Revision to Tripoli Rule Regarding Wireless Remote Switches

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jderimig said:
Bad implementation of a screw switch.
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It actually looks like the one from Missleworks. They are #6 screws. The screw thread is loose. Other than that the PCB is of high quality. As I posted a many pages back, you can save yourself from any screw loosening or closing by using VC-3 Vibra-tite resin.
 

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Speaknoevil said:
It actually looks like the one from Missleworks. They are #6 screws. The screw thread is loose. Other than that the PCB is of high quality. As I posted a many pages back, you can save yourself from any screw loosening or closing by using VC-3 Vibra-tite resin.
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I also posted a fix a while back as well, staking the end of the screw (dinging the end so it won't back out easily) then its tight either in or out. Those MWC screw switches are my favorite.
 
manixFan said:
At the weekly 'rocket lunch' I attend one of the guys bought a sample of a screw switch he and others decided to try in light of the recent rule. I wanted to design and print a 3D mount for it since it needs some clearance on the bottom. While I had it, I tried the experiment you see below. I repeated it several times. Sometimes it turned clockwise, sometimes the reverse. The altimeter I used is a Perfectflight Stratalogger with the optional connection for a LED. I cropped and resized the video so I could make it an animated GIF for simplicity.

This is a simple experiment anyone can try for themselves.


Tony
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cerving said:
Was that tightened fully (or backed out fully) first? I know that switch well, I find it hard to believe it would go intermittent so easily, unless the screw was closed very lightly.
Click to expand...

jderimig said:
Bad implementation of a screw switch.
Click to expand...


Sabrina said:
I’ll get right to the point...

The TRA BOD is attempting to solve a problem that doesn’t exist by adding an additional failure point. (told 'ya I'd get right to the point)
...

The BOD believes adding a mechanical disconnect increases safety, when it is a proven fact that added complexity increases the chance of failure.
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​

It doesn't matter if this is the best screw switch in the world or a cheap knock off. Even if it was the best screw switch in the world there is always the possibility it could fail either because of a thread issue or because the flyer did not tighten it appropriately. What does matter is what Sabrina so aptly wrote early on...The TRA BOD is attempting to solve a problem that doesn’t exist by adding an additional failure point.
 
rharshberger said:
I also posted a fix a while back as well, staking the end of the screw (dinging the end so it won't back out easily) then its tight either in or out. Those MWC screw switches are my favorite.
Click to expand...
Yeah, I saw that and that can be done. Another suggestion was somehow dremelling along the threads and laying in silicone sealant. I just prefer not to mess up the screw threads and potentially subsequently the embedded switch threads if I have to remove it or back it out a ways.
 
gavel said:
​

It doesn't matter if this is the best screw switch in the world or a cheap knock off. Even if it was the best screw switch in the world there is always the possibility it could fail either because of a thread issue or because the flyer did not tighten it appropriately. What does matter is what Sabrina so aptly wrote early on...The TRA BOD is attempting to solve a problem that doesn’t exist by adding an additional failure point.
Click to expand...

Again, every place I’ve found where energetics are controlled electrically, electricity is required to be physically interrupted until safely away from other people and ready to use.
Whether you think so or not we don’t go looking for fictional problems. We had multiple people who are knowledgeable about such standards caution us that allowing certain devices did not comply with widely accepted practices. We could ignore their advice, which could increase our exposure to liability, or we could take a step back while we figure out how to incorporate solid state switches and related software.
 
OK, so note that Steve DID NOT say that 1) We are banning electronic switches (or any other technology), 2) We are approving/certifying or not approving/certifying any piece of equipment, 3) You can only use blah blah switches/altimeters/timers/rubber duckies, 4) You can NOT use blah blah switches/altimeters/timers/rubber duckies, 5) Electronic switches are more/less/equally reliable compared to physical switches. It's very simple, as I stated before... the rule says, You need to have two independent "things" between the battery and the energetic, one of which must physically break the circuit.

What Steve DID say is that they are reviewing the technologies, and will make a decision on them eventually, based on how they fit into their safety model. Until then, this is the rule.

Ward, please go easy on the Beev...
 
