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Nosecone "attachment" - Stupid Question

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Peter

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I'm eagerly anticipating flying my AAMRAM 4" next weekend. I know this is likely a stupid question as I'll probably just use 3 screws but...Does anyone use a "slick" method for attaching the PML plastic nosecone while keeping it removable for access to the payload? Thanks in advance.
 

jetra2

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Masking tape is a rocketeer's best friend.

Jason
 

powderburner

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And here I thought that duct tape was a man's best friend.


Probably in this case, masking tape (or even cellophane?) is the best thing to use. Screws are OK too, but if you use them make sure you soak the surrounding BT with CA to beef it up.
 

Peter

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Thanks for the suggestions guys. I was looking for a stronger technique to use as I'm concerned that upon ejection of the piston the nosecone might "fling out" using just tape. Plastic rivets would be great if I could find them (non mailorder) as I'm pressed for time.
 

powderburner

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You could take a piece of plastic line for a lawn edger/trimmer and cut it into short lengths (it comes in a variety of diameters to fit different trimmers). Use a hot iron to briefly soften/melt one end and form a 'rivet head' and then trim to final grip length. Epoxy in place? or drill small hole for rivet and use a friction fit?

Don't overlook the small plastic bolts and nuts available at your local hardware stores. They are usually in the specialty hardware section (along with the stainless steel, brass, etc) and could also do the job you want. Or try finding them through your local electronics repair shop?

Just for grins, you should at least TRY taping the NC into place and pulling it off by hand. You would be surprised at how well a ring of tape will do the job
 

kgholloway

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For easy to use and remove fasteners try the "Panel Fasteners" sold in automotive parts stores like "Autozone".

They are plastic rivets that fit into a predrilled hole and then are expanded by driving in a screw. When the time comes to remove the nosecone just back the screws 90% out, pull the rivets out by the screws, and the nosecone will be easy to remove. The panel fasteners are reuseable and extremely strong. A friend recently built a 4" rocket by using them to hold a length of quantum tubing to the salvaged fin can from a PML AMRAAM. It flew and recovered perfectly on motors up to an I-211. Normally, however, my friends and I use them for holding avionics bays in body tubes.

Ken Holloway
 

DynaSoar

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Originally posted by Peter
I'm eagerly anticipating flying my AAMRAM 4" next weekend. I know this is likely a stupid question as I'll probably just use 3 screws but...Does anyone use a "slick" method for attaching the PML plastic nosecone while keeping it removable for access to the payload? Thanks in advance.
Unless you plan to fly it with a payload that's bouncing around inside hard enough to knock the nose off, tape would be plenty. If the payload is attached or cushioned, no sweat. Masking tape is the real deal. The wax surface makes it slightly sticky on the "outside" so it resists moving, but once it's moving it slides nicely. Figure: people trust it to hold big motors in their mounts.
 

llickteig1

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Originally posted by Peter
I was looking for a stronger technique to use as I'm concerned that upon ejection of the piston the nosecone might "fling out" using just tape.
I would share your concern, particularly if the ejection happens to occur at high speed. I've seen many a nosecone falling to earth all alone. While tape does work, things must be plenty tight to be sure. Why not be safe and use 'positive' retention?

Your screw idea is not a bad one. I use small machine screws with a large rubber flanged washer. They make a larger area so the screw doesn't pull through and they looks sorta cool. You should be able to find them an any home center.

--Lance.
 

BlueNinja

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I would use the panel fastener solution, as suggsted earlier. They're really secure. I use them for a retainer in my G-Force, however the screws need work and I need a spacer of some kind. That won't matter for a nosecone.
 
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