BLUE BRUISER - SKY PIRATE V3.0

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neond7

Sky Pirate
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After taking off a few years from the hobby, I'm jumping back in! The project I'm starting is a rebuild of my Sky Pirate Ver 2.0 which was fully documented here:

https://www.rocketryforum.com/threads/blue-bruiser-build.135244/

My Sky Pirate V2.0 in the build thread above was unfortunately lost on its first flight at the Tampa TRA field in February of 2018. I imagine its still hanging up in the tall cypress in the swamp.

Flight video here: https://www.nefar.net/Gallery/2018-02-TTRA/Sky-Pirate-2-L850-Jeff-Millner-NTSC.wmv

Shortly after losing the rocket, I had ordered replacement parts which I had placed in storage. The main difference this time is I won't be fiber glassing the blue tubes as I'll be trying an oil based sanding sealer.

I'll try and work quickly as the club is renting the Port St. Lucie fairgrounds for a launch event in May and I want to fly it there on an Aeortech L900DM.

So here we go with a quick pic of the parts. Hope you enjoy the build!!

Sky Pirate V3.jpg
 
Right off the bat I want to give Mark from StickerShock a huge shout out -
I emailed him this morning to see if he had the original SkyPirate art files and he did! He will bump the Sky Pirate version number to 3.0 and this rocket will be dressed to kill. 😎

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One huge difference with this build - I won’t be glassing the body tubes (just tip to tip on the fins).
Today I used Bondo spot putty to fill the seams on the upper section and after sanding smooth, I’ll use an oil based sanding sealer. I’m currently testing the sealer on some scrap tube and it seems to be working well.
I welcome any comments on experience people have had with this sealer as I’m deviating from my normal formula (build heavy, glass everything).
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I did a test fit of the fins, as you can see, it’s using the LOC n Fin tabs used on the original Bruiser (I actually bought the fins from LOC).
After some filing and sanding, everything fit nicely.40D17110-93A1-4D5D-925E-5CEDD70A6661.jpegC032159B-305B-47D7-B065-36B0CAEA3293.jpeg18D08D15-BE13-49DB-A6C5-77EBEA793332.jpeg
 
The part I really hate is installing flange mounts, so many ways things can go wrong. So many holes to drill, so many inserts to screw in, and hopefully it all lines up.
Thankfully the installation went fairly smoothly.
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After triple checking alignment was good on everything, it was time to epoxy that baby together.
As always, my “go-to” blend is two squirts each of West epoxy and slow hardener and two spoons each of high density filler and colloidal silica. Mix until smooth and thick like peanut and I made a ridiculously fat fillet to permanently affix the 75mm MMT to the front of the rear centering ring. B7C58DB9-D338-4995-9733-0F931A2C8159.jpegFFBC7F38-AAD4-43EB-B151-F9764D26BE8D.jpegC66F332E-E3F9-4BEE-9C0C-9390C7864C84.jpeg
 
Last step of the day was to make the backing blocks with brass inserts for the rail buttons to screw into. I will further sand these down so they are smaller, and the fronts will be shaped to match the curved radius of the tube.
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After triple checking alignment was good on everything, it was time to epoxy that baby together.
As always, my “go-to” blend is two squirts each of West epoxy and slow hardener and two spoons each of high density filler and colloidal silica. Mix until smooth and thick like peanut and I made a ridiculously fat fillet to permanently affix the 75mm MMT to the front of the rear centering ring. View attachment 450843View attachment 450844View attachment 450845
I have never used the inserts. I just place motor case in retainer slid it in MMT and use wood screws with expoy. Never an issue. Before it's going to pull out screws the CR will let go
 
I would like to find one maybe LOC would build me one with that attachment. Looking to build a very light Mini Magg
 
Do they not use that method anymore?? With good fillets and tip to tip fiberglass, they have proven to be extremely strong on my other birds.
 
Do they not use that method anymore?? With good fillets and tip to tip fiberglass, they have proven to be extremely strong on my other birds.
I have one built many years ago with old method and has flew on J reloads with no problems.
 
I have never used the inserts. I just place motor case in retainer slid it in MMT and use wood screws with expoy. Never an issue. Before it's going to pull out screws the CR will let go

I find rivet nuts are alot easier to align than the inserts:20210216_200805.jpg20210216_200758.jpg
Rough up the surface a bit with a file and secure with JB Weld. The silver colour is high temp paint.

Do they not use that method anymore??

