My 10 inch diameter...Paper Rocket.

EDIT- this thread started as a 'How I made ten inch diameter, ogive shaped nosecone, out of.....posterboard, a PBNC....' but I may as well show you what it's for! I'll pick up the edit in the next post.

PBNC as in... Poster board nose cone

I've previously made a 5.25", 2:1 ogive

. https://www.rocketryforum.com/showthread.php?26305-Paper-Ogive-Nose-cone&


This is intended to be a 10"x26". Iirc that makes it a 2.6:1 ogive?

I had a thread on the 'tool' that I eventually made to cut out the transitions, that worked out quite well.

https://www.rocketryforum.com/showthread.php?131386-How-to-draw-huge-radius-in-small-area

There were supposed to be 11 transitions, but the largest had a 17+foot radius that would have been...difficult..to cut.



The two largest are 3" tall, all the others are 2". They will overlap each other by about 1/4" or less. The ends were left long, and I will trim as I go.

I've started at the top, and am working my way down. I'll glue up each transition after double checking it with the next one.

So far, no glue, it's at 81 grams

op:

Oops, I guess I'm kinda busted. If you look in the upper right of that pic, you can see the matching tube.

This all started when I found a ~17" long, 10" diameter heavy cardboard tube..but -way- too heavy!



Before rolling my 'paper ' tube, using it as a mandrel, I cut a strip out lengthwise using a table saw. Then used a 1/4" dowel to fill in the gap I just cut, and wrapped the cardboard in waxpaper.

These pics are after the wax paper had been removed...easily.





All I have to do is remove that dowel and my wrapped tube slides right off.

This is the third time I'm using -drywall tape- to make a BT. The second (6") one I couldn't get it off the mandrel. The lengthwise "cut and dowel" fixed that!

Yes, drywall tape and yellow glue



Here it is, glue dried after 3 layers, back on the mandrel to fit it for it's first transition. I left a reveal to simulate a shoulder for now and haven't cleaned up the edges yet.

With the second transition, I used the shadow to find my overlap, which is about 1/4".



The transition ends are still long, and I'm using masking tape for a dry fit mockup. I don't plan on getting the ends perfect enough to be a flush butt joint. The ends will overlap.

As fat and chunky as this thing is, aerodynamics are gonna be out the window anyway.

Here's the 2nd and 3rd set ready to be fitted to the 1st -

Interesting build. I've laminated foam board with drywall tape and carpenter's glue but never thought of making a tube out of it.

rstaff3 said:

Interesting build. I've laminated foam board with drywall tape and carpenter's glue but never thought of making a tube out of it.

Click to expand...

I alternate the direction of the wraps. First left to right, then right to left, then..you get the idea. Crisscrossed.

The third layer of this is actually 2 opposing layers of adding machine tape. It was too thin and hard to work with when wet with glue. I thought I could have used it as the outer finishing wrap, but wasn't happy with it.

So , technically, this tube has 5 wraps. 2 drywall tape, 2 adding machine tape, then one more drywall.

While granted, this tube is not overly rigid, that's what extra centering rings are for in this case.

I'm thinking of basing this tube off of a BT80 sized central tube, with motor sizes and adapters ranging from 24 to 38mm.

The bottom two are 3", the next two, and the remaining six, will be 2" tall transitions.



I'm working and tightening my way around, 'tack-taping' on the -inside- to where I want the overlap, then pull and tape where ends of the arc meet. Hence, my reason for the clip..



The shadow knows. You can see the overlapping ends, still waiting to trim. I have some ideas for that as well.

:eyepop:
Subscribed.

Subscribed.

Fascinating and unconventional. Love the detailed explanations and photos. Looking forward to seeing this fly!

Kind of a cartoony/goony lookin' thang?!

16 inches of body tube under a 26 inch long nosecone.

It's gonna need a name....

Stu.

Stu? Because it's too short to be called Stubby

The original 5.25" prototype(s) in the middle, and a uber-light, 2wrap, 6 inch tube on the right.



Uber light? As in 23" long x 6" diameter at 116.2 grams.....?!

The original (5.25") is 3 wraps weighing in at 135 grams.

Uh-ohh...

Seems my numbers, or shortages thereof, are stacking up.

Things were starting to get tight, and it appears the #7 is....



...not going to work so well

I -knew- I should have left the ends even longer. It's certainly easier to cut off, than put back on. Doh!

Darn it, I only had 3 to go, and the top 'cone' is already glued together.

And, YES, this is the ugly side, for now, until I start gluing.

It was so close..



I think I'll end up having to tweak the angles and recut the last few transitions.

It's ok, I like a challenge

Now you know why I add that little strip with the tabs outside the smaller arc as a glue tab. Doing it that way, the transitions don't nest, but instead butt up against each other. The glue tab also adds a bit of rigidity to the nose cone. I have experimented with larger nose cones (largest was 4" diameter). One thing that really helps to keep everything straight is to use a central stuffer tube and two or more centering rings.

