Madcow Cowabunga Mammoth build

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Nathan

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The weather hasn't allowed me to do much painting on my square rocket lately so in the meantime I'm going to get to work on the build of my Madcow Cowabunga Mammoth. I need to get this started because I want to have it ready to start painting this summer so I can fly it at Higgs Farm this fall.

Since I bought this kit several months ago it has disappeared from the Madcow site so I'm not sure if it is still available. This is an 11.5" diameter fiberglass kit that will be about 8 ft tall.

Here are the components that came with the kit. Just the basics. The nose cone and shoulder are formed as a single component of hand-laid fiberglass. The inside is pretty rough but the outside is very smooth. The nose does not have an aluminum tip. There are only two centering rings, and a bulkhead for the nose. The motor tube is 98mm.
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Here are the additional components that I have bought so far. The CR on the left is a 3rd CR for the motor mount. All the other parts are for building a chute cannon dual deployment system, which will be a removable 6" diameter tube mounted in the airframe. The cannon tube will be made from the orange 6" coupler tube; the green 6" airframe tube is for making the forward end cap of the cannon.
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First step will be to clean all the parts. As usual there is a lot of gummy stuff on the fins which should come off with alcohol.
 
Now we see the Mammoth Cow again!

That 98mm cutout looks really lonely in those big centering rings...
 
Started working on the big motor mount. The center CR is positioned so that the fin tabs will exactly fit between the center and aft CRs.

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11.5” diameter! That’s going to be a sweet flight, what kind of motor are you thinking about?
 
11.5” diameter! That’s going to be a sweet flight, what kind of motor are you thinking about?

Unless I get some 98mm motor hardware someday I'll be flying it on 75mm motors with a 75-98 adapter. It sims at 5200 ft on a 5 grain 75mm motor. Due to the chute cannon tube in the upper airframe, I will not be able to fit a 6 grain 75mm motor. So if I want to go higher than about 5200 ft then I'll have to buy some 98mm motor hardware.
 
As usual, the fin slots were a little too tight, so yesterday I widened them a bit using the Dremel and a carbide cutting wheel. After than I was finally able to test fit the fins for the first time. The motor mount is not yet glued in.

I have also sanded the nose and fins with 220 grit, and rounded the leading edges of the fins.

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Unless I get some 98mm motor hardware someday I'll be flying it on 75mm motors with a 75-98 adapter. It sims at 5200 ft on a 5 grain 75mm motor. Due to the chute cannon tube in the upper airframe, I will not be able to fit a 6 grain 75mm motor. So if I want to go higher than about 5200 ft then I'll have to buy some 98mm motor hardware.

Would something like this work? On my 7.5" Thumper I used a tin can to allow the motor to extend into the avbay 4" inches.

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Would something like this work? On my 7.5" Thumper I used a tin can to allow the motor to extend into the avbay 4" inches.

Cool idea but no. I could just make the chute cannon tube short enough to make room for a 6 grain casing but that would barely leave enough room to fit the big 10 foot chute in the tube.
 
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Cool idea but no. I could just make the chute cannon tube short enough to make room for a 6 grain casing but that would barely leave enough room to fit the big 10 foot chute in the tube.
What about Head End Deployment? That nosecone looks like it could shield a blimp. Add a vent band and you're in there. Wouldn't hurt the CG/CP any either. Great excuse to get a Fruity Chute Iris Compact maybe. Or, you just might be inspiring me to get a Mega Cow.
 
What about Head End Deployment? That nosecone looks like it could shield a blimp. Add a vent band and you're in there. Wouldn't hurt the CG/CP any either. Great excuse to get a Fruity Chute Iris Compact maybe. Or, you just might be inspiring me to get a Mega Cow.

Yeah you could fit a couple of bowling balls in that nose, but I've already bought all the components for the chute cannon so I don't want to make major design changes now. If I want more space another option would be to install the nose bulkhead higher up in the nose.

Speaking of the Fruity Chute Iris Compact chute, it looks like I'll be buying a 7 foot one for my square rocket. My 6 foot Iris is barely enough chute for that rocket and my 8 foot Iris doesn't fit.
 
Wow! That’s a big rocket. I like these fat rockets.

I just went to the site, and they aren’t showing any 11.5” kits currently.
 
Now that I'm finished with my Square Rocket I'm finally getting back to work on this build. Just epoxied on the first fin.

There is a possibility that this rocket is not going to fit out the door of my shop room once all 3 fins are attached so I need to do some measuring before I glue any more fins on. I might have to move this build down into my garage, which would suck because it gets pretty hot out there in the summertime.

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The 11.5" kit is probably seasonal or discontinued. Nice build thread.
 
Now that I'm finished with my Square Rocket I'm finally getting back to work on this build. Just epoxied on the first fin.

There is a possibility that this rocket is not going to fit out the door of my shop room once all 3 fins are attached so I need to do some measuring before I glue any more fins on. I might have to move this build down into my garage, which would suck because it gets pretty hot out there in the summertime.

I see what you mean about maybe not fitting through the door!
 
The scale is amazing, totally love it. You got a pass on the "fit" but..Being a carpenter myself I'd have just built it and removed/replaced the door/casing/jamb later. Keep in mind though that when I was single I built custom Harleys and big block Mopar motors in my "spare" bedroom so I'm accustomed to such. Living with Wisconsin winters with no heated shop space lends itself to creativity in that regard. Sadly those days are over, now I am limited as to what is "allowed" in the house...That's a beautiful shop by the way.
 
I know it’s too late now, but that would have been a good rocket for a cluster of 2 or 3 75 mm motors.
 
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