How to roll Nose Cones?

I recieved advice a little while back from a user. And that changed the way i looked at rocketry. He said "After a while everything starts to look like a rocket part to you" After joining the NAR, and becoming a lot more serious (find my "How do you put a "p" level motor into a Gnome?" topic) I have started building my own rockets. I have run into one problem: I cannot make myself a nose cone. So if anyone has advice,templates or metiral choices (or other methods for that manor) Please inform me!

Thanks All, Evi (Ben)

Reply to
Evi
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Ben,

First off, many of us who design/build our own rockets still buy nosecones. I use lots of BMS cones.

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After that, you can turn them on a lathe. If you use non-standard tubes such as mailing tubes or paper roll cores, then that's commonly done. For smaller rockets, it is possible to use a drill instead of a lathe. Here's a good pic:
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Next, you can make conical cones by rolling paper. But, attaching them can be tricky. It helps to have a tube coupler to use as the base for the cone.

Some folks use plastic eggs as nosecones, but I haven't tried that.

HTH.

Doug

Reply to
Doug Sams

Don't know how big a rocket we're talking here, but I usually stock up on plastic eggs around Easter time for just this reason.

Reply to
Roger Ivie

"Evi" wrote .

I started with the the Fliskits free design and upscaled the ideas to Qualify level 1 with a card nose cone - you can see the completed rocket at alt.binaries.models.rockets

  1. Take some card from a cereal packet or thin card you could get through a computer printer.
  2. Draw a 90 deg segment with radius twice the diameter of the body tube, add a bit for tab
  3. Cut it out

  1. Crease the segment from the tip to the radial edge every few degrees. The tip is where the work needs to go...

  2. Form the segment into a cone, working on the tip to get it as neat as you can, perfect circularity comes later.

  1. Use wood glue to glue the tab inside the Hopis edge, you will find the glue helps the parts slide into position and softens the tip. Line the edge up with the

90 degree line adjacent to the tab and check the bottom edge is flush.

  1. For larger rockets make a similar cone with about a about 5mm smaller raduis and glue it inside the first.

  2. To make the shoulder roll up some card, say an inch wide on a large rocket, so it fits inside the body tube. Glue it and leave it to set tucked inside the body tube. Check from time to time its not stuck there.

  1. When both parts are dry glue the cone onto the shoulder, leave the shoulder tucked into the body tube to check it remains round.

  2. To fix cord to the nose cone fray its end a bit and work glue between the fibers, squidge it into the nose cone and leave to dry.

I have some build sequence photos I could post if you need them.

Halam

Reply to
Halam Rose

"Halam Rose" wrote in news:FvLVg.3160$ snipped-for-privacy@newsfe3-win.ntli.net:

I had the idea of using several plywood and/or balsa/cardboard/foamboard "centering ring" bulkheads of decreasing outer diameter spaced on a center standard paper bodytube,and laying strips of balsa or thick cardboard from front to rear around the rings circumference to make a NC shape,and then use a standard balsa NC for the very tip. You could use a coupler and smaller "centering rings" for the "NC" tenon.Then glass over the finished assembly,fill in any imperfections,finish like any other NC. Sort of like laying up a model airplane airframe. It would be mostly hollow and very light,so would probably need weighting for proper balance.

Anyone tried this?

Reply to
Jim Yanik

How about one of those styrofoam cones from Michael's covered with spackling?

Reply to
Darrell D. Mobley

I covered a Styrofoam cone with fiberglass to make a 4" nose cone for my "upscale Cineroc":

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It worked ... okay. It's difficult to layer fiberglass neatly on a cone shape. I ended up doing a lot of sanding and priming and filling with wood filler to get the 'cone to look okay.

-- Roger

Reply to
Roger Smith

"Darrell D. Mobley" wrote in news:NJqdnQEiNtAdybTYnZ2dnUVZ snipped-for-privacy@comcast.com:

I used one as a molding form for wet cardboard.It came out fairly decent.

Reply to
Jim Yanik

"Roger Smith" wrote in news:XSfWg.6853$ snipped-for-privacy@newsread4.news.pas.earthlink.net:

I suppose you could use that VCP program to print out cutting patterns for the cloth to wrap around the cone,like you can for making transitions. You'd still need to fill and sand a bit though.

Reply to
Jim Yanik

Thanks all for your wonderful answers! im gonna finnaly make my nosecones! And My Member Guidebook Just Arrived!

--Evi (Ben)

Reply to
Evi

How about "spin molding" them?

I was thinking of using a variable speed rotating assembly (which could be as simple as an old variable speed drill clamped in a vise) with a mold in the center, then with the glass cloth and resin applied, the speed could be controlled to wet out the cloth without excess resin pooling in the tip.

You'd need eye protection and a cardboard box for a splash guard, along with timing and patience but the end result would be worth it.

Mike Doyle

Evi wrote:

Reply to
syncbus

" snipped-for-privacy@gmail.com" wrote in news: snipped-for-privacy@i3g2000cwc.googlegroups.com:

Who cares if excess resin pools in the tip? all that does is make the tip more durable to impacts,and lessens the need for nose weight.

Reply to
Jim Yanik

Well to a point (no pun intended) you're right, I was just talking about excess that doesn't really add weight in terms of density.

If I'm going to add nose weight I prefer it to be dense and as far away from the COG as practically possible to keep the overall weight of the rocket down. I'll move everything I can to avoid the shortcut of piling on weight and only use it as a last option.

Mike Doyle

Jim Yanik wrote:

Reply to
syncbus

" snipped-for-privacy@gmail.com" wrote:

I see two sides to this. While I like the idea of keeping the overall weight down, nosetip weight tends to make the nosecone stable. In the event of a separation, the NC will come in ballistic. If you add the mass nearer the aft end of the nosecone, it will be more likely to tumble in.

So if I don't need the space (in the nosecone), I prefer to put the mass at the back end, even if it means more overall weight.

Doug

Reply to
Doug Sams

"Doug Sams" wrote

Interesting thought.

The moment of inertia must be different also, what effect does that have on the rocket and nose cones flights? Thinking it though causes my brain to wobble along a sinusoidal path.

Halam

Reply to
Halam Rose

I prefer to make sure the nose cone can't separate :-)

Reply to
Bob Kaplow

Much as I like Vern Estes, I think he did a disservice with his "move the CG back for tumble recovery" misconception.

With the mass toward the aft end of the nose cone the nose cone will still be stable--backwards--and will come in ballistic.

To get tumbling the CG has to be at the CP, and some disturbance has to initiate the tumble. (In the Astron Scout the exhaust gas out the single hole was this disturbance; notice the three holes of the original Scout were soon changed to a single hole?)

Reply to
Steve Humphrey

Steve,

Yes, that's possible. That's why I said "likely" :)

Seriously, fliers can use Rocksim to find the nosecone's CP, then place their weight accordingly.

Doug

Reply to
Doug Sams

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