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Alan R

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So there I was .. pondering my Christmas in July gift box... and it just looked like it needed a motor and some fins.
Y'all get these ideas too, right? I'm not the only crazy here?

We have round rockets, and we have square rockets, well, by golly I want a triangle rocket.

I was thinking about it out in the desert at a too-windy-to-fly club launch. I actually sketched out some ideas while I was sitting up late.

I was even thinking dimensions because when I came home I somehow knew it all had to be 3" multiples.

So a corrugated cardboard 'tube' - 3" sides and I would make this for a 24mm mount. D/E size
30" tall + 3" NC .. maybe 27" tall (3 cubed!) and 30" total
Was hoping to do something cool with the fins like that top-down sketch, but not sure it's going to be possible. Now I'm thinking I might make them 3-dimensional - like a single fold cardboard and open at the bottom; but they would just be attached to the sides.

IMG_0136.jpg IMG_20200704_053217421.jpg
 
You will notice that shipping box is all crushed because the corrugations are going the wrong direction.
Luckily.. I have a big box that's folded the other way.

I need 9" x 30" .. Ooops.. messed up the first cut. Try again.

It's kind of hard to square this up because the corregated stuff wants to pull the knife. Next time .. should run this through the table saw, but good enough for now.

Cut only through the outside layer lets it fold over. Not sure what I will do with the open corners. Cover with cardstock? or just a glue bead?

I'm not sure I'm going to glue this together just yet. Planning on making an inside flap for that, but I need to get a motor mount in here first while it's easier.

IMG_0143.jpg IMG_0145.jpg
 
I sim'd a 3" round version... the circular body is only about 10% larger than the triangular area (268" vs 243")

Good enough.

With a D/E motor I feel safe surface mounting all of this with titebond. The sim shows a regular E motor over 1000'. We'll see.
 

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@kuririn ... I think you've built one of everything already.

That's actually quite interesting. Like triangular tube fins.

I think I've decided to go with something a little more straightforward, but it's going to take some on-the-fly engineering. pyramidal shaped fins on the flat sides, open at the bottom, and I'm thinking possibly slot-cuts half and half to secure them
 
Combine the KISS Principle with outside the box thinking.

https://www.rocketryforum.com/threa...non-competition-helicopter.39114/#post-365863


Take a look at three sided Gyskelion, post 26. The fins are contiguous /coplanar with the sides. Easy attachment and automatically perfectly aligned. Yeah, they all go clockwise, or counterclockwise depending on which way you look, but the rocket doesn’t care.

Go to Wallyworld or a hardware or craft store and get shelf paper liner. If you find a color or pattern you like, you are ahead of the game, but even if you don’t, you can use it to “paper” your fuselage and give at a smooth outside edge, should minimize papering and priming, definitely will minimize the “seam” on your fuselage.
 
Go to Wallyworld or a hardware or craft store and get shelf paper liner.
Oh now I like that idea. Just wrap it. Might have some here. Need to look around.
I thought i was going to do some interior glue flaps and then some seam covering which I hadn't really figured out yet.
Thanks for the tip.
I also might play with that fin arrangement, but it doesn't quite fit my vision.
 
Oh now I like that idea. Just wrap it. Might have some here. Need to look around.
I thought i was going to do some interior glue flaps and then some seam covering which I hadn't really figured out yet.
Thanks for the tip.
I also might play with that fin arrangement, but it doesn't quite fit my vision.
There are some colorshifting gift wrap papers I've seen. I bet they would look cool. I might try some on a regular rocket tube using 3M 77 spray adhesive.
 
I’ve been working with the triangle Idea for a while myself.
Is that a plastic nc? and the body looks really smooth as well. More info on this?

I was trying to design a nose cone in Tinkercad for 3D printing, but it does not understand triangles. Pain in the butt. I also tried playing with openscad (more successful) and some other things, but the learning curve is more than I want to deal with just for this project.
It will probably end up being all corrugated cardboard.
 
The company that makes my square tubes says they can’t make triangle tubes, I’ve asked. You can’t keep pressure on the mandrel as it spins to accept the kraft layers. So, I’ve worked on alternative methods. The rocket pictured in my other post is made from flat mat board and laser cut to size with laser etched fold lines. It has a tab the length of the tube that glues on the inside. The nose cone is 3D printed. Everything else is traditional rocket parts. I’m trying to figure out if I can explain the making of the tube in instructions so that anyone could do it. Possibly a limited edition kit. It flies fine, it just needed some nose weight.0DCBE3FE-1BAB-4940-96B4-6FC62143E5F0.jpegA58998CF-ED4A-4F10-8837-D500C9D56EED.jpegD23132BC-F282-4458-872F-09C98F39AB61.jpeg
 
It has a tab the length of the tube that glues on the inside. The nose cone is 3D printed. Everything else is traditional rocket parts.
Pretty much what I'd planned on doing. Except for that pesky 3D triangular nc... I'll keep at it. By the time I'm ready for it, I might have it designed. Otherwise it'll be cardboard too.
In the meantime, I printed a compass today because I couldn't find one at the store. Needed so I could draw/cut those centering "rings".
Lasercut sounds like a dream.
It's a very nice looking bird. Best of luck with it!

