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Staging Timers for 2 stage rocket

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ColumbiaNX01

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I am wanting to stage from a M to and L. I have seen online the different Staging timers/accelerometers they are for sale but wanted to ask here for peoples opinions. I am looking for something that is user friendly, reliable, has safe guards in place. Preferably one that I can set up through the computer just like the Strataloggers. I am not a fan of the ones you have to set all the settings on the pad. What I want to do is have all the settings correct then just turn the switch on at the pad just like a altimeter. But is that possible?

Andrew
 

Titan II

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Missile Works RRC3. If you are not familiar with it, the manual on the website discusses its staging configuration.
 

Banzai88

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There are several threads that detail the settings, connections, concerns, and plans necessary for the RRC3.
 

ozwald

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I have several Xavien controls that may be suitable for your project that I am looking at trying to get rid of. I have the XSSRT-1, XSSET-1, and the XCIC-1. Will make you a great deal if your research deems any of the controllers suitable for your project. Reviews can be seen by googling the Xavien #'s
 

ColumbiaNX01

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I have several Xavien controls that may be suitable for your project that I am looking at trying to get rid of. I have the XSSRT-1, XSSET-1, and the XCIC-1. Will make you a great deal if your research deems any of the controllers suitable for your project. Reviews can be seen by googling the Xavien #'s
Interesting. What are those? Never heard of them.
 

ozwald

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Interesting. What are those? Never heard of them.
Xavier was a company out of Arizona. The XSSRT-1 and the XSSET-1 are simply timers that can be preset before the launch with dip switches and provide output to your 2nd stage, or airstarts. The XCIC-1 is a cluster controller . You can Google and find reviews on them.
 

dixontj93060

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Xavier was a company out of Arizona. The XSSRT-1 and the XSSET-1 are simply timers that can be preset before the launch with dip switches and provide output to your 2nd stage, or airstarts. The XCIC-1 is a cluster controller . You can Google and find reviews on them.
They are quality timers. I have used a few of the versions over the years. In fact, I still have their high-current 6-channel one. Here is a review by Doc Damerau: http://www.rocketreviews.com/xavien-xssrt-1-and-xdsrt-2--by-drake-damerau.html.
 

FredA

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Use a flight computer that understands if the sustainer is still flying before lighting....
If your booster fails to perform, you don't want the sustainer to light.
Timers should be outlawed at this point as a major safety weakness as there are much better solutions available.
 

dixontj93060

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Timers should be outlawed at this point as a major safety weakness as there are much better solutions available.
This statement seems extreme. Raven and RRC3 time/altitude gating helps, but it is still an approximation and isn't foolproof. There are methods to add tilt detect functions to inhibit timer staging also that achieve the same result. Each staging/airstart design should be required to take altitude and direction into account for safety, yes, but to outlaw legitimate electronics, come on.
 
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cerving

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The problem with a simple timer is that you have no way of knowing if the rocket is pointing "up" when it fires. Particularly with such a large project, you want to make sure that you're not going to be firing your sustainer over the horizon (bad) or downwards (really bad). The absolutely best way to do this is with a flight computer with a full IMU that can tell which way you're pointing. There aren't very many, and they're expensive... but then, so are are M motors. The next best thing, and from what I understand is the minimum recommended safety by TRA, is an altitude-at-time or velocity-at-time check before you fire the sustainer. Assuming that you model your flight properly, you should be able to set the thresholds so that if the rocket is off-vertical it will prevent the sustainer from lighting. Most flight computers that offer airstart support have some kind of altitude/velocity check.

The Eggtimer Classic does an altitude check (via the LDA), and has a minimum velocity at time check at the programmed time after your motor burns out (which you set with a timer). It also offers breakwire support as an additional safety check. Other altimeters may do it differently... most vendors have their documentation on their web sites, so you can look at it beforehand to see which one best suits your needs.
 

FredA

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outlaw legitimate electronics, come on.

I suppose you are in favor of mercury switches too....get real....timers are VERY unsafe.

