How do you make a Large Custom Nosecone?

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bandman444

bandman444

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Ok, so I'm throwing around some ideas for Summer/Winter build for my possible Level Three attempt the following summer (This thread is not about me and L3, see title)

But I really would like to do a fat short rocket.

An upscale madcow squat.


As an easy option I could buy the tube and nosecone from pml and use their 11.7" size stuff.

But what if I wanted it bigger....

Sonotube (or the like), centering rings, fins, all cut with my High Schools CNC router.

The thing I get stuck on every time is how to make a custom nosecone.

To put everything in size I am thinking 15-20" diameter, probably closer to 15" plus it wouldn't be conical (Phhh to easy), it needs to be ogive.

I'm curious as to your thoughts ON HOW TO MAKE A NOSE CONE FROM SCRATCH.


Sorry to have to emphasize a point more than once, but I feel that if I don't I will get responses like, "Your too young to start thinking about Level 3," or, "These are questions you should know if you are really thinking about going for level three."

Thanks guys

Hope to hear some good responses.

Bryce

Attached is a Rocksim file of one out of 11.7" pml gear

View attachment Squat 11.7.rkt
 
Last edited:
your not that young! :)

Make it from centering rings, spars, and foam! Ill link you to a drawing for my L3 Nike Build. Im using a 4" 5:1 Performance Rocketry cone as a 'tip' and a 4" tube will run down the center for weight/tracker etc.

Ben
 
Ya thats true I'm 17 so i'v got less than a year.

Also I added to the original post that it should be ogive, thanks for pointing that out Ben :)

Lots of foam, weight?
 
It will work for any style cone. I use 2 part foam and put it in each of the spaces and then carve it with a hacksaw blade and shurfoam plane.

Ben

P.S. sorry the PDF is weird, TRF wont let me upload the better file

View attachment L3 nosecone.pdf
 
You could wrap the foam mold in some sort of releasing medium glass over it then pull the foam out. Or digging back to my brief foray into making custom sub boxes you could have a central dowel with cr's spaced up to the tip descending in size as they go to the tip, stretch a fabric over the skeleton then glass. I havent seen anyone using the skeleton and wrap method in making a nose cone but it crazy easy to do. The other option probably most expensive and indepth would be to make a mold of half of the nose cone then connect the two sides. I believe the scotglas cone i have was made this way.
 
bandman444 said:
But what if I wanted it bigger....

Sonotube (or the like), centering rings, fins, all cut with my High Schools CNC router.

The thing I get stuck on every time is how to make a custom nosecone.
Click to expand...

Great question. I have the same goal... just acquired 36' of 16" Sonotube, which screams big rocket. I can make the rings and fins, so am looking for ideas to make a big Ogive nose cone. Planning on glass over blue foam, haven't yet figured how to make the shoulder. Look forward to following this thread.
 
Burner has the right idea. Glue up some foam and turn it to shape on a Flintstones lathe, cover in glass.

Nice looking cone Burner!
 
One problem is that a 17" scale nosecone is 63" long. Over 5 feet! Basically turning it is out of the question, but I do prefer that method for the shear fact iv done it before with amazing results. .....but that cone was 2.6" and maybe 8" long, not 5 feet long!
 
Once your glass is cured, you can melt out the blue foam with acetone.
 
you can get sleeves of glass, kevlar, and CF that strech pretty incredibly :)
 
also, doing it in 1-2ft sections and sandwiching together before glassing isn't out of the question, you can always fine tune the foam before you get into the glass work :)

just wondering, have you done any fiberglass stuff? can't remember cuz you got so many builds going lol. and i mean like laying glass, not a wildman kit :wink:
 
bandman444 said:
One problem is that a 17" scale nosecone is 63" long. Over 5 feet! Basically turning it is out of the question, but I do prefer that method for the shear fact iv done it before with amazing results. .....but that cone was 2.6" and maybe 8" long, not 5 feet long!
Click to expand...

OK so the nose cone is 63" - no big deal. We have done several nose conse made from shaped 1# styrofoam or stacked adn glued blue foam. We simply make a profile of the NC and shape the cone. We use a hot wire cutter to get the basic shape and then fine tune it by sanding. We will take a belt sander belt and cut it and hold it against a board and sand the nose while it is spinning in the jug.

SCUD_34.jpg

This is on the Arizona Rocketry Team SCUD We have it to rough shape and are getting ready to sand it.
SCUD_37.jpg


After getting the rough shape with the hot wire cutter, we have also used a router to get a better shape before sanding.
nose_roy1.jpg

This was on the UpScale Rocketry 14x gemeni DC so you can see it works for nose cones of all sizes!

As far as glass, we have used from 5.5 oz to 8.9 oz satin weave. and we take it in to account if we are adding more then 1 or 2 layers.
 
A couple techniques come to mind...

1) Stack foam, epoxy it together, shape with a sureform and sandpaper.

2) Cut bulkheads to match distances at set points. Stack foam to the distance in between, then hot wire, using the bulkheads to match the profile. When done, assemble everything into one big stack. Doesn't work on ogive nosecones.

Either method then requires the application of fiberglass and epoxy over the top, to give it a "skin".