Interesting, will be curious to see what your all up flight weight winds up being once you get stuffer tube and some structure for support and fins added. I'm a big proponent of going light and big.

I've been using foam structure and skin in rockets from 5.5" up to 10" diameter, for something this size, I'm finding about 20 oz for the airframe weight, for a 10" by 72" atlas missile for example, that's with skin and stringers/centering rings, most of the flight weight I'm finding comes in the other things, stuffer tube, parachute bay, fins.

Frank

I had thought about a tab of some sort, either a full circumference strip, or 3-4 equally spaced pieces, similar to how I'm doing the tape.

I used a 1/4" threaded rod with multiple centering rings when I made the 5.25" NC.

While I had -already- glued up a pointy cone for this one, I've made a different one NOT with a point, aka, hole...



Looks like some kinda fancy vase on the inside



I've recut a few of the pieces and modified others to try to fit AND look right. I may just keep refabricating my way to the top, also a reason for making a new top...with a hole.

I'm thinking a full length of rocket BT-80 stuffer tube, with possibly only ejecting the top 2 transitions, glued together.

The laundry would come out a smaller, BT-80 (2.6"?) sized hole and NC, instead of trying to pop, push, and fart out that huge 10" shoulder.

The stuffer tube would be over 2 feet long, plenty of room. I'm thinking with 24" chute, it should be down by....Tuesday.

I still have to make centering rings and motor adaptor tubes. I'll start with 24mm, then 29. I'm not planning for larger than 38mm, so I'll make three different interchangeable motor mounts to fit inside the BT-80 stuffer tube.

Im thinking corrugated cardboard, glued in alternating layers (3-4?) for CR's. 9.875 OD x 2.612 ID. I think 4, maybe 5, thicker centering rings, for as thin as the 'skin' is.

I'd better start thinking of...fins!

Consider some dollar tree foam board for the centering rings, they are about 1/4" thick so will help support the skin and will be lighter than cardboard, you can leave the cardboard on or soak it in water and remove it to help save weight, you an also make some holes in the centering rings to lighten them where you don't need the stiffness.

Frank

burkefj said:

Consider some dollar tree foam board for the centering rings, they are about 1/4" thick so will help support the skin and will be lighter than cardboard, you can leave the cardboard on or soak it in water and remove it to help save weight, you an also make some holes in the centering rings to lighten them where you don't need the stiffness.

Frank

Click to expand...

+1 on that

As far as weights?

The rolled 26x10 tube is 295 grams. The current state of the nosecone is 95 grams, but not glued, just taped together. A 34" BT80 tube is 155g. It's the thicker tube, not Estes.

I made some practice CR's with cardboard. I do have some 1/4 foam board, but I'll have to get more, it does seem considerably lighter.

I may just roll my own stuffer tube as well, everything -else- is custom. I'll use 'stock' tube when I build the motor holder adaptor thingies..

I have some ideas on fins, and using dowels and/or balsa as a framework.. The dowels (2 each fin?) would be TTW, tied to the CRs, and the lower most, poking nearly horizontal, or possibly defining the trailing edge?

Maybe the uppermost dowel could angled down and be used as the leading edge? A short piece to tie the upper and lower together, as used as the outer edge.

The fins would be built into, and around the dowels, like skinned, and...reskinable if damaged?

I can picture it in my head, but...

A very rigid inner structured, but thin-skinned, 3D slanted shaped, Nike Smoke/ HoJo looking fin.

Big FAT ones

OpenRocket is just gonna laugh at this thing.

The nosecone obviously isn't smooth, with 11 overlapping transitions! If you considered the hand rolled drywall tape tube smooth as glass? Uh...no, but I haven't filled the seams yet lol

I'm playing with some larger fin designs, and am using the 'invisable' base drag cone theory to compensate stability. What can I shoot for Cal wise? .7, .6?

Even 50 grams of nose weight would make a big difference by what the sim says. I've done short and fat, but not to -this- diameter.

How about .50 Cal and get a longer wire on the launch controller ?

Any input on --attaching-- fins to this...tub..would be appreciated. Something replaceable/repairable, like the dowel/skin idea?

I appreciate any comments and tips. I'll answer questions if there are any? I'm building this 'on the fly' and though I can take a calculated guess, i won't absolutely, -positively- know it will fly....till I hit the button.

If I can (safely) fly this thing on as small as an E 24mm reload, I'm just gonna....giggle.

110 feet at apogee? I'm ok with that, as long as my 2 second delay is drilled right lol

I finished remaking the top parts, now they all fit together well. As it stands now, it's about 37" tall.

Still just taped, and, yes maybe a little crooked, but...



I can't decide on 3 or 4 fins (Poll?) but I want oversized, big, obnoxious, and funny looking. But somehow light, thin and sturdy?!



Need a shoulder of sorts for the large part of the nosecone. I'm thinking only popping out the top 2 will work well.



Make a shoulder from the two top transitions to fit the 2.6" stuffer tube and be done with it?

