Revision to Tripoli Rule Regarding Wireless Remote Switches

[wsume99]

Regardless of how you feel about the merits of the new policy, one thing is certain, the announcement has been completely bungled. If you are going to announce something you know is going to cause a controversy and is going to be disruptive to some members you need to handle it better.

First, the wording of the written announcement is not as clear as it should be. Some members here, on the Tripoli Facebook group, and on at least one of the club email lists I’m on have interpreted the announcement to mean exactly the OPPOSITE of what it means. They’ve understood it to mean that the use of wireless remote switches are now REQUIRED. It’s because the announcement is poorly written. It starts off by describing wireless remote switches as reducing risk of injury, and it ends with a list of “approved devices”. The middle section talks about a requirement for a mechanical disconnect from power, but it doesn’t come out and clearly say in plain language that wireless remote switches do not provide a mechanical disconnect, so if that’s what you are using, you need to add a mechanical switch or disconnect your battery. I think it’s very easy to see how someone could misinterpret it. It reads like, “Remote switches reduce risk, you are required to have a disconnect, here are your approved devices.”

Next, if you are going to announce something controversial that will impact your members, you need to be ready to defend the decision. Explain your decision process. Why the change? It really hasn’t been justified in a clear way. It still seems like the answer is that there have been no safety incidents, but something we can’t really describe might possibly happen someday. When members ask detailed technical questions about the redundancy built into these devices and possible failure modes, the answers are not seeming to come from the Board or other decision makers — they are coming from other members. That’s ridiculous. Explain and defend your decisions. Don’t leave your members to fight about it!

And the last thing, which is really the most infuriating, is the decision to make the change effective immediately and the cavalier attitude shown to people who hear an announcement on Monday that means they won’t be able to fly on Saturday. It comes off as, “This is a change based on a worry over something that has never happened before, but we need to take action immediately, and if that means our members can’t fly next weekend, TOUGH!” That attitude toward membership is really disappointing.

Nailed it! Literally the poster child for how not to handle change.

 

[Frederocket]

In an informal survey I took of experienced flyers in our local club, every single unintended ejection charge event occurred in a system that used a mechanical switch. No one, including those of us who have used electronic switches for years, could recall an unwanted event in a system with an electronic switch. Of course there have been many more flights with mechanical switches, so that clearly plays a role. But if you go purely by the numbers, mechanical switches would have been banned long ago on the premise of safety due to the number of incidents they are associated with.

Simple thought experiment for those of you who like them, which is a better scenario: a few well characterized and known electronic switches designed by software and electrical engineers, or 1000 different solutions to the same problem designed by each individual flyer. Which group is more likely to create a safe and reliable system?


Tony

You may be right as for as your survey goes. However, I wonder how many of those unintended ejection charge events happened in the pit area, because the individual attempted a power on/continuity check after they loaded their BP charges. I know, that a mechanical switch has no effect on the root cause of any unintended event. There is absolutely no logic that a properly wired switch, in and of it's self, will cause and inadvertent/unintended firing of any piro charge . I stand by my previous post. Come to an MDRA launch, compliance will be enforced. I know I have required a mechanical switch between the positive side of power supplies and the electronic unit for all TRA L3 I have TAP'ed and approved for flight or just witnessed the flight. BTW, twist and tape works for a mechanical switch, if you do it properly, although I do discourage it's use on most high performance projects: A good quality screw switch is really the ticket.

 

[SDramstad]

Don't know where you source your switches, but there are some EXTREMELY crappy switches all over eBay and Amazon, especially bad are keyed switches and PC mount switches. Even for toggle and slide switches many of the plastic housings on cheap switches do not withstand the rigors of (poor) hobbyist soldering techniques, and in this case, you are deploying a ticking time bomb as the contact spacing and throw dimensions get compromised. As has been mentioned, the screw switches sold by Missleworks and others are often your best bet. Saying that, the large size of screw switches often don't fit the physical profile of high performance airframe designs. And screw switches are not immune from problems; at Airfest two years ago I had one jar open due to a shock during apogee deployment leading to loss of power to one altimeter in my av-bay, which unfortunately led to loss of GPS tracking making recovery painful.

