Very Big Nose Cone

Hello,

I could use a little guidance on building a pretty big nose cone. The cone is 50 cm long with a 10 cm long shoulder. The maximum diameter is 10.4 cm. We originally tried turning a plug out of MDF with the intention of using a fiberglass molding technique similar to that explained by John Coker (Here). However, the nose was just too big to turn and we lacked the appropriate tools to finish such a large part. At this point, we're stuck. Does anyone know a possibly better way to make a nose like this?

thanks

Ok, to translate a little it is a 4"x 19" nosecone. Why was it to large to turn- your lathe not up to the task?

Have you considered making the core out of foam, turn it to shape, laminate it with composite of your choice, and then melt foam with solvent? I know that has been done before.

markkoelsch said:

Ok, to translate a little it is a 4"x 19" nosecone. Why was it to large to turn- your lathe not up to the task?

Have you considered making the core out of foam, turn it to shape, laminate it with composite of your choice, and then melt foam with solvent? I know that has been done before.

Click to expand...

We are considering the lost foam core method, but it doesn't look as good since we can't really get the shoulder on the nose that way.

Sounds like the standard dimensions of a Giant Leap Pinnacle Nose Cone. Do you need a different profile?

https://giantleaprocketry.com/products/components_nosecones.aspx

terryg said:

Sounds like the standard dimensions of a Giant Leap Pinnacle Nose Cone. Do you need a different profile?

https://giantleaprocketry.com/products/components_nosecones.aspx

Click to expand...

Nope! Too small. Remember, this rocket also uses the metric system.

Lets see... 10 centimeters =3.93701 inches and 50 centimeters = 19.685039 inches. Now if we look at the pinnacle cone, we can see that its dimensions are 3.90 inches in diameter and 19.8 inches exposed length. That sounds like what you need.

Neilw said:

We are considering the lost foam core method, but it doesn't look as good since we can't really get the shoulder on the nose that way.

Click to expand...

Not sure why you dont think you can get a shoulder on a foam nose cone, we do it quite often, and on NC's as big as 16" Diameter.

Stack and glue your foam
Cut a pair of wood sides to act as your profile
Insert a closet pole in the center of the foam stack
Use the sides to act as runners for a sled and router and
Profile your Nose Cone.

rdbones said:

Not sure why you dont think you can get a shoulder on a foam nose cone, we do it quite often, and on NC's as big as 16" Diameter.

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Alternatively, you can add a shoulder made from a coupler tube later. The method I used once left the foam in the nose cone, but was pretty easy. What I did was to attach a centering ring of plywood to the bottom of the foam core. The ring was slightly smaller than the outside diameter desired for the nose cone (to account for the fiberglass). Since I was "turning" the cone by hand, it provided a good reference to ensure that the nose cone ended up the right diameter (and circular which is a good thing for a cone that will go into a tube).

Once the fiberglassing was complete, I attached a centering ring, sized to fit inside the coupler, to the bottom of the nose cone. Then I glued the coupler tube to it to create the shoulder.

-- Roger

littlemisterbig said:

Lets see... 10 centimeters =3.93701 inches and 50 centimeters = 19.685039 inches. Now if we look at the pinnacle cone, we can see that its dimensions are 3.90 inches in diameter and 19.8 inches exposed length. That sounds like what you need.

Click to expand...

The cone won't be 50 cm in length when we're finished. We're adding a 10cm metal tip. As well, there are several components that we want to put in the cone and they are attached to an aluminum threaded rod which runs between the tip and an eyebolt at the end.

If things really aren't going well, we could resort to the lost foam method as our fallback

Or you could buy a filament wount fiberglass nosecone that already has an aluminum tip and is the dimensions you need. (4" 5:1 VK)
And if i may, id like to give you a piece of advice for the rocket that the cone is for: MOAR BOOSTERS!!!!

littlemisterbig said:

Or you could buy a filament wount fiberglass nosecone that already has an aluminum tip and is the dimensions you need. (4" 5:1 VK)
And if i may, id like to give you a piece of advice for the rocket that the cone is for: MOAR BOOSTERS!!!!

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You sound like a rocketeer who also simulates using KSP!

Do you know anywhere where I could purches an NC like that?

Yes I do play KSP! And you can get them from Madcow, Wildman, Proline and Rocketry Warehouse to name a few.

littlemisterbig said:

Yes I do play KSP! And you can get them from Madcow, Wildman, Proline and Rocketry Warehouse to name a few.

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I looked at this a little more, and the stock nosecone looks like a good bet. It's design is very similar to our current NC and the price (compared to some of the things we've had to buy) is pennies! 4 inch OD is good. This makes the diameter only around 2.4 mm smaller than what we have now, so this can be solved by adding a layer or two of fiberglass. If we can't turn the plug, we'll definitely do this.

Glad to hear it'll work. You know what would be cool? Putting one of these https://www.shapeways.com/product/R5ZELUDY5/jebediah-kerman-on-iva?li=shop-results&optionId=43032440 somewhere in the rocket.

littlemisterbig said:

Glad to hear it'll work. You know what would be cool? Putting one of these https://www.shapeways.com/product/R5ZELUDY5/jebediah-kerman-on-iva?li=shop-results&optionId=43032440 somewhere in the rocket.

Click to expand...

That might just be possible... It happens that we require a 10 lb payload and our current payload is slightly underweight

Perfect noseweight then! Hopefully Jeb doesnt start smiling