Altimeter Bay Pics

[ksaves2]

The Perfectflite altimeters have a capacitor on the power leads to hold power for a few seconds in case you get switch bounce in your on/off switch or momentary opens on the power leads/battery. If you lose power for less then the capacitor charge time, it will come back without resetting/rebooting the altimeter.

BTW, what is the small circuit board with the resistor on it in the power leads?

Ummmm, if the installation is that shoddy, it shouldn't be flown. I think most fliers try to make sure the electrons flow unimpeded to their deployment devices.
It's best to design the bay so if the wires get jerked around during routine maintenance, one inspects them and be ready to replace or repair the wires if they get worn. I used solid core wires on one rocket and after seeing how the switch wires get bent after sliding the sled in and out, I replaced them with stranded.
Even with stranded one needs to inspect every connection before flying the rocket.

Also, make sure good quality switches are used and switch bounce will be avoided. The "twist and tape" folks will chime in here too. Kurt

 

[rharshberger]

Question (not a troll): When you mention which leg of the power supply do you mean the + or - wires? If that's the case, how would that matter? If the electrons can't flow, does it really matter which battery wire the switch is connected to? The switch terminal is in a
series with the battery anyways so whether or not one switches at the terminal block or the battery doesn't make a difference
one iota. The only "real" reason to do it at the battery (besides a not so smart reviewer) is because in a given case, it might be easier
for the builder to do it that way and they wish to proceed. The system is not "any safer" switched at the battery or at the switch block
on the deployment device.

Kurt

Kurt, after my emails with Jim Amos and Cris Erving both advised me that switching on a battery leg would satisfy the NAR L3 req. Below are the relevant parts of the emails between Cris and Jim and myself.

"The Eggtimer and the TRS hold one leg to ground, they switch on the positive lead. This is in contrast to most other devices which hold one leg to +V and switch on ground. That's because I use BJT's rather than FET's. In addition, the base of the BJT is held to ground with internal resistors on the transistor, and the input to the base itself is actually open due to the optoisolator design. It takes a fair amount of current (several mA) to fire the transistor, it's virtually impossible for anything other than an actual processor command to cause that to happen. I've had some customers actually try to trigger them with RFI, up to 15W... nothing happened."

"Hi Rich -
If you place the power switch as described for NAR L3 requirement, wire it in series with (+) leg of the battery with your described jumper on the RRC3 "switch" terminals. You're definitely compliant then as you've isolated the battery."

Below was the diagram I submitted for my L3 paperwork (I did make a mistake in that the Quark actually does not use a switch on the unit at all, so no jumper necessary).

 

[Steve Shannon]

Kurt, after my emails with Jim Amos and Cris Erving both advised me that switching on a battery leg would satisfy the NAR L3 req. Below are the relevant parts of the emails between Cris and Jim and myself.

"The Eggtimer and the TRS hold one leg to ground, they switch on the positive lead. This is in contrast to most other devices which hold one leg to +V and switch on ground. That's because I use BJT's rather than FET's. In addition, the base of the BJT is held to ground with internal resistors on the transistor, and the input to the base itself is actually open due to the optoisolator design. It takes a fair amount of current (several mA) to fire the transistor, it's virtually impossible for anything other than an actual processor command to cause that to happen. I've had some customers actually try to trigger them with RFI, up to 15W... nothing happened."

"Hi Rich -
If you place the power switch as described for NAR L3 requirement, wire it in series with (+) leg of the battery with your described jumper on the RRC3 "switch" terminals. You're definitely compliant then as you've isolated the battery."

Below was the diagram I submitted for my L3 paperwork (I did make a mistake in that the Quark actually does not use a switch on the unit at all, so no jumper necessary).


View attachment 310987

That's the perfect approach and really helps the L3CC or TAP feel comfortable. Nice job.

 

[rharshberger]

That's the perfect approach and really helps the L3CC or TAP feel comfortable. Nice job.

Thanks Steve.

My L3CC was great to work with. Due to travel distances, my build was fully photo documented on TRF and the Tri-Cities Rocketeers forum, he did a final inspection on site prior to the flight, during construction if he saw something he questioned I got an email (of course most of the TRF'rs asked the same questions so it we had good discussion and was a pretty smooth build).