I fully understand the rule and agree with the safety aspect. Last thing I want to do is poke someone in the eye with my NC blowing off. What I'd like to hear is what and how are we suppose to present our models for the RSO to insp. If you are using the twist and tape method, do you come to the table with the BP charges in your hand? Or do you take BP container out to the pad and assemble there? Is the rocket to be presented in parts, due to you still need to assemble it? As Steve suggested to me to use terminal blocks. Which I do use on some. But if that is the case, then I need to remove AV bay at pad, wire BP charges, assemble rocket making sure all recovery parts are in place and connected, pack my chutes. I would hate to get in a hurry due to everyone waiting on me and forget to hook up a quick link. Otherwise I come to the RSO with the rocket in pieces. If so, how does RSO check CG? Will the RSO have a new guide line for inspections? I would hate to drive for hours only to find out that an RSO had different guide lines that my rockets did not meet.
 
David Schwantz said:
I fully understand the rule and agree with the safety aspect. Last thing I want to do is poke someone in the eye with my NC blowing off. What I'd like to hear is what and how are we suppose to present our models for the RSO to insp. If you are using the twist and tape method, do you come to the table with the BP charges in your hand? Or do you take BP container out to the pad and assemble there? Is the rocket to be presented in parts, due to you still need to assemble it? As Steve suggested to me to use terminal blocks. Which I do use on some. But if that is the case, then I need to remove AV bay at pad, wire BP charges, assemble rocket making sure all recovery parts are in place and connected, pack my chutes. I would hate to get in a hurry due to everyone waiting on me and forget to hook up a quick link. Otherwise I come to the RSO with the rocket in pieces. If so, how does RSO check CG? Will the RSO have a new guide line for inspections? I would hate to drive for hours only to find out that an RSO had different guide lines that my rockets did not meet.
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I believe this has been fully covered in this thread. The rocket must have mechanically disconnected power to the electronics OR mechanically disconnect the deployment charges. Mechanical disconnect can be via a switch or unconnected wires (that will be twisted to make the connection). In that state go to the RSO. They may or may not ask you about the disconnect switches/wires among other standard things. After approval head to the pads. At or near the pad, if you have a wireless or magnetic switch in the open state, you may optionally make your mechanical connection with the rocket horizontal and facing away from any potential harm. Once the rocket is in the vertical pad position you can then enable the final switch stage, be it wireless, magnetic or mechanical. Similar final connection procedure for charges, although it is unlikely you are using solid state switches in that path.
 
Speaknoevil said:
I believe this has been fully covered in this thread. The rocket must have mechanically disconnected power to the electronics OR mechanically disconnect the deployment charges. Mechanical disconnect can be via a switch or unconnected wires (that will be twisted to make the connection). In that state go to the RSO. They may or may not ask you about the disconnect switches/wires among other standard things. After approval head to the pads. At or near the pad, if you have a wireless or magnetic switch still open, you may optionally make your mechanical connection with the rocket horizontal and facing away from any potential harm. Once the rocket is in the vertical pad position you can then enable the final switch stage, be it wireless, magnetic or mechanical.
Click to expand...

I believe that this has NOT been covered at all in the threads. When and where do you twist the wires. At the RSO table? Since that is what it appears that you are suggesting.Then that kind of defeats the purpose of the rule. Or, as you state, with the rocket vertical on the rail, you can now twist your connections. Boy, that will be about the most unsafe thing that I have ever seen.
 
David Schwantz said:
I believe that this has NOT been covered at all in the threads. When and where do you twist the wires. At the RSO table? Since that is what it appears that you are suggesting.Then that kind of defeats the purpose of the rule. Or, as you state, with the rocket vertical on the rail, you can now twist your connections. Boy, that will be about the most unsafe thing that I have ever seen.
Click to expand...
No, I said "unconnected wires" and I said, as has been said in multiple posts in this thread, that mechanical connections are made after making it past the flight line or at/adjacent to the pads (depending on the wording used in the post).

Not understanding your issue maybe... I said that optionally the mechanical connection can be made horizontally at the pad if your e-switch is in an open state. How does that defeat the purpose? Then when vertical, power having been applied to the e-switch, you do the final magnetic (physical) or Wi-Fi (command) sequence.
 
