Greetings --
Is it just me, or are little ejection canisters with flashbulbs getting harder and harder to find? How is everyone deploying their parachutes these days? Flashbulbs? Low-Voltage electric matches? Where to get, too?
Thanks--
Adam
Low-Voltage electric matches. A lot of the motor dealers sell them.
Not for long.
There are a number of sources yet for E-Matches. You may need to buy a gross or two and pay hazmat, but they are available.
Performance Hobbies has M-Tek ematches in stock and sells in small quantities.
Brian Elfert
and harder to find? How is everyone deploying their parachutes these days? Flashbulbs? Low-Voltage electric matches? Where to get, too?
I've been using Xmas tree lights or similar when I do dual deploy. They're cheap, low voltage, and available in dollar stores darn near year round. You _do_ have to break open the bulb to expose the filiment, and you have to make sure the BP stays in contact with it, but that's about it. I've heard it said that there's the chance of misfires due to filiment breakage but I've not had that happen yet personally. The only failures have been due to the above non-contact of the BP with the filiments (I'd left space and the powder shifted about), which happened while I was doing the initial testing. Since then it's been 100% success.
Chuck
I can see two issues with using filament bulbs in lieu of e-matches:
1) Filament breakage. I would be very nervous about this, especially on a high-G flight. With an e-match the delicate bridgewire is safely 'potted' in the pyrogen.2) An e-match throws burning material some distance (fire one in the open), meaning that even if the powder is not directly in contact with the e-match, you stand a very good chance of igniting it. With a small filament, I think it would be unlikely to ignite the powder if not in direct contact.
Just my thoughts, as far as I'm concerned when I can get ejection canisters ready-assembled with e-matches for 50p each, it seems silly not to. I'd rather spend that than trash =A3110's worth of altimeter, =A3whatever worth of rocket etc etc.
My .02 of whatever currency takes your fancy. Chocolate money probably :)
Niall
2) That's why you have to pack them correctly. You pour in the BP, then put some packing material such as cellulose on top, then tape it tightly.
I'll take Dark Chocolate :-)
1) Filament breakage. I would be very nervous about this, especially on a high-G flight. With an e-match the delicate bridgewire is safely 'potted' in the pyrogen.2) An e-match throws burning material some distance (fire one in the open), meaning that even if the powder is not directly in contact with the e-match, you stand a very good chance of igniting it. With a small filament, I think it would be unlikely to ignite the powder if not in direct contact.
Just my thoughts, as far as I'm concerned when I can get ejection canisters ready-assembled with e-matches for 50p each, it seems silly not to. I'd rather spend that than trash £110's worth of altimeter, £whatever worth of rocket etc etc.
My .02 of whatever currency takes your fancy. Chocolate money probably :)
Niall
Fair enough, I was expecting at least one person to have had many successful launches with them. I'll take the security of an e-match, one less thing to worry about as far as I'm concerned.
FWIW, I noticed in the FAQ section of the new CTI ProXX website that they managed to light a 6-grain J330 with the e-match placed 1" inside the nozzle. I think you'd have to be quite unlucky to fail to ignite the BP using e-matches!
Your time is limited.
If you mean I've not got much experience of ejection charges, fair point. However I'm drawing my observations from a wider group of people who, between them, collectively do.
If, on the other hand, you mean that e-match availability is an issue, I'm not concerned. Daveyfires and Oxrals perhaps, but there are no shortage of Czech or Chinese clones that work just as well. Again, looking to the experience of others, I know people who've been using these for ejection charges for a long time with no problems. The pyro guys (who are the usual source) wire them in series, no problems. E-matches aren't regulated in quite the same way over here, I sense that it is more of a US issue.
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