Nosecone help please, bad at math...

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McKailas Dad

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New to hobby (Nov.09), but I've enjoyed making a few of my own scratch builds. My 'Peanut' rocket was one of our first few... https://www.rocketryforum.com/showthread.php?t=9241

I am trying to make (another) NC for it, (it doesn't like being lawndarted :D) The first few turned out ok, but I'm trying to find an easier way to make large cardstock cones. I coat the inside with a couple layers of yellow glue, quite sturdy...

I found this... https://mathforum.org/dr.math/faq/formulas/BuildCone.html but I don't have a scientific calculator, and I wouldn't know how to use it anyway. :eek:

The 'Peanut' has a ~4" diameter. I have "case 5" where 'r' is 2 and 's' is 8. Can someone help me figure the rest of the equation? What if 's' is 7? 9? Do these equasions figure for overlap (glue strip)? I assume not...

These are going to have to be drawn, not printed, because 8 1/2 x 11 paper is'nt large enough, or am I missing something?

I've tried this https://www.delorie.com/rockets/transitions.html , but, again, the printer paper is too small. I guess to make a cone from a transition, dont cut the inner circle, right?


TIA

~Jeff
 
New to hobby (Nov.09), but I've enjoyed making a few of my own scratch builds. My 'Peanut' rocket was one of our first few... https://www.rocketryforum.com/showthread.php?t=9241

I am trying to make (another) NC for it, (it doesn't like being lawndarted :D) The first few turned out ok, but I'm trying to find an easier way to make large cardstock cones. I coat the inside with a couple layers of yellow glue, quite sturdy...

I found this... https://mathforum.org/dr.math/faq/formulas/BuildCone.html but I don't have a scientific calculator, and I wouldn't know how to use it anyway. :eek:

The 'Peanut' has a ~4" diameter. I have "case 5" where 'r' is 2 and 's' is 8. Can someone help me figure the rest of the equation? What if 's' is 7? 9? Do these equasions figure for overlap (glue strip)? I assume not...

These are going to have to be drawn, not printed, because 8 1/2 x 11 paper is'nt large enough, or am I missing something?

I've tried this https://www.delorie.com/rockets/transitions.html , but, again, the printer paper is too small. I guess to make a cone from a transition, dont cut the inner circle, right?


TIA

~Jeff

To answer your last question - pretty much. A cone is just a transition with the small diameter at 0.

There is a simple way to do larger cones on 8-1/2 x 11 paper - cut the cone in half, print two halves and glue them together. In other words, halve the arc of the cone. As long as the cone is not longer than the sheet of paper it will fit. If it is longer, you can always break it into a transition and a smaller cone and glue the two together. I've done both and it works fine.

As for the math - I just built a spreadsheet in Excel and put in the formulas for the transition from Stine's "Handbook of Model Rocketry". Once you have the formulas in the spreadsheet, you just need to plug in the values for the length, larger diameter and smaller diameter and it tells you the inner circle, outer circle and arc. I uploaded a version of the Excel spreadsheet to this thread:

https://www.oldrocketforum.com/showthread.php?p=93084#post93084
 
So, punching in the numbers here https://www.rocketreviews.com/tool_shroud.shtml ,

I input '0' for SR, '4' for LR and '8' for H, I get SR=0, LR=8.246211251235321 and Angle=87.31282501307987

Does that mean I can draw a 16.49242250247987" (LR x 2) diameter circle, and cut out 87.31282501307987 degrees? I'm think I'm going to round the numbers to 16.49 inches and 87.31 degrees, can I do that? It's not like it's rocket science...er, wait :rolleyes:

Do these numbers account for an overlap for a glue tab? Can I just 'up' the 87.312......to an even 90deg for this, or just add tabs to 87.312...?

I would prefer to make them in one piece, I'll draw it on poster board.

