Paper Ogive Nose cone?

[McKailas Dad]

I've made my fair share of conical nose cones, up to 4". Impressively sturdy and strong with a couple coats of glue. They even survive lawn darts!

Is there any way of making an ogive nose cone with paper/posterboard?

As I was searching, I thought of a few ways it could be done. 1) Make a series of transitions and stack them up. or 2) Long vertical strips with a curve matching the ogive, or a combination of both for strength?

Mind you, I am planning on using this on a 5.25" dia. rocket.....

[Orion]

This is something I've been contemplating, too. I've thought of making an internal cross frame to build upon with the series of transitions. If the transitions are thick enough, they can be shaped.

Orion

[McKailas Dad]

I've thought of making an internal cross frame to build upon with the series of transitions.

Oh, you mean like this?

There is another technique I found here, but both of those are foam based...

I may try my hand at the foam/fiberglass eventually, but I really want to make a giant paper ogive nose cone.

[Orion]

Yes, very much like that. Using the foam cone as a shape, could you use paper pieces shaped like the fiberglass on the one link, overlapping them so that it is quite thick? Then sand to shape? It would be almost like paper mache.

I've found that if I construct with damp paper such as forming tubes, I can let them dry on the form, then dampen them slightly and they will slide off of the forms easily.

I'm going to try a cone for a 2.375 inch rocket.

[McKailas Dad]

I was looking for something like this PDF, but needs to be upscaled (alot!).

Is there a simple program that will allow me to make a printable pattern like that? (Um, Eric?)

I have Pepakura Designer, but can't figure out how to use it yet.

The closest Pepakura file I found (from yes, Eric) was from a "Regulus-1 Target Drone" has a 'nosecone'...here.

[Rex R]

have you considered paper mache .
rex

[Orion]

I was looking for something like this PDF, but needs to be upscaled (alot!).

Is there a simple program that will allow me to make a printable pattern like that? (Um, Eric?)

I have Pepakura Designer, but can't figure out how to use it yet.

The closest Pepakura file I found (from yes, Eric) was from a "Regulus-1 Target Drone" has a 'nosecone'...here.

It looks like a good project for my applied geometry students. We are going to be building scratch cardstock rockets in that class soon. What are the exact specs you need for your large nose cone?

[McKailas Dad]

I've heard the chicken and the egg reference in making nose cones from scratch.

Need a shape to make a mold, but can't make the mold if you don't have the shape.

I'm thinking of using a transition calculator from here, and using the numbers from another Excel based(125-nosecones.xls) program from

(Its on Info-central, but I cant find it again...) this DOWNLOAD

I would make each of the transitions short (1/2"-1"?), the more there are, the smoother it would be.

Now, if I just had a nose cone, to use as a form, to make a nose cone...

[modeltrains]

Don't know if I'll actually make one, but this is a thread worth subscribing to for the "expansion of knowledge" factor alone.

[Orion]

I would make each of the transitions short (1/2"-1"?), the more there are, the smoother it would be.

Now, if I just had a nose cone, to use as a form, to make a nose cone...

I would try the 1" and then move to the 1/2" as I became proficient. I was impressed with the spreadsheet. That should make it fairly easy to construct sections.

I turned my nose cone for my L1 rocket on my lathe. I could use it to make nose cones slightly larger.

I use OpenRocket to design my scratch built rockets. It allows me to print (make into pdf) the shape of the nose cone which can be brought into a graphics program to enlarge. Then by using the method we use in geometry class to make cones, we could make the sections (transitions) to build an ogive (approximate) cone.

[powderburner]

Is there any way of making an ogive nose cone with paper/posterboard?

As I was searching, I thought of a few ways it could be done. 1) Make a series of transitions and stack them up. or 2) Long vertical strips with a curve matching the ogive, or a combination of both for strength?

Mind you, I am planning on using this on a 5.25" dia. rocket.....

I was playing with something like this a few weeks back and put together an EXCEL spreadsheet that grinds through the math. I figured that for a BT101-sized tube that I would need at least 20 gores around the perimeter to avoid a 'blocky' look. Then I saw what it meant to lay out and cut out 20 gores, and thought twice about what it meant to edge-glue all those joints, and went to another approach.

Anyway, if you want it, I can email the EXCEL thingy to you. I know what a pain it is to try to make sense of someone else's worksheet notes but I think I can talk you through it if you want to look it over.