The wiring diagram is as simple a system as I could come up with, there are no additional terminal blocks beyond the ones on the alts, the ematches used long enough leads to wire direct, and the batteries used JST connectors, my goal was as few wire connections as possible.

 

[Buckeye]

I put the switch on the power leads and leave the switch block closed with a small length of wire. This makes it easier to disassemble the altimeter sled and remove the altimeter. One less set of wires to mess with.

More importantly, why did this thread get revived yesterday after 7.5 years???? :surprised: Mustang67?

 

[ksaves2]

Kurt, after my emails with Jim Amos and Cris Erving both advised me that switching on a battery leg would satisfy the NAR L3 req. Below are the relevant parts of the emails between Cris and Jim and myself.

"The Eggtimer and the TRS hold one leg to ground, they switch on the positive lead. This is in contrast to most other devices which hold one leg to +V and switch on ground. That's because I use BJT's rather than FET's. In addition, the base of the BJT is held to ground with internal resistors on the transistor, and the input to the base itself is actually open due to the optoisolator design. It takes a fair amount of current (several mA) to fire the transistor, it's virtually impossible for anything other than an actual processor command to cause that to happen. I've had some customers actually try to trigger them with RFI, up to 15W... nothing happened."

"Hi Rich -
If you place the power switch as described for NAR L3 requirement, wire it in series with (+) leg of the battery with your described jumper on the RRC3 "switch" terminals. You're definitely compliant then as you've isolated the battery."

Below was the diagram I submitted for my L3 paperwork (I did make a mistake in that the Quark actually does not use a switch on the unit at all, so no jumper necessary).


Thanks, Nice diagram. I can envision the positive conductor going over to the switch terminals and quite frankly whether the switch is there or on the positive leg of the battery really doesn't make a difference. The battery is still isolated. I can see there is a single point
of failure between the + side of the battery and two points of failure by having two wires of a switch connected at the switch terminal. Electrically, it makes no difference. More reliable? Perhaps if one can't set switch wires in the terminals reliably. I still can't picture how in the heck the altimeter can do anything with an open switch on the negative wire.

Now if it has something to do with the fact that a high Rf field "could" set off a match with on open (off) off/on switch on the negative leg of the battery and not if there is an open (off) off/on switch on the positive leg that is a theoretical absurdity. An open switch on the terminal block achieves the same thing. Also it's absurd to think one is going to put a rocket in a high Rf environment without testing.

If that's the case, why isn't it required in a device's instructions to switch the + or - leg?

I do know of the AIM 2 altimeter has it in the instructions that the device is susceptible to Rf from trackers and to beware of that. Kurt

 

[ksaves2]

I put the switch on the power leads and leave the switch block closed with a small length of wire. This makes it easier to disassemble the altimeter sled and remove the altimeter. One less set of wires to mess with.

More importantly, why did this thread get revived yesterday after 7.5 years???? :surprised: Mustang67?

That's a good reason to do it if one finds it more convenient. Not that it's "safer" Kurt

 

[Mustang67]

I put the switch on the power leads and leave the switch block closed with a small length of wire. This makes it easier to disassemble the altimeter sled and remove the altimeter. One less set of wires to mess with.

More importantly, why did this thread get revived yesterday after 7.5 years???? :surprised: Mustang67?

I seen a altimeter bay that I thought was real nice and the photo helped me with my current project.
Are you not suppose to comment on an old post?

 

[Buckeye]

All good. Just surprised at the age of this one and wondering if there is more to the story.

 

[ksaves2]

There's no rule against resurrecting an old thread. Time and rules change. Nothing wrong with bringing a subject up in light of new developments.
I find it stimulating and thought provoking. Used to be in the old days, one had to have a "safety" switch on each match channel.
Don't believe me? Look at some of the pictures in old rocket magazines of L3 rockets and you'll see some of them with 6 switches on the outside or
phono plug switches. Four to isolate the ematches (which is really useless and stupid) and two to turn on the two deployment devices.

