ChrisAttebery
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NAR L3 WIRING - HELP!!
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Kurt,
I agree. Safety switches in the charges that blew on the pad would not have prevented the premature ejection. My point was simply that the next person who approaches that rocket or any rocket with unexpended charges needs an easy way to disable any remaining charges. A single switch in the connection to the battery is enough for most rockets.
Asinine is not spelled assnine, but that's funny.
I'm not sure why you keep going back to the safety switch issue. I believe the current wording supports having a single switch for the battery or other power source. A few years ago when we last discussed it that was our intent. We are discussing how to make this clearer again.
I'm sure that when the original poster talks to his L3CC this will all be settled.
I'm sure most of us have seen some rockets come in with unexpended charges that didn't splatter; I think you're exaggerating to make your case. [emoji4]
I think the OP has received enough "help" from you and me. If you wish to discuss philosophy of redundancy let's start our own thread.
Edited to remove my unnecessary snarkiness. Mea culpa, mea culpa, mea maxima culpa...
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Not for sure, but it was windy. It wasn't their Stratologger. There are ways to mechanically filter the effects of wind on an AV-bay, but most manufacturers now do some software filtering to prevent false apogee detection.
I'm not sure about the AltAcc. That was probably eight years ago. I agree about the glitchless initialization.
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Also agree on the unknown state of outputs during power up. However that hazard isn't any greater for a cert flight than any other flight. If its a real concern then it should be addressed broadly, not just at L3 cert time.
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unknown state of outputs during power up
This is why it is so advantageous to use a Double-Throw switch in the circuit to the pyro's and an altimeter smart enough to sense the output state (continuity) more than once.
Turn on the altimeter.
Then enable the pyro's.
Label the switches "SAFE" and "ARM" and [almost] anybody who finds the rocket can get it into a safe(r) mode.
Lastly - use color-coded wires in the EBay -- a rats nest of monochromatic wire is not good wiring technique.
This is why it is so advantageous to use a Double-Throw switch in the circuit to the pyro's and an altimeter smart enough to sense the output state (continuity) more than once.
Turn on the altimeter.
Then enable the pyro's.
Label the switches "SAFE" and "ARM" and [almost] anybody who finds the rocket can get it into a safe(r) mode.
Lastly - use color-coded wires in the EBay -- a rats nest of monochromatic wire is not good wiring technique.
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Thank you all for your spirited debate on this topic. Looks like it may be a non-issue with the Perfectflite altimeters that I am using (mileage may vary on other brands). When the switch is off, there is no power to the system and there is no capacitor that could potentially discharge. I emailed Perfectflite technical support, below is the transcript of that communication:
From: PerfectFlite Tech Support [mailto:[email protected]]
Sent: Wednesday, April 20, 2016 5:29 PM
Subject: Re: L3 Cert Question
1. No. The SL100's capacitor is not used at all for firing energy, it just provides brownout protection of several seconds for the altimeter's "brain".
2. You can use the switch terminal block, or splice a switch in the positive battery lead, or splice a switch in the negative battery lead. Any of those options will provide the same end result -- the switch terminal block is for your convenience and simply functions as a break in the positive battery connection. An open circuit on the switch terminal block will remove all power from the altimeter's circuitry.
At 01:49 PM 4/20/2016, you wrote:
Hello,
I am attempting an L3 certification through NAR using a pair of Stratologger SL100s and there is some uncertainty regarding the behavior of the altimeters regarding section 2.4 the Level 3 High Power Certification Requirements documents. This section reads:
My plan was to shunt the power switch (actually they ship already shunted) and then add a rotary switch to one of the power leads between the altimeter and the battery, thereby allowing me to turn it on and off by removing power.
My questions are as follows:
1. Do the SL100s capacitor remain energized (and able to fire a charge) when power is physically disconnected?
2. Does it matter if I put the rotary switch on the positive or negative power leads? Any advantage to one over the other? I had planned on putting switch on the positive lead.
Thanks!
Jeff
From: PerfectFlite Tech Support [mailto:[email protected]]
Sent: Wednesday, April 20, 2016 5:29 PM
Subject: Re: L3 Cert Question
1. No. The SL100's capacitor is not used at all for firing energy, it just provides brownout protection of several seconds for the altimeter's "brain".
2. You can use the switch terminal block, or splice a switch in the positive battery lead, or splice a switch in the negative battery lead. Any of those options will provide the same end result -- the switch terminal block is for your convenience and simply functions as a break in the positive battery connection. An open circuit on the switch terminal block will remove all power from the altimeter's circuitry.
