24/40 reloads and ignitor installation at the pad

[Rick Lindsey]

Do most clubs that require installation of the ignitor at the pad apply the rule to low power rockets?

I've only used our 24/40 hardware once, but the instructions with the E11J have you insert the ignitor while you're assembling the motor. I'm pretty sure the supplied copperhead will not fit through the nozzle until the pyrogen burns off, so I'm having difficulty imagining how i could install the ignitor at the pad.

I'm repairing a rocket that is perfect for 24/40 reloads, and while it's not an issue at our club, I'm wondering what to do if I travel to other sites (PMW, Orangeburg, and I forget what the tennessee club is called) that might have such a requirement?

-Rick

 

[BAR0051]

It depends on the club, most clubs require ignitors in G motors and above to be installed at the pad and since the instructions tell you to install the Copperhead during assembly there is not much else you can do. Talk to the RSO, they will help you out. This problem, and that of getting Copperheads to light Black Jack motors is why I got started making my own ignitors. I make ones that can be installed in those small motors, at the pad, but the clubs I belong to do not require it for F motors and smaller.

 

[terryg]

I install anything G and under before I go to the pad. The only time I would not, would be if I were using a low current igniter. My home made ones take their time even with a lot of juice. With a copperhead you will probably be installing the second and third igniter at the pad anyway.

 

[Rick Lindsey]

With a copperhead you will probably be installing the second and third igniter at the pad anyway.

Not with an E11 I won't... Taking the engine back to my table to disassemble it and insert a new one, maybe. The copperhead doesn't fit through the nozzle!

-Rick

 

[Breeze1913]

I've only launched a dozen or so composite motors, but I've always used the copperhead ignitors without a problem.

 

[bguff]

Not with an E11 I won't... Taking the engine back to my table to disassemble it and insert a new one, maybe. The copperhead doesn't fit through the nozzle!

-Rick

I've put together 8 reloads so far. With all but one, the igniter slide into the grain slots no problem (I actually have the propellant grains in the grain insulator, and the insulator in the rms case prior to inserting the igniter).

On one occasion the igniter head was too big for the propellant grain core, so i ditched the igniter and used an extra igniter i had laying around. You can buy 3 or 6 packs of Aerotech igniters in 8" length online last i checked.

 

[geof]

I've been told that if the pyrogen is slightly too big, you can gently sand it down a bit. That makes me nervous, but I also think than disassembling the motor is a very bad idea because it could dislodge the ejection black powder that you shook down into the delay component. If you don't like sanding/shaving, then maybe just try a few copperheads until one fits.

G

Caveat: Anyone who wants to risk sanding/shaving an igniter does so at their own risk. My advice is worth what you paid for it.

 

[Art Upton]

I would like to point out the rule to install ignitors at the pad is an HPR safety rule, not a model rocket safety rule.

Please make your RSO note of it.

 

[noise]

So far I haven't had a problem fitting copperheads into an E11 (through the nozzle, at the pad), as long as I grab the right size.

I have had my share of misfires with those things though (copperheads that is), I WILL come up with a two wire home brew ignitor that fits in the 24mm motor if it kills me.

 

[Handeman]

... With a copperhead you will probably be installing the second and third igniter at the pad anyway.

I disagree. I've been using 24/40 and 29/40-120 for about 5 years now and I've only had two that didn't fire. The first one was 5 years ago on my second reload. This year a G64 didn't go when I used tape instead of the cap to hold the igniter on a DD flight.

All in all, I think the copperheads have been very dependable. I always install them at the pad BTW. I also sand the C-slots during assembly to remove any oxidation and I leave the sanding dust in the slots. I think this helps ignite the motors.

 

[Lee Reep]

I'm not sure if you can still get it, but Foxfire in Idaho (or is it Firefox ? ...) sells a product called Liquid Element, a conductive pyrogen. I use CAT5 cable to get pairs of twisted wire, and these work great for the 24/40 reloads. They work fine for larger motors too -- I've made them bigger for 29mm and 38mm hardware.

You leave a small (~ 1/32") gap between the bare ends of the leads, and just dip a few times in the pyrogen. They are easy to slip into an assembled motor, since the leads are stiff compared to a Copperhead.

Although not required, I do a final dip in clear dope to seal the pyrogen and toughen it. I've also used Ambroid glue.

These igniters put out a good size ball of fire, so I've never had a motor fail to light.

 

[Handeman]

I'm not sure if you can still get it, but Foxfire in Idaho (or is it Firefox ? ...) sells a product called Liquid Element, a conductive pyrogen. I use CAT5 cable to get pairs of twisted wire, and these work great for the 24/40 reloads. They work fine for larger motors too -- I've made them bigger for 29mm and 38mm hardware.

You leave a small (~ 1/32") gap between the bare ends of the leads, and just dip a few times in the pyrogen. They are easy to slip into an assembled motor, since the leads are stiff compared to a Copperhead.

Although not required, I do a final dip in clear dope to seal the pyrogen and toughen it. I've also used Ambroid glue.

These igniters put out a good size ball of fire, so I've never had a motor fail to light.

What gauge wire do you use? I'm guessing about 32ga. to 40ga.

 

[BobH48]

I have started making igniters with 30 gauge wrapping wire from Radio Shack along with 30 guage nichrome dipped in QuickBurst QuickDip.

They are small enough to slip into an assembled 18mm D13 reload. If they'll go through that nozzle, they will surely fit through an E11 nozzle.

 

[Hospital_Rocket]

During the planning last this year, the subject of igniters in the smaller reloads came up and caused a whole boatload of rather "spirited" discussion. So I went right to both Tripoli and NAR to formally pose the question.

The I received answers from both

• NAR ~ Carl Tulanko, Chairman - Sport Services
• Tripoli ~ Paul Holmes, Chairman - TMT

Both explained that any motor under 80NS should be treated a model rocket motor.That being the case, having the igniter installed pre-RSO was in keeping with all applicable organizational and agency safety codes.

Paul did add an additional point in that per NFPA 1122 a model rocket motor should come with and be used with an igniter supplied for that motor. So hypothetically a specialized igniter could be grounds for refusing a flight.

However it should be noted that it is still up to the local club hosting the event. If they have decided no igniters prior to RSO, then one would have to live with that guideline.

If anyone needs copies of these letters PM me and I will send them.

 

[jadebox]

I would like to point out the rule to install ignitors at the pad is an HPR safety rule, not a model rocket safety rule.

Just to be clear, the rule is that the igniter is to be "installed in the motor only after [the] rocket is at the launching or prepping area."

-- Roger

 

[Art Upton]

Just to be clear, the rule is that the igniter is to be "installed in the motor only after [the] rocket is at the launching or prepping area."

-- Roger

Yes, you are correct Roger; that is the text of the HPR rule.

The preping area is an important piece of it.

The Model Rocket rules contain no such rule.

 

[paulk]

No problem here installing copperheads in an assembled 24/40 case, as long as I remembered to clean the flashing from the nozzle. I've done it with E11 & E18 motors in the field.

 

[gregzo]

I would like to point out the rule to install ignitors at the pad is an HPR safety rule, not a model rocket safety rule.

Please make your RSO note of it.

You are absolutley correct Art....but some feel they must FORCE HPR rules on non-HPR rockets. Some don't want to hear that the manufacturers TELL you to insert them during assembly. They will site safety rules that do not exist....

But....
As Hospital_Rocket says:
"However it should be noted that it is still up to the local club hosting the event. If they have decided no igniters prior to RSO, then one would have to live with that guideline. "

Remember to fly and have fun no matter what!!!