I'm using that BT-80 size tube I have as a mandrel to roll a new stuffer tube, I'll roll this one thicker with more wraps, considering it will be the spine of the rocket.

My initial thought is to recover using a squid line so that the rocket hits the ground on its side rather than nose first (rear ejection) or solidly fins first (nose ejection). You can locate the rear attachment point and lines so that it comes down at any angle, and will hit with one fin only first, or with two.

For the fins, you can slot your centering rings so that the fin tabs lock into them and take any landing strain and attach them through to the stuffer tube. Or you can use foam board with some carbon rods for stiffness and permanently attach them or build a fin box inside so that they are replacable.

Also, consider what is the biggest actual motor you want to fly, given a light structure, I doubt it will hold up to any 38mm motor. Think about nose weight with your largest motor and how you will attach it, on my large models often will attach any nose weight to the top of the stuffer tube on the outside, hidden by the lower part of the cone shroud. Since you are only ejecting the very top, that still puts the nose weight pretty far up. I don't like a lot of weight in my nose cone swinging around to do a wrecking ball on the rest of the model...It's a tradeoff to balast for your largest motor and then still fly on smaller motors. Think also about rail guide or lug attachment, since the skin doesn't have a lot of strength. I used some wooden brackets that attached to my centering rings and then attached rail guides to those wooden brackets, but you have to build that in instead of retrofitting them. Just some things to think about.

I wasn't sure what it was called, a squid line? I think I saw someone set up a Pemberton Bucky Jones like that, to come down and land sideways. I had also considered rear eject, but am trying to keep the weight towards the pointy end.

I'm not sure this would survive a 38mm motor either, and I'm actually trying to find the smallest motor it will fly on, goin for low and slow. I want it to float up like a balloon, not smack it to apogee with a 300lb hammer.

I still pondering fin shapes and how to attach them, both internally and externally. It makes sense to notch the CR's to help support them. I could also see carbon fiber rods being very rigid, but wooden dowels I are more readily available to me.

I'm going to roll up the stuffer tube and ponder this some more. I'm building in a scale I'm not accustomed to...huge!

Keep the tips and comments coming, my thought processes are slowing down, (i.e., I'm not sure how or -what- I'm doing next)

Though I don't have all the parts made, I could see this coming in around 1000 grams, and/or well under 2lbs...I think.

I've worked with OpenRocket quite a bit, but this ones..different. I'll stick around a 5-6:1 power to weight ratio, Is 25-30fps enough for (6') launch rail clearance? With an F12, it would leave at 21.7fps, with a G64 at 52.2fps! This will be a fair weather flyer, I have no intentions of fighting a 18 mph crosswind.

I've plotted graphs of flights in OR, but not positive I'm interpreting these correctly. I'll see if I can clean up my .ork file and share.

According to sims, it -should- launch on an E28, to a staggering 125 feet! I'd say more like 95 feet, but...?

I'd hate to see this thing crash, I'd be out about $4.75 in paper and glue! I made the NC for less than a dollars worth of posterboard lol


Figuring this to be built well, what do you suppose the largest motor this could handle would be?

"Squid line" is what I've always heard it called. I think I asked here, thinking it was an acronym or something. Turns out it's how you rig bait to catch squid. I wouldn't know, the only squid around here are cut into thin rings, battered, and fried. You can keep nose weight with rear eject. In fact, you could have it set up so that the nose weight is carried out the back when the motor mount is kicked out. A lot of boost gliders do this sort of thing.

You might be able to find "plain" carbon arrow shafts for use as spars, if you have a decent hunting/outdoors supply store near you. Wood, being grown and not made, can have hidden defects and nonuniformities.

I've been sitting on almost exactly this same project for a number of years (too many years). Mine's not made out of paper, though. A friend gave me the front section (nose cone and a bit of body tube) from a full-size Phoenix missile he had crashed. I've designed/built it a dozen times in my head. You'll probably get yours built first...

Though it is too late for this project, check out the latest Peak of Flight

Maybe it will be useful for the next round.

McKailas Dad said:

Though I don't have all the parts made, I could see this coming in around 1000 grams, and/or well under 2lbs...I think.
Figuring this to be built well, what do you suppose the largest motor this could handle would be?

Click to expand...

If you can keep it that light, think CTI Mellow - G33, H53, I55 An Aerotech I49 would also be a cool motor.

Rocketjunkie said:

If you can keep it that light, think CTI Mellow - G33, H53, I55 An Aerotech I49 would also be a cool motor.

Click to expand...

Ok you got me curious, I had to look up the specs on those..

The I55 with a 7.13, and the AT I49 with a 7.81 second burn?!

I would be a freckle faced, pig tailed, jump-roping, gum chewing, giddy little school girl, calling Daddy at work cuz "it's so cool!" with a burn time -that- long

I punched a couple very quick numbers, the I49 -theoretically- would take it to almost 1200 feet, the I55 to just over 1200.

I'll see if survives a G...first