At 01:49 PM 4/20/2016, you wrote:
Hello,
I am attempting an L3 certification through NAR using a pair of Stratologger SL100s and there is some uncertainty regarding the behavior of the altimeters regarding section 2.4 the Level 3 High Power Certification Requirements documents. This section reads:
My plan was to shunt the power switch (actually they ship already shunted) and then add a rotary switch to one of the power leads between the altimeter and the battery, thereby allowing me to turn it on and off by removing power.
My questions are as follows:
1. Do the SL100s capacitor remain energized (and able to fire a charge) when power is physically disconnected?
2. Does it matter if I put the rotary switch on the positive or negative power leads? Any advantage to one over the other? I had planned on putting switch on the positive lead.
Thanks!
Jeff
ChrisAttebery
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Way to go Jeff. Hand that to your L3CC and wire it up.
Hmmmm, sticky finger on the two "S's". I agree otherwise but only concern is if the L3CC insists his is the only way. Kurt
Help me find a realistic scenario where a passerby finds a rocket and needs to put charges into a safer mode. I'm not seeing it.
Plus unless they have identical keys for a keyswitch not gonna happen. If found more than a day later, the batteries are likely going to be dead anyways so what's the point in turning off a dead battery. Kurt
That's why it's not very smart to use key switches...
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Help me find a realistic scenario where a passerby finds a rocket and needs to put charges into a safer mode. I'm not seeing it.
Driving off the Playa from Balls a few years back.
Found a rocket off the beaten path late Sunday afternoon - most everyone gone.
Had to take the rocket.
But, it was a TWIST AND TUCK....and still beeping with what looked like an un-deployed main.
We wanted to leave it BECAUSE of the twist and tuck ... who wants to drive 500 miles with somebody else's crashed but still armed and beeping rocket????
Had to FIND tweezers so we could extract the wires and shut it down.
Then load the still somewhat iffy rocket into my van and take it home.
So there's your real life example. Nobody wanted to deal with the rocket all because it was not easy to disarm.
Have you or anyone you know ever lost a rocket?
What are you expectations for the person who found it?
Driving off the Playa from Balls a few years back.
Found a rocket off the beaten path late Sunday afternoon - most everyone gone.
Had to take the rocket.
But, it was a TWIST AND TUCK....and still beeping with what looked like an un-deployed main.
We wanted to leave it BECAUSE of the twist and tuck ... who wants to drive 500 miles with somebody else's crashed but still armed and beeping rocket????
Had to FIND tweezers so we could extract the wires and shut it down.
Then load the still somewhat iffy rocket into my van and take it home.
So there's your real life example. Nobody wanted to deal with the rocket all because it was not easy to disarm.
Have you or anyone you know ever lost a rocket?
What are you expectations for the person who found it?
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S'cuse me,
So the main didn't fire? Could have been:
1. Undersized charge. In that case it already blew and how is a safety switch going to help or immediate access to an on/off switch going to make a difference? You can counter it was a fault code it was beeping and not the altitude. O.K. we'll move on.
2. Faulty channel on the altimeter or failure of a connection. If that is the case how is a safety switch going to make the rocket any safer? The power
couldn't get to the ematch in the first place. Or...........
3. Ematch failed. Well if the ematch failed how the heck is it going to be a danger unless one puts an open flame to the powder holder?
4. Oh, one more. The programming on the channel was defective and the main didn't activate. If the rocket is down, I don't think the altimeter is going
to activate the main if one picks it up.
This is not a booby trapped IED meant to maim someone who handles it, it's a simple rocket deployment device. Put on safety glasses or face shield, point the end of the rocket away from anybody or anything and disconnect the battery. Or if it's easier to get into the main chute bay, disconnect the charge. Kurt
So the main didn't fire? Could have been:
1. Undersized charge. In that case it already blew and how is a safety switch going to help or immediate access to an on/off switch going to make a difference? You can counter it was a fault code it was beeping and not the altitude. O.K. we'll move on.
2. Faulty channel on the altimeter or failure of a connection. If that is the case how is a safety switch going to make the rocket any safer? The power
couldn't get to the ematch in the first place. Or...........
3. Ematch failed. Well if the ematch failed how the heck is it going to be a danger unless one puts an open flame to the powder holder?
4. Oh, one more. The programming on the channel was defective and the main didn't activate. If the rocket is down, I don't think the altimeter is going
to activate the main if one picks it up.