This assumes one-off nosecones, or very limited production. When we did the Delta III, where I needed 9 booster nosecones, one of the guys turned a plug out of oak, then I made a mold from that, and made 9 nosecones.

-Kevin
 
troj said:
A couple techniques come to mind...

1) Stack foam, epoxy it together, shape with a sureform and sandpaper.

2) Cut bulkheads to match distances at set points. Stack foam to the distance in between, then hot wire, using the bulkheads to match the profile. When done, assemble everything into one big stack. Doesn't work on ogive nosecones.

Either method then requires the application of fiberglass and epoxy over the top, to give it a "skin".

This assumes one-off nosecones, or very limited production. When we did the Delta III, where I needed 9 booster nosecones, one of the guys turned a plug out of oak, then I made a mold from that, and made 9 nosecones.

-Kevin
Click to expand...

you can still use foam to make a mold from, you can spray epoxy on it and continue finish shaping. it will be more than durable to make a mold with.
then you can make fiberglass nose cones from that mold.
(most of the cars that are used for making fiberglass molds, are made of a clay that isn't much stronger than faom. they spray a gel coat right on the clay.)

rbones said:
OK so the nose cone is 63" - no big deal. We have done several nose conse made from shaped 1# styrofoam
Click to expand...
Please, expound on this jig, i have an old drill press i thought of hoooking to a reistat and belt driving over to a jig.
one thing i found was the larger i made the nose cone, the lower the rpm had to be or i got wobble...how are you counteracting balance iniquities.
I really like your idea, i bet your neighbors are happy with your nose cone endeavors. i got some new neighbors this week, and plan on picking up some 16" tubes and breaking them into the "large rockets on the hill" the other neighbors get a kick out of...
 
ClayD said:
you can still use foam to make a mold from, you can spray epoxy on it and continue finish shaping. it will be more than durable to make a mold with.
then you can make fiberglass nose cones from that mold.
(most of the cars that are used for making fiberglass molds, are made of a clay that isn't much stronger than faom. they spray a gel coat right on the clay.)
Click to expand...

You can, but for a low volume nosecone, it's not worth the effort.

Even with nine nosecones, it's borderline. But, being in a cluster around the rocket, any variation becomes obvious very quickly.

-Kevin
 
troj said:
You can, but for a low volume nosecone, it's not worth the effort.

Even with nine nosecones, it's borderline. But, being in a cluster around the rocket, any variation becomes obvious very quickly.

-Kevin
Click to expand...

Ohh, I agree..
I was just trying to say foam works as a mandrel just as wood or metal does.
unless you want the ability to make a copy later on.
 
I just bought a 22.75" by 78" nosecone from Ken at Performance Hobbies. I believe he has two more. They are from a move set. Glass matt and polyester resin. Has a few dings. Looks air worthy given some 1/8" G10 rings to support. Paid $300. Mine measures to 1/8 inch on surface chord from tip to rim. Not bad?

Feckless Counsel
 
SMR said:
Wow, very nice, George. I hadn't been to your site before, very nice work. Thanks for sharing. Sather
Click to expand...

I agree thats VERY cool. Not sure how well it would scale up though.

I would say your best bet is to use foam and build a jig

Ben
 
ben_ullman said:
I agree thats VERY cool. Not sure how well it would scale up though.

I would say your best bet is to use foam and build a jig

Ben
Click to expand...

the pershing that launched at LDRS 27 was a wooden frame rocket. they built the whole thing including nose out of wood and then screwed the exterior onto it. wood is mighty strong, but gets heavy quick if you're looking to keep it strong when scaling :O
 
Burner said:
Glue some foam together, turn it and glass it.
Click to expand...

Too bad it doesn't show the thumbnail. I've turned many nosecones this same way. Invented(?) by Jim Cornwell and Mark Clark the Barny Rubble Lathe has served me well. 1" dowel with rings of 2" blue foam glued with Great Stuff foam. I have a frame that I use with 1" bearings. I have screwed in a cut-off screw and turned with a 500 RPM top variable speed 1/2" drill. Cornwell and Clark used a fan belt driven off the chuck of the drill. They made a 16" Mosquito nosecone using this method, my biggest only 8". Have a shop vac set-up or there'll be blue foam everywhere and you'll end up looking like Frosty the Blue Man:wink:
 
ClayD said:
Please, expound on this jig, i have an old drill press i thought of hoooking to a reistat and belt driving over to a jig.
one thing i found was the larger i made the nose cone, the lower the rpm had to be or i got wobble...how are you counteracting balance iniquities.
I really like your idea, i bet your neighbors are happy with your nose cone endeavors. i got some new neighbors this week, and plan on picking up some 16" tubes and breaking them into the "large rockets on the hill" the other neighbors get a kick out of...
Click to expand...

We will run a closet pole through the center of the nose cone the full length. That was put through the two end plates so there was solid support at both ends of the jig. The side plates were profiled to the shape of the finished nose cone and then screwed to the end paltes just wide enough to accept the raw foam.

The foam goes in and is rough shaped with a hot wire cutter, and a router for final form and sanded smooth, all but the tip. Once everything else is done we resupport the nose and cut the top few inches with a router and sand. The closet pole is actually the tip of the nose cone.
 

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