HPR Custom Build

thzero

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Started a new custom build... thought I'd actually create a bit of a log of it for once. Couple of goals for this rocket

  • Explore some new building techniques
  • Build a rocket that can be launched with I motors in the 2000-3000' range
  • Setup for dual deploy in one of two configurations
    • Dual deploy using Jolly Logic Chute Release
    • Dual deploy using altimeter based deploy (for drogue) with JLCR for the main
For my level 1 I had originally intended to build a 3" kit rocket from Madcow (Aerobee). However I ended up scratch building a 2.6" fiberglass to replace the Aerotech Initiator that crashed (ironically on the first use of JLCR) and broke two fins - that was my level 1. So I had this spare 3" kit, but not really into building the kit and besides on an I it'd go beyond where I wanted for altitude.

So I decided to try and learn some new techniques, specifically fiberglassing a paper tube. So this rocket will be built with based using.
  • Madcow kit
  • Few other LOC components including a LOC 3" electronics bay
  • Custom 3d printed sled for electronics
    • Missileworks RCC3
    • Featherweight Raven
  • Custom 3d printed altimeter and GPS holder
    • Missileworks GPS Tracking
  • Soller composite fiberglass sleeving and heat shrink tubing
  • Custom plywood fins, glassed tip to tip with fiberglass
 

thzero

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PXL_20200927_205444546.jpg

Started with ordinary Madcow/LOC 3" tubing with the outer Glassine layer removed.

PXL_20200927_211447648.jpg

Added the Soller fiberglass sleeve onto the tube. Inside I have two couplers to act as reinforcements to keep the tube roundness. This is a cheap rotisserie for a grill, and a quickly knocked together stand for it with some handy scrap lumber I had. Two 3" bulkheads were hammed onto the rotisserie square rod; not really ideal but it worked for now. The sleeve ends were tied off with some zipties after pulling the sleeve as tightly against the body as possible.

View attachment PXL_20200927_211454053.mp4
















Hey, it spins and should work.
 

thzero

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PXL_20200927_225453612.jpg

About to apply some some epoxy! I'm using West Systems and the 206 hardener.

PXL_20200927_230221133.jpg

Epxoy has been applied, and the heat shrink tubing has been slid onto the tube. I ended up with two sizes of heat shrink tubing, the 3.1" and 3.8". I found it harder to put the 3.1" on, but it gave a smoother finish. The 3.8" was much harder to heat and get smoothed out. I'd go with the smaller diameter if I do this again.

Once the I had done the heat shrink, I let the tube spin for 10-15 hours overnight.

PXL_20200928_123253540.jpg

Then I used a dremel to cut off the ends for a fiberglass covered tube. The coating was still pretty thin and wasn't smooth. So after doing some more reading, I ended up doing the tube with another layer of epoxy but this time without the shrink. Other than some bubbles (more reading on this one suggested a torch, mmms, or misting denatured alcohol can help cause the bubbles to decrease surface tension removing bubbles) I had a pretty nice tube.

Personally I did not like the "blue", so am going to paint anyways so wasn't that big of deal. So bunch of elbow grease as 120 grit sandpaper (lower grit didn't seem to work as well) which cut through the epoxy well I got a pretty smooth set of tubes.
 

thzero

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Yeah I was considering an L2 as either a 4" or 5", and was debating between doing tubes of my own with this technique, canvas tubes or fiberglass tubes. So since I had this rocket kit sitting here, I thought I'd try this out and see how it works out.
 

thzero

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PXL_20201006_134151081.jpg

The set of tubes mostly ready to go. Tube 2nd from the left still needs to be sanded and smoothed.

Building the ability to have multiple fin cans, i.e. the tube on the left. This fin can will be based on 38mm motors. Future possibility is a 54mm motor fin can.

The two main couplers, one being fin can coupler and the second being the ebay coupler, will include a LOC "stiffy" tube. The "stiffy" tube will be lined with the fiberglass; probably frankly overkill but oh well.
 

Andy Greene

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Looks good so far, wondering why the use of the JLCR if your going to use altimeter based drogue and main deploy ?
 

thzero

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Started working on the ebay...

PXL_20201008_201002451.jpg

My 3D printed ebay prototype. plates to support a Raven altimeter, and plate to support a Missileworks RCC3. Also printed a drill guide for the bulkheads.


