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Blue Phoenix Jr. build

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Joshua F Thomas

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Back in august I realized I was going to need a "sanity rocket" mid-way through my university semester, and I picked up the Blue Phoenix Jr kit from Always Ready Rocketry. ARR makes "blue tube", a material they seem to sell to the military for tank ordinance.

The kit is the smallest they sell, a 29mm engine mount in a 38mm x 36 in body tube. The fins are fairly exotic looking and are forward-swept. The kit was packaged simply, and the instructions are all of two pages with a single diagram. Experienced builders required. Calls for epoxy as the adhesive.

blue_phoenix_jr_1.jpg



I forgot to take a picture of the motor mount, but this is the motor mount installed in the airframe, which is pre-slotted for the through-the-wall fins. The shock cord is a nice strong 1/2" tublar nylon, and attaches to the motor mount by going under the forward centering ring and then having 3" of the cord epoxied to the MMT. Three centering rings of wide aircraft plywood are used. I was pleased by the sturdiness. The motor retainer seen above is an Aeropack and was not included, I purchased that separately. The kit does not come with a motor retainer.

Getting epoxy on each of the centering rings was kind of tricky - I used a dowel to pre-epoxy the place for the forward ring, then shoved the whole MMT forward and dripped epoxy in the slots just before the mid ring, and finally slathered epoxy on the rear ring and pushed the whole thing into place. Seems to be holding well.

blue_phoenix_jr_2.jpg


Fins are 1/8" plywood. Sturdy. The smart thing *would* have been to install these right after installing the MMT, but I didn't do the smart thing. I had to bevel the bottom edges of the fins a tiny bit to get them to fit into the slots after the MMT was installed and epoxy set. Oh, and you have to cut your own slots at the ends of the fins to accommodate the rear centering ring. One of them was less good than the other, as you can see.

blue_phoenix_jr_4.jpg


First fin installed and waiting for the epoxy to dry.

The strength of the blue tube is exceptional. I can't damage it with my hands or even hammering it against anything solid. You'd need a hammer and vice to do real damage to these tubes. The total mass of the build before motors should be around 30 oz / 850 grams. I expect to fly it on E to G motors depending on the field and get anywhere from 400 to 3000 feet on those motors. It's solid enough I suspect you could put an I motor in it for some real fun and have it do just fine. And if the chute doesn't deploy, I'm not even slightly worried about the body. The fins will snap before the frame even gets a dent.

More to come.
 

Nytrunner

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Blue tube is an excelleng material. I'm going to use their 2.6 tube to make a scale-ish PAC-3 to go with my L1

Of note: you're going to want to seal the inside of the tube (at least, and maybe the outside too) to mitigate swelling or warping as the material ages
 
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