Sorry, I am a bit anal about switches as my first job out of college was with AT&T Bell Labs testing the quality and reliability of phone system handset switch pads.

I use screw switches for the smaller rockets. They are pc mount and not much bigger then a pencil eraser. I use the schurter switches for my larger projects. Have never had a problem with either one.

 

[SDramstad]

In an informal survey I took of experienced flyers in our local club, every single unintended ejection charge event occurred in a system that used a mechanical switch. No one, including those of us who have used electronic switches for years, could recall an unwanted event in a system with an electronic switch. Of course there have been many more flights with mechanical switches, so that clearly plays a role. But if you go purely by the numbers, mechanical switches would have been banned long ago on the premise of safety due to the number of incidents they are associated with.

Simple thought experiment for those of you who like them, which is a better scenario: a few well characterized and known electronic switches designed by software and electrical engineers, or 1000 different solutions to the same problem designed by each individual flyer. Which group is more likely to create a safe and reliable system?


Tony

But was the switch the problem? A switch problem by it self wont set off a charge. It energizes the electronics that have failed and blows the charges on power up. Exact same thing could happen with a wifi switch. A failure in the wifi switch could accidentally energize the altimeter which fires the charges. A switch would have to be physically activated to turn on. Electronics could be triggered by just a build up of static electricity.

 

[Speaknoevil]

I use screw switches for the smaller rockets. They are pc mount and not much bigger then a pencil eraser. I use the schurter switches for my larger projects. Have never had a problem with either one.

Then you have never flown a high performance rocket. If you have any interest I can link to one or two high performance minimum diameter builds where flight control, full tracking (and yes, switches) were mounted on the motor forward bulkhead in approximately 1.75"H x 1.5"D. The motor and electronics assembly reached into the top recesses of the nosecone where any access hole is both unfeasible and would inhibit proper operation of the altimeter. Too, any frame mounted switches both would not fit, and would have destroyed the aerodynamic profile needed to maximize performance of the design.

 

[SDramstad]

Then you have never flown a high performance rocket. If you have any interest I can link to one or two high performance minimum diameter builds where flight control, full tracking (and yes, switches) were mounted on the motor forward bulkhead in approximately 1.75"H x 1.5"D. The motor and electronics assembly reached into the top recesses of the nosecone where any access hole is both unfeasible and would inhibit proper operation of the altimeter. Too, any frame mounted switches both would not fit, and would have destroyed the aerodynamic profile needed to maximize performance of the design.

You REALLY don’t know me, do you?

 

[manixFan]

...<snipped for brevity>... There is absolutely no logic that a properly wired switch, in and of it's self, will cause and inadvertent/unintended firing of any piro charge .<...snipped...>

Thank you, exactly my point all along.

So now show me how a magnetic switch is less safe than a mechanical switch? The concern is to prevent unintended ejection charge events. No one has shown how the magnetic switch is any less safe than any other switch.

This is rocket science after all, I'll I'm looking for is some evidence to back up the claim that so many have made.


Tony

 

[Jmhepworth]

I have a lot of confidence in the Tripoli Board. Individually, they each have more experience than I have. Collectively, it’s no contest. Their combined wisdom is much better than mine alone. And I’ve really enjoyed the interaction I’ve had with Steve, Skippy, Chris, and Gary. While the new rule appears to those of us in the cheap seats to have come out of nowhere, I’m confident the board discussed it thoroughly and applied their collective wisdom in a thoughtful way.

So, for me, now it’s a matter of how to apply it. I like having the ability to arm an altimeter remotely. I’ve seen too many charges blow out a parachute on the pad, some of them when the flyer was standing on a ladder arming the altimeter with a screwdriver through a vent hole. That’s scary. And whenever I arm a Raven in the sustainer of a two stage rocket (standing on a ladder) I pray the sustainer doesn’t light. And in small av bay, it can be a challenge to make everything fit. I have a Darkstar Junior that has two altimeters, one screw switch, and three batteries. There’s no room for another switch, so unless I want to rebuild the av bay, I’ll have to add a couple of wires, drill another hole in the av bay, and switch the Quantum with twist and tape.

