hold on a fuse attached to 5' leads. I did some bench testing with them on an RRC2 and every one fired. I added some black powder and tested a few more. Again, every one fired. I was very pleased with the results and the cost of about 40 cents each. The other good thing was that I can order more and have them shipped to me with no problems.
Anybody else seen these?

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Care to share your source? I need a new source as I'm down to only 4 Oraxals (SP?) left in my stock. Each flight of my 1/2 scale Patriot uses 4 matches (2 per altimeter)
-Aaron
Chuck Neff wrote:

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Try this:
http://www.fireworks.com/phantom%5Fmall/category.asp?cat3

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Interesting.. How do you mount these? Have any pics closer up of what these things look like?
These almost seem like the blank chips that you can get from firefox.
Chuck Neff wrote:

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SpartaChris wrote:

What's the secret to using the Firefox chips? I made up some and one burned out my MAD unit. Richard Galejs sent me a power chip to fix it though.
When I connected up one of the "ematches" to a plain battery it fired but like I said, it burned out my previously functioning MAD unit.
I'm sticking to ematches for now. M-teks work good in all my tests and are still available.
Kurt
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Kurt wrote:

The IRF 7101 used in the output of this and other units is somewhat fragile. The AltAcc uses it and I have used mine since 1999 without any trouble. The secret I think is that the e-match opens up quickly. If you look at the data sheet for the IRF7101 you will see that it is very limited by heat dissipation. It is so small that any significant current for more than a few tenths of a second will kill it.
From what I have seen of the MAD units, they use a capacitive discharge system. This limits the energy and you shouldn't have had any trouble even with a dead short on the output. Unless the series resistor to the capacitor were something like a 0R0.

--
David W. Schultz
http://home.earthlink.net/~david.schultz /
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Hey Chuck,
I bought a box and testfired two. Even put cannon fuse in one with no ignition. Did you pry the chip out of that plastic carrier in order to put it in a canister? Does this thing need something of a booster to get to work?
Kurt Savegnago
Chuck Neff wrote:

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Hey Kurt,
No, I did not pry the chip out. I separated the two pieces of the clip (removed the small rubber band and lifted the top off). The breakdown of the tests I performed are as follows:
Test #1 - (5) E-matches 1. Separated the "bundle" into individual twin lead e-matches. 2. Disassembled the clips by removing the rubber band and lifting the top off. 3. Attached lead ends (stripped) to my RRC2 outputs (I did double the lead end and twist to give it a larger surface area). 4. Turned on my RRC2 and activated the output test. 5. E-match connected to Apogee/Drogue outputs fired after 10 seconds followed by the Main (by firing, I mean I can visibly see the filament burn/flash).
Test #2 - (5) E-matches 1. Separated the "bundle" into individual twin lead e-matches. 2. Disassembled the clips by removing the rubber band and lifting the top off. 3. Attached lead ends (stripped) to my RRC2 outputs (I did double the lead end and twist to give it a larger surface area). 4. Placed the e-match end in a WD-40 cap. 4. Poured a small amount of black powder in the cap until about 1/2 the clip body was covered. 5. Turned on my RRC2 and activated the output test. 6. E-match connected to Apogee/Drogue outputs fired after 10 seconds followed by the Main.
I also tested (2) with a PML Co-Pilot altimeter (same basic design as the RRC2) with the exact same results.
What are you testing them with? I assume you can see the small spring shaped filament in the clip? Did you check for continuity before testing?
Chuck

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Thanks for the specifics Chuck. Always good to have some alternatives on hand. I tested only two using a 12v. battery and I was able to do a continuity check with one of them. I think I'll just open one of them and pour a little 4F on it and repeat the test at a distance. I was expecting a visible flash but didn't notice anything. Kurt
Chuck Neff wrote:

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wrote:

Hey Ted, hope your rockets aren't worth much more than that because I've seen a lot of Xmas bulbs not work.
Phil
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Phil Stein wrote:

Before I even think of using xmas bulbs on flights there WILL be some serious ground testing. If that fails then it's no to xmas bulbs.
I haven't worked out all the details yet but small glow plugs could have some promise.
Ted Novak TRA#5512 IEAS#75
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Ground testing isn't really gonna help with Christmas Bulbs because ground testing isn't representative of flight contitions. The filament on the christmas bulb is pretty weak and not soldered on, so that is one place where the stress of flight can cause a failure. Another is the bulb coming un-seated. Ground testing, while smart if you are trying to figure out how much BP to use, isn't going to be able to account for those things. And the one I used on my 3" Thor failed on an I211. I imagine it would have failed on a J350 or 570 as well.
Your best bet is to test the charges in flight as a backup to whatever e-matches you have installed. Really, you just want to make sure that you get them to fire with a high rate of success, so maybe stick 1/2 gram or 1 gram of powder in them or something.
the notorious t-e-d wrote:

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I've used Christmas bulbs with great success. The key is to use more than one for each ejection charge. I normally use 2 bulbs per charge for redundancy, but based on the canister size, one could use 3 or 4. It's not much more work to add more if desired. It's much less work and costly than replacing a rocket.
I also use ematches, and I always use at least 2 for each charge for the same reason.
Kevin

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Have you ever actually seen the filament break in flight conditions? I've flown christmas bulb charges with over 200 flights, including a K1275 and M4000, and only had 2 failures, both of which I figured out the cause and neither was due to the filament breaking. On one, I had left too much air in the charge and the BP wasn't touching the filament when the current flowed. Now I always pack a bit of flameproof wadding in the end before taping. On the other, the leads of the bulb had corroded enough to inhibit the current and prevent firing. Now I lightly rough up the leads with sandpaper if the bulbs have been stored for a while. I have had no failures since instituting those changes. Contrary to what others say, I also have had success with up to 5g charges (in a 7.5" rocket with shear pins). The size of the shrink-wrap tubing needs to be increased significantly the more BP you plan to put in. If you use a long thin tube of BP, the BP furthest from the filament will be blasted away without burning.
Don't let people tell you that christmas bulbs won't work. Try it, and think carefully about the failure modes, and you should have great success.
-- David

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