I've been making alot of larger diameter 'container'-rocs lately (low and slow, and funny to the RSO :D), and I would like to find an easier way for NC's...I've been eyein up that huge container of "Quaker Oats" (5"dia x 9 1/2"H), that maybe my first cluster, or maybe my first jump into the 'D' engines :dark:

Thanks, again :eek:
 
The engineer in me wants to walk you through the numbers. If you round your values, you'll end up with something slightly different than expected, but probably within tolerance. None of those numbers include a glue tab, so plan appropriately.

The lazy student in me wants to give you this:
https://v-serv.com/vcp/
which can print large nose cone roll templates across multiple sheets :D (along with all sorts of other cool stuff... and it's free!)
 
No need to get all tech with the tabs... Unless you make your cone super tight! The paper should stretch the little it needs for a tab

If it's me, which in this case it aint, but... I would Just run all the numbers to make your cone, then pick one end and scribble a triangle on the end of it. Start from the top flush, and end with a bottom width of whatever width you deem appropriate. Keep the bottom part in an arc, or sharper than the lower radius, so it won't stick out. Of course, a quick trim fixes that. ;) I woudn't bother going more a couple of centimeters though. (Just my thoughts) If you want a seperate tab, to hide, just draw a triangle width a base width double of the attached tab.
Voila! :)
 
Last edited:
New to hobby (Nov.09), but I've enjoyed making a few of my own scratch builds. My 'Peanut' rocket was one of our first few... https://www.rocketryforum.com/showthread.php?t=9241

I am trying to make (another) NC for it, (it doesn't like being lawndarted :D) The first few turned out ok, but I'm trying to find an easier way to make large cardstock cones. I coat the inside with a couple layers of yellow glue, quite sturdy...

I found this... https://mathforum.org/dr.math/faq/formulas/BuildCone.html but I don't have a scientific calculator, and I wouldn't know how to use it anyway. :eek:

The 'Peanut' has a ~4" diameter. I have "case 5" where 'r' is 2 and 's' is 8. Can someone help me figure the rest of the equation? What if 's' is 7? 9? Do these equasions figure for overlap (glue strip)? I assume not...

That's probably the easiest case because s is the radius of the part-circle you need to draw, and you already know that. The formula page uses radians for angles, but most people are more familiar with degrees, so angle T is r / s * 360 degrees. Which means you want to draw a 90 degree arc, i.e. quarter circle, radius 8. Actually you'll want a bit more than 90 degrees to make your glue strip, but the important bit is that you can draw this on a 8.5 x 11 sheet of paper.

If s is 7 or 9 then the angle increases or decreases respectively, and also doesn't work out as neatly as if s is 8.
 
OK - I ran the numbers you gave through my spreadsheet and get a circle diameter of 16.495" and an arc of 87.3 degrees. If you draw a circle with that diameter and run a vertical line through it, then a line at 43.65 degrees, you will have half your cone.

Attached is a pdf of the half cone - print two, glue them together and you'll have your nose cone.

View attachment 4 inch cone half.pdf
 
So, punching in the numbers here https://www.rocketreviews.com/tool_shroud.shtml ,

I input '0' for SR, '4' for LR and '8' for H, I get SR=0, LR=8.246211251235321 and Angle=87.31282501307987

Does that mean I can draw a 16.49242250247987" (LR x 2) diameter circle, and cut out 87.31282501307987 degrees? I'm think I'm going to round the numbers to 16.49 inches and 87.31 degrees, can I do that? It's not like it's rocket science...er, wait :rolleyes:

Doing this will result in a cone which is 8" vertical height, whereas you originally said:
I have "case 5" where 'r' is 2 and 's' is 8.
On the mathforum.org page, 's' is not the vertical height, it's the length up the side of the cone. Making this 8" means the calculations and measurements are a lot easier. For one thing, the length up the side of the cone is the radius of the circle you want to draw, which saves you a lot of calculating right there. :) For another, the angle is:

radius of body tube / radius of drawn circle * 360

This works out very nicely if the body tube is 2" radius and the drawn circle is 8" radius. So unless you're building a scale model which requires that the vertical height of the cone is exactly 8", I'd suggest going with the easier figures. :) (The vertical height of the cone in this case will be 7.746".)
 
