Dual Deploy Poll - Backup Altimeter
- Thread starter Starfire73
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Depends on size of rocket. To small of bay or tube, then no. If I have room to do 2 alts, yes. If the rocket is rather large or heavy, yes. if the rocket is something kind of weird, yes. Like the grain Bin.
Both of my two DD rockets have redundant altimeters. I have another in progress that will use only a single altimeter.
L-1 does not require dual-deploy. Nor does L-2. At least, when I certified.
I have not used a back-u, yet. I do have a current project I plan to though.
I have not used a back-u, yet. I do have a current project I plan to though.
Not including my L3 rockets, 2 of 8 L1 & L2 rockets have redundant altimeters.
As long as I can fit a second altimeter, yes I use two. My L1 was motor ejection only. Kept it simple.
You are correct 1 & 2 do not require it. But I have LPR stuff that has DD
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If the rocket goes out of sight I like a backup event. If its a plugged motor that means another altimeter.
For HPR, I always use single electronic deployment with JL Chute Release. There is no drogue or streamer. Motor ejection almost caused me a lawn dart so I consider it unreliable (delay timing) so I don't use it.
My system is fully redundant with:
Attached is a schematic and and a couple of pictures of my ebay.
My system is fully redundant with:
- Separate batteries for electronics and deployment
- Dual batteries for the above (actually, a third backup battery with diode OR'ing with the other two)
- Dual pyro charges (separate e-matches)
- Eggtimer Proton (main) and Quantum (backup) flight computers (WiFi arming of pyro channels)
- Parallel switches for both batteries
- Wiring is all home runs (vs daisy chains)
- Dual JL Altimeters 2 (I had them so I put them in)
- XT30 RC battery and pyro charge connectors (Very tight and rugged)
- Dual JL Chute Releases (in "series" so either one releasing allows the chute to open)
- For recovery I have a GPS-transmitter and beeper on board
Attached is a schematic and and a couple of pictures of my ebay.
Attachments
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Can you modify the poll slightly.
Yes, I use two of the same model altimeter
Yes, I use two different models of altimeter
I think it matters!
Next question, 2 ematches and 2 charges? Or 2 ematches in one charge?
That matters, too.
Yes, I use two of the same model altimeter
Yes, I use two different models of altimeter
I think it matters!
Next question, 2 ematches and 2 charges? Or 2 ematches in one charge?
That matters, too.
jdsmith39
Active Member
I designed my own AV sled and 3D print it, which has backup. I use the same AV sled (which I now have two of) in all 13 of my DD rockets. My sled will work down to a 38mm coupler. You can find it in my signature along with the bulkheads required to make it fit in a bunch of different diameters.
At 2.6 inch diameter tube (that's the smallest diameter DD I have right now), I can fit 2 e-matches and 2 charges (preferred approach). At 38mm, that most likely wouldn't be possible. In that case I'd do two e-matches to one charge. If I can make it work with 2 charges, I definitely will. But I don't have a 38mm DD rocket...yet.
At 2.6 inch diameter tube (that's the smallest diameter DD I have right now), I can fit 2 e-matches and 2 charges (preferred approach). At 38mm, that most likely wouldn't be possible. In that case I'd do two e-matches to one charge. If I can make it work with 2 charges, I definitely will. But I don't have a 38mm DD rocket...yet.
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rfjustin
Well-Known Member
Generically speaking my .02:
- L1, single altimeter, use motor delay as back-up
- L2, dual altimeters, truly redundant
Best,
- L1, single altimeter, use motor delay as back-up
- L2, dual altimeters, truly redundant
Best,
Dang !
I am feeling under-protected ...
All I've ever done is a single flight controller with single ejection charges, one Drogue and one Main.
But back in the days when I was working on AltAcc firmware, I would often fly two AltAccs -- one for ejection and a new one with new firmware for data only ...
Tony ( @manixFan ) now has me considering setting up redundant ejection charges on a single Blue Raven but I am still learning the gotcha's with the Featherweight 38mm, 29mm and 24mm AV-Bays so one thing at a time ...
IMO, motor ejection is less reliable than electronics and I've not used motor ejection for any HPR flight since 1995 or 1996 when I started trusting the AltAcc.
Each of my three HPR flights in 2023 were all Blue Raven Dual Deployment without motor backup.
-- kjh
I am feeling under-protected ...
All I've ever done is a single flight controller with single ejection charges, one Drogue and one Main.
But back in the days when I was working on AltAcc firmware, I would often fly two AltAccs -- one for ejection and a new one with new firmware for data only ...
Tony ( @manixFan ) now has me considering setting up redundant ejection charges on a single Blue Raven but I am still learning the gotcha's with the Featherweight 38mm, 29mm and 24mm AV-Bays so one thing at a time ...
IMO, motor ejection is less reliable than electronics and I've not used motor ejection for any HPR flight since 1995 or 1996 when I started trusting the AltAcc.
Each of my three HPR flights in 2023 were all Blue Raven Dual Deployment without motor backup.
-- kjh
I have seen all too many times someone stating that they have redundant altimeters, when they use 2 batteries and only 1 switch. And not referring to your post Justin, just commenting on needed 2 of everything to make it redundant.
@atestani --
Interesting idea -- OR'ing an extra battery ...
Do you have a picture ( edit: of the circuit ) ?
Thanks !
-- kjh
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Sorry, what is "OR'ing" for the battery? Interesting concept with the multiple batteries and diodes to provide some flow/isolation.
@kgh
I included the entire schematic of the ebay as "ebay.pdf". Let me know if it didn't come thru in my original post?
I included the entire schematic of the ebay as "ebay.pdf". Let me know if it didn't come thru in my original post?
Here is the circuit diagram again. It is in my original post but must not be showing. Can you see it now?
Thanks @atestani
It is there now on the original post and also on this one too !
I must have missed the schematic when I looked at your original post ... sorry ...
I've got some studying to do
Thanks again !
-- kjh
If a detailed explanation of the circuitry would help, just let me know and I will post it!
Starfire73
OpenRocket Wannabe
I use single altimeter the with motor charge (no reduction in delay) as my backup so it doesn't come in ballistic. If I ever go with a plugged motor I'll setup for a redundant, second altimeter.
I run a single altimeter in 2”, usually just a single altimeter in 2.6” rockets (depending on Av Bay size), and fully redundant dual altimeters in anything bigger.
If I can get two to fit, I use two.
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