Zip ties nose cone

[Jacktango22]

I am thinking about using zip ties to affix Kevlar shock cord (with a loop at end) to nose cone.

Very light and strong and easy to cut off if desired. One less swivel at the top.

 

[lakeroadster]

I am thinking about using zip ties to affix Kevlar shock cord (with a loop at end) to nose cone.

Very light and strong and easy to cut off if desired. One less swivel at the top.

A ziptie, does not, a swivel make.

 

[FredA]

I think you'll lose your nose cone.......that's what I think.

 

[dhbarr]

I did this for my L2, since I didn't have an extra bit of Kevlar to thread through the extra hole in my NC. Worked fine.

 

[dr wogz]

I say no.

Either tie the Kevlar to the NC, or loop the loop thru itself to attach the NC..

Pass the loop thru the NC eye, then make a byte in the Kevlar cord. Pass that thru the loop, then over the NC, pull tight. You should then have a half hitch / lark head knot on the Kevlar around the NC eye..

https://en.wikibooks.org/wiki/Knots...he lark's head is,ends of the fastening loop.

 

[prfesser]

Probably will be just fine, especially for LPR and MPR. 1/8" stainless steel quick links are reusable, easy to undo and redo if you need to change something, and stronger than nylon of the same general size.

 

[Jacktango22]

Good thoIshtar. I have used swivels for a while. It seems to me that there is a lot of complexity at the front of the tube when the ejection charge fires and I am experimenting with ways to reduce it (if possible).

 

[David Schwantz]

Not on my rockets

 

[lakeroadster]

FWIW: The other thing to remember about zip ties, especially the cheap ones, is they become brittle and break if they are old. Especially if they are subjected to UV.

 

[Hobie1dog]

as you can see, lot's of scepticism on doing this

 

[waltr]

FWIW: The other thing to remember about zip ties, especially the cheap ones, is they become brittle and break if they are old. Especially if they are subjected to UV.

Was thinking the same thing. Some of these can be brittle and easily snap.

It seems to me that there is a lot of complexity at the front of the tube when the ejection charge fires and I am experimenting with ways to reduce it (if possible).

Not sure what you mean by complexity...
For MPR and up the nose is directly connected to end of shock cord. Chute connected to loop on cord a bit below the nose.
Next, which I feel is very important, is to either do taped bundles or braid the cord to resists being pulled apart. This absorbs energy and slows the cord extending reducing shock to the recovery system.

 

[Jacktango22]

This is all very helpful input guys. I am a recent retiree and am getting back into this hobby —— which is so much more sophisticated than it was in my youth.

I am only doing mid power (not sure I will try for Level one). The “complexity“ I have in mind in the physics of the many different forces at the time of ejection — with the parachute and it’s attachments flying out in the middle of it all —- realizing that my goal is a “good” flight for me —- meaning a full chute deployment and an intact recovery of the vehicle.

It’s an art form I think…. Getting all this just right on a regular basis.

 

[bjphoenix]

It’s an art form I think…. Getting all this just right on a regular basis.

There are a lot of little aspects of rocketry where you can do your own little experiments to try to do better or easier or whatever than what is commonly done, I like to do some of those myself.
For LPR the loads are relatively low, it is easy enough to do your own little experiments to see if something has a chance of working before you actually do launches. For MPR it is harder because the loads are higher but the concept is somewhat the same. I've seen some pretty large zip ties.

 

[FredA]

In another thread someone posts about amazingly high G-loads due to ejection.....
Greater than 100G's.
Zip-Ties don't do well with shock.
How's your chosen Zip-Tie rated for shock?