I confess, I have a beef with the rules pertaining to the new Wifi switches from EggTimer. The purveyor contends that the ematch channels are isolated
and not active until nearing the expected event settings. Putting a physical switch on a device should be optional but it isn't. Using a physical switch doesn't
add one bit of safety to the configuration at all. The only thing a physical switch will allow is one to pre-prep the ebay, connect the batteries and keep the external
switch off so the batteries don't drain. This would only apply if there isn't a separate pyro battery for each device. If that is the case, there will have to be
two additional switches in dual device installations to turn these batteries off as all of the dual batteried installations I've seen and measured, if one turns off the power supply to the
flight computer, the continuity circuits will "STILL" draw current through the pyro battery for the continuity check!!!

So...... If one wants to pre-prep a dual power source device, both batteries need to have a physical switch on them. That's the reason I
go with a single large capacity battery and don't bother with two unless the maker of the device recommends it like the ARTS II.
As I recall, the instructions of the ARTS II "strongly suggests" it. I have one new, unflown one. One battery = one switch.
Two batteries = two switches.

The flier should be able to connect power to their remotely activated device, button up the ebay and go fly unencumbered by external switches. In small rockets like a Go-Devil 38 a Quantum or a magnetic switch is mandatory aside from "twist, tape and stuff it back in".

Just remember, do the L3 with the switches and once done, you'll be free to do what you want safely mind you as long as you can dance around an RSO. At small launches that's easy to do.

Another thing. On installations with Magnetic or remote switches I thoroughly bench test with live matches doing "switchless" testing.
A Featherweight Mag switch defaults to power "on" when the battery is connected. One has to turn it off with the magnet. I've tested
it with ematches on the RavenIII and nothing happens when power is applied. Yeah it starts to beep but I use the magnet to turn it
off and take to the pad and turn it on with the magnet.

One needs to remember that magnetic switches or Wifi switches do draw a little current so one can connect up batteries without
a physical switch and let the rocket sit for weeks. The battery will be drained. What I describe is the battery is connected to the device
onsite, ebay buttoned up and one goes flying.

People will rant and rave about what if there's a "major" electronic failure and the charges blow? Well, do you clean your handguns while
pointing them at somebody? Balderdash! Once one turns on the manual switch....... Kaboom! You think we point rockets at people while
prepping them? Plug the battery in and it's goes bang, so what? Make sure no one is in the area and wear safety glasses. Sheesh.

All this is only applicable to deployment devices. Staging is a different matter when dealing with large sustainer motors.

Kurt

 

[Steve Shannon]

Kurt,
As you very well know the requirement for a physical break in the circuit between power source and electric match is only part of the NAR Level 3 certification procedure. Nobody has to "dance around an RSO".
But your statement begs the question. Why would you feel it necessary or okay to "dance around an RSO?" The RSO is there to help us all have a safe launch experience.



Steve Shannon

 

[FredA]

Wow - encouraging people to do shady or unsafe things and to dance around the RSO is really poor form..

 

[ksaves2]

Wow - encouraging people to do shady or unsafe things and to dance around the RSO is really poor form..

Fred and Steve come on. At small launches and at busy launches it intentionally and un-intentionally occurs frequently. One just has to screen the scary videos of launches gone bad. Those switch requirements are for L3 cert flights right?
Well, I bet there are plenty of small projects out there with magnetic switches that have oh lord a LIVE battery attached to them or has a WiFi switch type device that comes to the table with the battery connected and no external switch.
I have a Wildman Jr. I have a small hole in the aft bulkhead for a Featherweight screw switch. Turn on, duct tape over the hole, good to go. No obvious external switch and no one has ever questioned how I turn it on or off.

EggTimer TRS I fly in a 38mm minimum diameter cardboard rocket on J's. No one asks me how I attach the battery to it. I use one battery to power both the device and the pyro circuit. I plug the battery in take it to the RSO and no has ever questioned
me about it. Oh, since I hate unduly draining a battery, I did put a Featherweight screw switch on the pyro circuit not because it is safer but because of my paranoia of unduly draining a battery. I might not have done that if the EggTimer TRS receiver
didn't have an indication of ematch continuity at the receiver.