MANY available flight computers are capable of knowing if the sustainer has achieved a minimum altitude before they fire ... this is "easy" and "cheap" insurance.
 

dixontj93060

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The problem with a simple timer is that you have no way of knowing if the rocket is pointing "up" when it fires. Particularly with such a large project, you want to make sure that you're not going to be firing your sustainer over the horizon (bad) or downwards (really bad). The absolutely best way to do this is with a flight computer with a full IMU that can tell which way you're pointing. There aren't very many, and they're expensive... but then, so are are M motors. The next best thing, and from what I understand is the minimum recommended safety by TRA, is an altitude-at-time or velocity-at-time check before you fire the sustainer. Assuming that you model your flight properly, you should be able to set the thresholds so that if the rocket is off-vertical it will prevent the sustainer from lighting. Most flight computers that offer airstart support have some kind of altitude/velocity check.

The Eggtimer Classic does an altitude check (via the LDA), and has a minimum velocity at time check at the programmed time after your motor burns out (which you set with a timer). It also offers breakwire support as an additional safety check. Other altimeters may do it differently... most vendors have their documentation on their web sites, so you can look at it beforehand to see which one best suits your needs.
Don't get me wrong, and note, I did say "tilt detect" and so I 100% get this. But velocity-at-time and or altitude-at-time is still just an approximation. What if you have an airframe anomaly right at or just after achieving those minimum hurdles. You still don't have a tilt detect implemented and you could inadvertently fire a stage or airstart in the wrong direction. In fact, if you go through failure/event analyses for thrust in the wrong direction, I'm not so sure that a combo tilt-detect and timer isn't safer than a velocity or altitude versus time algorithms.
 

dixontj93060

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outlaw legitimate electronics, come on.

I suppose you are in favor of mercury switches too....get real....timers are VERY unsafe.

MANY available flight computers are capable of knowing if the sustainer has achieved a minimum altitude before they fire ... this is "easy" and "cheap" insurance.
I won't even acknowledge this bigoted post with an answer.
 

cerving

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Don't get me wrong, and note, I did say "tilt detect" and so I 100% get this. But velocity-at-time and or altitude-at-time is still just an approximation. What if you have an airframe anomaly right at or just after achieving those minimum hurdles. You still don't have a tilt detect implemented and you could inadvertently fire a stage or airstart in the wrong direction. In fact, if you go through failure/event analyses for thrust in the wrong direction, I'm not so sure that a combo tilt-detect and timer isn't safer than a velocity or altitude versus time algorithms.
A full IMU integrates a gyro, accelerometers, and a barometer so you know how high you are and where you are pointing. The reality is that you only really need to know that you're more or less vertical, so tilt-detect works fine, in conjunction with a timer and a velocity/altitude check so that you can't accidentally trigger it on the ground. It's best to have all three, but if you have to give up something then you can approximate the tilt-detect function with the altitude/velocity @ time function IF you model it carefully. Having a good stable vehicle and enough thrust in the booster motor so you don't weathercock goes a long ways towards ensuring that it's going to be pointing up when staging time comes.
 

FredA

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I won't even acknowledge this bigoted post with an answer.

Pot calling the kettle black ... boy do you have "issues."
 

rms

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Altus Metrum, Telemega with gps or Easymega without gps. Both have gyro tilt check
 

dixontj93060

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Pot calling the kettle black ... boy do you have "issues."
I've been advised by a few wise and experienced rocketeers (that know you) to just put down the keyboard and slowly step away...
 

ksaves2

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Use a flight computer that understands if the sustainer is still flying before lighting....
If your booster fails to perform, you don't want the sustainer to light.
Timers should be outlawed at this point as a major safety weakness as there are much better solutions available.
Listen to Fred lads. Andrew wants to do an M to an L! Not a G to an F. The stakes are very high if the L is fired pointing at the crowd. Not a big deal if the L doesn't light, the recovery devices will deploy. Use a timer? Sheesh.
The ONLY thing I'd trust at a large launch for a project of this magnitude is a Tele-Mega or Easy-Mega period! There was a Rocket Tiltometer that is out of production that was good too: http://www.rocketiltometer.com/
Perhaps someone is developing a similar device but I'm not aware of it yet.