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Steve Shannon said:
You can, but you must also have electronic deployment. Here’s the rule from NFPA 1127:

4.10.2 A high power rocket launched with an installed total impulse greater than 2560 N-sec (576 lb-sec) shall use an electronically actuated recovery system as either a primary or backup deployment method.
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I was not aware of the 2560 threshold, although I have always flown redundant electronic recovery systems in L powered flights. Where did the current M motor threshold for L3 come from? Perhaps it should be lowered to 2560, especially if L3 will continue to be the only cert mechanism for electronic recovery. TRA's arbitrary rules should align with the government's arbitrary rules.
 
David Schwantz said:
I believe that this has NOT been covered at all in the threads. When and where do you twist the wires. At the RSO table? Since that is what it appears that you are suggesting.Then that kind of defeats the purpose of the rule. Or, as you state, with the rocket vertical on the rail, you can now twist your connections. Boy, that will be about the most unsafe thing that I have ever seen.
Click to expand...

David,
I don’t understand the problem. You really only need one break for power to the avionics or one break for each charge if you choose to break on the deployment side.
I think the following is true: You have designed an avbay that uses pull pin switches. That’s sufficient as mechanical breaks to the power, but because of the way you’ve done it you have to pull the pull pins to assemble your avbay. For most people they would simply assemble the avbay, complete with ematches but no BP, insert the pull pins (and hopefully tape them down to prevent accidental activation), then add the BP and continue prepping the rocket.
Then take it to the RSO table for inspection, followed by taking it out to the pad. Once it’s standing up take out the pull pins, listen for the beeps, insert and hook up the igniter and walk back to see it.
Why won’t that work? Is your avbay fully inserted into a body tube so you cannot put the pull pin in at a safe place in the process?
 
rrobe99999 said:
I was not aware of the 2560 threshold, although I have always flown redundant electronic recovery systems in L powered flights. Where did the current M motor threshold for L3 come from? Perhaps it should be lowered to 2560, especially if L3 will continue to be the only cert mechanism for electronic recovery. TRA's arbitrary rules should align with the government's arbitrary rules.
Click to expand...

I don’t know where L3 => M came from. Maybe one of the other organizations arbitrarily chose it. [emoji846]
Once upon a time all we had was “Certified”. That was before my time.
 
Boy Steve, I do not understand why people cannot read. That is exactly how I do it. My question all along has been "how do you now present the rocket to the RSO for inspection"? If you need to physically connect anything at the pad, twist and tape, plug into terminal blocks, plug in the battery, do I now bring it to the RSO in pieces or do I disassemble it at the pad and the reassemble everything. Also,IMHO, you might consider making the new rule more clear to others, as one person stated that you are now requiring 2 separate devices to interrupt the current and that is not so. You post #1 states that all that is required is a physical disconnect. So a Quark, that has no wifi switch, all I have to do is unplug the battery, and now the rule is met. But again, now that I have to plug the battery back in, do I bring it up as a mess of parts, or take it all apart at the pad.
 
David Schwantz said:
Boy Steve, I do not understand why people cannot read. That is exactly how I do it. My question all along has been "how do you now present the rocket to the RSO for inspection"? If you need to physically connect anything at the pad, twist and tape, plug into terminal blocks, plug in the battery, do I now bring it to the RSO in pieces or do I disassemble it at the pad and the reassemble everything. Also,IMHO, you might consider making the new rule more clear to others, as one person stated that you are now requiring 2 separate devices to interrupt the current and that is not so. You post #1 states that all that is required is a physical disconnect. So a Quark, that has no wifi switch, all I have to do is unplug the battery, and now the rule is met. But again, now that I have to plug the battery back in, do I bring it up as a mess of parts, or take it all apart at the pad.
Click to expand...
OMG. :sick:
 
As long as it’s physically powered down when you have energetics installed you don’t have to do anything different. Take it to the RSO table fully built but with pins in and taped down.
 
Speaknoevil said:
At or near the pad, if you have a wireless or magnetic switch in the open state, you may optionally make your mechanical connection with the rocket horizontal and facing away from any potential harm. Once the rocket is in the vertical pad position you can then enable the final switch stage, be it wireless, magnetic or mechanical. Similar final connection procedure for charges, although it is unlikely you are using solid state switches in that path.
Click to expand...

