Cz's Wildman Demon 98 Build Thread

Flew the Demon 98 yesterday on a CTI K1200WT. Gorgeous flight to 9753ft. Just kept coasting and coasting... love this rocket!

Eric
Where did you fly yesterday?? Didn't see you at Bong.

QCRS!

I was told that MMWP was the last launch until MWP. Rats. Must have been a special invite launch only. I am not special.

crossfire said:

I was told that MMWP was the last launch until MWP. Rats. Must have been a special invite launch only. I am not special.

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Perhaps it was kept quiet to keep the number of fliers down? The corn is up and wouldn't want to subject the crops to damage. A few people tippy-toeing around might be tolerable.
I don't know but if a launch occurred that might be the reason why. Anything to protect a launch site is fine in my book.

Kurt

That's exactly what the reason was. Gary, you know you are special and we love you!! We ran a small end of season launch for the "usual suspects" it was a purposefully small launch to protect the field. The farmers were working the fields as we flew.

Jason
I was at the Bong and we were rained out by Noon. Just kidding you about Princeton. You guys need a launch were you don't have to worry about others. Thanks for all your work running QCRS.

Yeah, about 10 years ago the Peoria group held a launch along the lines of a mini Midwest Power and the landowner approached the group after the launch and pointed out the neighbors were grumbling. We stopped doing that and lowered the waiver from 25k to 15k to avoid ticking off the neighbors again and to minimize the prospect of a "main at apogee" leading to a rocket that lands in Metamora. Things have been good since.

Once the corn goes in, we stop flying. Part of that is based upon that a member went out to fly another time in the no-till field after the corn was in and a motor started the stubble on fire. Fire department called, landowner was out there and flier paid to have the damaged acre re-planted. That smoothed everything over so the site wasn't lost.

I heartily sympathize with whatever needs to be done to preserve a launch site. Kurt

Dear CZ,

I have a problem. My boat tail coupler doesn't look like yours below. Yours is so big and long.

View attachment 299083

Instead mine can only be described as short and stubby, 1" or so (see below). Should I be worried? Will my rocket perform?



Is this really a problem? What would you recommend?

Sincerely,
Impuissant Hoosier

dixontj93060 said:

Dear CZ,

I have a problem. My boat tail coupler doesn't look like yours below. Yours is so big and long.

View attachment 299083

Instead mine can only be described as short and stubby, 1" or so (see below). Should I be worried? Will my rocket perform?

View attachment 299084

Is this really a problem? What would you recommend?

Sincerely,
Impuissant Hoosier

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Hmph... It's not so much about the size and length of the coupler... It's how you use it...
Once the coupler is epoxied into the body tube, it's effectively one piece with the boattail, so it shouldn't much matter. Also, just for added security, I put a rail button through the body tube at the coupler so there's a mechanical joint in addition to the epoxy joint.
If you're worried, just pull it out a little... And put more into the body tube than the boat tail.
Is that the middle of your coupler there? Your coupler sure is stubby, but if you use it right, it'll do the job just fine. Maybe even better... Because it's lighter by a couple ounces.

Is it glued in all ready? if not call Tim he can help out with short coupler.

crossfire said:

Is it glued in all ready? if not call Tim he can help out with short coupler.

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Yep, it's in there nice and tight.

Mine is close to yours, Tim. Maybe 4" total length. I was just gonna split the difference and put 2" in each side...

Adrian

jd2cylman said:

Mine is close to yours, Tim. Maybe 4" total length. I was just gonna split the difference and put 2" in each side...

Adrian

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But if you install the CR where it should be, at the forward edge of the fin tabs; and since the CR is sized to fit the coupler and not the full width of the boat tail; it only makes since for the coupler to be inserted fully, otherwise you have a "floating CR."

dixontj93060 said:

But if you install the CR where it should be, at the forward edge of the fin tabs; and since the CR is sized to fit the coupler and not the full width of the boat tail; it only makes since for the coupler to be inserted fully, otherwise you have a "floating CR."

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Oh, I hadn't got that far. I'm still washing after sanding... I do happen to have another coupler that I can use... Hmm... Oh Tiiiiimm.... :wink: :wink:

Adrian

dixontj93060 said:

Dear CZ,

I have a problem. My boat tail coupler doesn't look like yours below. Yours is so big and long.

View attachment 299083

Instead mine can only be described as short and stubby, 1" or so (see below). Should I be worried? Will my rocket perform?

View attachment 299084

Is this really a problem? What would you recommend?

Sincerely,
Impuissant Hoosier

Click to expand...

How long was your coupler and motor mount to start with ?

WILDMANRS said:

How long was your coupler and motor mount to start with ?

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My coupler is 3 7/8" long and my motor tube is 10 7/8" long.
It's not the size, it's how I use it... :eyeroll:

Adrian

WILDMANRS said:

How long was your coupler and motor mount to start with ?

