BLUE BRUISER BUILD

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neond7

Sky Pirate
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I have started (yet) another build this summer, guess I'm a glutton for punishment who likes to spend long hours in a murderously hot Florida garage. Anyway, this begins the construction of the "BLUE BRUISER". This will have a 75mm motor mount so I can use bigger motors.

Here is a screenshot of the design in OpenRocket.

Bruiser.jpg

As you can probably tell, its a mashup of Blue tube and the fins and nose cone from a LOC Bruiser. I've already built a LOC Bruiser, LOC Warlock, and LOC Doorknob over the past few years, all of which are 7.5" designs with the "loc-n-fin" method of fin retention. I like it and will be using the same fins on this build.

FINS.jpg

Here are some pictures of my original Bruiser build back in 2012. You can see I probably overkilled the epoxy on the fin locks, but they aren't going anywhere (but up).

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On all three of these builds, I had applied tip to tip fiberglass and they have flown dozens of times without any fin issues. I had eventually converted my LOC Doorknob to dual deploy, and it has had many successful flights on "L" impulse motors. My goal is to fly this Blue Bruiser on full "M" motors. With such a large, draggy airframe, it won't be going supersonic unless I use a really large "M". I'll probably be sticking to motors in the Aerotech 75/5120 range. The L900DM is also a fun motor for that size case. These fins will get fiberglass tip to tip (1x 6oz and 1x 3oz) as well and I'm confident as long as I stay sub mach, things will be fine.

The blue tube airframes, motor mount, and avionics bay are on order from Always Ready Rocketry, and a 75mm Aeropack motor retainer is on its way from Wildman. I considered an SPC aluminum thrust ring but I didn't want 20+ ounces of weight right at the back on the rocket. As you can see from the design file, stability is currently marginal and will probably require some nose weight. I'll swing test it when its complete to find the actual CG and add nose weight until it is comfortably stable.

Hopefully the tubes will arrive this week so I can glass them. Please - no comments regarding if this step is necessary. I know..... its Blue Tube. But I'm doing it regardless.

So, enjoy the build and hopefully this will be punching big holes in the sky before too long!
 
Cool! Love the Bruiser (and Magnum too). I'm liking your style, Jeff; and watching with interest! Keep up the good work!:)

-Eric-
 
Just a heads up - the blue tubes arrive tomorrow!

The 6oz s-glass should arrive this week as well.

This build will be progressing soon. :) Beast mode engaged....
 
Parts have arrived, nicely packed from Always Ready Rocketry.

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I may or may not use all three centering rings - they are really thick and heavy.

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And of course the stacked shot! :) I'll be cutting the motor mount shorter, I wasn't sure how long I was going to make it so I had him ship the whole piece.

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This baby is going to need a big parachute!
 
Man the motor tube is huge! Very cool and a clean house to boot. And the wife says "that's really neat honey, now move it out to the shop".
 
I got my blue tube Warlock a few weeks ago. Dave does a great job with the BT kits. With my surgery I have been slowed down building the Warlock.
 
FWIW, I use a Top Flight PAR120 for the main in my Bruiser...nice slow landing for my overweight Bruiser!

Bruisers on M's are the best...looking forward to watching the pieces come together.

-Eric-
 
I'll keep a careful weight log of the parts as this build progresses.

So far the parts weighed out to 13 lbs, 13.6 oz.

I'm guesstimating final completed weight will be in the 24 lb ballpark without motor.
 
Despite excruciating heat, I fiber glassed the upper body tube, switch band, and upper and lower avionics bulkheads.

As always, measure a dozen times and cut once. I am using one wrap 5.8 oz s-glass and one wrap 3 oz fiberglass.

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Same for the switch band.

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All ready to go!! Also cut out a wrap of Teflon release film (the brown stuff). It goes on last and creates a great surface to finish with as well as laying down the seams.

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Teflon applied - in about 2.5 hours the West slow epoxy will cure enough I can peel off the Teflon and cut the overhang on the tubes while they are still soft and green.

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Always ready rocketry supplied some seriously thick avionics bay bulkheads - I only glass them to make it easier to clean ejection residue.

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I sandwiched the bulkheads between tiles under weights while it cures.

ImageUploadedByRocketry Forum1470591953.911541.jpg
 
I test fit the loc-n-fin tabs. The slots cut by Always Ready Rocketry were perfect length, but their slot cutting tool left the ends rounded. I used a Dremel and squared off the ends of the slots and the fins fit perfectly.

ImageUploadedByRocketry Forum1470596359.953326.jpg

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Next step will be to glass the lower airframe and then I can epoxy the fins and fin keepers into place.
 
I'm counting 5, 6 jugs of Gritty Kitty... Who's the crazy cat lady, you or your wife?
 
I'm counting 5, 6 jugs of Gritty Kitty... Who's the crazy cat lady, you or your wife?

Oh... We do have *cough* five *cough* of the little felines. It was supposed to have stopped at four, but a little Maine coon snuck into the pride earlier this year and found a forever home.....
 
So, moving right along, Teflon was removed and I'm happy with the finished surface.

