DarkStar Mini Build Thread

It's a mini build thread for a DarkStar Mini...

I bought this from Bay Area Rocketry with my "birthday money" at last December's launch. I haven't been taking pictures, but here's an outline of what I've done so far:

1. Washed all the FG parts.
2. Used WD40 to get some sticky residue off the fins.
3. Washed the fins again.
4. Drilled 3 vent holes for my altimeter2
5. Drilled 2 holes for rail button installation
6. Sanded the centering rings for fit/adhesion
7. Filed a notch in the forward centering ring for the shock cord.
8. Sanded the MMT and the fiberglass NC shoulder for adhesion
9. Rinsed all the parts again.
   
   I'm planning to use the "Foam and Fly" method for assembly, so no epoxy needed this time.
   
   
10. Tacked the NC pieces together with CA.
11. Took 12" of Kevlar off the length supplied, tied an overhand knot in it, and tacked the ends inside the NC with CA.
    
    The NC will get filled with 2-part foam probably this weekend, securing the Kevlar mount point.
    
    Moving on to the body - I test fit the parts, and found that the #8 screws that came with my rail buttons were too long. I found some 1/2" screws that are just long enough that they rest against the MMT when fully installed. They should be secured by the 2-part foam, but if not, I'll re-install them with a bit of epoxy.
    
    Test fit complete, time to move on...
    
    
12. Tacked shock cord and forward CR to the MMT with CA
13. Installed tape tabs on rear CR and inserted MMT into BT.
14. Ensured positioning of MMT so that Aeropack retainer will sit flush with end of BT when installed.
15. Tacked in 3 rear fins with CA, ensuring good alignment as I went.
16. Used "popsicle sticks and clothespins" for alignment of forward fins with rear fins. (this mostly worked, I ended up with slight alignment issues I think some of my sticks were warped.)
17. Attempted to pull rear centering ring off with tape tabs. Succeeded in removing tabs from ring, with ring still installed in BT.

Oops.

Spent more than an hour trying to get the ring out with various methods. If anyone is interested, I can discuss these further.

I was able to remove the CR without damaging the rocket. YAY!

I'll be foaming the fins and the nose cone, and installing the rear CR and motor retainer this weekend. I'm also planing to do fin fillets with epoxy clay, but not sure I'll get to that this weekend.

So, here's a picture of my progress so far:



Planned color-scheme: Black body, green fins and NC tip, and decals from StickerShock.

WD40 to clean the stick stuff off fins? I learn something new each day.

cwbullet said:

WD40 to clean the stick stuff off fins? I learn something new each day.

Click to expand...

Yeah, It worked pretty well. I'd like to say I came up with the idea all on my own, but I think I read about it here somewhere....

/me does a quick search...

yep - it was even on another DS Mini thread

cwbullet said:

WD40 to clean the stick stuff off fins? I learn something new each day.

Click to expand...

I use wd40 all the time to remove stickers, tape, etc. the kids love stickers and they end up everywhere - floor, table, toys. wd40 works great!

Well, that kind of worked...


I got the nose cone foamed just fine, so I went ahead and mixed another batch of foam to fill the fin area.


The first area filled fine.


I had a little trouble with the second area. (Notice the small void near the forward fin an the mess on the outside of the tube.)


I was obviously not working fast enough, because at this point the foam was really expanding. I didn't manage to do much but make a mess. The rear of the tube in the third section got foamed, but I've got huge voids here.

I'm not sure how to fix this. I guess I need to drill a couple of holes in the side of the airframe to inject more foam to fill the voids. Thoughts?

That is what I did, though I drilled a "fill" hole at the botom of the void, and a "relief" hole at the top of the void. I assumed that the initial pour would be an effective air seal, and any additional foam would try to compress the air pocket, so I gave it an exit.

Result? Fully foamed fin can, with little dimples where the putty shrank in the fill/vent holes ...oh, well, what can you do....

G.D.

Here's how I fixed my foam problem:

Using a couple of small files and some tweezers, I carved out and extracted the foam "plug" from the aft end of this section:



I also sanded some of the exterior foam mess off. (I didn't do the whole thing since I figured I would just need to do it again after my second foaming attempt.)

I inserted a drinking straw into the cavity to use as a conduit to get new foam down past the "bubble" of foam also visible in the image above. (I was planning to take a picture when I came up with the idea, but forgot about it until after I had started mixing foam.)

I then mixed about 5ml (2.5 of each a and b) of foam and used a syringe to pump it through the conduit. I moved the rocket around a bit to make sure the foam completely filled the void, removing the straw conduit as the foam expanded. (I did not use the entire batch of this foam. Closer to 1/2) The foam expanded and nicely and just barely cleared that bubble. Once that had cured, I still needed a bit more foam, so I mixed 2ml more (1 of each part) in the syringe and finished filling the cavity.

Once everything was cured, I carved off the excess foam, sanded the exposed mmt and cleaned up the rest of the body tube exterior, and then installed an aeropack retainer using jb-weld.



I chose to leave off the rear centering ring, as it's not really needed with the foam and AeroPack on there. I especially like how the outer diameter of the retainer matches the air frame.

A quick run to the hardware store for quick-links and the sporting goods store for some barrel swivels (I'm fresh out of both.) and major construction on the rocket it done. Current weight 16.5 oz (no motor)

She is flyable now, but there is still a bit more clean up to do. I'm also planning to add some small fillets with epoxy clay, not to mention priming, sanding, painting when I have time + good weather.

Also, I have some nice StickerShock decals to apply, and I think i'm going to go with a smaller nomex blanket.

Lookin great! Makes me want to build my own. I just love the look of the DarkStar fins!

I finally got around to adding the fillets:



Once the clay cures, I'll sand them down and get the rocket ready for painting.

I've also picked up a dual deploy upgrade kit, but I'll be flying this as single deploy to start with.

After not quite a year sitting naked, my DarkStar Mini is finally painted:

View attachment 160546 View attachment 160547 View attachment 160549
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There's a couple of minor masking errors, but I'm pretty happy with the overall result.

Decals have been applied!
View attachment 160592

Very nice!
Love the green with the black

Thanks Ken!

Nice work, Robert.

Without the door in the background to provide a sense of scale, it look just like the full-sized one.

Great build and the black finish with the StickerShock decals really look nice.


Sent from my iPad using Rocketry Forum

Thanks for the compliments! I just got a coat of "Rocket Polish" (Mixture of "Pledge with FutureShine" and "SimpleGreen") applied this evening, so it should should be looking really slick by tomorrow. I'll take some good "on the pad" photos before launching on Saturday.

The paint job is sweet. I love the way the neon green and black pop!!!!

AfterBurners said:

The paint job is sweet. I love the way the neon green and black pop!!!!

Click to expand...

Then you'll love these photos:



My actual on-the-pad photos didn't come out as nice because I was facing the sun when I took them. The launch was beautiful, boosted to 1490 ft on an Aerotech F-56, but I think I'm going to swap in a slightly larger chute for subsequent flights. The rocket comes down fast on the little 18in chute that came with the kit, and while the fiberglas can take it, I've already chipped the paint on the nose cone.