A couple more dual deploy questions

I'm still working on getting everything put together for my first dual deploy rocket, and I had a couple more questions.

How do you connect your e-matches to your altimeter? I don't want to do it directly. I was thinking about using a terminal block on each end of the electronics bay, but it's only a 2 inch diameter rocket, and I worry they'll be too big, since I already have the eyebolts and sled rails on each end.

Second question is what kind of e-match do you use? Any particular brand better than another, or should I just buy the generic ones from Amazon?

I drilled holes through the bulkheads, ran a pair of wires through the holes and then epoxied them into place. One end of the wires connects to the altimeter and the other end to the e-match.

I use Quest igniters.

Drill holes through the bulkhead. Pass the ematch through the hole. Tie it on the altimeter side of the bulkhead for strain relief.

I use the new "legal" jtec lighters.

Zeus-cat said:

I drilled holes through the bulkheads, ran a pair of wires through the holes and then epoxied them into place. One end of the wires connects to the altimeter and the other end to the e-match.

I use Quest igniters.

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How do you connect the wires you ran through the bulkhead to the e-match? Just twist them together, or use a wire nut or what?

May I ask why you do not want to connect directly?

Titan II said:

May I ask why you do not want to connect directly?

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So I can completely seal the E-bay off from the powder charges, and so I don't have to take the E-bay apart to hook up a new match if I want to launch again.

Understood. Sealing is easily done with putty. The second reason is understandable.

Titan II said:

Understood. Sealing is easily done with putty. The second reason is understandable.

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I am trying Doghouse Rocketry charge wells, the eyelets around the screws on the AV side go to the Alt. The screws are extra long, and then use their brass knurled nuts and wrap the wires around them- hand tighten the knurl nut. No putty necessary, no terminal strip, very simple

This will be my first, so take it with a grain of salt

Nick@JET said:

I am trying Doghouse Rocketry charge wells, the eyelets around the screws on the AV side go to the Alt. The screws are extra long, and then use their brass knurled nuts and wrap the wires around them- hand tighten the knurl nut. No putty necessary, no terminal strip, very simple
View attachment 262259
This will be my first, so take it with a grain of salt

Click to expand...

I am just now getting into dual deployment but this seems like a pretty simple idea. Seems like you could use the all threads holding your e bay together. Attach leads from the altimeter to them on the inside of the e bay and the e match to the outside. BUT you would only be able to use it for one charge as hooking all the charges this way would set them all off at once. Simple machine screws through the bulkheads should work using the same principle. You would only need to remove a nut wrap the new lead and replace the nut.

Or something like these attached to your bulkheads. Epoxy em in place and should be pretty airtight. The speaker terminals are used on airtight speaker boxes after all.



Mike

Either of the above devices will work. The green terminal block there is quite space-efficient, and has terminals on the bottom you can attach to wires inside the av-bay, and seal with epoxy as you mount it. The speaker connection may be a little tight in such a small av-bay bulkhead.


Later!

--Coop

The problem with the speaker connections is that they depend on a spring loaded mechanical connection. The shock and vibration of a rocket flight could cause the connection to fail much easier then the terminal blocks.

Here's how I did my 2 inch av bay with redundant altimeters and external terminal blocks. Bit of a squeeze but very happy with the results.

https://www.ausrocketry.com/forum/viewtopic.php?p=52235#p52235

This past weekend I had a successful first flight using a deployment altimeter and dual deploy. I am using the MJG Technologies 'Firewire Initiator' referenced earlier as the 'legal jtek lighters'. Just a note on these: there was an early production 'issue' resulting in some failures. After contacting MJG, they replaced my full order. Their performance in subsequent testing and the first flight I just mentioned has been flawless.

I am wiring directly to the altimeter and sealing the hole in the av-bay bulkhead with a pinch of putty covered with masking tape. I realize the drawback of having to open the av-bay to re-wire between flights, but accept this compromise to eliminate additional connection failure points.

I usually just put small screws through the end caps and double nut them. This seems to work even on 24mm.
If you use CF be sure to use a sleeve or the screw will short out through the CF.