redundant dual deploy

askrob

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I'm in the planning stages of a 4 inch rocket. I've done dual deploy before, but not redundant dual deploy. So, I'm thinking of an Eggtimer Proton as the primary with an Eggtimer Quark as a backup. I've flown the Quark before, so familiar with it. However, what is confusing me is how do I disarm both? I believe the Proton has the capability of arming and disarming via wifi. Do I need a physical switch (most likely a pull pin) for both, or just the quark? How has others done it?

I should mention that there will be 2 batteries, so 2 complete separate systems.
 

GalantVR41062

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Redundant dual deploy, 2 of everything but the rocket and motor. I run: 2 batteries, 2 switches (twist n tape, wifi, screw, etc), 2 altimeters, 2 charge wells/charges/ematch, on my bigger projects I have a twist n tape on one leg of each ematch and left open until final preparations are made to launch.

The main point is no power to energetics prior to being at and or on the launch pad pointed in a safe direction. Staging motors and initiators are tricky also, definitely talk with your local prefect, RSO and LCO about the process.

All you could want to read on switches:
 

rharshberger

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I'm in the planning stages of a 4 inch rocket. I've done dual deploy before, but not redundant dual deploy. So, I'm thinking of an Eggtimer Proton as the primary with an Eggtimer Quark as a backup. I've flown the Quark before, so familiar with it. However, what is confusing me is how do I disarm both? I believe the Proton has the capability of arming and disarming via wifi. Do I need a physical switch (most likely a pull pin) for both, or just the quark? How has others done it?

I should mention that there will be 2 batteries, so 2 complete separate systems.
For general safety having disconnects (switches) between the batteries and the Altimeters is good practice whether needed or not by the altimeter.
 

cls

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Bunch of related questions here.

Do you want 2 of the same altimeters, so you can understand the startup beeping, and they'll likely detect apogee closely. Or, do you want 2 different altimeters, so both won't fall the same way...

Some folks think it's better to have 1 charge well, with 2 ematches. That way, 2 charges going off at the same time won't destroy the rocket. Never seen that, personally. Or run 2 separate charges , for mechanical redundancy, maybe slightly advantageous...

Difficult to evaluate these trade offs without good numbers for reliability. I think the big guys work really hard on the decision tree and failure analysis. In the end, what makes you most confident and is easy to set up without error, is the best way.

PS don't forget about motor delay for backup apogee charge. Sometimes I use a really long delay so lots of tracking smoke...
 

askrob

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Redundant dual deploy, 2 of everything but the rocket and motor. I run: 2 batteries, 2 switches (twist n tape, wifi, screw, etc), 2 altimeters, 2 charge wells/charges/ematch, on my bigger projects I have a twist n tape on one leg of each ematch and left open until final preparations are made to launch.

The main point is no power to energetics prior to being at and or on the launch pad pointed in a safe direction. Staging motors and initiators are tricky also, definitely talk with your local prefect, RSO and LCO about the process.

All you could want to read on switches:
Thanks! Sounds like I should have a physical disconnect until the rocket is upright at the pad. I'll plan that in my design. I'll be doing two of everything, batteries, altimeters, switches, e-matches, and charge wells.
 

askrob

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Bunch of related questions here.

Do you want 2 of the same altimeters, so you can understand the startup beeping, and they'll likely detect apogee closely. Or, do you want 2 different altimeters, so both won't fall the same way...

Some folks think it's better to have 1 charge well, with 2 ematches. That way, 2 charges going off at the same time won't destroy the rocket. Never seen that, personally. Or run 2 separate charges , for mechanical redundancy, maybe slightly advantageous...

Difficult to evaluate these trade offs without good numbers for reliability. I think the big guys work really hard on the decision tree and failure analysis. In the end, what makes you most confident and is easy to set up without error, is the best way.

PS don't forget about motor delay for backup apogee charge. Sometimes I use a really long delay so lots of tracking smoke...
I want the telemetry data from the proton, but that's a good question. Should I do two protons or 1 proton and 1 quark. My thought was the proton and quark. I'm already familiar with the quark, and it's simple. The proton would get me more data and feedback to what is happening.

I've used motor ejection as a backup before, which works well. I'm thinking of launching with some motors that are plugged.
 

rharshberger

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I want the telemetry data from the proton, but that's a good question. Should I do two protons or 1 proton and 1 quark. My thought was the proton and quark. I'm already familiar with the quark, and it's simple. The proton would get me more data and feedback to what is happening.

I've used motor ejection as a backup before, which works well. I'm thinking of launching with some motors that are plugged.
I am fond of using one recording and one max altitude reporting altimeter. My choices of recording altscare typically RRC3, Protons, or Quantums. Choices of altitude only are Quarks, RRC2. If the altimeter has the ability to alter the beeper tone, it helps separate the sound of two identical altimeters in the same rocket.
 

cerving

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The Proton and Quantum incorporate an electronic wireless switch on the deployment power, similar to a WiFi Switch. The energetics are OFF until you arm them remotely on the pad AND a launch is detected. You can also bypass the remote arming feature if you want to use a mechanical switch... your choice. If you do bypass the remote arming, the deployment power is still switched off, until the altimeter goes through it's arming sequence and launch detect occurs.
 
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