Head-end ignition through a smoke grain?

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We used a magnetic switch on our second multistage rocket this year and never looked back. There's always a risk with anything.

Here you have speculated on three different things of which you clearly do not have first-hand knowledge. Please don't. I left the relevant part in.
 
I don't know how it ended. But here's an external link to a news website that google picks up. Kurt's comment of not wanting to stand next to an L when it ignites made me cringe a tad.
https://www.sandiegoreader.com/webl...t-filed-over-injuries-suffered-at-large-and-/
People like this woman put rocketry at risk. Maybe this media incident is a false rumor. Or spectators really don't know better.

The article had things wrong and you like to drag threads into the weeds with things for which you have no experience.


Steve Shannon
 
Here you have speculated on three different things of which you clearly do not have first-hand knowledge. Please don't. I left the relevant part in.

A Featherweight mag switch could "technically" be an issue because it defaults to "on" when power is applied. Soooooo....... One can get around that by disconnecting one of the power out wires to ones device, plug that battery in, swipe it off with the magnet,
hand the magnet to someone else to hold and then attach the wire to ones device and seal up the ebay. With a large rocket that would be very easy to do.

Is that what I do? Naaaaahhhhhhh, but I have to qualify I use it for single stage deployment and not a multi-staged rocket. In a small rocket, can be hard to disconnect and reconnect wires. In my instance I bench tested with contained ematches connecting
the battery and rapidly swiping the switch off. It works fine but again it's not wired to an M motor but just two less than one gram charges. I use a full welder's helmet with a clear face shield and prep in an isolated area onsite. If anyone has a line on magnetic switches that default to "off" with power connection give a shout out.

Steve Shannon et al. I am not suggesting that electronic activation is the only way to deal with staging safety but has the potential to alleviate a lot of guess work for the simpleton I profess myself to be.

How does one test a shunt? Easy. Get one's ignition device, plug it into the battery (Lipo or whatever), plug the ignition device into a computer so you can activate the channel you are using or it will be much easier if you can activate it wirelessly without a computer if your device allows. Then wire up your live staging igniter whatever that may be and stick in your proposed parallel shunt. Oh BTW use the parameters you're going to be using to "fire" your igniter on your
device (ie. the time of circuit activation 1 sec, 2 second or whathaveyou) Now step back, clear the area and push the button to activate the igniter. So, it didn't ignite? Great. The shunt did what it was supposed to do.

Is your electronic deployment/ignition device still operable or is this a one time test? Did your deployment/ignition device smoke instead of your igniter? Well, now you can go out buy a new one and show the RSO your burned out one and truthfully say your shunt worked.

If your igniter lit with your shunt in place you have two problems. One, it lit when it wasn't supposed to meaning your device/battery was able to shove a lot of current out and number two have the output circuits been damaged or
life shortened by the test?

If your device can turn on after the test, now the only unknown is what is your devices' resiliency after such a rigorous test? Good question.

I hope a reader realizes if they comprehensively test a shunt with their electronics as stated above there is a good chance you could "kill" them and I am not suggesting they do so. But how else will one know if that shunt
will "save them"?

Using a Quantum or a WiFi activated power switch (so one can use any electronic device they want to allow for staging) that has a reliable mechanical switch in place to "make ready" the wireless switch is something that would alleviate some guesswork for me. Knowing that connecting a battery to a wireless switch that defaults to "off" kinda makes me feel good. (If one is only using their wireless electronics to fire deployment charges I don't think a mechanical switch is needed but for me I don't want to be standing next to that M upper stage when power is applied to the electronics even though I know it will be all right. I'd rather be "all right" from 25 to 50 feet away or more.)

What "saves" people from staging accidents is shunts or no shunts the modern devices function reliably nearly 100% of the time. The worst case scenario is when power is applied to a "defective" device that activates the ignition
circuit as soon as it's turned on. Very rare? By God yes but with a wireless switch that defaults to off, one can apply power to the deployment/staging device "from a safer distance away". A shunt? Sure if it does it's job and the deployment/ignition device goes into default mode or shuts down AND the flier recognizes that, the launch can be aborted.

