Ever have one (or more) of "them" kits....

I typically have multiple builds going in parallel, so while glue is drying for one step on one kit I'm working another step on a different kit.

At this time I have 2 build going, and both have an issue...

More Viper - motor mount. They basically sell their version of OOP Estes kits. For one step on the motor mount they made a change on where the CR go. But they neglected to provide a dimension - or even any text! Where Estes had an explanation on what to do, their instructions had a blank white area. So I went to Jim Z rocket plans and found out the correct way to build it. Fortunately before I had glued anything up. Not a major problem but a but frustrating

But the other "kit". A Shrox Skonk Wulf. This is the plan pack before Apogee started selling a kit. No "namby-pamby" laser cut fins, These are templates and a knife to attack a piece of tree......
The tube marking guide is missing. Not a big deal, I can make my own.

I cut the fins and glued them up. I papered them. I did some more assembly. Seems great, right?
Start building the motor mount. The directions state to glue the CR 1/4" from the end of the tube, which I did

WRONG

It needs to be at least 5/8" back. Need to throw that one out and start again

But wait - the fins don't fit per the drawings.... There is a problem with the fin templates as well !!!!!!

ARGGGGggggg :cry::cry::cry:

Then to make matter worse, I goofed on the final fin assembly. I should have made a left wing and a right wing. I made 2 rights.
Now I can fix the right/left issue, but the bloody fins are not going to fit anyway.

I have to figure out how to fix this - or just scrap it and buy a complete kit from Apogee

But just so...so.... aaaahhhhh

Sorry to hear about your problems there... This sounds like a case where simulating things with OpenRocket *BEFORE* building could have helped you find out where the conflicts were.

les said:

...More Viper - motor mount...

Click to expand...

I found their Super Viper instructions confusing on that point. I decided to mount the thing protruding a little bit aft and put on a BOAT TAIL!

https://www.rocketryforum.com/showthread.php?46791-MoreRockets-com-Super-Viper&p=1654932#post1654932

View attachment 308656

Hmmmm.... I have the Skonk Wulf plan pak in my build pile, so after reading of your travails I decided to double check. The fin marking guide is on the same page as the canopy mask. I agree that the 1/4" location for the rear centering ring will result in the aft end of the fin (where it attaches to the motor tube) sticking out about 1/8" instead of being flush. But why throw it out? The engine when mounted will also be sticking out a bit, so it will look flush to the engine. Hardly noticeable and still flyable. As for your two right wings, try flipping one over to get a left. And what kind of problem are you having with the fin templates? Please clarify, maybe someone can help you out.
Please hold off on scrapping your work, these sound like they are quite fixable. Cheers.

K'Tesh said:

Sorry to hear about your problems there... This sounds like a case where simulating things with OpenRocket *BEFORE* building could have helped you find out where the conflicts were.

Click to expand...

I assumed the fin templates and instructions from Shrox would have been correct.....

First time I've had this issue with a Shrox kit. This is my 5th build of one of his designs, but the first from just a plan pack

kuririn said:

Hmmmm.... I have the Skonk Wulf plan pak in my build pile, so after reading of your travails I decided to double check. The fin marking guide is on the same page as the canopy mask. I agree that the 1/4" location for the rear centering ring will result in the aft end of the fin (where it attaches to the motor tube) sticking out about 1/8" instead of being flush. But why throw it out? The engine when mounted will also be sticking out a bit, so it will look flush to the engine. Hardly noticeable and still flyable. As for your two right wings, try flipping one over to get a left. And what kind of problem are you having with the fin templates? Please clarify, maybe someone can help you out.
Please hold off on scrapping your work, these sound like they are quite fixable. Cheers.

Click to expand...

Too late. Already scrapped and re-used what I could for the new mount
But the bigger issue is the fins under hang the body tube and externally mount to the motor tube. The fins are 5/8" wide where they meet the motor tube but the tube would be only 1/4" long. So the fins would extend past where the motor is by 3/8" making removal difficult. But then again the fins are supposed to mate against the body tube, but are about 1/4" too short. This is what I was referring to the issue with the template. I'll get some pix tonight as well. Too frustrated last night to deal with it

I'll have to double check. I don't recall a canopy mask sheet. Either I placed it off to the side or my pack was short. I may need to ask you to send me a copy. I'll double check tonight when I get home

I built the Shrox kit mentioned above and never had an issue, but then again I never follow the instructions exactly and modify the build as I go.

I forget did the plan pack call for the Dynastar BT-80 nose cone??

les said:

Too late. Already scrapped and re-used what I could for the new mount
But the bigger issue is the fins under hang the body tube and externally mount to the motor tube. The fins are 5/8" wide where they meet the motor tube but the tube would be only 1/4" long. So the fins would extend past where the motor is by 3/8" making removal difficult. But then again the fins are supposed to mate against the body tube, but are about 1/4" too short. This is what I was referring to the issue with the template. I'll get some pix tonight as well. Too frustrated last night to deal with it

I'll have to double check. I don't recall a canopy mask sheet. Either I placed it off to the side or my pack was short. I may need to ask you to send me a copy. I'll double check tonight when I get home

Click to expand...

+-

Yeah, the 1/4" measurement should be 5/8". Hope you made the adjustment on your new motor mount. By two right wings did you mean that the wing tip for the left was glued at a 30 degree up dihedral instead of down? If so, just cut the fin tip at the dowel joint, sand smooth, and reglue. If you need the fin guide/canopy mask page, I'll be happy to send it to you.
BTW I don't know if you'll be better off with the kit from Apogee. Stick on decals rather than water slide. Also I heard that the fin slots were cut way out of alignment. That is something that is not correctable. You don't need through the wall fins on a low power rocket. Cheers.

AfterBurners said:

I forget did the plan pack call for the Dynastar BT-80 nose cone??

Click to expand...

PNC-80K nose cone, doesn't have to be Dynastar.

kuririn said:

+-

Yeah, the 1/4" measurement should be 5/8". Hope you made the adjustment on your new motor mount. By two right wings did you mean that the wing tip for the left was glued at a 30 degree up dihedral instead of down? If so, just cut the fin tip at the dowel joint, sand smooth, and reglue. If you need the fin guide/canopy mask page, I'll be happy to send it to you.
BTW I don't know if you'll be better off with the kit from Apogee. Stick on decals rather than water slide. Also I heard that the fin slots were cut way out of alignment. That is something that is not correctable. You don't need through the wall fins on a low power rocket. Cheers.

Click to expand...

Yes, I can cut the wing tip off and redo it, but need to find a way to fix the other problems

For those not familiar with the kit, the fins are supposed to reach the motor mount.

Here is the original mount with only 1/4" of the motor tube showing



And here is the new mount with 5/8". But the fin doesn't reach the motor tube like it should. I looked at the Apogee Rocksim file and my tab is about 1/16" short, but the gap is a lot larger than that. I may try to splice in a piece of balsa to fill the gap



And I can't find the page with the tube marking guide or the canopy mask. If anyone could provide me a copy I would appreciate it. Thanks

Here's the page you requested.

View attachment SCN_0001.pdf

I included a ruler to check that your printout is correctly sized.
Good luck with your build.

Thanks - Thought I already replied but don't see the post

Repair in progress...

Final fins with fix