igniter insertion in a CTI N2600 / 98mm

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dr wogz

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Hi,

As I read thru a student paper, I'm a little concerned. Do you need to wrap & tape an igniter to a stick to insert it into the motor?

the way I read their paper, they are taping eh igniter to a stick, then inserting this all into teh motor, then attaching the cap onto the nozzle.

I can see using a stick to push it in / up the hole.. but not leaving it in..
 

Rocketjunkie

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Large motors normally come with a paper tube that you tape the igniter to it. Insert it in the motor and leave it there. It will be incinerated when the motor lights. Otherwise, tape it to a piece of 1/8" wood dowel and leave it in. When the motor lights, it won't stay long :)
 

Antares JS

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I've heard of this. I assume it's because the core diameters and throats of the big motors are too big to reliably hold the igniter up at the top of the motor. If something gets bumped, the igniter is much more likely to be knocked out of place with all that room to move around.
 

dr wogz

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Ok, I stand corrected. Just seems odd that a stick would remain inside.. But I get why. And yes, as Antares said, I fully understand (and expect) that

having never done this, nor have seen the 'up n close' of large motor prep, I asked the question.

thanks!
 

3stoogesrocketry

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Ok, I stand corrected. Just seems odd that a stick would remain inside.. But I get why. And yes, as Antares said, I fully understand (and expect) that

having never done this, nor have seen the 'up n close' of large motor prep, I asked the question.

thanks!

Instead of wood , I chuck my Ignitor leads up in a cordless drill and spun them and 1rps to wind them up and stiffen them up .
 

crossfire

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I use a wood dowel. Tape igniter wire to to in a couple of places. Insert into motor all the way up. Than with igniter installed I have maybe a foot of dowel sticking out of motor the part sticking out tape somewhere to keep igniter from falling down. Many times I can tape it to the rail or somewhere on the pad. If your motor cuffs you need igniter not to slid down and lite motor 2nd or 3rd grain down. I leave red cap off.
 
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mikec

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CTI gives you a cardboard tube or a wood stick to do this, it comes in the reload kit.
 

jimzcatz

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if you have to ask this question, are you REALLY ready for an N motor? Ignitor sticks should have been standard practice on your way to L3. These are 1/8" dowels not Tongue depressors.
 

mrwalsh85

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if you have to ask this question, are you REALLY ready for an N motor? Ignitor sticks should have been standard practice on your way to L3. These are 1/8" dowels not Tongue depressors.
...And Jim strikes again.

If you have to make the above statement, you clearly cannot read or do not care that folks are asking questions because they don't know what they don't know. Not everyone knows what you know.

If they are invited to ask questions, then they will learn. If they're admonished for asking questions, then they will just accept the fact that they will have to learn the hard way and to be honest, I don't want someone in the hobby getting hurt because they had to learn the hard way!

The OP said nothing about flying an N motor of his own. He stated that he was reading a student paper about their procedures and was asking questions about such. C'mon, Jim...
 

jimzcatz

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Once again my mouth has overstepped my ability to make rational decisions. I missed or just ignored the finer details of the original question. I appreciate being called to the carpet and most humbly apologize for once again being an idiot. Good luck with the project.
 

dr wogz

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thanks Mike & others.

yeah, a 200 page student team paper..

I'm mentoring some uni kids for their 'Launch Canada' attempt (same as NASA or SPA student initiative, but with maple syrup and a lot of 'eh' ..)

While this makes sense, I've never personally seen it or have I packed an L3 motor, let alone a CTI motor.. hence why I asked.. Now I know..
 

mrwalsh85

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When we flew Marvin the Martian on the 6" O motor (with a 2" nozzle throat), I used 1-1/2 E28 grains with two e-matches taped to the head end of (2) 1/4" x 4ft dowels taped together. The motor itself is 6 ft long. Worked OK. We recovered the igniter wires and there were broken pieces of dowel taped along the igniter wire.

10/10 will do again. Might use an I357 grain next time ;)
 

Tim51

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When we flew Marvin the Martian on the 6" O motor (with a 2" nozzle throat), I used 1-1/2 E28 grains with two e-matches taped to the head end of (2) 1/4" x 4ft dowels taped together. The motor itself is 6 ft long. Worked OK. We recovered the igniter wires and there were broken pieces of dowel taped along the igniter wire.

10/10 will do again. Might use an I357 grain next time ;)
Well I'm some way yet from an N or an O motor, but I just love reading these kind of stories...keep 'em coming. And thanks / kudos to the OP for starting the discussion.
 

JimJarvis50

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if you have to ask this question, are you REALLY ready for an N motor? Ignitor sticks should have been standard practice on your way to L3. These are 1/8" dowels not Tongue depressors.
A couple of years ago, I was working the pads at the Spaceport event. One team was flying an O3400. When the time came, I handed the ignter to the team lead and he looked at me and ask "what's this for?". Just a humorous rocketry moment ....

Another Jim
 

OZRoc

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You can also use the guts out of an old matchstick blind. Seen AT flyers use this.
Cheers,
Mark
 

David Schwantz

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I also use a stick on motors with LONG igniter wires. Mainly due to the fact the wires are flimsy and I do not want them to fold over while getting them to the top of the cores.
 

JimJarvis50

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A couple of years ago, I was working the pads at the Spaceport event. One team was flying an O3400. When the time came, I handed the ignter to the team lead and he looked at me and ask "what's this for?". Just a humorous rocketry moment ....

Another Jim
Although in defence of the student, it seems possible that it was the stick that confused him. The thermite at the end of the stick probably would have done the same.

I always use a stick on larger motors. On the pad, it's typically tied off to the pad itself in some manner. On staged flights, I typically use a string to hold the stick in place. The string is glued to the bottom grain or the nozzle. For the particular flight in the picture, hopefully to be flown this weekend, I've sanded down the stick a bit since the nozzle throat isn't very big. After inserting the stick, I use superglue to glue the string to the stick. Just need to keep the stick in place momentarily so that it doesn't get ejected when the igniter fires.

Jim

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