GPS arming before going to the launch pad?

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Clivus

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Hi,
I'm planning a Level 2 Madcow Prion and I am either going to do a Coker Nosecone bay or get one from APE. I'd rather not have a screw or switch to the outside of the nose cone for arming if I can keep from it. I also probably would rather do the 6 hex screws at a prep table instead of with the rocket on the launcher. Is GPS considered an electronic that is not to be armed until the rocket is on the pad?
I've searched but I can't find the answer.
 
Hi,
I'm planning a Level 2 Madcow Prion and I am either going to do a Coker Nosecone bay or get one from APE. I'd rather not have a screw or switch to the outside of the nose cone for arming if I can keep from it. I also probably would rather do the 6 hex screws at a prep table instead of with the rocket on the launcher. Is GPS considered an electronic that is not to be armed until the rocket is on the pad?
I've searched but I can't find the answer.

No, you will be fine. It is common place to arm the tracker before going to the RSO. That said, it is good practice to turn it on as late as possible, and turn it off as soon as is recovered to keep frequencies as clear as possible.
 
Most of the GPS systems we use don’t fire BP charges, so they would be safe. There are a couple of exceptions: the Eggtimer TRS and Altus Metrum electronics are combo DD and GPS (there may be others I’m not familiar with and hopefully other posters chime in if I’m missing one).

For GPS transmitters that aren’t combos it would be fine to power them up before. In fact I always power up my systems at my prep table, confirm they’re working, and then seal them up in the rocket before heading out to the pad. It keeps pad time at a minimum so I’m not holding up other launchers.
 
Altus Metrum TeleGPS is safe to arm because it's track only. I think Mega is the pyro and track model. I've only used TeleGPS which was armed on two different complex L-1 multistages with different RSOs. So Altus Metrum track only products are fine to arm.
 
Altus Metrum TeleGPS is safe to arm because it's track only. I think Mega is the pyro and track model. I've only used TeleGPS which was armed on two different complex L-1 multistages with different RSOs. So Altus Metrum track only products are fine to arm.

Oh?
 
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The Eggtimer TRS uses a separate battery/switch to arm pyros. It's safe and actually commended to turn the computer/GPS side on before going to the pad so you can pair it to your receiver and acquire GPS lock.
 
Altus Metrum TeleGPS is safe to arm because it's track only. I think Mega is the pyro and track model. I've only used TeleGPS which was armed on two different complex L-1 multistages with different RSOs. So Altus Metrum track only products are fine to arm.

Theres the TeleGPS which is just a tracker, the TeleMetrum which is DD and tracker and the TeleMega which has 6 pyro channels and is a GPS tracker.
 
Theres the TeleGPS which is just a tracker, the TeleMetrum which is DD and tracker and the TeleMega which has 6 pyro channels and is a GPS tracker.

I've armed a TeleMetrum on the bench in a horizontal position with charges attached in the past. The TeleMetrum (and I would also expect TeleMega) sense their orientation on boot and if they don't detect they're vertical they won't boot into flight mode. So you can wire everything up, turn it on, take it out to the pad, rack it up, and then return to the flight line and reboot the computer via the RF link. Upon reboot the FC will sense it's vertical and enter into flight mode.

Your RSO might not support this process, but the hardware is able to support this use case. I've not done it in years myself but the possibility is there.
 
I've armed a TeleMetrum on the bench in a horizontal position with charges attached in the past. The TeleMetrum (and I would also expect TeleMega) sense their orientation on boot and if they don't detect they're vertical they won't boot into flight mode. So you can wire everything up, turn it on, take it out to the pad, rack it up, and then return to the flight line and reboot the computer via the RF link. Upon reboot the FC will sense it's vertical and enter into flight mode.

Your RSO might not support this process, but the hardware is able to support this use case. I've not done it in years myself but the possibility is there.

I’m glad you haven’t done that in years. It’s completely against NFPA 1127 which is the heart of the safety code of both TRA and NAR. That’s why the RSO should not allow it. In fact, at some launches, if you arm your electronics (those with charges) and approach the RSO table, you’ll be asked to leave the launch. Please don’t do it, much less explain to people that they too can do it.
 
I’m glad you haven’t done that in years. It’s completely against NFPA 1127 which is the heart of the safety code of both TRA and NAR. That’s why the RSO should not allow it. In fact, at some launches, if you arm your electronics (those with charges) and approach the RSO table, you’ll be asked to leave the launch. Please don’t do it, much less explain to people that they too can do it.

This... At last years LDRS,(36), we made this a no exception rule. As a result, we experienced no inadvertent deployment charges being fired in prep areas.
https://www.rocketryforum.com/showthread.php?139109-LDRS-36-Update-1
 
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Theres the TeleGPS which is just a tracker, the TeleMetrum which is DD and tracker and the TeleMega which has 6 pyro channels and is a GPS tracker.