The Raven is good but it's not nearly 100%. Sure if Mr. Experience is flying a smaller project and has done so successfully with a Raven, fine. Show me the log of the prior successes.

If Andrew wants to go out in the middle of no where and fly by himself so be it. He just has to worry about not having the rocket go off pointing at himself.

Fred my friend, I'll stand and help you fight the flames.

I've not flown any HPR two stagers but I've seen way too many hairy outcomes from poorly planned ones including the looping underpowered two stager at Midwest Power a few years ago where the timer fired the second stage at
a very low angle. That is very scary stuff.

Kurt
 

sharkbait

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This reminds me a little bit of the " should you cert a L3 with a kit" thread.

No offense Andrew, and maybe I'm wromg here, but it seems to me from the questions you asked and the comments you made on some of the suggested products that you haven't staged before, and there's nothing wromg with that. This is the place to seek the knowlegde you desire.

But I would have say that maybe you should gain some experience staging with a little less ambitious project first rather than coming striaght out of the gate with a big M to an L project. Gaining some experience with smaller staging projects first would seem to make good sense as far as safety goes, just as we do in the certification process.

By the way, I just absolutely love Fred's posts. ( no offense Tim)
 

JimJarvis50

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Just my opinion, but an altitude check is for safety whereas tilt detection is for the waiver. I use both - either something like a Raven in combination with a tiltometer, or an EasyMega, which does both in one unit. For staging, it is rather hard to beat the Altus Metrum product.

Jim
 

FredA

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Yep - M staging to an L is not a cheap project and proper avionics is not the place to skimp.
Lighting an L when it's off axis will likely cost you the rocket and if you are lucky that's all it will cost you.....

I own a Tilt-o-meter myself and use it for our big projects along with an altimeter that knows to check the altitude.
Wish it was still in production.

Thanks for the support Kurt & John.....
 
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Salvage-1

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A few years back I was starting with clusters and staging. Did a few nice flights, everything worked well, things did what was expected, no complaints.
Then, back to back, I had two failures.
The first was a cluster flight with one of the simple flight computers that checks altitude and speed, etc, before lighting. Well this flight had issues, one of a clustered pair lit, lifting the rocket off the pad, then the second pad start lit about 100ft up, which caused a rocket that was already tilting to have more issues. Then the two airstarts lit. The computer knew that the rocket had reached 400ft min, and that it was travelling faster than 100ft/sec, my check states. Problem was, it was doing it sideways.
Second flight, 2 stage, the timer failed to sense lift off and so didnt do what was wanted, but, did it safer. Both stages ended up eating dirt, not really the timer to blame.

After these. I have saved up my nickles and dimes, and now own a TeleMega and all the little fiddly bits that you need with it, including radio, etc. etc.

Yes... Just the fact that you can limit 2nd stage fire if the rocket is off vertical. Worth every penny of the rockets that went before.
 

ColumbiaNX01

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This reminds me a little bit of the " should you cert a L3 with a kit" thread.

No offense Andrew, and maybe I'm wromg here, but it seems to me from the questions you asked and the comments you made on some of the suggested products that you haven't staged before, and there's nothing wromg with that. This is the place to seek the knowlegde you desire.

But I would have say that maybe you should gain some experience staging with a little less ambitious project first rather than coming striaght out of the gate with a big M to an L project. Gaining some experience with smaller staging projects first would seem to make good sense as far as safety goes, just as we do in the certification process.

By the way, I just absolutely love Fred's posts. ( no offense Tim)
I do not want to sink any money into something until I have all the facts about different components.
 

ColumbiaNX01

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Yep - M staging to an L is not a cheap project and proper avionics is not the place to skimp.
Lighting an L when it's off axis will likely cost you the rocket and if you are lucky that's all it will cost you.....

I own a Tilt-o-meter myself and use it for our big projects along with an altimeter that knows to check the altitude.
Wish it was still in production.

Thanks for the support Kurt & John.....
Yes a project like this is alot. I want to dot all my i and cross all my t before I get started.
 
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