Tiedown Rope Length?

[David Paule]

I plan to get some tiedown rope. I've selected the type and size (high-tech core, polyester or Technora cover, double braid and 1/4" diameter) but don't know the length. Any recommendations?

I expect that the wing ropes and tail rope will be different lengths.

Dave

[Ironflight]

Considering the at most tie-downs are set up for airplanes much larger than a -3, I carry enough for a 40-foot spacing. I would have to go dig out the kit, but I think I have 25’ for each wing, and probably a 15 or 20 for the tail. I’ve using 5 or 6 mm climbing rope, so not terribly heavy. A set of lightweight carabiners is also part of the kit.

Paul

[David Paule]

Thanks, Paul, looks like 70' then.

I'll be getting New England Ropes Endura Braid, 1/4" diameter. Strength isn't an issue at around 4,500 lbs.

Dave

[Blw2]

Is this for taking with you, for use in transient parking...just in case?
guessing this because if it was for your own fixed location you would know the spacing and how much you need....

70ft of climbing rope makes for quite a big pile of rope....

This is just a thought based on some experience in non-aviation applications.... have you considered using dynema rope (such as Am-steel) for that use? It's very strong so a much smaller diameter can be used...taking up much less space in storage, and probably lighter weight too. Maybe there's something about it that I'm not considering, that makes it not good for the application.... so this is just a thought to consider

[rockwoodrv9]

I had never heard of Dyneema Rope. I looked it up and it is pretty impressive. I saw this - a different brand and pretty cheap if it lives up to the specs. 8500 lbs pulling strength for 1/4" sounds hard to believe. At $20 I may give it a try on my ranch and see how it works. If good, it would be a nice replacement for the bigger rope I have in my plane. https://www.amazon.com/dp/B096LTDR1X...d_plhdr=t&th=1

Originally Posted by Blw2

This is just a thought based on some experience in non-aviation applications.... have you considered using dynema rope (such as Am-steel) for that use? It's very strong so a much smaller diameter can be used...taking up much less space in storage, and probably lighter weight too. Maybe there's something about it that I'm not considering, that makes it not good for the application.... so this is just a thought to consider

[David Paule]

Dyneema won't hold knots under sustained load. I have pull-tested it and watched the line slowly slither through the knot, which held shape and tightness. Even a stopper knot doesn't help.

And the full strength is unobtainable with knots, since they reduce the assembly strength by as much as 50%. That said, and within its limitations, it's excellent. It's tough and somewhat resistant to abrasion. The way to obtain 100% of its strength is through a spliced loop. I prefer Brummel splices, or did back when I still had my sailboat, but perhaps there are other suitable splices too. The Brummel splices are fairly easy to make.

If you look up the Endura Braid which I'm planning to get, you'll see that it's got a Dyneema core and a polyester cover. The cover adds the ability to pull the rope and hold a knot, since bare Dyneema is a bit slippery.

I've got like 80' or 100' of 1/8" Dyneema line laying around which I used in a block and tackle to pull my non-RV back into the hangar. It was hard to keep that from tangling. I now have a wonderful tug that does the job so nicely.

The main criteria for tie-down ropes is low-stretch. That takes the right material and a large enough diameter to build EA. E stands for Young's Modulus, a material characteristic, and A for the cross-sectional area. I would buy the 3/16" Endura Braid except that I felt it would be too stretchy.

Dave

[MacCool]

For conveniently and rapidly shortening the rope after using the carabiners to secure both ends (wing/ground anchor), what would be the preferred buckle or other such device? It seems to me that that would be the weak spot in any tie-down mechanism....(excluding security of the ground anchor, of course).

[David Paule]

Hook the 'biner on the wing tiedown loop. Tie the rope as tight as you can and knot it with three half-hitches. Repeat on the other wing. Go to the tail tiedown, clip the 'biner to it, and use that rope to pull the plane aft until it's very firmly anchored.

No rope adjustments needed nor desired.

Do not leave slack in any rope. The last thing you want is for the plane to move - in strong winds, that'll lead to rocking or bouncing and the dynamic overload will fail something. And the plane will be lost.

Dave

[rockwoodrv9]

I got the WROUGH Synthetic Winch Rope 1/4 x 50 Winch Line Cable Rope Breaking Strength for 8500lb today and tried to pull my truck with my tractor across the snow covered mushy grass. It worked fine. Im not sure how much it stretched. I will try and figure out how to test it. Maybe just pulling my truck in park with the tractor and marking a 4- section and see how far it stretches before it breaks. The pull test gave me confidence in its strength.

I will let you know how the test goes. So far, for $20 I will get more to use around the ranch. I like it.

[dstates]

For my current high wing airplane I purchased 15' long double braided nylon dock lines. They have been plenty long for all tie downs that are anywhere near the wings & tail.

What I like about a dock line is that it has a braided in loop or eyelet at one end. Normally that would go over a cleat on a boat, but I see it as one less knot I have to tie. Just feed the loop in through the tie down on the ground and then feed the other end of the rope through the loop and pull tight.

I also wish I would have bought bright yellow, orange or red lines instead of the dark color I have now. I think that would be safer for those walking around the plane.