Not so unless you are using a "TRA approved" switch. The Featherweight Mag switch is not currently approved, so you would have to climb the ladder with your magnet.
 
NikeMikey said:
Not so unless you are using a "TRA approved" switch. The Featherweight Mag switch is not currently approved, so you would have to climb the ladder with your magnet.
Click to expand...
Maybe I misspoke, and certainly didn't comment on a ladder... Mechanical switch horizontal, e-switch vertical (whether wireless or magnetic). And yes, since Adrian's design requires a swipe within inches of the device, then yes, you may need to climb a ladder (depending on where it is located in your rocket). I don't think the "ladder climbing" has anything to do with approval, it is the physics of the design, but maybe Steve has a different viewpoint.
 
Speaknoevil said:
Maybe I misspoke, and certainly didn't comment on a ladder... Mechanical switch horizontal, e-switch vertical (whether wireless or magnetic). And yes, since Adrian's design requires a swipe within inches of the device, then yes, you may need to climb a ladder (depending on where it is located in your rocket). I don't think the "ladder climbing" has anything to do with approval, it is the physics of the design, but maybe Steve has a different viewpoint.
Click to expand...

The advantage of the switches I listed as “approved” was that they are remotely activated. In our original decision to allow the WiFi switch that was why we liked it: you didn’t have to climb a ladder to turn on your altimeter.
The magnetic switch was just never submitted at that time. It just was, but I want Tripoli out of the device approval process. Our goal, with the help of the manufacturers, is to establish some minimum requirements for how rocketry electronics should behave.
 
Steve Shannon said:
The advantage of the switches I listed as “approved” was that they are remotely activated. In our original decision to allow the WiFi switch that was why we liked it: you didn’t have to climb a ladder to turn on your altimeter.
The magnetic switch was just never submitted at that time. It just was, but I want Tripoli out of the device approval process. Our goal, with the help of the manufacturers, is to establish some minimum requirements for how rocketry electronics should behave.
Click to expand...
Understand. In any case though, it is the intent of Tripoli to mechanically disconnect any electronic switch (FET, opto-isolated, etc.) operated by any control mechanism (Wi-Fi, magnetic, etc.), correct?
 
manixFan said:
At the weekly 'rocket lunch' I attend one of the guys bought a sample of a screw switch he and others decided to try in light of the recent rule. I wanted to design and print a 3D mount for it since it needs some clearance on the bottom. While I had it, I tried the experiment you see below. I repeated it several times. Sometimes it turned clockwise, sometimes the reverse. The altimeter I used is a Perfectflight Stratalogger with the optional connection for a LED. I cropped and resized the video so I could make it an animated GIF for simplicity.

This is a simple experiment anyone can try for themselves.


Tony

(full video available on request)
View attachment 406603
Click to expand...

you need to whack the screw and slightly mash the threads so it is tight in the nut
 
jbr said:
you need to whack the screw and slightly mash the threads so it is tight in the nut
Click to expand...
Several of you have misinterpreted the video. The screw switch did not open, it closed due to vibration and powered on the altimeter. The whole point of the new rule isn't to prevent switches from opening accidentally, it's to prevent them from closing. It failed at the very thing it is supposed to prevent.


Tony
 
Just received my order of switches from MissileWorks. I ordered the switch+cover which is very nice kit and perfectly resolves the naked-switch issue shown in the video. The cover provides a surface that the screw hits when unscrewing, so you can apply a bit of torque to hold the screw closed, and a bit of torque to hold the screw open. In both cases, it should prevent vibration from moving the screw.
Yes, instead of the outrageous price of $2.95 for the switch, you have to pay the even more outrageous price of $4.95 for the switch+cover. Guess I'll skip Starbucks tomorrow.
 
manixFan said:
Several of you have misinterpreted the video. The screw switch did not open, it closed due to vibration and powered on the altimeter. The whole point of the new rule isn't to prevent switches from opening accidentally, it's to prevent them from closing. It failed at the very thing it is supposed to prevent.
Tony
Click to expand...

Exactly! Maybe we need to add "a mechanical switch that has been 'whacked', 'staked', 'glued', or is a 'good implementation' is required". ;)

NikeMikey
 
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