ImageUploadedByRocketry Forum1470598577.135754.jpg


The fiberglass overhang was then trimmed.

ImageUploadedByRocketry Forum1470598614.745992.jpg

One boo boo- i didn't use Teflon under the bulkheads and they were a bear to pry off the tile. Oops. Other wise they came out great.

Weight for the upper tube was 1 lb 15.6 oz prior to glass, it's now at 2 lbs 12.2 oz. Overall, less than a pound added.
 
It's tough to avoid being adopted by fluffy four-legged fur balls, I know.

Where do you get your teflon film?
 
Sweet, thanks. Will you do a close-up of the finished surface? It looks really smooth. I'd like to see how it compares to the finished surfaces of my parts and the release film I use which don't appear to be as smooth as yours.
 
Sweet, thanks. Will you do a close-up of the finished surface? It looks really smooth. I'd like to see how it compares to the finished surfaces of my parts and the release film I use which don't appear to be as smooth as yours.

It's very smooth with a slight texture from the Teflon release film.

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I always give it a light sanding, wipe it down with denatured alcohol, and then shoot some high build primer on it. There are always a few little nits and slight wrinkles from the glassing, but sanding and Bondo fix that.
 
I have now glassed the 44" lower section. The 3oz glass I'm using as a veil layer only comes in 38" widths, so it doesn't go all the way down to the bottom. No problem, as I'll be doing tip to tip glass on the fins later. It won't be noticeable when the additional glass is added.

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Wow, there they are again! That Gritty Kitty is really coming in handy for you! Project Gritty Kitty Express... Kinda has a ring to it. Hold a household vote and I'm sure you'll have 6 paws up. Thanks for the close-ups. Your surfaces do appear to have a bit less imprinting than mine. Is that the porous or non-porous teflon film?
 
Wow, there they are again! That Gritty Kitty is really coming in handy for you! Project Gritty Kitty Express... Kinda has a ring to it. Hold a household vote and I'm sure you'll have 6 paws up. Thanks for the close-ups. Your surfaces do appear to have a bit less imprinting than mine. Is that the porous or non-porous teflon film?

It's porous, it bleeds out the excess epoxy.

Ironically, I do have several cat themed rockets. Hello Pirate Kitty, Hello space Kitty.....
 
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After 2.5 hours I stripped off the Teflon. It has a few more wrinkles than I would have liked - the 3oz was a bear to lay down today. A little work with some Bondo and a finishing sander and it will be smooth again.

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A few minutes with an exacto knife and the overhang was cut off and the fin slots opened up.

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Weight before glass - 3 lbs 10 oz.
Weight after glass - 4 lbs 15.2 oz.

All in all, a small price to pay to avoid filling in spirals.....lol. :)
 
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That's looking really good! Great job with the fiberglass!
 
This evening I test fit the fins and fin locks that I had acquired from LOC Precision - wasn't sure if the fiberglass increasing the OD of the body tube would cause any issues. Happily, everything fit like a glove!

ImageUploadedByRocketry Forum1470883912.600620.jpg

The test fit of the very thick rear centering ring also went well, not too tight, not too loose. Just right.

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Here is a stacked shot of the main components, including the switch band.

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So far, weight is exactly 11 lbs, 11.2 oz. I'm very happy with how things are turning out.
 
It was an expensive afternoon, I ordered most of the rest of the parts I will need for this build.

1. Two (2) PerfectFlite CF100 altimeters. Three actually, as I needed one for my Mad Cow Frenzy that is currently sitting neglected in a box pining to be built. Patience little one, your time will come.... Note - they are cheaper when you order three or more.

2. One LOC Angel "large" and one LOC Angel "Drogue" parachutes. Mark from LOC Precision will make them in red and black colors to match the final rocket colors. His parachute build quality is A+, most of my rockets fly chutes he made.

3. One Aeropack 75mm flange assembly. I had originally ordered the Aeropack assembly style that is JB welded to the motor mount, but I felt the flange style retainer would be better suited to this build. I'll skip the little wood insert/screw nonsense - pain in the rump to line up all those holes. I'll just drill holes all the way through the centering ring and add tnuts to the back of it. I'll pick up some 1" screws and it will be indestructible.

4. One 25 ft two loop Kevlar shock cord and one 25 ft three loop Kevlar shock cord from One Bad Hawk. Got a shipping notice later in the day! Another excellent customer experience, I had used a set of their Kevlar shock cords on my L3 cert launch a few months ago and really liked them. I also ordered some welded eye bolts, as I like to thread one on to the front of my 75mm motor hardware and then use a 3 ft Kevlar cord to attach it to the u-bolt on the top centering ring. Just a little insurance policy to help prevent the motor hardware from separating in the event things went awry.....

5. Although I haven't ordered the vinyl yet, I've started working up the final theme with Mark from StickerShock. I'll use a slightly modified version of what I used for my original LOC Bruiser back in 2012. Thankfully he had kept the file.

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This will be the final vinyl design - Mark from Stickershock suggested adding the "v2.0" which I love. It pays homage to my original Sky pirate rocket.

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