I preferred Flashcubes (NOT Magicubes, they have their own charging mechanism) but many people, myself included, used the bulbs bearing the AG-1 designation. Both types have stiff wire leads rather than other flashbulbs that have twist-in connectors.
There is an very detailed article on them at:
Excellent, thank you!
David Erbas-White
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?
Glad to help. If anyone has any similar articles or documentation of hobby rocketry techiques or tips, I would be happy to publish them for the community.
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:
They'll work fine on the ground. Also you won't launch unless your altimiter tells you you have good continuity. Where I think people have problems is with G force on take off, charges also contribute to the stress in the filament, the main charge gets a jolt when the drouge deploys and when the charge for the drouge blows.
I'm not saying they always fail but they fail to often for my taste.
Phil
Try this:
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:
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
Phil Isn't there a problem with some of the newer bulbs because they have a shunt that keeps all other light burning when one goes out in the string? Thought I read this somewhere when I was thinking of using them. Made me nervous.
Damn - that's enough to make me more nervous. THat shunt would make an open filament appear to the altimiter as though it were good.
Come on you guys - $20-$500 for propellant. At least a similar amount for casing. $100-$200 per altimiter. $100 and up for the rocket. Spend $2 on a friggin ematch!!
Phil
Aaaahhh Phil,
You're 125% correct here. Last I heard, Performance Hobbies still sells M-teks and one can go to Quickburst.net and get Cosmos ematches for a $1.00 apiece. I dorked a MAD unit on a ground test with a firefox ematch kit. Don't know what I did wrong but it ain't worth the trouble. Just buy commercial.
Kurt
Of course he's right!
I only mentioned alternatives as all I've been hearing is that nowadays a LEUP is required to purchase ematches(but not ignitors). Now I'm starting to wonder if that is true.
Ted Novak TRA#5512 IEAS#75
Ted,
Last I heard those places were selling them and if one is nervous, stockpile some. I was playing with the firefox alternative too but didn't have any luck. These igniters look promising as mentioned by Chuck Neff up in one of the other replies.
I think a real major issue is finding a low current match one could reliably count on to light a motor off of a staging timer. M-tek is supposed to be coming out with one but I don't know what will be required to purchase those.
Kurt
THere seems to be a lot of inconsistencey between what dealers will or won't sell you without a LEUP. If one won't sell you ematches, try some other ones or share with a friend.
Phil
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.
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.
E matches are not going to have corroded leads. How many ematches can you buy @ $2 vs crashing a $1000 rocket? You be the judge. Oh and if you ever see me at RSO and I find out you have bulbs, you will have a problem. Someone else might let them slide - that's their prerogative.
Phil
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:
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
Test #2 - (5) E-matches
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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