Don't forget everyone's favorite, the Telemundo weather tracker:

mexicoweathergirl.jpeg
 
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I’m glad you haven’t done that in years. It’s completely against NFPA 1127 which is the heart of the safety code of both TRA and NAR. That’s why the RSO should not allow it. In fact, at some launches, if you arm your electronics (those with charges) and approach the RSO table, you’ll be asked to leave the launch. Please don’t do it, much less explain to people that they too can do it.

I feel like this has been answered before on other threads, but I can't see where. It wasn't specifically addressed on the LDRS thread. I use an Eggtimer Quantum pretty regularly. That altimeter checks continuity while it is on but not armed, but it does not arm until commanded by Wifi. Actually, I don't think it will even arm if the altimeter expects continuity on a channel based on your settings and finds no continuity.

For small rockets, I would like to use the following procedure with my Quantum:
In prep area:
Assemble altimeter with charges
Plug in battery and check continuity
Button up AV bay and rocket
Take to RSO table and pad

At pad:
Load rocket on pad
Arm Quantum via Wifi
Connect motor igniter
Launch

Is this acceptable under normal TRA/NAR rules? The altimeter is not armed until the rocket is on the pad. Obviously, the LDRS rules at MDRA were different, and I would respect those if I were at a launch when they were in effect.
 
I feel like this has been answered before on other threads, but I can't see where. It wasn't specifically addressed on the LDRS thread. I use an Eggtimer Quantum pretty regularly. That altimeter checks continuity while it is on but not armed, but it does not arm until commanded by Wifi. Actually, I don't think it will even arm if the altimeter expects continuity on a channel based on your settings and finds no continuity.

For small rockets, I would like to use the following procedure with my Quantum:
In prep area:
Assemble altimeter with charges
Plug in battery and check continuity
Button up AV bay and rocket
Take to RSO table and pad

At pad:
Load rocket on pad
Arm Quantum via Wifi
Connect motor igniter
Launch

Is this acceptable under normal TRA/NAR rules? The altimeter is not armed until the rocket is on the pad. Obviously, the LDRS rules at MDRA were different, and I would respect those if I were at a launch when they were in effect.

Yes, using the Quantum without a physical switch is permissible. Leave it disarmed until you arrive at the pad as you listed.
 
Be careful with the Quantum. It is possible to open your web browser to the deployment "test" page (192.168.4.1/test), specifically the countdown page, if it is a cached page in the browser. The quantum will think that you are doing a deployment test, execute the countdown (without asking for the code), and fire the charges. I have seen this happen. A best practice is to clear your browser history after using the Quantum. You can bookmark the home page (192.168.4.1) if you like.
 
The quantum instructions include the following advisory concerning the browser and testing sequence:

"If for some reason you need to abort a test, all you need to do is to close your browser BEFORE it counts down to zero. After you close it, you should open the Status Page; re-opening the test page immediately after closing it may cause it to be resumed from that point, depending on how your browser caches pages."

I would encourage bench testing (I use mini christmas light bulbs in place of igniters) for anyone that has a Quantum. Get familiar with how the browser interacts with the unit so you avoid accidentally executing a deployment test.
 
Cris can comment on this issue with the quantum, but I think it was resolved with a firmware update. Now every 'test' page requires a unique code before it fires.
 
Cris can comment on this issue with the quantum, but I think it was resolved with a firmware update. Now every 'test' page requires a unique code before it fires.

Yes, according to the release notes, software 1.03 fixed this.

"To prevent this, when a deployment test is completed a new random validation code is generated. This prevents a cached page from launching a test, because it will fail the validation; instead, you’ll get the test home page."

I wonder if the issue of stopping a test and then "accidentally" resuming it was fixed by software 1.03? The release notes say when a "test is completed."

A useful interface enhancement would be the inclusion of a large "abort" button that flashes on the web page during a test countdown. Pressing this would both stop the test, and reset the Quantum so the countdown could not be resumed. The system would require a new code to begin the test countdown from 10...9...
 
Yes, using the Quantum without a physical switch is permissible.
On what basis is a system that's powered but waiting for an external RF event to "arm" acceptable, but a system with robust accelerometer-based lockouts forbidden?

They're both powered and the only thing keeping them from firing is some software.

It's not that I disagree with your conclusion, but it's a subtle distinction. I prefer to rely on a simple physical switch whenever I can.
 
It's not that I disagree with your conclusion, but it's a subtle distinction. I prefer to rely on a simple physical switch whenever I can.

I power my Quantum up at the pad (with a physical switch), connect wifi, and then arm. I do this primarily to conserve battery power since quite a bit of time can lapse from when I close up the ebay at the prep table from when it is on the rail and launched. This also allows me to power the system off upon recovery. If the system stays powered on from prep table to post flight, I run the risk of depleting my LiPo to a low voltage state. Yeah, I can toss in a larger 2S LiPo but that adds weight and takes up more space.
 
The Quantum has a switch on both leads of the deployment charge. It would require two switch failures to accidentally fire a charge. Most other altimeters have charges looking for a ground on only one side.
 
