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kmyren1

Severe line twists with full toggle turn- why did this happen?

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I recently purchased a Hornet 170 and have done only two jumps on it. I weigh 145 lbs and have 36 jumps total.

My second jump on the rig, I tried a full toggle turn (toggle all the way down to my hip) with the right toggle to see how the canopy would turn. I pulled fairly quickly, from full flight to hip in about two seconds. The canopy almost immediately got severe line twists, so much so that my head was pushed down and I almost cut away. I had tons of altitude so waited about 4-5 seconds and the line twists worked themselves out.

Any idea what happened here? Is the canopy not loaded enough to make such turns, or are the flight characteristics of the Hornet just not conducive to such turns?

Any insight would be greatly appreciated!

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kmyren1

I recently purchased a Hornet 170 and have done only two jumps on it. I weigh 145 lbs and have 36 jumps total.

My second jump on the rig, I tried a full toggle turn (toggle all the way down to my hip) with the right toggle to see how the canopy would turn. I pulled fairly quickly, from full flight to hip in about two seconds. The canopy almost immediately got severe line twists, so much so that my head was pushed down and I almost cut away. I had tons of altitude so waited about 4-5 seconds and the line twists worked themselves out.

Any idea what happened here? Is the canopy not loaded enough to make such turns, or are the flight characteristics of the Hornet just not conducive to such turns?

Any insight would be greatly appreciated!



The canopy turns quicker than your body.
You can do that on most canopies, I have managed to do it with a 230.
One thing you can do to prevent it is to pull down the slider and open up your cheststrap.
That makes your risers spread out from your shoulders instead of going straight up from your shoulders.
When the risers are spread out it is much harder to get in to linetwists the way you did.

Read up on what loosening the cheststrap and pulling down the slider does and how it effects you and your canopydrills when canopy is open.
And what it does to your EP.
Then talk to a instructor on your DZ.

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What can happen is that you can stall one side of the canopy. So rather then a banking turn and a spiral one side actually stalls and back slides. One side of your canopy tries to go backwards as the other is going forwards. Think flat spin. It can give you severe line twist almost instantly and feels weird. Some times it feels like your almost thrown and spinning on your back backwards. And this isn't necessarily a wing loading thing. Now some canopies do this more easily then others but that doesn't necessarily mean that this is a bad canopy. It's all about how you fly it. You're getting to know your canopy. That includes learning the limitations of your envelope.

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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Hellis

***I tried a full toggle turn (toggle all the way down to my hip) with the right toggle to see how the canopy would turn. I pulled fairly quickly, from full flight to hip in about two seconds. The canopy almost immediately got severe line twists



The canopy turns quicker than your body.
You can do that on most canopies, I have managed to do it with a 230.

Without being able to know 100% for sure without video or being there, this is the most likely explanation.

I've turned myself into twists a few times - once by accident early in my jumping career, and a couple more times on purpose just to see, later on. Sudden, powerful toggle inputs can put you behind your canopy enough.

I think there's a Brian Germain article somewhere called "clean up your turns" or something like that, that has some useful things to say about maintaining line tension through the turn. It doesn't refer to twists but the ideas in there are relevant.
--
"I'll tell you how all skydivers are judged, . They are judged by the laws of physics." - kkeenan

"You jump out, pull the string and either live or die. What's there to be good at?

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RiggerLee pointed out the idea of stalling one side of the canopy. That's possible, but I'd say more common if one already has the canopy really slowed down. Otherwise putting on a lot of brake will just cause a sudden turn & dive.

Now the line tension thing Joellercoaster mentioned is important. That's the traditional way people would get themselves into line twists back in the 1990s when canopies got faster. (E.g., one Canadian jumper with 4000 jumps died in the mid 1990s when she put herself into diving line twists while maneuvering around too quickly, and she was too low to chop or didn't chop in time.)

Anyway, with some canopies if you snap into a diving turn too quickly with a toggle, you lose line tension as the canopy dives for the horizon and you get suddenly yanked towards it. (Rather than smoothly being pulled along in a turn more gradually entered.) It is worse if you snap into the turn and let up quickly too, say making a 90 degree turn, rather than trying to keep the G's up in a continuous spiral..

All this is why canopy drills that suggest doing quick turns back and forth, are there for you to get a feel for the natural timing of the turns, so you can sashay left and right in a rhythm with your canopy that keeps the canopy and lines loaded up.

Going back to the example of a sudden turn, once the tension is gone or reduced for a moment, the resistance of the lines to twisting is similarly gone or reduced, and with your momentum in turning, your body rolls along the long axis and you twist up under your canopy. Once that first half twist is in the lines, there's almost no resistance to twisting so you keep winding up until the momentum is gone. So it isn't the canopy twisting on you; you twist up under the canopy.

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This makes a ton of sense. I was practicing my flares and plane-out point under canopy before making this turn. I wouldn't be able to recall my speed just before making this sharp turn, but it's possible it was immediately after practicing a flare, before my canopy had time time to surge forward and gain speed again. I will make sure I'm going full speed next time and gradually try the turn again. We'll see what happens:(. thank you for your detailed reply!

