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Manufactured Fin Guide Off

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dford

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I picked up a 38mm Go Devil at last weeks hump day sale and the fin guide templates, yes both, are off +\- 1-2 degre
I kind of figure they supplied these for a reason. The fins need to be pretty much spot on.
Should I make my own guide or try to get new ones considering the necessity for it to be absolutely correct? I mean this thing does ride mach+ and high altitude....??

Thought I should mention I traced out the guide on paper and used a protractor at least four times to make sure it isn't me messing it up. I also placed lines on the airframe with angle iron according to the guide, turned the guide along the lines and when turned from one line to the next they are off the same amount as on paper.
 

DavidMcCann

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One or two off from each other (front to back) or off 1-2 degrees from being vertical to the body tube?
 

dford

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20160915_102408.jpg

You can see the misaligned holes with the outer edges aligned.
If I aligned the holes two of the fin slots become covered. Essentially it is off one fin thickness apart from each other. I would say root cord to adjacent fin root cord it is off.
To be honest I haven't dry fit the fins. Just tried. Don't fit.

Hmm. Now that I take anot her look... Check this photo out.
20160915_143104.jpg

Can you see at the tip of the slot? The rounded "hole" that is off to the side and hasn't been carried all the way to the center? I wonder if I mark that paralllel to the slot down to the center and sand it, it'll shift the degree of the fin into place.

No no no. It is way further off than the tiny hole at the tip of the slot....sighs:facepalm:
 
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BLKKROW

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If you would like a precise easy to use fin guide, check out my product:

[video=youtube;35_8D8sySno]https://www.youtube.com/watch?v=35_8D8sySno[/video]

At $10.00 for a pair of 38mm fin guides you cannot get anything better.
 

Banzai88

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Why not ask the vendor to replace them?
If the CNC is off, machine or program, just pulling another set from stock will likely land him in the same predicament, and here's why:

That happened to me with the fins and fin alignment guides on this same rocket that he's working on. I didn't mind that the fin slots were a little tight, a quick pass of the file on each side and they slid right in with no issues, and I expected that. My fin guides are off in the same way, clearly offset. I confirmed it with a fin guide printed from payloadbay.com. Call to the vendor and another set later, still off, despite repeated emails with a picture and a phone call. That was earlier this year when they took over sales and distribution of this model. Looks like nothing has been done to correct the issue.

Same thing happened with my fin sets. First set you could see where the stack of 3 sheets of fiberglass plate had slid during cutting, making 3 different sized fins. Call for a new set, same issue, except now I had 6 fins, 2 of each size, with enough difference in size that sanding to fit would have removed too much to be acceptable to me. I finally abandoned all hope and ordered fins and fin guides from a 3rd party (upscale cnc). Perfect fins and guide first time.

In all reality, assembled as is would probably be OK, but certainly far from 'correct' and I'm betting not what the OP expected when he paid for the kit.
 

CoyoteNumber2

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If the CNC is off, machine or program, just pulling another set from stock will likely land him in the same predicament, and here's why:
Bummer. Do other Madcow kits exhibit this problem or just the Go Devil?
 

markkoelsch

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Madcow has taken over the sales only, correct? So this goes back to Madcow, or to Curtis?
 

dford

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Bummer. Do other Madcow kits exhibit this problem or just the Go Devil?
I wonder the same thing. I really hope people are checking their fin guides before using them.
I really really hope the rest of rocketry warehouse products arent the same way as banzai mentioned...
 

Banzai88

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So it looks like the 5th misalignment type in my previous post? http://www.rocketryforum.com/showthread.php?136140-Types-of-Misaligned-Fins-and-Their-Effects

It seemed that the consensus was that these types of misalignments weren't catastrophic, though. It would drive me crazy looking at the end result, though. I'd make a new one using the payloadbay utility.
Yes, that perfectly illustrates what my fin guides looked like (except 3 fin). It's originally a RW kit, no telling what, if anything, MC has done with it, but I know 100% that they were made aware of the issue.

It's definitely NOT what you want with an altitude grabbing mach buster, and NOT what you paid for.
 

dford

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It's definitely NOT what you want with an altitude grabbing mach buster, and NOT what you paid for.
Agree. More time and money. Which are at a premium for me right now. :roll::bangpan:
 

Banzai88

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Madcow has taken over the sales only, correct? So this goes back to Madcow, or to Curtis?
Initial stock was off the shelf inventory from Curtis. I KNOW for a fact that mine came out of that pile (if the guy on the other end of the phone and follow up emails is to be believed) because I called Mad Cow and ordered a custom orange tube kit and talked to them, and it was made clear to me that the fins, nose cone, and guides were already cut, showing in stock in their computer, and it would be several days or so turn around on cutting the tube and shipping. This occurred just a week or two AFTER the take over and several weeks BEFORE they had the kit back up for sale on their web site.

No telling how deep that stock was, but for them to still be shipping offset guides, new or old stock, is a little disappointing.
 
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DavidMcCann

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My tomach came with laser cut cardboard guides, spot on and worked great.
 

75Grandville

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I had the same issue as well, plus a couple others. The fin guides had at least one fin clearly off. I plan to print out a couple of templates from payloadbay.com and do it myself. Mike shipped the other items out, and offered to send replacement guides. I declined, as I want to try to build this weekend, and if I make my own guides, that should be correct. Will look at that $10 guide, however.