Hi,
I'm planning a Level 2 Madcow Prion and I am either going to do a Coker Nosecone bay or get one from APE. I'd rather not have a screw or switch to the outside of the nose cone for arming if I can keep from it. I also probably would rather do the 6 hex screws at a prep table instead of with the rocket on the launcher. Is GPS considered an electronic that is not to be armed until the rocket is on the pad?
I've searched but I can't find the answer.

GPS that is not deploying any charges is fine. If it has charges attached that would be a no go. This is why having gps separate from deployment electronics is a good thing.
 
This is why having gps separate from deployment electronics is a good thing.

One reason I got the new Featherweight system. I can move it from rocket to rocket regardless of the flight computer (or lack thereof) installed.
 
On what basis is a system that's powered but waiting for an external RF event to "arm" acceptable, but a system with robust accelerometer-based lockouts forbidden?

They're both powered and the only thing keeping them from firing is some software.

It's not that I disagree with your conclusion, but it's a subtle distinction. I prefer to rely on a simple physical switch whenever I can.

At LDRS 36, the Tripoli BoD was asked to rule on the use of the Eggtimer WiFi switch, a separate piece of equipment which serves only as a switch. We considered some online comments about how the WiFi switch operated (including the fact that two solid state switches must be commanded to close and the fact that the WiFi switch always comes up in the off condition) and weighed the risk of a software failure against the risk that routinely occurs as a result of having a flyers face right next to the body of a rocket in order to turn in a physical switch, especially when a person is on a ladder. We felt the WiFi switch could actually enhance safety on the range.
About a month ago someone here asked if the Quantum would be covered by the same ruling. I understand the Quantum is functionally equivalent to a WiFi switch providing power to an altimeter. Based on that I gave my opinion that the Quantum would fall under the previous ruling. I don’t know if the switch portion and the altimeter portion share a processor and code. I didn’t think of that at the time. Separate code and processors would be optimal.
Yes, you’re right, a software glitch occurring in the Quantum could result in the altimeter powering up. It would still require some condition(s) to detect launch and arm the altimeter. Maybe Cris Erving can explain those conditions.
Personally, I also prefer a physical switch when I can easily reach and turn on/off the switch, but for staging or any time using a switch is difficult, I think the WiFi switch is an improvement.
 
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You can arm the rocket while standing away from the rocket should the 2nd stage accidentally light off (as opposed to standing directly next to rocket while turning on a switch).

Exactly. Many of us have seen instances where someone turns on the staging electronics and the motor ignites. Or when arming an altimeter and a deployment charge goes, knocking a person off a ladder.
Theoretically it should never happen if a person has done an end to end test with the igniters out of the motors and the electric matches out of the powder, but crap happens sometimes and we don’t want someone maimed, blinded, or killed, whether it was their mistake or simply a gust of wind that affected the altimeter in an unexpected way.
At last year’s BALLS, a friend forgot to arm his rocket and he had already walked most of the way back to the LCO table. He paused, brought out his cell phone, and armed his rocket from a surprisingly long way away.
 
Big danger is Rf interference. I've seen a 2 watt dog tracker shutdown two Adept 22's for a ballistic flight. Most of the modern rocket electronics out there are relatively immune to this but if it says in the manual
that a deployment device is not immune to Rf, don't fly it with an Rf tracker. The old AIM 2 had that in the manual.
At LDRS 36, the Tripoli BoD was asked to rule on the use of the Eggtimer WiFi switch, a separate piece of equipment which serves only as a switch. We considered some online comments about how the WiFi switch operated (including the fact that two solid state switches must be commanded to close and the fact that the WiFi switch always comes up in the off condition) and weighed the risk of a software failure against the risk that routinely occurs as a result of having a flyers face right next to the body of a rocket in order to turn in a physical switch, especially when a person is on a ladder. We felt the WiFi switch could actually enhance safety on the range.
About a month ago someone here asked if the Quantum would be covered by the same ruling. I understand the Quantum is functionally equivalent to a WiFi switch providing power to an altimeter. Based on that I gave my opinion that the Quantum would fall under the previous ruling. I don’t know if the switch portion and the altimeter portion share a processor and code. I didn’t think of that at the time. Separate code and processors would be optimal.
Yes, you’re right, a software glitch occurring in the Quantum could result in the altimeter powering up. It would still require some condition(s) to detect launch and arm the altimeter. Maybe Cris Erving can explain those conditions.
Personally, I also prefer a physical switch when I can easily reach and turn on/off the switch, but for staging or any time using a switch is difficult, I think the WiFi switch is an improvement.

For staging electronics a WiFi switch that defaults to off when power is applied is a drop dead improvement over a direct switching on of a staging device. Some folks have recounted on how a perfectly good device (the last time they flew it)
blew charges the next flight on the pad when the switch was turned on. With the WiFi switch to staging electronics, the mechanical switch could "activate" the WiFi switch and one can be at a distance to arm. If no boom/whoosh, could approach
to take a listen if need be. Some devices show continuity at a distance so that step might not be needed.
I'd put a solid mechanical switch on a WiFi switch that is going to a staging igniter. It's a no brainer as opposed to shunting. Kurt
 
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