Copperheads & Aerotech...any tips?

If a motor goes off in my face, I will be the poster child for why you do not install igniters in modroc motors before they are vertical. You can say that Tom Koszuta would not have had this happen if he listened to Phil.

My point is simple: don't treat modrocs like HPR You are enforcing rules that do not exist. Installation of HPR iginters is in the NAR safety code. Installation of modroc igniters is not. This is not my opinion, it is fact.

I don't RSO. I've done some very limited LCO. My volunteer work is that I hang around on Sunday after the last lauch to help breakdown. I usually don't get to the site early enough on Saturday (or Friday) to help setup, but sometimes I do.

As I mentioned I do have some flexibility.

I'm usually not at RSO more than 2-4 hours unless it is at PARA. There, I usually do it all day. If you are determined to put that ignitor in because the rules don't say you can't, find a different RSO.

If you haven't done it, don't tell me how to do it. If you don't like it tough s..t.

Phil

Why are people launching in violation of the safety code?

There must be a safety interlock in series with the launch switch. In a relay system, that is the relay.

No safety in series with the relay is far WORSE than walking around with an igniter in the motor. I've seen 2 HPR motors go off in the fliers face because the controller did not have this simple safety feature. You can read about one of them there:

If everything is operating correctly and the system confirms to out safety rules, it should not happen. When there is a malfunction in the system, bad things can happen.

Phil

No, the switch is the switch. The safety key has to be somewhere where it can be inserted and removed from a safe distance, which means not at the pad.

If you REALLY want safety at the pad, the unplug the firing leads from the box before connecting to the ignitor, and reconect them after you've cleared the pad. Or remove the power connection from the relay box while connecting the ignitor.

Totally agree.. it should be back at the flight line.

No, a closed launch switch allows current flow to the igniter, and an open one prevents it. In a relay launch circuit, that is the relay. Closing the relay launches the rocket, does it not. What the single relay circuit people call the launch switch is simply a 10' pole that presses the launch switch.

No single relay system has a safety interlock because an interlock must prevent current from reaching the igniters.

Nothing in those single relay systems prevents current from reaching the igniters.

They do not conform to NFPA guidelines and are inherently unsafe. Searches will turn up many stores of when they fail, they fail closed (shorted). "Bad things can happen" as Phil said BECAUSE they do not have a safety interlock. If the system did have a safety interlock and the launch switch (the relay) was shorted, the rocket would launch when the person installed the safety key.

Would you like a worse design than the single relay? Use only 1 battery. If you have someone launching rockets with a single battery relay controller, you best point out a sort within the pad box completely rules out the "relay control box". A fire at our field uncovered that niffty feature.

Absolutely. So you must have another wire feeding the pad box to provide the removable interlock. Motor with a pull pin perhaps.

The Pratt Hobbies Universal Launch System, a relay based system, does have a safety interlock at the pad, complete with warning buzzer. I still short the clips together every time before hooking them up.

Kevin OClassen

The other tip I saw go unmentioned is how to make the damn thing light... There are three methods I see most often... Heat up the leads on the side opposite the pyrogen with a lighter (provided the igniter is NOT inserted in the motor... That'd be a horrible idea), the leads will peel apart and you'll have two easy leads for clipping. Masking tape one side both sides of it so that the tape leaves about a 1/4-1/2 inch space on both sides of the lead. Buy one of those aerotech clips... those work pretty well.

Biggest reason I see crapperheads not work is a short before the pyrogen.

I held a lighter on one for 5 minutes and I never could get it to light. ;-)

Yeah, it's hard to smoke 'em when they won't light :)

Doug Successful Copperhead user thanks to Bic lighters...

And the best fix is higher voltage to "blow" the shorts.

NASA. 1971. 110 pages of info about ignitors, and nothing I saw relevant to spontaneous ignition aside from a mention that ignitors shall be tested to show they are not susceptible to electrostatic discharge and that systems are to be tested to determine their susceptibility to accidental ignition from current induced electromagnetic radiation. This covered hypergolic, pyro, and a handful of other ignition methodologies. But it was 110 pages of a scanned document (I could not search), so perhaps I missed something.

Anyway, this applies to modern dipped ematches used in toy rockets exactly how....?

That said, you must have one serious bug up your ass to still be gnawing on this bone. Ok, you win.