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kmyren1

This makes a ton of sense. I was practicing my flares and plane-out point under canopy before making this turn. I wouldn't be able to recall my speed just before making this sharp turn, but it's possible it was immediately after practicing a flare, before my canopy had time time to surge forward and gain speed again. I will make sure I'm going full speed next time and gradually try the turn again. We'll see what happens:(. thank you for your detailed reply!



It's best to do a high altitude hop'n'pop and use the canopy time to find your stall points on toggles AND rears. You really dont want to find those stall points by accident when near the ground...

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kmyren1

This makes a ton of sense. I was practicing my flares and plane-out point under canopy before making this turn. I wouldn't be able to recall my speed just before making this sharp turn, but it's possible it was immediately after practicing a flare, before my canopy had time time to surge forward and gain speed again. I will make sure I'm going full speed next time and gradually try the turn again. We'll see what happens:(. thank you for your detailed reply!



Could anyone say what the recovery arc is like on a Hornet? My understanding is that this is more common on canopies with shorter recovery arc, no?

I managed to do a one sided stall after practicing flares on a Silhouette 190 (which has a very short recover arc). Luckily no line twists but it sure was a quick drop from 1500 to 1000 feet... "No shit, there I was..."

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Could anyone say what the recovery arc is like on a Hornet? My understanding is that this is more common on canopies with shorter recovery arc, no?



What size? This thread has been started with Hornet 170.

You can expect a fairly short recovery from canopies that big.

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kmyren1

Good information-thank you very much for the reply. I do wear my chest strap a bit tighter than most, I'll try loosening it up a bit. Thank you!

Quote




Just to be clear, what he meant was to loosen it AFTER opening. "Tighter than most" is good for the freefall part. Ask your instructor to show you and explain the concept. ;)
HISPA #93
DS #419.5


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yeyo

Just to be clear, what he meant was to loosen it AFTER opening. "Tighter than most" is good for the freefall part. Ask your instructor to show you and explain the concept. ;)



Just to be even more clear ;), you should loosen it not just after opening, but after releasing your brakes and completing your canopy control check.
"It's amazing what you can learn while you're not talking." - Skydivesg

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kmyren1

Good information-thank you very much for the reply. I do wear my chest strap a bit tighter than most, I'll try loosening it up a bit. Thank you!



And too keep this posting.
To make it even more clear:
There is no point of opening the cheststrap unless you pull down the slider (except for comfort, but that is a personal preference).
The cheststrap will not spread your risers more than your slider allow it, thus not help the issue this thread is about.

If you look at a canoy from the front with the slider up you will see that the riser are straight.
If you sit in a childs swing it is easy to create linetwist because the chains/lines are straight.
With some angle on them it becomes much harder.

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phoenixlpr

Quote

Could anyone say what the recovery arc is like on a Hornet? My understanding is that this is more common on canopies with shorter recovery arc, no?



What size? This thread has been started with Hornet 170.

You can expect a fairly short recovery from canopies that big.



This was in reference to the OP's Hornet 170. Right you are that size has a big impact on the recovery arc. In my (admittedly rather limited) experience canopy type characteristics still have a significant impact though. Compared to the Sabre2's I've jumped the Silhouette damn near stalled itself from auto-flare after a hard turn...

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Snowcrash

***

Quote

Could anyone say what the recovery arc is like on a Hornet? My understanding is that this is more common on canopies with shorter recovery arc, no?



What size? This thread has been started with Hornet 170.

You can expect a fairly short recovery from canopies that big.



This was in reference to the OP's Hornet 170. Right you are that size has a big impact on the recovery arc. In my (admittedly rather limited) experience canopy type characteristics still have a significant impact though. Compared to the Sabre2's I've jumped the Silhouette damn near stalled itself from auto-flare after a hard turn...

Let's have a thought experiment.

You have managed to put your canopy into dive somehow.

Why is your fairly big canopy is coming out of dive?

That system fly/falling consist of your canopy, lines and your body.
If the air resistance of your canopy is significantly greater than the air resistance of your body you canopy is getting out from the dive by itself.

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Snowcrash

***This makes a ton of sense. I was practicing my flares and plane-out point under canopy before making this turn. I wouldn't be able to recall my speed just before making this sharp turn, but it's possible it was immediately after practicing a flare, before my canopy had time time to surge forward and gain speed again. I will make sure I'm going full speed next time and gradually try the turn again. We'll see what happens:(. thank you for your detailed reply!



Could anyone say what the recovery arc is like on a Hornet? My understanding is that this is more common on canopies with shorter recovery arc, no?

I managed to do a one sided stall after practicing flares on a Silhouette 190 (which has a very short recover arc). Luckily no line twists but it sure was a quick drop from 1500 to 1000 feet... "No shit, there I was..."

I jump the exact same canopy Hornet 170 wingloaded @ 1:1. I'd imagine that what you said on planing out, then flaring then turning is exactly what happened.

A couple weeks ago I did a toggle stall with plenty of altitude for the first time on my Hornet. It had a very quick recovery. 1st time I've ever tried that wasn't as bad as I thought but definitely a weird feeling making a perfectly good canopy 'go away' and then come back.

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