Questions on line weight.

[rexracer]

I just got a Prism Hypnotist that I'm going to be towing a 100' tube tail with. It came with 85' of 150# Spectra line, and I bought a LPG 150# x 150' lineset so I can show off that tail. I'm looking at the kite, and I'm thinking that it's no bigger, and maybe smaller, sail area wise, than my Rev, which I fly on 90# most of the time. I had my Vented Rev in30+ mph gusts and it was pulling hard. Hard enough where I was worried about breaking the 3 wrap frame.

I guess what I'm trying to figure out is why the Hypnotist needs 150# and the Rev only 90#. At a guess, the inputs don't put as much peak stress with a 4 line, while snap turns on a 2 line put more peak stress.

I would love to hear from anyone who ever broke a line that wasn't damaged, and what it took. Could I fly the Hypnotist on 50#? Would I go to snap a square corner and snap a line instead? How about 90#?

Just so everyone understands, I'm just trying to get a feel for the limits, I'm not planning on flying my new kite on 50# line any time soon, but maybe a 120' set of 90# for flying in light winds would work if I modified my flying a bit to keep peak stresses down. Maybe stick to push turns. How about line weight for slack line tricks? is heavier line better or lighter?

Has anyone here experimented with line weights or stressed them to failure? I realize that line failure can be dangerous not only for the kite, but for anyone nearby also. I'm curious by nature and am always looking for the "why" of things. Some things never change.

[Wayne Dowler]

Let's do some math - 4 x 90 = 360 2 x 150 = 300 So 4 lines at 90# are actually stronger than 2 lines at 150#!! Might have some differences in the real world, but a good start! That's why almost all Rev fliers just use 90# lines, they're plenty strong! 150# is only used in extreme conditions!

You really need to read your lines for sag or droop! That will tell you if they are strong enough for the day's conditions!

[West Australian]

Wayne's math is spot on.

Dual and Quad are different beasts.

Power Quad is also another story, as they have Stronger front lines than back lines as most of the force is on the front lines.

In the lightest of winds the Hypno can be flown on 90#.

I would not risk it on 50#. A hard pull could snap your line.

I find a full Dual sail works well enough on 150# and there was no noticeable gain for me on lighter lines.

But you could try out 90# and see if you prefer it.

The Zephyr I usually flew on 90# though. But only because that is what it came with.

[Hadge]

The Hypno is a big kite with a fairly strong pull so you are going to need a fairly strong line. Remember than the line poundage shown is a minimum braking strain so the actual is probably going to be 10-15% more with a good quality line. I wouldn't fly it on 50lb , but you should be OK on 90lb in lower wind speeds.

[Reef Runner]

I agree, that 90# LPG, or 100# BB, should be sufficient, in the middle of your wind range, tail or no tail. If it was really kicking up, as I was setting up, I might slap on the 150# LPG, or a 140# BB. (LPG laser pro gold - BB berry blue) Either way, if that kite is really pulling on you, making you step forward, every now and then, it might just be telling you something! As Wayne said, watch your line sag. If they are constantly sagging and drooping, as you fly, then you've probably got lines that are too heavy for the existing conditions. Likewise, if they are banjo tight all the time, well, you might just be on the verge of a failure.

BTW, I have never broken a line, maybe due to luck, or maybe due to using the upper end (?) of the strength spectrum, but either way, I've never felt like I was pushing it too hard, either. As for Wayne's theory on 4 lines verses 2 lines, that's kinda what I've always felt to be true, when comparing to Revs, anyway. I rarely use more than 50# LPG on my B2's, which I fly, almost exclusively these days, but that's quad line, and it's a smaller size Rev. Some days, when the wind is pretty nice (8 - 12 mph), I will actually fly the B2 vented sails with the 50# LPG, and bump up to 90#, on the standard sail. With 10+ winds, it's pretty obvious that the standard is pulling much harder than the vented sails, so why drag around the extra line weight on the vented ? One thing that I will say, about Wayne's math theory (and I think he will agree), is, that during normal, outdoor quad-line flight, the upper lines take most of the stress, most of the time. Pulling straight on against the wind, I suppose the force is spread out pretty equally, on all four lines, but I feel that during normal flight, the upper lines definitely take most of the abuse. I know for a fact, that after a long period of flying, I will sometimes begin to notice, that my top lines are longer, than my bottom lines. This usually becomes evident, when you pair up the lines, and wind them up. When I see that this has occurred, I usually make a note, to switch the bottom lines to the top, and the top lines to the bottom, the next time I hook them up to fly. This will eventually equalize things back out, once again. And speaking of upper verses lower, I do know (as WA mentioned) that there are several quad line kites, both sails and foils, that come from the manufacturer, with different strength lines (stronger top lines than bottom), which seems to bear out our theory, that there is more stress on the upper lines (in quad-lines, that is). Oh well...........we just deal with it !

[SHBKF]

I have broken (lots of stuff) 50 lb 75' lines with a small kite, the HQ Shadow. During the same session an even smaller kite did not have enough power to fly these lines without drooping as mentioned above. I think the light lines are, for me, limited to shorter sets. Longer lines get me into higher winds as the distance from the ground increases. Have flown quad 50' x 50 lb sets with no problems in light gusty winds. If a kite is generating enough pull to move you then think about the strength needed to do that & adjust upward. Others note the sounds of the lines as the wind makes them whine or sing. Big single line kites are in a class of their own as are the larger foils. I have flown a Power Blast 2-4 on the 50 lb lines, but I break things.

[rexracer]

I have broken (lots of stuff) 50 lb 75' lines with a small kite, the HQ Shadow. During the same session an even smaller kite did not have enough power to fly these lines without drooping as mentioned above. I think the light lines are, for me, limited to shorter sets. Longer lines get me into higher winds as the distance from the ground increases. Have flown quad 50' x 50 lb sets with no problems in light gusty winds. If a kite is generating enough pull to move you then think about the strength needed to do that & adjust upward. Others note the sounds of the lines as the wind makes them whine or sing. Big single line kites are in a class of their own as are the larger foils. I have flown a Power Blast 2-4 on the 50 lb lines, but I break things.

That's what I mean. If I have a pair of 90# lines then they should (theoretically) be able to lift me off of the ground. A 90# line should be able to pull my arm straight before it breaks.

I think I may have to rig up my digital fish scale to see what kind of pull I'm getting on the lines. I should be able to fly a kite with 1 strap and a fish scale!

[SparkieRob]

Don't forget that knots reduce a lines strength.

[Wayne Dowler]

It is true that the top lines of a quad take more stress, but with your top leaders adjusted out enough, you get an almost equal pull on all 4 lines!! Most Revs (not all) are about control, not power, so that's why Revs have the same top lines as bottoms! Power quads are a different story altogether!! Sorry, I don't fly them - my stroke left me with bad balance!!