A Go-Devil 38 with single all-thread, Raven III and a Magnetic Switch. Charges are attached and the battery is plugged in and secured. Lordy, lordy the Raven starts to beep until the magnet shuts the switch off! Oh my!
With it shut off, I go to the table tell 'em it has a Raven and a tracker along with a J500 and go fly.

I believe a certification flight should reflect current practices that are carried out safely, routinely and not being stupid to the point of absurdity of "Well, a physical on/off switch HASTO be on the POSITIVE leg of battery and not on the terminals
the altimeter manufacturer provided." If it's so unsafe to do, why is that altimeter allowed to be flown in any rocket launch?

I'm sooooo dramatic because it appears the rules do not allow magnetic switches or Wifi switches on L3 certification flights UNLESS they are switched mechanically! Makes no sense whatsoever since those devices
are used safely in other flights routinely now without additional switching.

I'm not worrying because I have an L3 candidate rocket with two keyswitches I can use to be in compliance but I have other projects that are mechanically switchless that I will continue to fly. Kurt Savegnago

 

[FredA]

The "Positive Leg" thing is indeed ridiculous.
Some TAP pulled that out of some orifice.

BUT -- cert flights are teaching moments....and so is posting here with "information."
Nobody who respects this hobby should in any way encourage any activity that requires, encourages or even makes a vague reference to "dancing around the RSO."
Period.

You should know better and post better.

Perhaps we need better RSO training to instantly reject any rocket presented with a dance.
I do think we need better RSO training on what is acceptable and what to reject.

Personally - no OBVIOUS way to turn off a beeping rocket is a no-go in my book .... might be fine for you recovering YOUR rocket, but not so nice for anyone else who finds it. Looks like a beeping bomb to the un-initiated and there are plenty of occurrences of just that.
But I know you are all happy I don't make the rules.....

 

[ksaves2]

The "Positive Leg" thing is indeed ridiculous.
Some TAP pulled that out of some orifice.

BUT -- cert flights are teaching moments....and so is posting here with "information."
Nobody who respects this hobby should in any way encourage any activity that requires "dancing around the RSO."
Period.

You should know better and post better.
Perhaps we need better RSO training to instantly reject any rocket presented with a dance.
I do think we need better RSO training on what is acceptable and what to reject.
Personally - no OBVIOUS way to turn off a beeping rocket is a no-go in my book .... might be fine for you recovering YOUR rocket, but not so nice for anyone else who finds it. Looks like a beeping bomb to the un-initiated and there are plenty of occurrences of just that.

Fred, Look at the diagram above posted by Rich. It's implied if he so happened to have a switch on the terminals of the altimeter it wouldn't be kosher for an attempt. Yes the Quark doesn't have power terminals I know 'cause I built four of them.

Dancing around is simply answering what questions are asked. Not arguing or bickering. I contend that a Magnetic Switch or Wifi Switches are perfectly safe "by themselves" period.

If I chose to fly an EggTimer TRS with no switches, just a securely connected battery to the flying electronics it is perfectly safe. You can't even tell the device is active because the device has to be armed at the receiver.
It's silent otherwise and is safe. No one will be harmed by handling the rocket with the battery connected to the TRS and live charges period. Now if a person starts diddling with the receiver and puts the
device into manual mode to testfire charges that would be assault. But in that case, the device starts screaming like crazy for 10 seconds before it fires the attached charges. I don't know about you but if a rocket
started a siren while I was handling it, I'd drop it and run like hell.

When armed at the pad with the receiver it beep/screams like crazy fly me fly me!!! If there is no continuity on the pyro side it will beep default.

You don't understand, with magnetic switches off or a remote switch inactive, nothing is beeping or turned on. There is no indication because there is no power to the circuitry. There is power going through
the mag switch or Wifi device so it can be told to turn on the device.

These remote devices are to make it safer to remotely activate a rocket. (I believe we are getting very close to be able to do that in a staged rocket situation much more safely. It has dangers that are a heck of a lot worse than
simply having deployment charges go off. That of course is not an issue in a certification situation.)