PXL_20201008_201321873.jpg

With the screw switch in its holder. With deciding to use the LOC stiffy tube inside the ebay coupler, it was a bit too tall. Had to do some surgery to resolve the issue.

PXL_20201010_164151720.jpg

With aluminum threaded rods in place.


PXL_20201010_164240597.jpg

With the bulkheads.

PXL_20201010_164555464.jpg

Now just have to setup the charge wells, as well as the terminal blocks.
 

thzero

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Here are my Tinkercad links for the ebay sled

 

thzero

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Well, started a bit on the fin can...

Drilled the hole for the forged eyebolt.

PXL_20201011_185218323.jpg

PXL_20201012_013740927.jpg PXL_20201012_013747105.jpg

Then installed the eyebolt. Red Loctite was applied to the nuts, then JB Weld. This will be the top centering ring.
 

thzero

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PXL_20201011_184522987.jpg

The coupler with the LOC stiffy tube inside which is slide flush with the bottom of the coupler.

PXL_20201011_205924201.jpg

The centering ring will sit within the top lip of the stiffy tube. This will form the top of the fin can that the bottom tube will attach to.
 

thzero

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Then I drilled out the 6 connection points for the t-nuts and screws that will attach the fin can and the bottom tube together.

PXL_20201011_213512173.jpg
 

thzero

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Attached the middle ring that goes on the top of the fins. The connection coupler will rest on top of this ring as it gets glued into the top of the fin can.

PXL_20201011_185457595.jpg
 

thzero

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And then also attached the forged eyebolt to the bottom bulkhead of the electronics bay. Same as before, red Loctite on the nuts, and then JB Weld.

PXL_20201012_013733137.jpg PXL_20201012_013725835.jpg
 

o1d_dude

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Um...When I use an eyebolt in a centering ring, I orient the opening so that it’s easily accessible when/if the time comes to replace the shockcord...generally so the opening is accessible from both sides.

By placing the opening facing a body tube wall makes that much more difficult to do.
 

thzero

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Um...When I use an eyebolt in a centering ring, I orient the opening so that it’s easily accessible when/if the time comes to replace the shockcord...generally so the opening is accessible from both sides.

By placing the opening facing a body tube wall makes that much more difficult to do.

Sure, if there is a body tube in the way... in this case there isn't. This is essentially a "zipperless" design.
 

Banzai88

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Wood hardener. Never heard of that product, going to have to look into it. ETA: just looked it up. WOW, the MSDS on that stuff is nasty! Acetone/Ketone based. Use with a respirator and ventilation, for sure!

I've been using minwax sanding sealer to the same effect and for the same reasons. Sand with 400, smooth as silk!
 

thzero

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Yeah... outside use til it cures for sure.

I meant to try it with the long cure epoxy that LOC was suggesting to basically achieve same goal... and forgot.
 

thzero

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Got more done on the fin can... the bolt are drilled with t-nut backing to be able to attach the lower tube to the fin can in the "zipperless" design.

PXL_20201014_001628082.jpg

Here you can see the t-nuts that were epoxied on the backside, and then ground flush. Same will happen to attach the upper payload tube to the top of the ebay, and then the nose cone to the upper payload tube.

PXL_20201014_001940982.jpg

Started process of gluing the motor mount into the fin can tube. Just epoxied the middle ring into the tube; it sits right on top of the fins (not yet glued) and used the bottom centering ring to make sure its straight, etc.

PXL_20201014_003313863.jpg
 

thzero

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Well, got a bit impatient and screwed up the fincan... which caused a delay as I had to redo another body tube and get it squared away.

PXL_20201018_193323009.jpg

Now that I have the replacement fin can (the white band is a 3d printed guide), got the booster tube bolted into the mount.

PXL_20201018_193335204.jpg

And now its glued in... used SystemThree epoxy; fast hardener (15 minutes). Also added small arrows onto the tubes to help with alignment.

PXL_20201018_223021005.jpg
 

thzero

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Next I got the upper payload tube setup to attach to the electronics bay.

PXL_20201014_001950882.jpg

PXL_20201018_235451812.jpg

So now it can be bolted onto the electronics bay. This would only be used when not doing full dual deployment and rather using the Jolly Logic Chute Release.
 

thzero

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Well, got one set of the inner filets done using Rocketpoxy. Going to do the external fillets next, then do a second set of internal filets against the outside of tube.

PXL_20201022_221050431.jpg

Then onto fiberglassing (tip to tip) the fins.
 
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