I appreciate all of your help. I had been searching the archives here, and all over the web to try to find an (easy) answer.

daveyfire The engineer in me wants to walk you through the numbers. If you round your values, you'll end up with something slightly different than expected, but probably within tolerance. None of those numbers include a glue tab, so plan appropriately.

The lazy student in me wants to give you this:
https://v-serv.com/vcp/
which can print large nose cone roll templates across multiple sheets (along with all sorts of other cool stuff... and it's free!)
Sounds cool, but this doesn't appear to work on my Vista laptop, but thanks.

gpoehlein OK - I ran the numbers you gave through my spreadsheet and get a circle diameter of 16.495" and an arc of 87.3 degrees. If you draw a circle with that diameter and run a vertical line through it, then a line at 43.65 degrees, you will have half your cone.

Attached is a pdf of the half cone - print two, glue them together and you'll have your nose cone.

Perfect! I'm finally grasping the math, but if all else fails, I will print this, glue together and trace to posterboard...It's difficult enough for me with one tab. (duh, never mind, glue one, let dry, then the other...:caffeine:) I still think I prefer to make it a 'one piece'.

On the mathforum.org page, 's' is not the vertical height, it's the length up the side of the cone. Making this 8" means the calculations and measurements are a lot easier. For one thing, the length up the side of the cone is the radius of the circle you want to draw, which saves you a lot of calculating right there. For another, the angle is:

radius of body tube / radius of drawn circle * 360

This works out very nicely if the body tube is 2" radius and the drawn circle is 8" radius. So unless you're building a scale model which requires that the vertical height of the cone is exactly 8", I'd suggest going with the easier figures. (The vertical height of the cone in this case will be 7.746".)

Good eye, adrian, my value for 's' is 8... Seeing there is only about 1/4 height difference from the vertical compared to the length of the side, of your example, I'm not gonna lose sleep over it. It's a cartooney looking odd-roc, no scaling required :D.

I did draw (trammel) my first couple 'Peanut' NC's on an 8x10, but I was just guess-tamating. I would rather do it the 'right' (and repeatable) way.

Thanks, again, (again?). I'm glade yous guys are so durn edjamakated. At leest mi spelin iz betr dan my addin and multiplaktin...:roll:
 
Quote:
daveyfire - The engineer in me wants to walk you through the numbers. If you round your values, you'll end up with something slightly different than expected, but probably within tolerance. None of those numbers include a glue tab, so plan appropriately.

The lazy student in me wants to give you this:
https://v-serv.com/vcp/
which can print large nose cone roll templates across multiple sheets (along with all sorts of other cool stuff... and it's free!)
--

Sounds cool, but this doesn't appear to work on my Vista laptop, but thanks.

Just for reference: Technically the last update to VCP (that I am aware of) was version 1.64 sometime around '96. However, it was written in Visual Basic, and compiled with VB3, a 16-bit version. This continues to work for most people even in newer versions of windows. But, it does contain compatibility problems, mostly in trying to print to newer USB printers.
Gary produced a new version, 1.65 that was just a recompile of the 1.64 code using VB6, a 32-bit version. This version is sometimes called VCP6 because of that, and the name of the new executable file is vcp6.exe. This version is almost impossible to find anymore. (I have a copy ;) ) The 1.64 source is still available on the site daveyfire provided if anyone wants to take on an update project.
Also, Gary produced another program called VCT - Rocketry Construction Toolset, around '02 I think. It includes some of the tools from VCP, plus some additional ones (like a marking guide to cut a tube at a mitered angle). I don't know if he ever made that source code available. I don't have it, but I sure would like to if anybody else does.

Sorry to hijack the thread, but I never see this mentioned anywhere, and thought it might be helpful to some one besides me.
 
