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  #1  
Old 05-19-2018, 05:39 PM
erik442's Avatar
erik442 erik442 is offline
The Alpha Kid
 
Join Date: Mar 2012
Location: central PA
Posts: 31
Default Twist Lock Nosecone

Most of my builds use tubes that average around 2" in diameter. Due to length they often have a payload section or use center break recovery deployment. I was looking for a way to retain the nosecone that didn't involve friction fit or tape. I came up with a simple system that holds the cone securely but still allows access to the tube.

I make a wood disc by tracing a centering ring, then cut the ends off along the grain. I put these ends into the tube at the depth of the cone shoulder with a drop of glue to tack them in place. Once dry, I glue their edges securely to the tube interior. The center of the disc is attached to the cone with a shim of wood the same thickness underneath plus a shim or two of cereal box flap to drop it just below the tabs.

Chamfer the edges slightly to allow the center to glide under the tabs with slight resistance.
Insert the cone and twist 90 degrees for a secure fit. I had trouble with the center half breaking the glue joint depending on how tightly it fits, so I added a wood screw on the cone side (two on larger models).
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  #2  
Old 05-19-2018, 05:46 PM
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Joe Wooten Joe Wooten is offline
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Very Cool! I like that idea.
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  #3  
Old 05-19-2018, 08:01 PM
DavidQ DavidQ is offline
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Join Date: Aug 2011
Location: Washougal Washington
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I've been considering that some of the builds I want to do should have removable motor mounts, so they can be exchanged for different sizes. I think this locking technique could work for that as well.
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  #4  
Old 05-19-2018, 08:02 PM
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GlenP GlenP is offline
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Join Date: Dec 2015
Posts: 78
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Nice contraption.

I rigged up a twist-lock coupler/baffle from a dowel and slotted multiple-ply paper-towel rolls for this made-from-parts-in-the-recycle-bin upscale of the Centuri Excalibur. I found a nose cone from an Amazon in a field and it was a perfect fit for a cardboard tube from wrapping paper and the lower section was made from paper towel rolls. It was kind of too long to transport in the car, so I made the twist-lock/baffle to allow me to take it apart right under the transition, and still pass the ejection charge to pop the nose and chute in the upper section. Not too pretty, but was kind of a prototype made as a proof of concept. I call this 24mm upscale Machete. The 13mm downscale is called Sting. :-)
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  #5  
Old 05-19-2018, 09:43 PM
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neil_w neil_w is offline
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Join Date: Nov 2015
Location: Northern New Jersey
Posts: 335
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Yes, yes, yes. I am a huge fan of this idea. Your execution looks very clean.

There are many ways to do it. I did mine with 3D printing, first in a rocket I dare not name because GlenP is in the room (installation shown here). Photos attached.

I also made a barely useful video showing how it works on another rocket.

Mine is designed with a built-in stop, so you insert the nose, turn about 90 degrees clockwise until it stops, and you're good to go.

[BTW Glen that upscale Machete is absolutely gorgeous]
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  #6  
Old 05-20-2018, 05:51 AM
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ghrocketman ghrocketman is offline
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Join Date: Jul 2005
Location: Michigan
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I like rockets with a locking nose cone that don't separate in the middle.
The ejection charge permanently (and explosively) "separates" the rocket permanently.
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  #7  
Old 05-20-2018, 04:19 PM
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GlenP GlenP is offline
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Could probably fashion a better version of my simple flow-through twist-lock coupler/baffle for something like a Mean Machine or Thunder ROC clone using 3D printed parts or a version similar to the first post with vent holes in it.
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  #8  
Old 05-23-2018, 11:30 PM
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GlenP GlenP is offline
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Quote:
Originally Posted by neil_w
... in a rocket I dare not name because GlenP is in the room ...
[BTW Glen that upscale Machete is absolutely gorgeous]


I know better than to give you a hard time about the name of that rocket.


Thanks, I used the "Challenging" paint scheme from the original Centuri instructions for that one.
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