The remote devices make it a heck of a lot easier to fit the necessary hardware into a smaller rocket in it's most basic form. Battery and remotely activated deployment device and it's SAFE without any added switches!!

I guess it's ok to have rules that don't reflect the utility of the more up to date and safe hardware. Saying switches on the positive leg of the battery is the only thing safe for a certification flight implies that what we do
in other instances is "unsafe" and it clearly is not.

Kurt

 

[FredA]

Kurt,

You don't get it.....
You implied people should skip-past or spoof the RSO -- never acceptable.


The remote devices make it a heck of a lot easier to fit the necessary hardware into a smaller rocket in it's most basic form. Battery and remotely activated deployment device and it's SAFE without any added switches!!

It's not about ease, it's about safety. I am not at all a fan of magnetic or wireless arming. Impossible to disarm. Underscore the "I." You may like those methods, but I don't.

And to reiterate, I agree that switching the positive leg is NOT the only way to do things safely ... but I do think there should be a real, hard switch in the system that kills ALL power to the avionics controlling deployment or ignition. Anything powered up but "asleep and disabled" is prone to possible inadvertent wake-up....
I also think those circuits need a disconnect and shunt, but I've been over that before numerous times.
Again - you're all lucky I don't make the rules.

 

[Ted Cochran]

You folks know there are double pole switches that can be used for dual battery altimeters, right?

 

[FredA]

You folks know there are double pole switches that can be used for dual battery altimeters, right?

Of course.
I typically use two 4PDT switches per rocket.
One that controls power to the avionics.
One that disconnects and shuts all four pyro's that are in my typical rocket.

 

[DAllen]

LOL

I wonder what some of you would say about my technique to turn electronics off and on.

Take two wires from the power source and the other to the alt. Poke them through hole in the side of the airframe & twist together. Tape remaining slack to the outside of the rocket. To disarm, pull tape off, snip the bare end of the wire. It will never ever ever turn back on after that point until I re-strip the leads. Plus, double pole switches? Those are HUGE for a rocket.

I of course do not tuck the wires back into the ebay cause that's just silly. I want to be able to turn the daggum thing back off when I am walking/driving back to the flight line so I don't go crazy(er).

 

[FredA]

DPDT....Those are HUGE for a rocket.

Seems to fit fine in the 38mm Ebay I built last year.
Maybe huge for something smaller...but I wouldn't know since I don't build that small, even 38mm is rare.

 

[DAllen]

DPDT....Those are HUGE for a rocket.

Seems to fit fine in the 38mm Ebay I built last year.
Maybe huge for something smaller...but I wouldn't know since I don't build that small, even 38mm is rare.

Oh really? Where do you get them? I can't seem to find any that are a reasonable size.

 

[Steve Shannon]

Fred, Look at the diagram above posted by Rich. It's implied if he so happened to have a switch on the terminals of the altimeter it wouldn't be kosher for an attempt. Yes the Quark doesn't have power terminals I know 'cause I built four of them.

Dancing around is simply answering what questions are asked. Not arguing or bickering. I contend that a Magnetic Switch or Wifi Switches are perfectly safe "by themselves" period.

If I chose to fly an EggTimer TRS with no switches, just a securely connected battery to the flying electronics it is perfectly safe. You can't even tell the device is active because the device has to be armed at the receiver.
It's silent otherwise and is safe. No one will be harmed by handling the rocket with the battery connected to the TRS and live charges period. Now if a person starts diddling with the receiver and puts the
device into manual mode to testfire charges that would be assault. But in that case, the device starts screaming like crazy for 10 seconds before it fires the attached charges. I don't know about you but if a rocket
started a siren while I was handling it, I'd drop it and run like hell.

When armed at the pad with the receiver it beep/screams like crazy fly me fly me!!! If there is no continuity on the pyro side it will beep default.

You don't understand, with magnetic switches off or a remote switch inactive, nothing is beeping or turned on. There is no indication because there is no power to the circuitry. There is power going through
the mag switch or Wifi device so it can be told to turn on the device.

