Sorry! For the record I'm using GLR's Tubular KEVLAR® 1/2", and I think it's rated at 7k-8k lbs. I trust the loops. But haven't stressed them past K's. I don't trust tubular nylon, had it break--though I believe the Event Horizon uses tubular nylon quite successfully. I WILL make an L3 version of GLR's Fireball, which is Kevlar rolled up into a ball that hits the BT instead of the tubular harness. Man, I'm glad I ask these questions... 😉

My bad, Bruce! For some reason, I was thinking you were using flat stuff... You will do superb with the tubular Kevlar. It is wonderful stuff.

FWIW, I failed an L3 attempt because my sewn loops failed. It was on a piston strap. It was a perfect boost, perfect day, perfect everything -- until the main opened and the loop tore, dropping Mr. Booster from 1000'. Approximately 3 hours after that heartbreak, all my shock cords had KNOTS instead of sewn loops. I used a knot called a "turle" knot, which is sometimes used by flyfishing enthusiasts. Never a problem since.

After a very rocky start to my L3 (I blew it twice) I have had 7 great M or N flights on the knotted Kevlar, all without a hitch, some on really heavy birds. I'm going to try to make it 8 straight if it ever rains again :-O

JW

You have to show me that "turle" knot. Not using a piston, just Kev pad. The sewn loops WERE to be used to hold Quikllinks that attached to the U-bolts, etc. Not anymore though. Thanks! 😉

Found this knot site: http://shoreangling4u.tripod.com/knotguide/index.html

There are WAY too many knots in the world...

John and I both use about the same kind of knot. Ive seen to many of the loops fail and wont use them either. Its kinda like this deployment bag im not gonna use. All sewn with loops, Flat Nylon shock cord and its all kevlar but sewn together with nylon/polyester thread. As far as I am concerned all strikes against it for anything good to use. Should be using tubular kevlar, able to tie knots, and kevlar thread. So I will just have to do it with a large chute protector pad or 2 from kevlar. A properly tied knot should cinch down on itself and not weaken the fabric as well as not come loose.

All the loops in GLR's tubular Kevlar cords use Nomex thread and say the loops are stronger than the cord itself. I thought about using a deployment bad, but as you did, decided against it.

From GLR's site:

Laboratory tested. The loops are stronger than the cords!

Loops are sewn with fire-resistant NOMEX®!

Laboratory tested. The loops are stronger than the cords!

Loops are sewn with fire-resistant NOMEX®!

Good luck 😉 I'm tyin' knots...

Hey, let's go knots! I mean, it's knot like you're trying to get a point across. I really would prefer that knot happen. 🙂

Hey I use nothing but sewn loops and have never had one fail, but to each his own. I (should say Donna) uses very strong thread and we use very strong machine stitching . Flat kevlar also has been fine for me, and any knot except robert DeHate's finger trap will become the weak link in the chain, that much isn't opinion. Theres a good rocket material strength site somewhere which subjects various materials to very precise testing--iirc the knots (tho I don't recall which kind) failed at about 1/2 the load that the material did. Just stress multiplication. Might be one of those issues where you need stronger material to overcome the weakening of the knot, not sure, but the longer the material--I think i had close to 50' for apo, and 30 for mains with my L3 shot, the less stress everywhere!
John S

Okay, okay... so I take the loop and pass the line through it, THEN tie a knot. How's that? 😀

During medical school I had the opportunity to help out with a few heart transplants and innumerable by-passes--by help I should say apply retractors to keep the field open, and harvest huge strips of vein and get to sew up these gaping leg wounds. But what impressed me most was the surgeons skill in tying knots thru these tiny vessels, really simple stitches, but paid a helluva lot more than your tailor. 😉 Sure they needed understanding of the anatomy and physiology, but really the anesthesiologist took care of that end, and it came down to their skill at abutting a couple of worms together.
John

and any knot except robert DeHate's finger trap will become the weak link in the chain, that much isn't opinion.

All's I know is that I'm unscathed with knots, and 0 for 1 with stitching. $300 worth of reload later (plus hundreds of dollars of damage to the rocket)... No stitching for me. Still, everyone should go with what they are comfortable with.

I know of no one who had a knot fail; I personally have had stitching fail. Incidentally, the turle knot, like most any flyfishing knot, is designed specifically to weaken the chain as little as possible.

The best endorsement I've ever heard is from one of our club's members who is a rock climber, who told me he uses the exact same knot (and not stitching) when he is hanging from a mountainside. Pretty much convinced me which way to go...

Still, everyone should go with what they are comfortable with.

I know of no one who had a knot fail; Incidentally, the turle knot, like most any flyfishing knot, is designed specifically to weaken the chain as little as possible.

The best endorsement I've ever heard is from one of our club's members who is a rock climber, who told me he uses the exact same knot (and not stitching) when he is hanging from a mountainside. Pretty much convinced me which way to go...

Ditto

JW,
I have never had a knot or loop fail to my knowledge but i have lost three rockets this year so not sure... but its early in the game, bound to sooner or later. With rock climbing, fishing, sailing, you need a way to locate knots on the fly. At best a knot can do no harm. Thats the beauty of bob's knot--it isn't and causes no weakness. Not to get personal but how'd you lose your nose cone at Balls? Where did it break?
John

Bruce, I may l know little about rockets, yet I try to learn. What I do know is this, I have been a Ironworker for over 40 years. I have used rope, wire, and nylon chockers. I have lifted THOUSANDS of loads and never have I had a loop fail, Never. You pass the live end through the loop and put the hardware in a "bite". That is why they call them chokers. In a choke, the bite has 2X the cap of the line. A 1/2 inch Kevlar is rated at 8,500lb. dead pull. The chock or basket is rated at 17,000lb. It will never fail. Period, I bet my life on it. All the time. 8)

That's a good endorsement, Tim. Actually, if I were a rock climber, I WOULD trust them to hold me up. 🙂