[gpoehlein]

I've made my fair share of conical nose cones, up to 4". Impressively sturdy and strong with a couple coats of glue. They even survive lawn darts!

Is there any way of making an ogive nose cone with paper/posterboard?

As I was searching, I thought of a few ways it could be done. 1) Make a series of transitions and stack them up. or 2) Long vertical strips with a curve matching the ogive, or a combination of both for strength?

Mind you, I am planning on using this on a 5.25" dia. rocket.....

I have done something along the lines of the first version. I have approximated the shape of the nose cone with a (small) series of transitions. Attached are two of my nose cones: an NC-50K and NC-20N. Each is made from one cone, two transitions and a cylinder (not counting a second cylinder for the shoulder). These are pretty easy to build and work well. I chose this method for its simplicity to build - if you really want a more accurate shape, you could add more (shorter) transitions, but that increases the complexity of the build. For example, using 1/4" segments would make a nice version of the 50K, but you'd have to make ten or eleven segments for a 2-3/4" nose cone. Smaller and shorter cones can quickly become a nightmare. The four segment versions I do look pretty good sitting on a launch pad, so I think they work pretty well.

[UncleVanya]

You can make an ogive-like cone by taking a tube and cutting triangular sections from it in a pattern like this but longer (^^^^^^^^^^^). Then when ready to form the cone rather than gather them together tightly, you use a rubber band at the tip to hold them loosely together and allow them to curve from where they start. Then invert the cone and drop epoxy in the tip. You need to either fiberglass to cover the gaps of fill some other way like with sheets of paper, epoxy with fillers etc.

[Massrokit]

Check this out.

http://rocketry.files.wordpress.com/...nose_kits2.pdf

You could expand on this.

[McKailas Dad]

I will be picking up some posterboard soon. Obviously, my printer won't print out a ~15 inch circumference transition. (I wish!)

With making such a large nose cone, while there will be alot of pieces, they shouldn't be too small to work with.

I found another calculator here, that instead of printing a PDF, it just gives me the numbers for the radius.

I'm thinking of mounting a vernier caliper on a trammel (circle cutter), to hopefully get extremely accurate cuts. Yes, I am that particular...

While I'm at it, I may draw a reference line, to help in assembly of the stacking of the transitions.

Is there a way to modify that '125-nosecones' spreadsheet, so that the 'X' axis is constant, or be able to input a value? It would be easier (for me) to work with in say 1/2" 'slices' on the 'X', vs .3 or .6". The 'X' values change with different sizes of nosecones...?

That, and if 'X' could be input, you could put the value at the thickness of the material you have. That would be great for using the pink (or blue) foam insulation panels, 1/2" thick.....each piece could be made nearly perfect....

Thanks again for any and all suggestions!

[kjohnson]

The Japan team at TARC this year had made their cones from paper. You can do an ogive shape by taking a tube, and cutting a series of petals out of the tube, then bending the remaining tube material together you can make an ogive shape.

Here are a couple of photos from the US Rockets site:
http://v-serv.com/usr/tubecut.htm

To get a better curve, you have to have more slices, and adjust the shape of the petals you cut out. Kind of like making a parachute using gore patterns, but you are removing the parts of the cylinder that are in the way of your cone.

Here's a bad sketch. You'd cut out the grey areas.

kj

[bandman444]

http://rocketryforum.com/showthread.php?t=24710

Check out the fourth post in my thread. If you have the tube it is soooooo easy and comes out looking great!

If it is for a scale nose cone you can just add a couple centering rings to make it the correct shape.

Bryce

[rockets4kids]

Papier mache over foam does indeed produce strong, lightweight nose cones. I've been doing it that way for several years now.

[BABAR]

Starting with a tube and making long partial lengthwise diagonal cuts, then gather the tip works well. I was very happy with the shape on this rocket, the build section shows how the nose cone was made.

http://www.rocketreviews.com/umm-me-...om-markel.html

[McKailas Dad]

I am having a heck of a time with this.

I think its the math thats getting me

I'm working with two different spreadsheets, the "125nosecones.xls", and "transitioncalculator.xls". (found here)

Using the numbers from '125...' to input to 'trans..', skipping roughly 1.5" between X values.

