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Nose Cone/Tube Tolerance Question

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BRC

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This sounds abit silly but here it goes...How much resistance should there be when placing a nose cone on the tube assembly...?? Should the nose cone fall off if turned upside down, as it would on my (not yet assembled), Gemini Titan 4"..?? :y: Thanks for reading and the access to the forum, great stuff.....
 

Pippen

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Welcome to TRF, BRC. There are no silly question here, especially on the beginner's forum.

Shoot for the happy medium--tight enough where it won't fall off when turned upside down, but not so tight that you have to appy much force to remove the nosecone when you twist it. If they're loose when you first get the kit sometimes all it takes to get it right is the normal amount of primer and paint that you spray at the top of the body tube. If it's still loose after priming and painting, we wrap the shoulder of the nosecone (the part that inserts into the body tube) with a wrap or two of electrical tape.

I'm sure others will offer solutions that work for them.:)

Have fun with the build and we'll be looking for the pictures!
 

Trident

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A great way to tighten the fit of a loose nose cone is to swab a VERY thin coat of Thin CA around the inside of the top of the body tube. I use a Q-tip, wet it with CA, and then run it all over the top 1"-2" of the inside of the tube. When dry, it can take a little sanding with fine sandpaper, and then you have a nice tough tube, which won't tend to peel or "mush" with repeated insertions of the nose cone.

Be very careful with Thin or Super Thin CA, it can run easily, and gluing your fingers to the tube is possible. (Yes, I have personal experience in this area...)
 
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powderburner

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There have already been some very good responses posted. I especially like the advice to soak the front end of the BT with a few drops of CA. I do this in general, but if you need to tighten the NC fit (a little) you can also add more CA to the inside of the BT (swab/smear with a disposable Qtip). Make sure to sand lightly after the CA sets up, so the inside surface will be smooth. Fin sandpaper is OK, but I like fine sandpaper better (sorry Lee, I couldn't resist).

My rule of thumb is that if I hang the rocket by the NC (holding only the NC) and give it two or three sharp upward jerks, if the NC separates then the fit is probably loose enough. And if I grab the other end of the rocket and hang it nose down and give it two or three sharp upward jerks, if the NC stays put then the fit is probably tight enough. Then again, I try to design and build with minimal ballast weight in the NC, and if you have very much ballast there then the NC might fall off more easily.

This approach leaves a pretty wide middle ground where the NC is fitted more snugly than I like, but I have rarely seen this result in a stuck NC (and subsequent lawn dart). If the kit comes with a plastic NC, they almost always release cleanly at ejection. If the NC was balsa, and made by one of our outstanding NC vendors (Sandman, BMS, others), they are checked for fit pretty well when they are made, and they also almost always release cleanly.

When it comes down to it, it's pretty hard to make a NC stick too hard in a BT unless you have some BT crimps or damage, or a loop of shock cord that has pushed out and gotten stuck between the NC and BT, or if the NC itself has some damage on the shoulder. A little common sense and a minute of time for inspection and field testing will work for you 99 percent of the time---just about anyone will get that nervous feeling that tells them something might be wrong when the NC sticks too hard.
 

powderburner

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BRC,

Welcome to TRF! We're glad you jumped into the forum and hope to hear a lot more from you.

I'm guessing that your use of terminology like "tolerance" means that you might be a "new member" but that you are not exactly a "new" member...if that made any sense.

So, can you tell us what you are working on? A kit? Your own design?

(And, if you have been watching this forum for long, you KNOW we want to know: )

Do you have any pictures?
 

BRC

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BRC,

Welcome to TRF! We're glad you jumped into the forum and hope to hear a lot more from you.

I'm guessing that your use of terminology like "tolerance" means that you might be a "new member" but that you are not exactly a "new" member...if that made any sense.

So, can you tell us what you are working on? A kit? Your own design?

(And, if you have been watching this forum for long, you KNOW we want to know: )

Do you have any pictures?

I had ordered a Neubauer 4in. Gemini Titan Kit 1/30th Scale as I have always been partial to the Gemini Program as a kid..I received it in time to start construction (as soon as my wife and her mom head for Virginia next Saturday !!!!) which is when its just me, the dogs and my Titan...I checked the packaging and couldn't resist putting the capsule in the tube and was amazed of the loose fit...Already have my epoxy, CA, tools of construction/destruction..I have built a few plank on bulkhead ships so I wanted a change....
There is a few clubs in my area (Tampa) but they are more for the high power rockets..(Gimme time !!)..,
Thanks for the great advice, Im sure as I get going Ill be asking more..I have been scouring over the forums, again great stuff..and the PIXS !!!!
Ill post some when I get goin !!
 

powderburner

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(yeah, it was a bad pun)

There is a few clubs in my area (Tampa) but they are more for the high power rockets..(Gimme time !!)
You should go ahead and contact them, and show up at their launch. I'll bet they give you a warm welcome and try to get you to come back.

If anyone looks down their nose at someone else's rocket because it is smaller, I don't consider them real rocketeers anyway.

And if you want to see really small, check out the MicroMaxx kits at Fliskits. You can launch those things from your driveway!
 

Chrisn

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what has using the word tolerance got to do with it?
 

RoyAtl

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what has using the word tolerance got to do with it?
He's using the definition "allowable deviation from a standard."

"clearance" - "the distance by which one thing clears another; the space between them," might be a better term for his use, but "tolerance" is accepted (or you could say it was tolerated!).
 

Trident

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Fin sandpaper is OK, but I like fine sandpaper better (sorry Lee, I couldn't resist).
Yeah, I edited my post right before I saw your reply, and you make a good point...

But really, I must emphasize that when I run out of body tube sandpaper, I find that the fin sandpaper works quite well ...
 

Chrisn

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He's using the definition "allowable deviation from a standard."

"clearance" - "the distance by which one thing clears another; the space between them," might be a better term for his use, but "tolerance" is accepted (or you could say it was tolerated!).
I know what it means.

It was in response to powderburner... forgot to use the quote button.
 

brianc

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There is a few clubs in my area (Tampa) but they are more for the high power rockets..(Gimme time !!)..,
Hey! I flew my MicroMaxx Saturn (to celebrate the 40th anniversary) at
the last TTRA launch, so come on out! HPR, LPR and everything in between
is welcome there.

http://www.ttra.ws/


Welcome to TRF, too!
 

Pippen

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But really, I must emphasize that when I run out of body tube sandpaper, I find that the fin sandpaper works quite well ...
That's impressive. ;) Usually I'm just feeling fortunate to even find sandpaper.
 

Chrisn

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Can we finally finish this off topic chit chat? ;)
 

Jeter09

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A great way to tighten the fit of a loose nose cone is to swab a VERY thin coat of Thin CA around the inside of the top of the body tube. I use a Q-tip, wet it with CA, and then run it all over the top 1"-2" of the inside of the tube. When dry, it can take a little sanding with fine sandpaper, and then you have a nice tough tube, which won't tend to peel or "mush" with repeated insertions of the nose cone.

Be very careful with Thin or Super Thin CA, it can run easily, and gluing your fingers to the tube is possible. (Yes, I have personal experience in this area...)
/thread over

I agree with this guy.
 

Micromeister

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Welcome to the Forum BRC:

Another way to adjust the fit of your NC; should you not have CA available or just don't want to add more to the tube is to attach a couple small pieces of masking tape or adhesive backed vinyl spaced around the shoulder of the NC testing the fit as you add each strip, until you have the "fit" your looking for. These strips will stay with the NC for the life of the model.
 
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