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The coupler is like 4" and the MMT is long enough, maybe 10". Now that I look back at the instructions, I see that the coupler was positioned independent of the CR. In building, I really thought the CR should be positioned against the fin tabs for support/strength, thus the coupler needed to go some 3" into the boat tail and thus the short exposed length. It's no big deal, I will make it work.

it is designed for 2" both sides

WILDMANRS said:

it is designed for 2" both sides

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Allll righty then... That's how I'll do it. Got the Aeropack on the mmt tonight. Tomorrow night, bridle. How far ahead of me are you, Tim?

Adrian (who is building at a blistering pace<for me> to be ready for the MWP XIV dragrace)

jd2cylman said:

Allll righty then... That's how I'll do it. Got the Aeropack on the mmt tonight. Tomorrow night, bridle. How far ahead of me are you, Tim?

Adrian (who is building at a blistering pace<for me> to be ready for the MWP XIV dragrace)

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Adrian, if it is me (Tim) you are asking, I'm moving along quite nicely here. Full fin can done internally and externally with main body tube attached. Now moving over to av-sled and tracking options.

Only one slight slowdown... I was a bit too aggressive in removing material from the HED coupler to get it to fit into the nosecone. It had a few pits and was a bit small so got some tilting/sticking. I have now covered the affected area with a slurry of laminating epoxy/milled FG and am waiting for that to cure before fine sanding/polishing to get it "perfect." I still think it was a better way to go than sending the nosecone back to CTI though. At least with mine, the walls on the nosecone are already thin whereas the coupler wall was thick (actually looked thicker than the airframe before I started sanding).

Oh, and also placed my Stickershock order yesterday .

I donated my CTI nose cone to CZ and replaced it with the WM FW metal tip cone. It fits perfect.

I sent 4 cones to CTI. When I got them back, they slid right on the couplers. Well worth the $24.00 in shipping IMHO. They also included a coupon for $24.00 of CTI products from Mr Wildman. Now if I could just remember to take it with me to Tim's...

Adrian

dixontj93060 said:

Adrian, if it is me (Tim) you are asking, I'm moving along quite nicely here.

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Yes I was. Wow, you're moving right along. I need to try building that fast... :eyeroll: Yeah, right...
Oh well. I think I'll get it done by MWP. Hopefully MWP XIV... :blush:
I forgot about ordering Stickershock... Darn. Might have to fly nekid...

Adrian

jd2cylman said:

I sent 4 cones to CTI. When I got them back, they slid right on the couplers. Well worth the $24.00 in shipping IMHO. They also included a coupon for $24.00 of CTI products from Mr Wildman. Now if I could just remember to take it with me to Tim's...

Adrian

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Is that still an option? I've got a couple that work, but I'd rather them be better...

CzTeacherMan said:

Is that still an option? I've got a couple that work, but I'd rather them be better...

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Ask Wildman.

jd2cylman said:

Yes I was. Wow, you're moving right along. I need to try building that fast... :eyeroll: Yeah, right...
Oh well. I think I'll get it done by MWP. Hopefully MWP XIV... :blush:
I forgot about ordering Stickershock... Darn. Might have to fly nekid...

Adrian

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About 10 minutes with my Festool Rotex 90 this morning and now have a perfect coupler fit! Did a mock up of the av-bay yesterday evening and decided to use a Missileworks 3" sled that I modified to hold two alts (instead of a 4" design). I did that because with the smaller sled and offsetting it slightly from center it left more than enough room for a BRB GPS unit. So I'm feeling pretty good about the setup right now; I'll just have to do some transmission testing with the BRB to see how, or if, range is changed with the aluminum plate couplers (antenna mounted through and extended into drogue bay). Worst case if I do see an effect, I'll just move to G10 bulkheads.

No pics (cuz I'm lazy), but I got the fin can built and started working on the internals. Glad I didn't glue the coupler in yet, as my hands aren't as steady as they used to be, so that extra 2" helps to get the glue in the right spot (mostly)...

Adrian

CzTeacherMan said:

-6 feet of Kevlar Strap for Y-harness to motor mount

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Hey Cz,

Thanks for the build thread, looks great!

I'm building one for a Wildman CT drag race and one thing I wanted to check with you on is the 6 feet of kevlar strap noted...I had a 10' strap and cut it down to 6', but now it seems too short by about 2' of strap to match pic #2 of post #12.

Should it be 8'-10' of kevlar strap?

KenECoyote said:

Hey Cz,

Thanks for the build thread, looks great!

I'm building one for a Wildman CT drag race and one thing I wanted to check with you on is the 6 feet of kevlar strap noted...I had a 10' strap and cut it down to 6', but now it seems too short by about 2' of strap to match pic #2 of post #12.

Should it be 8'-10' of kevlar strap?

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Yep. I had to use 8' to make it the length I wanted out the top...

Adrian