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- Feb 22, 2017
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I'm beginning a new thread so as to not hijack the e-match thread I started this on.
Gearing up for my very first pyro dual-deploy flight and ground testing has begun. I've done tests on the altimeter and e-matches but I'm still waiting for the reload shop near me to get 4F BP in stock so I can test the ejection charges.
I'll be using a StratoLoggerCF for my alt. Powering this is a Turnigy 2S 300mah Lipo. (discharge 35C-70C).
E-matches purchased off ebay are these ones: https://www.fireworksigniter.com/eproducts/90.html
Specs are as follows:
1. 21°C(70°F)resistance: 1.3±0.15Ω — 1.7±0.15Ω
2. Fire current: 0.40A /0.37A
3. Safety current: 0.25A 5S/0.18A 5S
4. Testing current: 0.5MA
This is my first time using e-matches and I wanted to see how they fired, so I just shorted one across a battery. Pop. Check.
Next I bench tested my altimeter. I snipped off two christmas tree lights from an old strand, tinned the ends and attached one each to the drogue and main pyro circuits. To pull a vacuum, I put everything inside one of the canisters that hooks up to my FoodSaver vacu-bagger. Worked like a charm. Drogue lit up after it sucked all the air out, then the main lit when I pressed the "unseal" button on the lid.
Next I did the same thing, but with e-matches attached instead of the lights. I used 2 matches per channel as I'm going to to be putting two matches in each charge for redundancy. This was a little tricky since the match heads were outside the canister, meaning the four wires bending over the lip of the jar prevented a perfect seal. I eventually got it to pull enough of a vacuum to set off the drogue, and the main popped almost immediately after. All four matches lit. I forgot to note the battery voltage before and after, but there was only a slight drop in voltage after firing the matches as I recall.
Next up I'll be testing everything inside the actual rocket, but until then, my questions so far:
1. Is this an acceptable battery for my altimeter? Power range for the StratoLogger is 4-16V and I'm at 7.6 with my 2S lipo.
2. Am I using the right e-matches? So far in testing they seem to be ok, but I just want to double check as I'm EE challenged. I would love it if someone could explain how the above e-match specs translate to real-world rocketry.
3. The StratoLogger specs says not to exceed 5 amps for the output current. If I understand this correctly, my battery of choice can provide more than that, but the matches only require .4A to fire each. That would only be 1.6A total? Am I ok here? I don't want to blow up my altimeter. Everything tested ok on the ground.
4. E-match question: do people take those little plastic caps off or leave them on? I'm going to be holding my charges in glove tips taped to the bulkhead.
5. Am I missing anything?
Next up I will do as follows:
- Test the whole set up again (sans black powder) inside the AV bay using a shop vac to pull a vacuum.
- Test my ejection charges (no altimeter - just some long wire and a battery) to see if they are sized properly. I'll be using 2x 2-56 shear pins on the nose cone. Booster will be friction fit.
- Finally test the entire setup with full ejection charges using a shop vac.
Now the big question: would it be considered acceptable to not have a second altimeter for redundancy? I have an Adept22 I can use as a backup, but my preference would be to keep this first flight as simple as possible. I am intending this to be my L2 cert flight, so I need a J motor. Unfortunately none have a delay long enough.
Gearing up for my very first pyro dual-deploy flight and ground testing has begun. I've done tests on the altimeter and e-matches but I'm still waiting for the reload shop near me to get 4F BP in stock so I can test the ejection charges.
I'll be using a StratoLoggerCF for my alt. Powering this is a Turnigy 2S 300mah Lipo. (discharge 35C-70C).
E-matches purchased off ebay are these ones: https://www.fireworksigniter.com/eproducts/90.html
Specs are as follows:
1. 21°C(70°F)resistance: 1.3±0.15Ω — 1.7±0.15Ω
2. Fire current: 0.40A /0.37A
3. Safety current: 0.25A 5S/0.18A 5S
4. Testing current: 0.5MA
This is my first time using e-matches and I wanted to see how they fired, so I just shorted one across a battery. Pop. Check.
Next I bench tested my altimeter. I snipped off two christmas tree lights from an old strand, tinned the ends and attached one each to the drogue and main pyro circuits. To pull a vacuum, I put everything inside one of the canisters that hooks up to my FoodSaver vacu-bagger. Worked like a charm. Drogue lit up after it sucked all the air out, then the main lit when I pressed the "unseal" button on the lid.
Next I did the same thing, but with e-matches attached instead of the lights. I used 2 matches per channel as I'm going to to be putting two matches in each charge for redundancy. This was a little tricky since the match heads were outside the canister, meaning the four wires bending over the lip of the jar prevented a perfect seal. I eventually got it to pull enough of a vacuum to set off the drogue, and the main popped almost immediately after. All four matches lit. I forgot to note the battery voltage before and after, but there was only a slight drop in voltage after firing the matches as I recall.
Next up I'll be testing everything inside the actual rocket, but until then, my questions so far:
1. Is this an acceptable battery for my altimeter? Power range for the StratoLogger is 4-16V and I'm at 7.6 with my 2S lipo.
2. Am I using the right e-matches? So far in testing they seem to be ok, but I just want to double check as I'm EE challenged. I would love it if someone could explain how the above e-match specs translate to real-world rocketry.
3. The StratoLogger specs says not to exceed 5 amps for the output current. If I understand this correctly, my battery of choice can provide more than that, but the matches only require .4A to fire each. That would only be 1.6A total? Am I ok here? I don't want to blow up my altimeter. Everything tested ok on the ground.
4. E-match question: do people take those little plastic caps off or leave them on? I'm going to be holding my charges in glove tips taped to the bulkhead.
5. Am I missing anything?
Next up I will do as follows:
- Test the whole set up again (sans black powder) inside the AV bay using a shop vac to pull a vacuum.
- Test my ejection charges (no altimeter - just some long wire and a battery) to see if they are sized properly. I'll be using 2x 2-56 shear pins on the nose cone. Booster will be friction fit.
- Finally test the entire setup with full ejection charges using a shop vac.
Now the big question: would it be considered acceptable to not have a second altimeter for redundancy? I have an Adept22 I can use as a backup, but my preference would be to keep this first flight as simple as possible. I am intending this to be my L2 cert flight, so I need a J motor. Unfortunately none have a delay long enough.