2.56" Black Diamond

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Dec 31, 2002
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One of the many items I will need to get back to hybrids, is a rocket that will take the 36" long Sky Ripper Systems J144. I have looked at all the kits offered, and the only one that strikes my fancy costs $400 :eek: "No way?..." That is the 54mm Shock Value from Shadow Composites.

So anyways, I have a Vaughn Brother Rocketry 2.56" nose cone, and the fin can from my VBR Javelin. My EX L1 rocket fence posted on a G33J motor, the only salvageable parts were the fins, that were still in the fin can. Mix these items with a little Quantum tube, and start a sim software design, and you have a performance oriented 3FNC.

Without internals added yet, here is my Black Diamond in the ruff...
Man... When I first saw "$400".... :eek: I could make a rocket that size out of mailing tubes for $20... :eek: Zats scary.

Good luck with your build!

Gotta hate it wheny yer rocket lawn darts, but ya gotta love it when the parts make something like that... :D

Now... How the ($#&(&#% are ya gonna get that thing back DOWN, dare I ask? Drougeless dual? Something that size on a J must go well over a mile, wouldent it? :eek:

You are right, this is one long motor. Long enough that the drouge wil mount to a eyebolt that is screwed into the bulkhead of the motor. Below is a pic of my son holding the 36" 38mm motor.


I'm not real big on drogue-less designs, but that is an option for this rockets recovery from high altitudes. The rocket should hit a design weight of 4.5 to 5 pounds depending on what SRS motor I use, the main design goal of course is to fit the bigger one of the three.


I will place my order to Commonwealth Displays this weekend for the needed parts, and hopefully begin construction by the end of next week.


A screamer in the ruff is right, 3FNC's are never boring if they can be made to scream when they leave the pad..:D
...well I just placed my order to Common Wealth, and it looks like I will have to revise my weight "guestimates" for the Black Diamond.

Shipping weight alone was right at 5 pounds...that did not include fins, nosecone, recovery, or glue...I may very well be looking at a 7 pounder...
sweet motor, that rocket is definately gonna get some altitude:) 4.5-5lb. rocket on a J, oh yeah!
Originally posted by Johnnierkt
Shipping weight alone was right at 5 pounds...that did not include fins, nosecone, recovery, or glue...I may very well be looking at a 7 pounder...

I'd doubt that the rocket will end up *that* heavy. They usually round items up for shipping weight calculations to make life easier. I'm building another 2.6" Arcas right now (glass over phenolic, G10 fins, dual deploy, 54mm mount with staging capability... methinks L1175 to K185 would be nice!) that weighs a little over two lbs without chutes. I think you'll end up right around your target weight.
L1175 to a K185, man that thing is gonna go outta sight, would be cool to see that launch:)
I have a slightly stretched VBR Javelin that I put a 54mm mount into, that is just itching to burn a HyperTEK K240...The Javelin weighs 4.5 pounds "dressed to kill." I would use the SRS J in the javelin, except that the booster tube is only 34" long stock.
I have a slightly stretched VBR Javelin that I put a 54mm mount into, that is just itching to burn a HyperTEK K240...The Javelin weighs 4.5 pounds "dressed to kill." I would use the SRS J in the javelin, except that the booster tube is only 34" long stock.

Sounds like a great rocket for the SRS I motor ;)
Hey Todd, I believe that the Javelin may be able to fly on both the H and I motor. I will be able to test that at next months launch in Manchester, TN I hope.

I have flown this rocket on an EX KNCP I-159 and it hit right at 3500 ft. With the SRS "I" motor, I anticipate the same results...
I am very impressed with the quality of service from Common Wealth Displays...The parts for my Black Diamond are here!! I'm at work now, but I will run it down a little more this evening, and post the optional updated version of the Black Diamond...I found the fin can from my Missile Works Bull Pup that bounced in the middle of the road (long story) and the G10 fins on that dog might look real nice on this rocket too.

I will model the new look and see which one appeals more.