These remote devices are to make it safer to remotely activate a rocket. (I believe we are getting very close to be able to do that in a staged rocket situation much more safely. It has dangers that are a heck of a lot worse than
simply having deployment charges go off. That of course is not an issue in a certification situation.)

The remote devices make it a heck of a lot easier to fit the necessary hardware into a smaller rocket in it's most basic form. Battery and remotely activated deployment device and it's SAFE without any added switches!!

I guess it's ok to have rules that don't reflect the utility of the more up to date and safe hardware. Saying switches on the positive leg of the battery is the only thing safe for a certification flight implies that what we do
in other instances is "unsafe" and it clearly is not.

Kurt

Wow, it's like playing the game of gossip.

Kurt,
There's nothing in Rich's diagram that would not be acceptable for an L3 attempt. Having a switch on the terminals of the altimeter is perfectly acceptable. It depends on the altimeter and the manufacturer's recommendation.

Kurt and Fred,
There's nothing in the certification rules that stipulate which leg to the battery may be switched. No TAP or L3CC made that recommendation. It was the manufacturers' recommendations for which leg to switch. Why? You would have to ask them, but in circuits that include reactive devices and BJT or FETs it can definitely make a difference. Rich wisely asked and then took their advice.

Personally I really like the idea of being able to arm my ejection charges from a safe distance and I've said so before, but Fred is also right. There should be a way for someone to safely disarm everything if a rocket is found by someone else or if a person's cellphone craps out at the wrong time. For me that's as simple as having an additional mechanical switch in series with the electronic switch. And, Kurt, while I understand your concern that adding one more element might reduce reliability, switches are some of the most proven reliable elements.

DAllen, I have no problem with twist and tape. For exactly the same reasons as you I would not twist and tuck. I've used it myself at times. A person has to understand what the possible effects might be of potential electrical noise when making the connection. The old AltAcc was sensitive that way.


Steve Shannon

 

[Bat-mite]

My L3CC told me that the requirement to physically break the circuit for an L3 was dropped by NAR -- only, they haven't updated their paperwork to reflect it. With the level of technology employed by modern-day altimeters, this is an obsolete requirement. You just need to be able to switch it off. I confirmed this with NAR HQ. I don't know what kind of effort would be required to get the documentation changed.

 

[FredA]

"Miniature DPDT....Oh really? Where do you get them? I can't seem to find any that are a reasonable size. "

Did you look?
A quick (<1 minute) search at Mouser and I found many.
Check their part number 642-MS22 as one of dozens of example.

 

[DAllen]

"Miniature DPDT....Oh really? Where do you get them? I can't seem to find any that are a reasonable size. "

Did you look?

Uhhh yeah. That's why I said "can't seem to find any."

Never heard of Mouser until this thread.

Thanks for the part #

 

[Steve Shannon]

My L3CC told me that the requirement to physically break the circuit for an L3 was dropped by NAR -- only, they haven't updated their paperwork to reflect it. With the level of technology employed by modern-day altimeters, this is an obsolete requirement. You just need to be able to switch it off. I confirmed this with NAR HQ. I don't know what kind of effort would be required to get the documentation changed.

That's right. We did vote on changes last April, but I preferred not to comment on those changes until they have been approved by the NAR trustees and appear in the L3 certification procedure. When this first came up a few weeks ago I shot an email to our leaders asking why it hadn't been updated yet. So, I am in the awkward position of using and explaining the old procedure while knowing that it should be changed soon. Of course someone will disagree with the new procedure also. It's inevitable.


Steve Shannon

 

[FredA]

That's right. We did vote on changes last April

April!!!
Isn't that like 10 months ago?

How can one follow rules that are "secret" as in not available for reading????

It is CRITICAL that members of both NAR and TRA get updated on rule changes and documentation be up to date....
Posted rules MUST be kept current and there should be a change log.
I would also hope the secretary captured the salient points of discussion that led to the rule change.

A WTF moment......

 

[Steve Shannon]

That's right. We did vote on changes last April

April!!!
Isn't that like 10 months ago?