On a new av bay I’m working on (6 inch Wildman), I have gobs of room, so I’ll just put in two screw switches and keep the Quantum, RRC2 and a WiFi switch. I can close the switches before raising the rail and arm everything from a safe distance to avoid standing on a ladder. That should work great.

Two questions? Is it better to put the switch on the positive side of the battery or the negative? Or is it just irrelevant? And when using two batteries on the Quantum, should the switch be on the altimeter battery or the deployment battery? I’m thinking the deployment battery.

Joe

 

[cerving]

Two questions? Is it better to put the switch on the positive side of the battery or the negative? Or is it just irrelevant? And when using two batteries on the Quantum, should the switch be on the altimeter battery or the deployment battery? I’m thinking the deployment battery.

Joe

Which side you put the switch on is pretty much irrelevant, convention is to put it on the "+" side. If you're using two batteries on the Quantum, put the switch on the deployment side (between your battery's "+" lead and the Quantum DP+ pad); that cuts off power to the ematches, which is what it required by the new rule.

 

[Frederocket]

Thank you, exactly my point all along.

So now show me how a magnetic switch is less safe than a mechanical switch? The concern is to prevent unintended ejection charge events. No one has shown how the magnetic switch is any less safe than any other switch.

This is rocket science after all, I'll I'm looking for is some evidence to back up the claim that so many have made.


Tony

A magnetic switch is not mechanically activated. It is activated via a magnet and in theory, could be activated via a unintended magnetic source. That is the logic, no matter the likely probability... If you can show me that likely probability is mute and can not happen under any circumstances, I would be inclined to agree with your premise. What I do know for sure, the fireworks industry and explosive industry, will not allow such magnetic switch circuitry between the power source and the firing panel. They use a manually activated mechanical switch to power up the firing panel, whether computerized or manual.

 

[manixFan]

A magnetic switch is not mechanically activated. It is activated via a magnet and in theory, could be activated via a unintended magnetic source. That is the logic, no matter the likely probability... If you can show me that likely probability is mute and can not happen under any circumstances, I would be inclined to agree with your premise. What I do know for sure, the fireworks industry and explosive industry, will not allow such magnetic switch circuitry between the power source and the firing panel. They use a manually activated mechanical switch to power up the firing panel, whether computerized or manual.

I have personally witnessed several different mechanical switch designs which were activated in an unintended manner. One was a 'pull switch' that when removed, allowed a mechanical switch to close. The end of the rod that was pulled out had ring on it that snagged on something when the rocket was moved, and the altimeter powered on. The second was a mechanical key switch that required the user to turn the key 90 degrees to activate the switch. Similar scenario, while the rocket was being moved, the key bumped against something that caused it to turn, and the altimeter powered on. I'm sure I'm not the only one who has witnessed such 'failures' of a mechanical switch.

If a switch is activated accidentally, it does not matter if it is mechanical or electronic. The logic that only magnetic switches could be activated accidentally seems fundamentally flawed.


Tony

 

[H_Rocket]

It may have been said elsewhere, however I think the concern is not that this is a switch, it is an enable function on an already running active device. The additional layer of switching is used to act against an electronic failure that could cause an ill timed event.

 

[Frederocket]

I have personally witnessed several different mechanical switch designs which were activated in an unintended manner. One was a 'pull switch' that when removed, allowed a mechanical switch to close. The end of the rod that was pulled out had ring on it that snagged on something when the rocket was moved, and the altimeter powered on. The second was a mechanical key switch that required the user to turn the key 90 degrees to activate the switch. Similar scenario, while the rocket was being moved, the key bumped against something that caused it to turn, and the altimeter powered on. I'm sure I'm not the only one who has witnessed such 'failures' of a mechanical switch.

If a switch is activated accidentally, it does not matter if it is mechanical or electronic. The logic that only magnetic switches could be activated accidentally seems fundamentally flawed.


Tony

I do not know how to help you understand further, the difference between manually activated switches and electronically activated switches and how manually activated switches are safer and the better choice. I made my point with examples. You either understand the principle and except it as fact or not. I guess sometimes logic as applied to safety is a difficult concept to understand or except. I have nothing further to contribute to this thread, except regurgitate the facts of my experienced opinion. I counted to 11 before hitting "post reply".

