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Sirius Rocketry Eradicator build thread

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deangelo54

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Wait, so they required you to cut the fin slots...if true..that stinks!
I built the Scion and Executioner where I had to cut fin slots. I have built about 6 or 7 scratch built kits where I had to cut fin slots. It's a lot easier when you have a template from the manufacturer. Having the customer cut the slots significantly reduces costs. Use a straight edge and sharp blade. I use a 6" metal ruler as a straight edge. If I can do it, 99% of you all can do it.
 

deangelo54

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Yes all 4 fins at the same time.
I have the instructions for the Eradicator. It looks like an interesting kit to build. The Sirius website lists the skill level as Level 2. I would consider it a Level 3. Your posts will prove to be very helpful when the time comes to build the kit.
 

shawn_rocket

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As you can tell from my avatar, the Eradicator is my favorite rocket, besides a Estes Solar Warrior!! Great build, and I may upsize it in the near future.
 

deangelo54

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I hope you stick around. I may have some questions. Certainly not the typical three fins and a nose cone rocket.
 

deangelo54

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I received my Eradicator kit just before Christmas. I have separated the plywood parts, sanded the fins and Vanes, sanded the glasheen from the tubes and cut the four fin slots.

When test fitting the CR's on the MMT tube, they are lose. The CR's also fit loosely inside the lower and upper body tubes. I was wondering if others had the same issue with the CR's and if so, how did you deal with it?

I have some of those green paper rings left over from my Estes PSII kits. They fit snugly over the 29mm motor tube. They could help keep the CR's in place. But I still have the problem with the CR's loose fit inside the body tubes.

I'm concerned about properly attaching the upper 3" tube over the Vane Centering ring.
 

deangelo54

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Thanks for providing the URL for the thread. The thread deals with the lose fit of the CR's on the MMT tube. What about the lose fit of the CR's inside the body tubes? Would it make sense to glue paper around the CR's before gluing or epoxying the MMT assembly inside the body tube?
 

neil_w

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Thanks for providing the URL for the thread. The thread deals with the lose fit of the CR's on the MMT tube. What about the lose fit of the CR's inside the body tubes? Would it make sense to glue paper around the CR's before gluing or epoxying the MMT assembly inside the body tube?
That's what I do. Just make sure the paper is well-glued to the ring. I like the resulting fit in the body tube to be a bit on the tight side, so the paper and glue joint will be under compression.

Oh, and this solution presumes thick centering rings. Would be tough to do with cardstock or even fiber rings. I almost always use 1/8" thick light ply rings where it works well.
 

deangelo54

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That's what I do. Just make sure the paper is well-glued to the ring. I like the resulting fit in the body tube to be a bit on the tight side, so the paper and glue joint will be under compression.

Oh, and this solution presumes thick centering rings. Would be tough to do with cardstock or even fiber rings. I almost always use 1/8" thick light ply rings where it works well.
Since the kit is the Eradicator, I am working with 1/8" plywood fins.
I'm going to follow your advice and paper the outside of the CR's.

I have never had CR's this loose. If anything, they are usually too tight and I have to sand them a bit, which is easier to deal with.

You advice is much appreciated.
 

bobbyg23

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As you can tell from my avatar, the Eradicator is my favorite rocket, besides a Estes Solar Warrior!! Great build, and I may upsize it in the near future.
Did somebody mention an upsize? 4" top tube, 3" bottom tube. 38mm motor mount.
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Should be fun.
 

deangelo54

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The things I see rocketeers do never ceases to amaze me. I'm honored to be part of the same hobby.
 

deangelo54

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Hi bobbyg23, your Eradicator is looking real good. I forget if I asked if you had the same problem with your kit as I am. The centering rings fit loosely in the body tubes and the MMT tube fits loosely in the centering rings?
 

bobbyg23

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Hi bobbyg23, your Eradicator is looking real good. I forget if I asked if you had the same problem with your kit as I am. The centering rings fit loosely in the body tubes and the MMT tube fits loosely in the centering rings?
I recall them being a little loose. I don't remember how much though.
 

shawn_rocket

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Did something similar with my AT Arreauxbee-HI!
bombpopAT-AHI.jpg


lol Great minds think alike! Back in September 2020 with TripoliMoKan. Great flight up, (a safe) ballistic recovery.
 

deangelo54

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I ordered some CR's from Apogee that will hopefully fit well in my Eradicator kit.
If not, then I will wrap paper around the MMT tube and the OD of the CR's. Then I can use the Apogee CR's for scratch build projects.
BTW, Nice Job!
 

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