Where to get lightweight 38mm nosecone?

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Tallman

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For a minimum diameter rocket with a longburn 38mm motor (H45) I'm looking for a light palstic or balsa (?) cone. I have a LOC one but it's fairly heavy; for best altitude I want to keep this very light (about 8 ozs all in w/out motor). Any ideas? I could turn one I suppose on a drill but a hollow one will be useful for chute/altimeter space.
 

jetra2

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I can't imagine a LOC cone being heavy enough to seriously effect your altitude. It would probably actually be better for the rocket since it will be making it near the optimal weight in which you can get the maximum amount of speed and altitude.

Although, if you really don't want to use the plastic cone, our own sandman has been doing some awesome hollowed out balsa cones recently. PM him through TRF or e-mail him at [email protected] .

Jason
 

Stymye

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or,just turn a balsa cone and hollow it out
 

rstaff3

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jetra brings up a good point about optimal wieght. Might be an LOC cone is a better choice.
 

Zack Lau

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You can polish a plastic cone for a smooth, ultra light finish.

It takes a bit more work to get a smooth finish on a balsa nose cone.

Have you figured out the target CP/CG for your rocket? You actually want the nose to be heavy and the tail to be light--the place to save weight is the fins, not the nose cone. A real Nike Hercules has hollow fins to save weight. By making the fins lighter, yet stiffer, you move the center of gravity forward. This means can make the fins even smaller, since you don't need the center of pressure as far back. Smaller fins result in less drag and more altitude, until the rocket becomes unstable. :eek:

Does your altimeter have a barometric sensor? The sensor typically needs to be set back from the nose cone to get accurate readings. This isn't a problem with accelerometers, but they have their own set of problems and aren't as common.
 

Tallman

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<<Have you figured out the target CP/CG for your rocket? You actually want the nose to be heavy and the tail to be light--the place to save weight is the fins, not the nose cone>>

Fins are 1/8 basswood, soaked in CA, very stiff, light (I've used thinner ones on Machbuster clones without a problem). Epoxy fillets add weight, unfortunately. I don't use Rocsim but am roughly eyeing the LOC Aura and THOY Robin as similar templates, although my fins in shape and placement are closer to the LOC Weasel (with relatively more span, however, as this roc is about 27" long). So I'm figuring the CP is about 18-19" from the nose. WRASP suggests optimal weight is around 8oz, and I'm at that with fillets and LOC cone before altimeter, chute/streamer, paint. I'll just shave weight where I can and go with whatever results. How far back from the nose/payload joint should the altimeter hole be? I'm thinking of getting that itty-bitty one from PerfectFlight.
 

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