 

[manixFan]

I do not know how to help you understand further, the difference between manually activated switches and electronically activated switches and how manually activated switches are safer and the better choice. I made my point with examples. You either understand the principle and except it as fact or not. I guess sometimes logic as applied to safety is a difficult concept to understand or except. I have nothing further to contribute to this thread, except regurgitate the facts of my experienced opinion. I counted to 11 before hitting "post reply".

I understand the fact that mechanical switches may be safer in theory. But that does not render magnetic switches unsafe or unsuitable for our purposes. That is what I feel is the flawed assumption behind this entire argument. I'm sorry if I don't accept the logic of 'that's the way it's always been'.

Here's an example you will understand. Not all cars protect their occupants equally in the event of a crash. Yet, we choose cars that we know are less safe than others available to us. Does that make our choice unsafe? That is the basis I am operating from. I realize you and many others take a different position. At the end of the day it is human error that is the far greater risk to safety than the choice of a switch.


Tony

PS: your reply in post 319 does not address my point that just because one option is perceived as safer, that a second option is unsuitable.

 

[H_Rocket]

I would still say that an active device like a magnetic switch based on a Hall Effect sensor should have the same mechanical interlock as the WI-Fi switch. A semiconductor does not have a guaranteed failure mode.

 

[John Taylor]

You apparently do not know very many electricians... I have seen with my own eyes more than one electrician check for live wires with a fingertip. Lick fingertip, smack wire quickly. it won't hurt you but you know whether the wire is live without spending time hunting for a breaker box. Not all electricians work with a helper....

I have been a licenced master electrician for 32 years with a total of 44 years as an electrician. Only fools ck for power with their fingertips. We have meters and voltage testers for that. Safety is always first and foremost in my trade. Inconvenience is not an excuse to bypass safety.
Working on electrical equipment that has automated controls still requires manually operated disconnect switches to be opened to insure safety before any work or putting oneself in harm's way.
I don't mind using a mechanical means of disconnect in my rockets to insure safety. Just my opinion.

 

[Buckeye]

Regardless of how you feel about the merits of the new policy, one thing is certain, the announcement has been completely bungled. ....

^^^ This post nails it!^^^

Poorly worded, no justification, and irrational implementation. 3 strikes. You are out, Tripoli.

 

[manixFan]

It has been asserted that I, and many others, by using a magnetic switch, have been in violation of TRA rules that require a mechanical switch. However, no one has been able to show where that requirement exists in any of the TRA safety rules, guidelines, NFPA regs, or in any official communication. (Prior to this rule change.) As a result, I feel that those of us who have been using the magnetic switch have not been in violation of TRA rules and that the switch sufficiently 'inhibited' the firing of the charges to meet the spirit of the regulations.

I understand that the board has now tried to clarify TRA's stance on both magnetic and wifi switches. While I obviously disagree with that rule, of course I will abide by it. In all fairness to the board and to Steve, we can only assume they have the safety of the sport and its participants and spectators in mind. It is unfortunate that a prior lack of clarity on this issue has allowed so much time, energy, and money, to be spent on products whose value is now greatly diminished, and that for many of us (vendors included) it will require a significant amount of effort to bring our current designs into compliance with the new rule.

I sincerely appreciate the very difficult role that Steve Shannon has been thrust into with this decision, and admire how well he has handled the tremendous amount of consternation this decision has caused. I feel that this was a very useful discussion in spite of the occasional heated back and forth.


Tony

 

[Frederocket]

I understand the fact that mechanical switches may be safer in theory. But that does not render magnetic switches unsafe or unsuitable for our purposes. That is what I feel is the flawed assumption behind this entire argument. I'm sorry if I don't accept the logic of 'that's the way it's always been'.

Here's an example you will understand. Not all cars protect their occupants equally in the event of a crash. Yet, we choose cars that we know are less safe than others available to us. Does that make our choice unsafe? That is the basis I am operating from. I realize you and many others take a different position. At the end of the day it is human error that is the far greater risk to safety than the choice of a switch.