How can one follow rules that are "secret" as in not available for reading????

It is CRITICAL that members of both NAR and TRA get updated on rule changes and documentation be up to date....
Posted rules MUST be kept current and there should be a change log.
I would also hope the secretary captured the salient points of discussion that led to the rule change.

A WTF moment......

Fred,
There are no secret rules. Until new rules are published I will continue using the procedure that is published. I cannot speak for all L3CC members.
I completely agree with you about tracking changes and capturing the discussion that led to the changes. I don't know how that's officially done in the NAR, but I hang onto my emails.


Steve Shannon

 

[ksaves2]

DPDT....Those are HUGE for a rocket.

Seems to fit fine in the 38mm Ebay I built last year.
Maybe huge for something smaller...but I wouldn't know since I don't build that small, even 38mm is rare.

Ditto, I have a few and they are huge and heavy. I've had good luck with a locking toggle switch on the aft bulkhead to switch on a MAD unit for an apogee only deployment. Never seen the the switch come back in the off position but
once the charge fires, the device has done its job and power is no longer needed. Could probably get away with it with a dual deploy device but I wouldn't do it. Kurt

 

[ksaves2]

Wow, it's like playing the game of gossip.

Kurt,
There's nothing in Rich's diagram that would not be acceptable for an L3 attempt. Having a switch on the terminals of the altimeter is perfectly acceptable. It depends on the altimeter and the manufacturer's recommendation.

Kurt and Fred,
There's nothing in the certification rules that stipulate which leg to the battery may be switched. No TAP or L3CC made that recommendation. It was the manufacturers' recommendations for which leg to switch. Why? You would have to ask them, but in circuits that include reactive devices and BJT or FETs it can definitely make a difference. Rich wisely asked and then took their advice.

Personally I really like the idea of being able to arm my ejection charges from a safe distance and I've said so before, but Fred is also right. There should be a way for someone to safely disarm everything if a rocket is found by someone else or if a person's cellphone craps out at the wrong time. For me that's as simple as having an additional mechanical switch in series with the electronic switch. And, Kurt, while I understand your concern that adding one more element might reduce reliability, switches are some of the most proven reliable elements.

DAllen, I have no problem with twist and tape. For exactly the same reasons as you I would not twist and tuck. I've used it myself at times. A person has to understand what the possible effects might be of potential electrical noise when making the connection. The old AltAcc was sensitive that way.


Steve Shannon

Ok, so noted but it was said it was done to please the L3CC which implies that perhaps one could deny it if it weren't done otherwise. Your point about having a rocket "disarmed" if found by someone at a distance is moot,
unless they have the key for a key switch or the right phono plug it ain't gonna happen. If the rocket failed and all's that's left is a splattered rocket, there's nothing left to disarm. If the electronics failed and a charge failed to go off
one has a prepared charge present but again, if the circuitry failed, there's nothing left to disarm. If it appears the rocket has been lying out there for a long time, the batteries are likely dead and there's nothing left to disarm,
especially if the charges performed as planned. If an ematch failed, again there is BP present but there is nothing to disarm. It's a hazard if someone messes with it with a lit cigarette in their mouth (ie. opens it to look at the BP) but not if it's undisturbed.

The proper way to deal with this at a launch, especially if the found rocket is large is to note the position (I carry a GPS that can mark the site) and tell the flier where it's at and they can deal with it. I'm prepared to hand the GPS to them so they can go get it and would offer to help if they need it. If it's a small rocket and it's way the heck out there when I'm getting mine, I'll bring it back in especially if I see the charges already fired. I had the good fortune
of finding a rocket with a GPS tracker and I didn't quite have it packed up for the long trek back. Flier pulled up and I was able to bum a ride back! My tracking solution didn't have a map otherwise I would have driven onroad
to get to the site more easier.

With a device like the EggFinder TRS the battery can be connected to it with no switch and it won't be making any noises whatsoever and is not in an armed mode until remotely activated. There isn't a beeping rocket when
handed to an RSO. There's a low key beep about every 15 seconds on the receiver that indicates it's bonded to the altimeter. Kurt