Tubular Nylon Replacements

[edwardw]

Hey guys,

I have a couple questions about TN. I have been using 9/16 TN for connecting my parachute and my two sections. I really like TN, but it is bulky and weight a lot. I want to use drogue-less dual deploy with my L1 rocket-rebuild - and wondering what alternatives I have to TN for keeping the two sections together? Also - any other ropes/cords I can use for attaching the parachute to my e-bay u-bolts?

Thanks!

Edward

 

[Ryan S.]

there are some climbing cords, but they are hard to tie and the knots become bulky and I dont think you save any weight. There is also tubular Kevlar but I think that is just as heavy. IN the end Tubular Nylon yeilds the best results because it is easy to knot, doesnt take up to much space, and is strong

 

[Missileman]

as far as I know right now TN is about the best thing readily available.
It does seem to me I read about Spider Wire in larger than fishing line sizes but can't seem to find anything about it right now. I would imagine it would be costly if you can find it.

 

[edwardw]

What do you think about 500-1000# kite cord?

Edward

 

[Rocketjunkie]

You can get tubular nylon in smaller sizes. It's used for lacing snowshoes.

 

[edwardw]

Where do they sell it? I'm looking for 1/4ish sized...


Thanks!

edward

 

[rstaff3]

You can get some nice Kevlar cord in that size from Pratt Hobbies.

 

[Rocketjunkie]

Originally posted by edwardw
Where do they sell it? I'm looking for 1/4ish sized...


Thanks!

edward

https://www.snowshoe.com/shop/product.cfm?p=11 lifetime supply
You might want to keep an eye on eBay. Tubular nylon comes up occasionally.

 

[mkmilion]

I too need tubular nylon or Kevlar but can't figure out the "size" in relation to inches. I need something a tad smaller that 3/32". If anyone with such knowledge please help me. BTW if you are familiar with the Estes Blurrz Rocket Cars. I seek something that is exact or simliar to the tether line used with those kits.

 

[Ryan S.]

you could use something of smaller diameter and you might save weight but I still would Use tubular. If you use a "line" then your chances of zipper are huge because there is mor pressur because the force is not spread out as much as with tubular nylon

 

[rstaff3]

It is not that difficult to make anti-zipper devices for your Kevlar twine or small braid (or for larger types for that matter). On modroc sized lines, this can be as easy as a piece of tape folded across the line at the point it touches the BT. On the Pratt mini kevlar braid, I have used a rubber ball and even bubble wrap covered in cloth tape.

https://www.pratthobbies.com/products.asp?id=1&pg=2

 

[kgholloway]

One item that I've used for mid-power rockets is nylon cord from REI (https://www.rei.com). Their 4mm accessory cord has a breaking strength of about 700# and is much easier to pack into a confined space than 9/16" TN.

The only problem with the cord is that for maximum strength you need to "whip" loops into the ends of the cord instead of tying a knot. Whipping loops is easy to do, you basically use a light thread wrapped around the cord to "squeese" the tag end of the line to the running line. Get a copy of "Chapman Knots for Boaters" from your local library. It has a chapter on whipping with photographs and illustrations.

Ken Holloway

 

[mkmilion]

I am using it as a guide/tether line for a ground based rocket powered project. I plan on posting the results but in the mean time I need the cord first. I appreciate all of the comments though.