New to hobby (Nov.09), but I've enjoyed making a few of my own scratch builds. My 'Peanut' rocket was one of our first few... https://www.rocketryforum.com/showthread.php?t=9241

I am trying to make (another) NC for it, (it doesn't like being lawndarted :D) The first few turned out ok, but I'm trying to find an easier way to make large cardstock cones. I coat the inside with a couple layers of yellow glue, quite sturdy...

I found this... https://mathforum.org/dr.math/faq/formulas/BuildCone.html but I don't have a scientific calculator, and I wouldn't know how to use it anyway. :eek:

The 'Peanut' has a ~4" diameter. I have "case 5" where 'r' is 2 and 's' is 8. Can someone help me figure the rest of the equation? What if 's' is 7? 9? Do these equasions figure for overlap (glue strip)? I assume not...

These are going to have to be drawn, not printed, because 8 1/2 x 11 paper is'nt large enough, or am I missing something?

I've tried this https://www.delorie.com/rockets/transitions.html , but, again, the printer paper is too small. I guess to make a cone from a transition, dont cut the inner circle, right?


TIA

~Jeff

Hi ~Jeff,

New member here, but I have been designing cardstock models for quite some time. Here is a PDF that should help you with your nosecone design.

I'm a member of Paper Modelers.com and I have a thread there with comments on this PDF.

Some talk about an easier way to figure the math, problems with this PDF, etc...

Here is the link if you want to know more. https://www.papermodelers.com/forum/tutorials/7956-how-hand-draw-cones.html

Hope this helps with your designing!

Best regards,
Mike Bauer

View attachment Hand Drawing Cones (1).pdf
 
Hand-rolling nose cones is one area where math won't help you much -- unless you can figure out way to factor in the thickness of the paper. Paper nose cones are *much* more easily made from multiple layers of thin paper rather than a single layer of thick paper.

The secret to hand-rolling paper nose cones is to make a solid form, a conic mandrel, upon which to wrap your nose cones. Once you have this form, you can roll your paper stock around it, tape it in place, trim it to size, possibly save a template, and then roll it with glue.

There is a chicken and egg problem here, because you either need a lathe to make a mandrel (and if you had a lathe you would just turn a cone on it) or you need to make a cone from paper without a mandrel. I'll let you in on my secret here. ;-)

First off, just practice rolling cones without glue or worrying about the size. Just get a feel for how the thickness of the paper effects the nose vs. base of the cone. There is a bit of a trick to rolling a cone such that as you add more layers the length of the tip extends rather than bunching up. Sometimes you still need to remove a small bit of material to prevent this. Start practicing with typing/copy paper, then move up to heavy bond, and then possibly tagboard. This might sound silly, but you will learn a lot. Seriously.

The next thing is to roll some cone forms. This works best with heavy coated paper. An old poster (or yearly wall calendar) is perfect. You can use glue here if you want, but just taping the inner and outer seams is fine for now. Work on making a nice sharp point.

Now, find a jar or tube where you can place the cone tip down, and have the mouth of the jar keep the base of cone round. It may help to mark the center of the jar if you cannot eyeball it.

Fill the cone with something that will harden. Plaster of paris or quickset cement will work just fine. If your paper is porous, you may need to coat it with vaseline (petroleum jelly) to keep it from getting waterlogged. When it dries, you now have a mandrel!

In reality, this mandrel won't be perfect, but you can use this mandrel to roll a glued cone, which you can then fill with PoP/cement, which *will* be pretty darn close to perfect.

Just make a bunch of these with different L/D ratios. Once you have a stock of mandrels, chances are that one of them will just be close enough to whatever you want to scale to.

As to materials for the final cone, I find that kraft paper (builder's paper from the hardware store) and diluted TiteBond II (or any white glue like Elmers) make the best cones. You will be *amazed* at the strength of a cone made this way when you can roll it against a solid mandrel!

For finishing, coat the entire surface of the cone with thinned fill-n-finish. This will allow you to sand without bringing up the paper fuzzies. You may need several coats here to get a nice smooth finish.

I have some tips for gluing the cone on straight as well, but I'll save them for another message....
 
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