This is not a booby trapped IED meant to maim someone who handles it, it's a simple rocket deployment device. Put on safety glasses or face shield, point the end of the rocket away from anybody or anything and disconnect the battery. Or if it's easier to get into the main chute bay, disconnect the charge. Kurt
Or, if the rocket is built the way we're recommending, just turn off the avionics with a switch that's accessible from outside.
You're sure working hard to avoid the obvious, Kurt. I don't get it.
[emoji1010] Steve Shannon, L3CC [emoji1010]
Granted if there is an external screw switch one can simply grab a screwdriver and turn it off. I will not blindly stick a screwdriver into someone else's ebay and potentially trash their electronics. You're assuming a stranger who is unfamiliar with a particular rocket is going to know what the switch arrangement is? If the switch thing is so important maybe you ought to petition that keyswitches should be outlawed on all certification attempts? Maybe NAR should be mandating Schurter switches only
for Certification attempts?
If a rocket has been on the ground for days, the batteries are going to be dead. If it's at a major launch, mark the waypoint on ones handheld GPS and tell the RSO to forward the location to the owner where their rocket is at. If the launch is just over and strange rocket is found, disconnect the battery if there's not an external switch accessible open the ebay for gosh sakes and deal with it. Kurt
vance2loud
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My first Av Bay used internal switches which are activated by removing a pin and I have seen quite a few others use a similar system where each switch gets turned on in sequence as the pin is removed.
After reading this thread I am starting to consider making all my Av bays at least have a clearly visible switch to disable the electrics. I don't feel that there needs to be multiple switches per altimeter but at least some clear way to disable things without requiring any special tools.
I am starting to think however that the least amount of external switches the better as any such system needs to be kept as simple as possible for it to be effective.
After reading this thread I am starting to consider making all my Av bays at least have a clearly visible switch to disable the electrics. I don't feel that there needs to be multiple switches per altimeter but at least some clear way to disable things without requiring any special tools.
I am starting to think however that the least amount of external switches the better as any such system needs to be kept as simple as possible for it to be effective.
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Those are all great points, Kurt. I agree. That's what we want people to think about: how to design and construct a rocket that minimizes risk to its owner and everyone else.
I mount my switches where anybody can access them, in the outer wall of the av-bay. I use slide switches that NKK specs at 50 gees of shock in six axes and two million operations between failure. I would also be comfortable with screw switches. I haven't seen the shock ratings for the Schurter switches, but those switches were originally designed as voltage selection switches for power supplies, which is an operation that does not require millions of ops between failures.
Most key switches that I have seen are imports with no ratings for ops between failure or mechanical shock.
[emoji1010] Steve Shannon, L3CC [emoji1010]
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Care to share your source of this goodness?
Sure, just look at the specs for the power switches, series CS, page 1 of 4:
https://www.nkk.com/documents/products/slide/cs/cs.pdf
[emoji1010] Steve Shannon, L3CC [emoji1010]
https://www.nkk.com/documents/products/slide/cs/cs.pdf
[emoji1010] Steve Shannon, L3CC [emoji1010]
In fact, here's a link to buy it.
https://www.arrow.com/en/products/m...jpQCFahRMm5pU71U6ZyslTUguVUqC1i5aYaAsCC8P8HAQ
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Pic?
I'll try to find a link to the SPST version today. I'll post the picture for dhbarr also of the switches on my "More Cowbell" rocket, which I really need to fly this summer.
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This can be wired as an SPST by simply using two of the terminals, center is common. I install mine so down is armed. As I think of it there may not be a two terminal SPST version.
[emoji1010] Steve Shannon, L3CC [emoji1010]
[emoji1010] Steve Shannon, L3CC [emoji1010]
Also, these are the three solder lug SPDT version which should be NKK part MS12AFW01. These are rated for 50k cycles, not 2M like I crowed about before, so I guess I'll have to eat some crow pie.
[emoji1010] Steve Shannon, L3CC [emoji1010]
UhClem
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I was going to ask where you found that figure because I couldn't find it. I am tempted to add some of these to my next Mouser order. I have used horrible Rat Shack switches that tend to fall apart if you pull too hard on their terminals. I added some strain relief but they still bother me.
For the life of me, I don't know. It's beginning to worry me. [emoji856]
[emoji1010] Steve Shannon, L3CC [emoji1010]
I've used twist and tape also, but I wouldn't on a cert flight. Not that it's against the rules, but I wanted my cert flights to let the persons certifying me know that I had really thought about my project and was ready to move up. It's definitely something to discuss with your TAP or L3CC.
[emoji1010] Steve Shannon, L3CC [emoji1010]
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