You may want to check your nosecones. When I put the coupler in the NC, then put the NC in the upper tube, and rolled it on a flat surface, it clearly showed as being "off". Looks like the tip was deformed/bent. Contacted Mike, and he offered immediate replacement, no questions asked.

My suggestion - if you have quality issues, go to the vendor before going to the forum. I've made multiple purchases from MadCow, and have always been happy with their products. This is the first time I've had an issue, and they were immediately ready to make it right.

Plus, MadCow needs to know that you are having issues, so they can correct them. They need (courteous) feedback so that they can be aware.


I'm planning to stuff a Loki Research K627 in mine (have the casing, just need the reload), so I'm being extra picky. Sims to 20k and Mach 2, if I can get the surface finish smooth enough. And if I can figure out the tracking - I really want to get this back! I've got to do some more research on MD rockets, shear strength, etc. Maybe do a tip-to-tip in CF to strengthen the fins. Ripping them off and re-kitting the rocket is not what I am hoping for!
 
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dford

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okay so what i'm going to do to save time and money is use the same fin guide material that was sent to me in the order. i'll re template the guide onto paper, then line it out back onto the jig and trim it out.
i think there is enough room from the outer edge of the guide to the tip of the slot for an additional slot in the CORRECT position if i'm careful and depending on how strong the jig material is...

i also PM'd madcow via facebook about five hours ago the link to this thread. haven't heard anything back. kind of disappointing from a "local" company.
 

TopRamen

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I'de throw that guide right in the trash because it would peeve me and upset me to have it in my presence.
Quit looking at it and use your computer to print a proper guide then verify it with your measuring tools.
It's a shame that someone stuffed that in a package anyhow though, but we all screw up stuff from time to time, or get fed up and say "Good enough", when we know it is not perfect.
 

dford

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I had the same issue as well, plus a couple others. The fin guides had at least one fin clearly off. I plan to print out a couple of templates from payloadbay.com and do it myself. Mike shipped the other items out, and offered to send replacement guides. I declined, as I want to try to build this weekend, and if I make my own guides, that should be correct. Will look at that $10 guide, however.

You may want to check your nosecones. When I put the coupler in the NC, then put the NC in the upper tube, and rolled it on a flat surface, it clearly showed as being "off". Looks like the tip was deformed/bent. Contacted Mike, and he offered immediate replacement, no questions asked.

My suggestion - if you have quality issues, go to the vendor before going to the forum. I've made multiple purchases from MadCow, and have always been happy with their products. This is the first time I've had an issue, and they were immediately ready to make it right.

Plus, MadCow needs to know that you are having issues, so they can correct them. They need (courteous) feedback so that they can be aware.


I'm planning to stuff a Loki Research K627 in mine (have the casing, just need the reload), so I'm being extra picky. Sims to 20k and Mach 2, if I can get the surface finish smooth enough. And if I can figure out the tracking - I really want to get this back! I've got to do some more research on MD rockets, shear strength, etc. Maybe do a tip-to-tip in CF to strengthen the fins. Ripping them off and re-kitting the rocket is not what I am hoping for!
Good luck with your build. Sounds super intense. And fun.
I did only send them this thread link. I figured they would see it and move forward with contacting me.
I will check my nose cone. That'd certainly be a problem if it were to be off as you described it.
 

75Grandville

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Good luck with your build. Sounds super intense. And fun.
I did only send them this thread link. I figured they would see it and move forward with contacting me.
I will check my nose cone. That'd certainly be a problem if it were to be off as you described it.
I hope it's fun and intense! I've actually got until next August to complete, unless I find an alternate launch site with a higher waiver.

I know I e-mailed MadCow directly about replacement parts, and he got back to me within 30 minutes.
 

tab28682

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.........

My suggestion - if you have quality issues, go to the vendor before going to the forum. I've made multiple purchases from MadCow, and have always been happy with their products. This is the first time I've had an issue, and they were immediately ready to make it right.

Plus, MadCow needs to know that you are having issues, so they can correct them. They need (courteous) feedback so that they can be aware.

........
I agree with you, except for one detail. I think it is worth going to the manufacturer AND to announce a kit glitch of the type described by the OP here on TRF.

No need to rip and trash a kit or a manufacturer over a glitch and only rant and rave here on TRF. Tell the kit company about the problem and let them work it.

However, also post the problem in an informative way here on TRF so that others with similar kits can quickly check them for the same problem. This gets the news out to more folks faster than it would happen any other way.
 

Banzai88

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I guess that some folks just don't read the whole thread and all of the responses.

Madcow is WELL AWARE of the glitch, I told them about it back in MAY of this year! We traded emails, phone calls, and photographs.

The fact that it's 4 months later and they're still sending out fin guides with the same problem is ........disturbing.
 

dford

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Madcow has messaged me back and they are working on the issue.
For me this doesn't set me back from ordering through Madcow. I like them more than other places. I'm pretty confident they will continue to provide awesome service. Humans make humanly mistakes. I'm not one to judge.
Besides. I've already created a new guide and am using reshaped pieces from the old guides as a check it twice type guide.
 

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