Bear with me, but shouldn't the first number (at the base) be 5.25" x 3.14"(pi) for a radius of 65.94"? Or, if I'm setting up a compass, it should be 8.2425", for a diameter of 16.485", right?

The numbers from the spreadsheets don't match this...

If I punch in for a 5.25" to 5.04", 2.5" tall, it gives me a radius of 62.56" and 60.05". Un-crunching the numbers, wouldn't a 62.56" radius come down to a 4.98" diameter tube?

[McKailas Dad]

Using the transition calculator, I input 5.5" for the large diameter, 4.64" for the small diameter, with a height of 4".

It said it should have a radii a 25.8476 and 21.8248.

I was skeptical of the numbers, but I attempted to make one anyway.

I ended up with a transition about 1 1/4" tall. What happened to 4"?

This is really drivin me up a wall.

If I weren't so d%#n stubborn, I would have given up by now.......


Thanks,

[McKailas Dad]

This is some of what I'm working with, maybe that will help.

[gpoehlein]

Using the transition calculator, I input 5.5" for the large diameter, 4.64" for the small diameter, with a height of 4".

It said it should have a radii a 25.8476 and 21.8248.

I was skeptical of the numbers, but I attempted to make one anyway.

I ended up with a transition about 1 1/4" tall. What happened to 4"?

This is really drivin me up a wall.

If I weren't so d%#n stubborn, I would have given up by now.......


Thanks,

Perhaps you accidentally used the numbers as diameters instead of radii?

Here is the spreadsheet I use to calculate transitions. The formulas are based on those presented in Stines Handbook of Model Rocketry.

Given the size of your transition, I get:

Outside Diameter = 51.45"
Inside Diameter = 43.405"
Arc = 38.484 degrees.

The numbers you have look correct for the radius of the outside and inside circle, but remember that is just the distance between the center and outside - The numbers I give are for the diameter (distance from one edge of the circle to the other through the center). Also important is the arc - That is how much of the circle you need. To make your transition, you need to draw both circles (one inside the other), draw a line from the center to the outside, then measure 38.484 degrees from that line. Draw a second line from there from the center to the outside. When you cut it out, the length of teh arc along the outside edge will be the circumference of your large tube and the length of the arc along the inside edge will be the circumference of your smaller tube.

The last two columns (Y and sin theta) are just steps in the calculations and can be ignored.

[Orion]

This is some of what I'm working with, maybe that will help.

I ran the numbers and they are very close to what I got, in the thousandths of an inch differences.

If I scribe two arcs using radii of 25.728" and 21.705" with an angle of 38.33 degrees, I would get a transition of 4 inches length with a 5.5 diameter on large end and 4.464 on the small end. I'm not sure how you would have gotten the 1.25 inch length.

[McKailas Dad]

Orion, thanks, that's exactly what I needed. Now that I see a picture of it, I got it! I was not drawing the radius correctly, I was, like Greg said, using the diameter...

I suppose that would be why my transition height was ~1/2 of what it should have been.


Back to the drawing board.

[bandman444]

I know this may not help you, but this is a visual description of the "triangle" method others have discribed.

http://www.youtube.com/watch?v=4-rfazz1Z3c

Bryce

[McKailas Dad]

Well, this is what I came up with. I would try to explain, but this should make it easier...

I cut and pasted a chart of the sizes I wanted.


Using lengths of poster-board, I made templates of the radius.
These are used both for making alignment/reference lines, and for cutting. Here's #4 template


After using a compass to find and mark the angle, I used my template with a thumbtack fulcrum, I first made a pencil reference line. This line is not to cut.

A new #11 blade is poked thru the template (after the pencil line at 7.7762 mark <above>), to score and cut in multiple passes. Then I cut all 6 pieces out, starting with the largest.
That is on 2 pieces of 22"x28" poster-board...sorry sideways.


Here's #4 of 6...


Wanna see what I did with the pieces I cut out? You will have to wait till tomorrow...

[Rex R]

heheh, I think I know some of it...but I'll let Jeff have the honor of disclosing unto us what he has been up to .
rex

[McKailas Dad]

Yup, Rex has seen it in person.

Being the first here to see it, Rex, what did ya think of it?

(more pics later....)

[McKailas Dad]

Oh fine, it's later, but just a tease.

The coupler I made from cutting down a piece from the 5.25" tube.