We'll see what I end up with here soon.
 
I’ve been working with the triangle Idea for a while myself.View attachment 423498
Triangles work great and look cool.

Do a light cardstock outer wrap, with three heavy cardstock internal panels.

cardstock centering triangles

Light cardstock pyramid nose cone with three internal reinforcing triangles cut just a bit smaller ( one seam to fill, could potentially cover it with a decal.)

Everything except the motor mount tube packs flat. Makes me wonder if you could just squash a BT20 flat and reshape it by shoving a used motor casing in it when you build it.

I am not a business man, but seems like if you could pack everything FLAT shipping would be much cheaper and less likely to get crushed.
 
Finally getting back to this. I got distracted by various things including my L1 flight :D Now it says we're supposed to have some nasty hot summer weather next couple of days. Might as well stay in and do some building.
Thank goodness for back-to-school season, even if the kids aren't actually going back to school. I picked up an old-school compass and had to futz around a bit trying to remember how to centerize a 3" equilateral triangle. Ran it through the old copier-printer a couple of times.
Spray mounted it to a cereal box, then doubled up the cardstock offset 90 degrees, glued it down and put a brick on it while it dries.

That should hold an E12 motor once its all glued in.

IMG_0187.jpg
IMG_0188.jpg
 
Finally getting back to this. I got distracted by various things including my L1 flight :D Now it says we're supposed to have some nasty hot summer weather next couple of days. Might as well stay in and do some building.
Thank goodness for back-to-school season, even if the kids aren't actually going back to school. I picked up an old-school compass and had to futz around a bit trying to remember how to centerize a 3" equilateral triangle. Ran it through the old copier-printer a couple of times.
Spray mounted it to a cereal box, then doubled up the cardstock offset 90 degrees, glued it down and put a brick on it while it dries.

That should hold an E12 motor once its all glued in.
@Alan R Both my Dad & his Dad were sheetmetal workers. When I got out of college in 1973 I got a job working at a large sheetmetal company where my Dad was the foreman. I started out low & as my skills improved I started working making Walker Pug Mills, clay mixers for ceramics people. Look it up.
Near the Pug Mill area there was a long, wide table with a large roll of brown paper at one end. When one of the sheetmetal workers got an assignment to build something they would go to this table & lay it out on paper which they would later transfer to sheetmetal. Using straight edges, compasses, & trammel points they would lay out some of the most intricate 3D pieces in 2D. No computers, no calculators, just well known tricks of the trade.
See if you can find an old sheetmetal layout book and take a look. You will be absolutely amazed. I am.
 
straight edges, compasses, & trammel points they would lay out some of the most intricate 3D pieces in 2D. No computers, no calculators, just well known tricks of the trade.
See if you can find an old sheetmetal layout book and take a look. You will be absolutely amazed. I am.
Maybe it would tell me how to construct that darn nose cone ;)
 
Moving along slowly. My rocket room is not air conditioned. I did manage to get my motor mount done.

Tube is scratch cause I don't have anything this size. Kraft paper wrapped an E motor.

IMG_0200.jpg
 
Gluing engine mount. Red straw is for kevlar thread shock cord attachment.

I think I'm going to need a full kraft paper wrap around the body. Or maybe use that shelf paper someone suggested. I might go take a look around today for that. I had to cut through the outside layer of the cardboard in order to bend the edges. It's going to need some reinforcement.
IMG_0206.jpg IMG_0208.jpg IMG_0207.jpg
 
Duct tape is your friend! Works great for reinforcement, heck I have seen a few rockets finished with it, since it comes in so many colors and patterns now.

It’s right up there with dental floss as one of my favorite building items!
 
after multiple distractions over the last few weeks finally got back to this. Had to clean the workbench first. It was covered with random tools, chainsaw grease, various nuts bolts and all sorts of random thingys.

I added a kraft paper glue wrap. Trimmed it down to size on the last fold. Should hold it together just fine. I'll trim it down tomorrow or the next day or maybe in a few more weeks after the workbench accumulates another layer of random bits and bobs. hahaha

IMG_0221.jpg IMG_0222.jpg
 
Nah, used foam adhesive on all pair of cups. Bottles are to weight them down so the seam doesn't separate.
Just pushed all the extraneous "thingys" to one side and voila! Instant work space.
;)
 
The company that makes my square tubes says they can’t make triangle tubes, I’ve asked. You can’t keep pressure on the mandrel as it spins to accept the kraft layers. So, I’ve worked on alternative methods. The rocket pictured in my other post is made from flat mat board and laser cut to size with laser etched fold lines. It has a tab the length of the tube that glues on the inside. The nose cone is 3D printed. Everything else is traditional rocket parts. I’m trying to figure out if I can explain the making of the tube in instructions so that anyone could do it. Possibly a limited edition kit. It flies fine, it just needed some nose weight.View attachment 423585View attachment 423586View attachment 423587
If you can do that to make the body, suspect wouldn’t be much more difficult to make an origami nose pyramid the same way, with an origami nose cone shoulder as well. Suspect this would be cheaper than plastic nose cone, plus it packs flat. The only round item for packing would be the motor mount tube, and even that might not suffer too much from being shipped “flat”, just reshape it during construction with an empty motor casing.
 
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