I just weighed all the parts that came in the box, and they only weigh 2 pounds even...I will be real close to my 4.5 to 5 pound limit. :cool:
Well, I admittedly sluffed off on this project, as our flying season ended rather quickly. Since there was no rush, I have been kinda taking it slow.

The tubes have been cut, the fins mounted, and here is my Diamond in the ruff on a dry fit:
Here is a close-up of the fins and the drawn centerlines for rail button placement. These fins are reserected from what is left of my Level 1 rocket; a VBR Javelin, which impacted under thrust from a G33 that came up to pressure late.
Looking down the barrel so to speak; here is a pic of the 38mm motor mount installed without the rear centering ring. This lasy ring will be installed after I have mount the aft rail buttom.
In this pic of the fins again, the fillets are in place.
Anti-zipper design sort of???

Well, in most anti-zipper designs, the coupler will have a bulkhead at the end with an eyebolt for recovery attachment. Since the SRS J motor is 36" long like the Black Diamond booster is, the upper bulkhead of the SRS motor becomes the attachment point, and also becomes the second part of the anti-zipper design.

Pictured here is the 38mm adapted portion of the upper end of the booster. This will help to support the long motor, and the shock of being pulled to one side or another during recovery. It is merely a centering ring with a 1/2" long piece of motor mount tube. It is mounted in the airframe to the base of the coupler.
Nice design!!!

R U going to fibreglass those fins? I know it's hard to fibreglass over quantnum tubing but you might want to think about it.

I love the fin shape!!!
Thanks GL-P, I'm kind of fond of the design myself :D I have always loved the fin shape that VBR made for the Javelin...as for glassing, I won't be doing that. I have made multiple fillets on the lead centering ring at the front of the fins; I have filleted the fins to the motor tube; I have fillets where the fins meet the bodytube internally, and externaly; and I have added extra epoxy in before installing the rear centering ring. The booster then was set on it's end to allow the epoxy to run back down and fillet the rear centering ring at the fins. Whether or not this last trick worked I do not know...it was good in practice.
Those fillets should make it real strong!!! I've done internal fillets before and it worked out great!!!

Looks awesome!!! What colour will she be?
I have three options in mind:

Because the name suggests a Black color, I am leaning towards all black...how original huh? :rolleyes:

or, black with silver cone and silver fins...maybe a few silver stripes thrown in to break up the black

or maybe a carbon copy of the above pattern; all silver with black cone and fins and black stripes.

Silver is somewhat touchy to work with and usually turns out looking like it is un-mixed and swirly. I have even achieved a burnished aluminum look...hmmm burnished aluminum is not half bad.
Hiw about red with a black diamond. It is called "Black Diamond" after all
When I came up with the name Black Diamond, I pictured a black rocket with a long tail of mach diamonds behind it :D

I own one rocket with red in the base coat, and it was given to me. I don't know what it is, but I just don't paint red rockets.

When you look at the fins, they sort of form the shape of a diamond...

Black Diamond is also a song from one of my favorite bands of all time, K I S S
Ahhh. Just an idea!!!

Black body with silver fins and nc sounds to me like it'll look the best.

Everyone loves mach diamonds!!!:D :D :D
...man do I need to complete some projects!

While my wife is painting graphics on my L3 project, I made some more progress on the Black Diamond.

I had ordered a 2.56" E-Bay from Binder Design, and the tubes did not quite work out just right. A few emails to some local members, and I had what I needed to make the Binder Design kit work...

I have sprayed the kit down with a coat of KILZ primer, and tomorrow I will hit it with a coat or two of paint. I hope to fly this vehicle at ST2005 on the J144 from SRS as planned.

Pictured is the booster on my road side paint stand.
Here is a pic of the booster with the rail buttons installed. Don't let the white coat of primer throw ya, this will get the appropriate color of paint. ;)
Here is an off shot capturing the long rocket with the coat of primer. Seeing as I built this one kinda light (4 -5 pounds), I could grab some serious air time on the SRS J144...I will post more tomorrow when I finalize the PJ.