I am not making a rule suggestion here. Whatever one does they need to be careful, thoughful and nonetheless need to be aware of any local venue rules that a prefecture has in place. No timers allowed? They can do that. No two stage flights allowed without tilt testing? That's a big swallow one but a group could mandate that too. All two stage flights need to be approved in advance? I've seen that posted on a prefecture club site.
Cripes there's a group that mandates that aluminum nosecone tips have to be painted in order to fly on their site. You darned tooting if I was going there to fly, I'd prime and paint my Al nosecone tips. (No, painting them with a
Sharpie is not acceptable!)

Now back to HEI. I really like what I'm seeing though for gosh sakes CJ, Boron! What surplus sale did you get that from? The rest of us mortals can only lust after that stuff. Kurt
 
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Yes they are 38.00 for the "floating'' closure. You will need to purchase the screw on ring as shown in pic.
A run of 6 was done in each size, there is 1 left in 38 as of now in stock. The way these things are going, there will be larger runs made. Over 50 of varying sizes and types [from 29-98CTI- AT-Snap ring types] are currently in field and being used.

I'll put up some pics of most of them Sunday.

Prices are simple: 29mm = 29.00 38mm=38.00 54mm=54.00 and so on. Unless some custom work required.

I was curious to know if you could post some pictures of these?
 
Just as an aside. Last I looked about 10 days ago the 29mm forward ring closure was out of stock at most entities. I 'spect they'll be back sometime though because they're used with current reloads. Kurt
 
I was curious to know if you could post some pictures of these?



Top: CTI 75 closure At RAS 38 & 29 closure. All factory stock

Center: AT 75mm AT 38mm AT 29 mm [Head End Ignition closures.]

Bottom: CTI 54mm CTI 38mm [Head End ignition closures]

DSCN0205.jpg



Business end [inside]:

[75mm AT ] [54mm CTI] 38mm AT & CTI [29mm AT]

DSCN0207.jpg

Installed 38 & 29mm AT and needed RAS ring closure.

DSCN0214.jpg DSCN0211.jpg
 
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Top: CTI 75 closure At RAS 38 & 29 closure. All factory stock

Center: AT 75mm AT 38mm AT 29 mm [Head End Ignition closures.]

Bottom: CTI 54mm CTI 38mm [Head End ignition closures]

View attachment 343127



Business end [inside]:

[75mm AT ] [54mm CTI] 38mm AT & CTI [29mm AT]

View attachment 343128

Installed 38 & 29mm AT and needed RAS ring closure.

View attachment 343129 View attachment 343130

Very cool. I’ll be in touch about some of these. I’ve been considering a 54MD two stage and wanted to use the motor as the coupler. I have CTI hardware but can’t find a flush aft closure so I’ve been looking at the Loki/AMW/gorilla cases without thrust rings. The ignition was always a hurdle in my mind but these would make that much easier. Do you make any of these for the fwd closures for those snap ring cases?
 
Just as an aside. Last I looked about 10 days ago the 29mm forward ring closure was out of stock at most entities. I 'spect they'll be back sometime though because they're used with current reloads. Kurt


I just got one 2 weeks ago,from Ken Allen [Performance Hobbies] it's best to call, Never find them on his site....LOL.
 
Top: CTI 75 closure At RAS 38 & 29 closure. All factory stock

Center: AT 75mm AT 38mm AT 29 mm [Head End Ignition closures.]

Bottom: CTI 54mm CTI 38mm [Head End ignition closures]

View attachment 343127



Business end [inside]:

[75mm AT ] [54mm CTI] 38mm AT & CTI [29mm AT]

View attachment 343128

Installed 38 & 29mm AT and needed RAS ring closure.

View attachment 343129 View attachment 343130
As a shameless plug, I have an unused one of the 38 HEI AT ensures for sale in the yard sale.
 
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