Tony

I counted to 11 again and I digress. No one expounded on, "that's the way it's always been" However manually actuated switches are the excepted standard for disconnecting the power source from pyrotechnic control circuits. That's just the way it is; "the way it's always been" has nothing to do with the logic establishing manually operated switches as the best practice. Your reference to cars has absolutely no logical relevance to the issue. Maybe taking up a hobby that does not include pyrotechnics would be a better option for those whom do not understand the application of switch usage in pyrotechnics.

 

[Steve Shannon]

It has been asserted that I, and many others, by using a magnetic switch, have been in violation of TRA rules that require a mechanical switch. However, no one has been able to show where that requirement exists in any of the TRA safety rules, guidelines, NFPA regs, or in any official communication. (Prior to this rule change.) As a result, I feel that those of us who have been using the magnetic switch have not been in violation of TRA rules and that the switch sufficiently 'inhibited' the firing of the charges to meet the spirit of the regulations.

I understand that the board has now tried to clarify TRA's stance on both magnetic and wifi switches. While I obviously disagree with that rule, of course I will abide by it. In all fairness to the board and to Steve, we can only assume they have the safety of the sport and its participants and spectators in mind. It is unfortunate that a prior lack of clarity on this issue has allowed so much time, energy, and money, to be spent on products whose value is now greatly diminished, and that for many of us (vendors included) it will require a significant amount of effort to bring our current designs into compliance with the new rule.

I sincerely appreciate the very difficult role that Steve Shannon has been thrust into with this decision, and admire how well he has handled the tremendous amount of consternation this decision has caused. I feel that this was a very useful discussion in spite of the occasional heated back and forth.


Tony

Thanks, Tony. I agree that you have not been in noncompliance. It’s impossible to comply with rules that are poorly communicated or not communicated at all. We (the board) must do better and I’m sorry.

 

[Steve Shannon]

I counted to 11 again and I digress. No one expounded on, "that's the way it's always been" However manually actuated switches are the excepted standard for disconnecting the power source from pyrotechnic control circuits. That's just the way it is; "the way it's always been" has nothing to do with the logic establishing manually operated switches as the best practice. Your reference to cars has absolutely no logical relevance to the issue. Maybe taking up a hobby that does not include pyrotechnics would be a better option for those whom do not understand the application of switch usage in pyrotechnics.

I think that’s where we (I?) made our mistake. I thought we all knew that, but it isn’t documented on the Tripoli site and it should be.

 

[manixFan]

...<snipped for brevity>...Maybe taking up a hobby that does not include pyrotechnics would be a better option for those whom do not understand the application of switch usage in pyrotechnics.

pyrotechnics: the art of making or the manufacture and use of fireworks

I have never considered our hobby as pyrotechnics. To expect that all of us in the rocketry hobby see what we do as pyrotechnics is obviously a huge error in judgment. The fact that so many of us used for years what are now deemed as unsafe methods is proof of that error. I can only follow the rules that are provided by TRA, and as Steve says, I was not in violation until this change. In my experience, a magnetic switch is a suitable inhibit and I have not seen anything to change that. I appreciate that in the world of pyrotechnics that may not be the case. But until recently, those rules did to apply to us and it is unfair of you to assume that all of us see the two as equal. My hobby is not pyrotechnics and never has been.


Tony

 

[Speaknoevil]

...and how manually activated switches are safer and the better choice. I made my point with examples.

Wow! This is a blatantly false statement. Your small sample size only makes you feel better about mechanical switches. DoD MTBF data, where most component reliability data comes from, proves your statement false.
---
I am sorry. Mixed you up with another Fred on this forum. Post above is now toned down.

 

[Frederocket]

• 

 

[Speaknoevil]

I don't know who you are, but you know what you can do with your insults... You know how to contact me. I'm always amazed by those who run their mouth and hide behind a screen name...

I will PM you my name and number.

 

[DAllen]

 

[Frederocket]

I will PM you my name and number.

 

[Speaknoevil]

• 

In your Inbox.

 

[watheyak]

Oops. Deleted.

 

[Frederocket]

In your Inbox.

I think we are good now. Didn't change my mind on the use of manual activated switches for our purposes, based on the reasons previously stated. I appreciate the walk back and apology. Piece brother.