My understanding is Loc 3.0 have dispensed with the Loc 'n' Fin system and gone with conventional tabs.
 
I have one built many years ago with old method and has flew on J reloads with no problems.
I have a LOC Doorknob using LOC Fin tabs that I’ve flown multiple times on “L” impulse motors. Once the fins are glassed, they are fairly indestructible. The Sky Pirate I lost was flown on a 75mm “L” and if the swamp hadn’t eaten it, the next flight would have been an M1500G.
 
I find rivet nuts are alot easier to align than the inserts:View attachment 450965View attachment 450966
Rough up the surface a bit with a file and secure with JB Weld. The silver colour is high temp paint.



My understanding is Loc 3.0 have dispensed with the Loc 'n' Fin system and gone with conventional tabs.
I assume on the larger 7.5” rockets, the long fin roots add a lot of weight?
 
I assume on the larger 7.5” rockets, the long fin roots add a lot of weight?
I also assume so (I haven't built one). Loc 3.0 seem to have incorporated their Removable Nose Weight System into most of their stubby rockets to off-set the increases in tail weight.
 
Had a Saturday to myself so it was time to get some work done!
First project was to fiberglass the avionics bay end caps and the front centering ring. The ejection reside is much easier to clean up if it’s glassed, and just in case, a little extra structural integrity never hurts.
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Here I’ve cut out the first layer - 6oz S-glass.
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The second layer is 3oz. As always, West Systems is perfect for laminations.
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After a few hours of being sandwiched between two tiles with a weight on top, I ripped off the porous peel ply and trimmed it while the epoxy was still green and pliable.FCC764D9-78D2-4FEA-99F7-B3ABBFA1ED78.jpegD6FF8C94-F5AC-4BEF-80D7-BC6E8A8C9FAF.jpeg7FF3E52C-8F71-43A1-B08A-868F52D90F94.jpeg
All three pieces came out perfectly. A little work with a mouse sander and the edges will be smooth as butter.
 
I am using two 5/16 stainless u-bolts on the front centering ring. After figuring out the best spot to attach them I drilled the holes and assembled the parts.

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I only test fit it it on the MMT. Because of the fin keeper tabs and rail button attachments, i will have to slide the front ring in from the front once the rear centering ring has been installed.
 
5BF9A34D-BD01-4EC7-9D92-85DC5377DCA0.jpeg1F50D418-981F-4139-B8B9-E22F5106B55D.jpegD8F99D70-E6AC-47AB-AFA6-4CC6385A5BB7.jpegNext I whipped up my favorite mixture of West Systems epoxy with high density filler and colloidal silica and made those fin keepers a permanent attachment along with the rear rail button backing.
 
Last for the day, I added a dab of epoxy to the back of the u-bolt threads. Despite the lock washer, the nut could theoretically vibrate loose so this is cheap insura
 

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This morning I got the front centering ring epoxied into place and added a nice fillet in addition to the ring of epoxy I pushed it through. To use my “dad” humor - “That baby isn’t going anywhere”.... .

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Next up was some love for the avionics bay. I drilled out the fiberglass from the mounting holes and installed the all-thread. After sanding the bulkhead edges smooth, I assembled it for a quick test fit. All went well.5DFE8E25-0B29-4062-AED2-892ADAD6AE61.jpegDFA7A9DA-CF51-4E80-8C82-E1CF0B591D00.jpeg8D464591-9DC3-45BA-8328-8AD8C9A84516.jpegBE58AA69-ED00-44E9-96B5-C8DCB645EF00.jpeg
 
The avionics bay shipped with a serviceable wood sled, but I kicked it up a notch with some black G10 plate. I used the wood sled as a template and traced out the shape and cut it.
I then lined up the brass sled rails and marked their outline on the G10. I used a sharp blade to rough up the plate for better adhesion.
I’m using Aeropoxy for this step, I like this for attaching smaller pieces. Once I got the epoxy placed, I smooshed the brass into it and shaped a smooth fillet with a popsicle stick.



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Looking sweet! Waiting for LOC to get 7.6" cones back in stock then will be ordering a Bruiser EXP lol
 
Moving right along this weekend - time to get some fin work done.
I use a 1/4 inch square rod to make perfectly aligned guide marks for the blue tape.
I also remembered I had forgotten to bevel the fins when they were off (I’m so out of practice!).
A dremel sanding wheel and a finishing sander soon has them nicely beveled.
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