Carbon Hyperloc 835 Build

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Dec 13, 2022
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Avon, CT
Hi All,

After building more Estes rockets than I can count, I decided to build my first HPR. For Christmas I purchased a Hyperloc 835 kit that I will hopefully be able to get my L1 cert (maybe L2?) with. To make things interesting I decided to sheath the body in a light carbon fiber sleeve sold by Soller Composites and may add my own arduino based flight computer after my L1 cert. The 1/8th in plywood fins will be getting laminated in roughly 6oz cloth and filleted on with JB weld. Hopefully this will be able to hold up to any 54mm diameter motor I can fit into it and flights over mach 1 but we will see as I have no previous experience in either HPR or composites.

To start this is roughly what I was left with after unboxing the kit (photo from


All parts were then dry fitted together and the roughly 75" long rocket was ready to begin assembly.

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The first step I did was wrapping the upper body tube in a carbon fiber sleeve. This was done using soller composites own resin and heat shrink tubing. The glassine layer was peeled off and the tube was sheathed in the sleeve. The sleeve was covered in resin and the heat shrink tubing was then put over the tube and shrunk starting from the center and moving towards the ends. The motor centering rings were used to hold the shape of the tube under the compression of the heat shrink and to keep the wooden "dowel" from bonding to the tube. Once the resin had set (about 6 hours after lay up) the excess carbon was then cut off and the heat shrink was removed. While others on this forum have had trouble with Soller Composites heat shrink tubing bonding to the resin, I did not and found it was easily removed due to the inside of it being coated in some form of release agent. Soller composites resin is meant to cure at over 80 degrees and the 45 degree rainy Connecticut weather was probably not the best for this resin, hence the 6 hour set time after being brought inside.

Before saturating with resin
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After saturating with resin
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After heat shrink was applied
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Final Product, all thats left is sanding the tube and squaring the ends up.
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That is all for now, more updates to come as the build moves along!


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Now this is a first poAst that I can get behind!!!

Welcome and great first HPR project!!!

One of the people here ( @Theory ) built something very similar (Carbon Laser LOC) recently and with spectacular results!

I am sure you will not be disappointed by the performance of this once it is complete.

Your wonder about if this will handle any 54mm you throw at it. Based on what I am seeing with your build skills thus far and your approach to the built, I can most certainly say that it'll more than likely handle any 54mm motor you throw at it. Maybe not the Loki 54mm M motor, but that's more due to physical size of the motor.
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Reminder/warning/hint: You will probably want a tracker of some sort. My LOC 835 with a J went to 5K ft. With the body tube covered in carbon, you'll need to put the tracker in the nose.
Thanks for the kind words and advice!

Nice wrap. Soller composites has several different carbon fiber sleeves. Which one did you use?
I used the 4 in 3k light carbon sleeve (7.5oz). The tube is now considerably stronger and stiffer than the regular cardboard tube unsurprisingly.

Rocket Surgeon, where do you fly? CATO?
Right now, I don't fly at any club. I will most likely be joining CATO and launching the rocket once I return from school. Id love to come out and see the launch on the 21st.

Your rocket is a 4". What size Soller shrink did you use?
5" diameter was used and fit well.
Very cool!

Can confidently say that my carbon wrapped Laser Loc 313 will hold up to any 54mm motor I put in it (can’t fit the 40” long M). Took a K2050 with no problem.

With the carbon the airframe will be good however the nose cone might be problematic if you really want to push it. I filled my with 4 pound expanding foam to give it more rigidity

Keep up the great work
Beauty! I love soller stuff, i did my EZI in that same carbon


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Work on the rocket continues!

The centering rings are filleted onto the motor mount tube with JB weld. Once again the cold makes it difficult to work with as the resin becomes almost too thick to work with if allowed to cool to the outside air temperature. I also switched the position of the middle centering ring with the aft centering ring as I will be using an aeropack retainer instead of the system provided by Loc. While I wish I could attach the fins to the motor mount tube then slide the entire assembly into the rocket body (like DMehalko did on his carbon loc EZI build) the body tube is too long to allow this with the extension tube attached as I am unable to even get close to reaching the forward centering ring. Although I could lay up the body tube and extension tube separately, glue the motor mount tube, then glue the extension tube to the body tube, Id rather have the carbon sleeve be uninterrupted for both aesthetics and increased strength.




All was well until I filleted the backside of the middle centering ring not realizing the fins are supposed to fit flush with this face of the centering ring. Oh well, I plan on dealing with this by just adding a matching radius to the leading edge of the fin tabs.

The motor mount tube assembly was then glued into the main body tube while being sure that the middle centering ring is flush with the front of the fin slots.

The first 25in of nylon shock cord was wrapped in tin foil tape to protect it from ejection gases. It was then attached to the eye bolt. The body tube extension was then glued onto the main body tube. Ready to be sheathed in carbon fiber!

(Seam of extension and body tube)

I started to sand the nose cone down before noticing that the seams would need to be filled in with some sort of filler. Any recommendations for something that can fill the seams?

The e-bay was assembled. The white spacer ring was not glued on and will be sleeved in carbon fiber later.

Now its beginning to look more like a rocket!

Rocket Surgeon, bring some rockets on the 21st !
At the rate this build is moving along, it seems like it may be completed by then. I am not sure what the process looks like for getting an L1 certification but Id love to attempt my L1 this if its completed by the 21st. I just applied to become a member with Tripoli, although Im not sure what else is required to join CATO or become L1 certified other than launching a rocket with an H/I class motor.

Did the carbon fiber wrap add weight to the rocket? If so, how much?
Unsure of exactly how much weight it added, but it was very little compared to the rigidity it added. Using both hands I am unable to squeeze the end of the tube hard enough to break it. When I lay up the main body tube I will weigh it before and after to roughly see how much weight is added per foot of body tube.

Beauty! I love soller stuff, i did my EZI in that same carbon
It was actually your youtube video () that originally inspired me to build a rocket using this method.

I am a NOOB -- Can I ask why you only carbon fiber wrapped the upper stage?
The lower stage will be wrapped in carbon also, I just had not installed the motor tube yet. The next update will most likely show photos of this.
I started to sand the nose cone down before noticing that the seams would need to be filled in with some sort of filler. Any recommendations for something that can fill the seams?
I use Bondo Glazing and Spot putty.
Keep in mind, If you wrap the entire tube in carbon fiber, including the electronics bay, any electronics that use telemetry or depend on 2-way communication, such as GPS or certain flight computer features, may have a hard time transmitting at best. Since carbon fiber interferes with RF.
The work around this would be to mount your GPS and stuff in the nosecone and just have your ejection charges in the ebay.
But this being your first level 1 build, you may not plan on using dual deploy or electronics at all. (Although I do recommend at least a Jolly Logic chute release for anything bigger than a J motor. My hyperloc build with tip to tip FB fins did 4,000' with a J270.