First Fire Junior igniters

[WilliamD]

Guys,
I hate to keep pestering with the clustering questions. Still trying to work up the nerve to launch a big Gemini Titan I built. I bought some First Fire Jr. igniters, thinking they looked ideal for clustering with composite motors (long leads, etc.) Of course, on the packaging, they say "not recommended for clustering". Has anyone ever used them to ignite a composite cluster? I'd appreciate any thoughts or advice.
thanks,
Bill

[jpummil]

Bill,

What's the motor config for your cluster?

Quest makes an 8" version of the Q2G2 which might be about as ideal as you could get with standard igniters. I *LOVE* First Fire's, but have never tried them in cluster configs.

http://www.questaerospace.com/itemde...c=7025&eq=&Tp=

[GregGleason]

Somewhat related:

http://www.hawkfeather.com/rockets/clusterwizard.pdf

Greg

[qquake2k]

I would think the First Fire Jr.'s would work, as long as you have a 12 volt system and enough current at the leads. I've never tried it, though.

[blackbrandt]

Bill,

What's the motor config for your cluster?

Quest makes an 8" version of the Q2G2 which might be about as ideal as you could get with standard igniters. I *LOVE* First Fire's, but have never tried them in cluster configs.

http://www.questaerospace.com/itemde...c=7025&eq=&Tp=

Would this work for an Airstart of a G80-T from a Raven3?

[cwbullet]

Q2G2s work well for airstarts, but I usually redip them.

[CarVac]

I used FirstFire Jr's to ignite my twin 29/40-120 motor powered Giga Drill Breaker. I have only tried it with two kinds of motors: the G76G and the G138 New Blue Thunder. Out of two launches with the Mojave Green, the first had an ignition delay difference of about 1/3 second if I remember correctly, and the second had a delay of 1/15 second. The New Blue Thunder is considerably easier to ignite so it had a delay of about 1/30 of a second.

I haven't experimented with other igniters yet, out of fear of CATO, so I can't offer any advice on alternatives. I think the best person to ask would be JDcluster who does crazy things like this all the time it seems. I do want to try G64W's, but have been hesitant because of 1. all of the CATO's I've seen and 2. the propellant is harder to ignite.

[blackbrandt]

Q2G2s work well for airstarts, but I usually redip them.

in pyrogen?

[cwbullet]

Magnilite.

[blackbrandt]

Can I get a link for that?

[WilliamD]

Thanks guys, for the helpful advice, my configuration is twin F50-4T's.

[cwbullet]

Rocketflite Magnelite will work or you can use the low voltage version with the low voltage wires.

[CarVac]

How do you determine how much pyrogen to use? Do you dip a range of amounts and use them one by one in increasing order? How do you avoid CATO's?

[Wayco]

Can I get a link for that?

http://www.rocketflite.com/store/ind...tegory&path=59

[blackbrandt]

http://www.rocketflite.com/store/ind...tegory&path=59

What if I don't need all that?

[CarVac]

You really ought to dip your own igniters if interested in staging, unless you put a CTI motor in the sustainer. Everything else that is capable of igniting composite motors needs high current and is difficult to light with an altimeter.

[Wayco]

What if I don't need all that?

Here is just the pyrogen:

http://www.rocketflite.com/store/ind...&product_id=54

I wrap my own igniters and use their pyrogen, some folks redip ready made igniters for a more intense burn.

[cwbullet]

I personally have never had a CATO with a magnelite. I have launched many rockets with them. I am not saying it does not happen. I am pretty careful to make sure the igniter fits the opening. If it is too tights, I choose another igniter.

You can make your own igniter blanks. I use a nichrome wire wrapper and multiple sizes of nichrome depending on the voltage to be used. The smaller the nichrome, the more brittle, so be careful.

[blackbrandt]

Here is just the pyrogen:

http://www.rocketflite.com/store/ind...&product_id=54

I wrap my own igniters and use their pyrogen, some folks redip ready made igniters for a more intense burn.

Sorry, what if I don't need all of that pyrogen?

[cwbullet]

It will make several hundred igniters. I have gone through about 2 in 4 years. I make them and people borrow (use) them. You will use more than you think.

[CarVac]

I haven't found anywhere that sells less than the typical 40 gram amount. If you do find it, let me know.

[blackbrandt]

So borrow it off a friend or fellow flyer?

[CarVac]

Has anyone ever used FireStar pyrogen before? The 40-gram kit is a good deal less expensive than the magnalite pyrogen.

[cwbullet]

Firestar is ok. It is a little more fragile. Just keep the igniters is a well protected case.

[blackbrandt]

These? Can't you get single ones of these, pre-dipped?

[cwbullet]

Nope, they come as a kit unless something has changed.

[BobH48]

I wrap my own igniters also and have been more than happy with Quickburst pyrogen. I haven't tried any other pyrogen because after making a "boatload" of igniters, I still have more than half of it left.

[cwbullet]

Quickburst is more than able to light a motor also. I have used all 3.

[Handeman]

I wrap my own igniters and use my own pyrogen recipe. The hardest ones to get right are the ones for the smaller motors. I cluster a pair of 29/40-120 in various propellant types. I've never had a time when one didn't light, although I had a pair of G64Ws where the rocket was 50 feet up before the second motor came up to pressure. I'm not sure you can completely avoid that situation when you cluster APCP.

I always use a old analog multimeter to get accurate ohm reading on the igniters and try to match them within about 1/4 ohm. I'm not sure that is really necessary, but with homemade igniters I think it's good practice since the resistance will usually vary much more then commercial.

[CarVac]

I guess that's unfortunate since I probably won't be clustering anything else but 29/40-120 cases; everything else is much more expensive.

Can you use the ematch style heads in them without the ematch plugging the nozzle on ignition?