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Tonto

Built in turn on GTi?

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Hi There,

I did 3 dives on a borrowed GTi on Saturday. I swear it had a turn to the left. The suit may be a little on the short side for me.

The only way I could get it to fly straight was by pointing my left toe in and pushing out sideways with my heel in a gimpy kind of way...:S Then it flew great!

Could a too tight suit cause this? It was consistant through 3 flights - and the suit/rig was assembled symetricaly. I have 40 something wingsuit dives, and this is the 1st heading control issue (1st any issue actually) I've had.

t
It's the year of the Pig.

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Tonto, are you quite certain that you had the suit hooked up correctly? Is it possible you had it hooked up differently right/left? That would obviously cause problems and I have found more than a couple of people hooked up incorrectly when I inspected their gear prior to a flight.

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Tonto, are you quite certain that you had the suit hooked up correctly? Is it possible you had it hooked up differently right/left? That would obviously cause problems and I have found more than a couple of people hooked up incorrectly when I inspected their gear prior to a flight.

Yeah, some people have managed to route the cutaway cable through or under the legstrap, not just the lateral, on one side. I saw this just recently, and it was only on close inspection. One side of the suit was "scrunched" up a wee bit. The suit wasn't flown that way, but I would imagine that one leg would be pulled up one to two inches, which would definitely put in a turn.
"¯"`-._.-¯) ManBird (¯-._.-´"¯"

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Hey Chuck.

Absolutely certain. I had the guy who owns the suit, and 2 others with wing suit experience check it out both on the ground, and when I was wearing it after the 1st dive had revealed the problem. It literally got down to people saying, "Well, there's an empty hook knife pocket there... could that do it? Maybe the LQRS?"

The suit owner jumped it like that without changing hookup or rig. (And of course said he had no turn issue whatsoever..but still ended up with line twists:D which is something I have yet to get;))

The turn was consistant and slow, maybe 3 degrees a second, so easy to correct for. Felt a bit like a wheel alignment problem. Everything looked straight, felt straight, but it went skew - then when I did the gimpy foot thing, it went straight.

100% sure the rig was symetrical. I did 3 dives... and was obviously quite keen on solving the riddle.

I'm completely mystified...

t
It's the year of the Pig.

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I lent my GTi to a friend and he came back complaining of an involuntary turn. In that case the suit was a little big for him and he thought it was because he couldn't properly tension the wings. I just blamed the pilot!

Tonto did you get any video of you in flight? It doesn't take much of an asymmetry to cause a turn....

Gus
OutpatientsOnline.com

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No video I'm afraid.

All 3 dives were solo's. The 1st one I did a right turnout (Porter has a Right door exit) and needed to pull the suit past the centreline which took quite a bit of input.

After checking things out on the ground and making sure things were even on both sides I went for the second jump. Again the suit went off to the left, but I had briefed the pilot I would be doing a left decent, and allowed it to go where it wanted to, correcting only for the straight line sections of my flight.

Much checking on the ground and debate followed, but on the 3rd flight the suit again moved to the left.
I wore a proTrack on only the 1st dive, but my vertical speeds were about 10mph HIGHER on the GTi than they normally are on my Classic - so I was obviously arching quite a bit more out of insecurity.

I have flown this suit once before in rather crappy conditions, in near darkness when I had fewer wingsuit dives - and it flew straight then. Maybe cos its getting cold now (Southern Hemisphere winter coming) I had more clothes on this time and that had some effect. What amazed me was how consistant it was, and how exacting (and uncomfortable) the gimpy foot positioning was. Driving home Saturday night I was getting cramps on the outside/back of my right calf muscles I'd been using to trim out the problem.

I must add that all other Birdmen on the DZ were overjoyed that I'd run into a problem! They've been having a far more exciting learning curve than I have thus far!

t
It's the year of the Pig.

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An issue I had a few dives ago was my rig had shifted on my back from sitting in the Cessna and I could'nt center it on my back before I exited. The turn was a slow banking turn that was corrected by the same foot pressure thing you used to fix yours.
Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

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That could be an issue - but in the Porter which runs in REAL slow, and leaving last, I literally have about 45 seconds between 1st exit and when I get out which is plenty time to feel if things are not right.

Anyway. I'll probably find that it's gone away next time I jump that suit. I'll be back on a Classic this weekend and that should be a blast since they've always been so good to me, from the 1st second of my 1st wingsuit dive. I'm learning, and from the replies I've got this far, we all agree that something is assymetrical somewhere, and that's what caused the turn. I don't think it was me, as I have some awareness out there and would fix the problem. It may be the suit - which is fine cos its not mine.:P
It could be the rig and the way it was hooked up incorrectly in some way no one could notice - but I'll probably get it right next time.

I do appreciate the experience I've gained at controlling something beyond myself - and was reminded of a few Tandems I've done when you correct a student's turn by doing your own thing.

I'm learning.

t
It's the year of the Pig.

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Very light. About 10 kts. When I first felt it I thought I may be "weathervaning" into a different layer, but it happened all through 180 degrees on both right hand and left hand turn outs.

t
It's the year of the Pig.

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I don't see winds causing a heading change. A crab, possibly, but not a heading change. (certainly not over 180 degrees).

My bet is still that your rig is akilter somehow, as Phree says. I know that when I am trying to tighten up my rig in the plane, I never can tighten it perfectly (the way it should be in freefall), unless I am in a skyvan and can stand all the way up.

j

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I know that when I am trying to tighten up my rig in the plane, I never can tighten it perfectly (the way it should be in freefall), unless I am in a skyvan and can stand all the way up.



Well... with a wing suit that gets done on the ground. No way am I undoing my suit on jump run to adjust legstraps. I also sat in different positions in the kite on the 3 dives, and the only consistant factor I have is the turn.

I hear you, and agree that it's a lack of symetry somewhere - but I'm insistant that I and others were looking for it for the whole day - and didn't find it.

t
It's the year of the Pig.

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Well... with a wing suit that gets done on the ground. No way am I undoing my suit on jump run to adjust legstraps. I also sat in different positions in the kite on the 3 dives, and the only consistant factor I have is the turn.



Well, I have tweaked my legstrap tightness without any problems. pretty quick to do if you have the room. I know in my rig, if I am moving around a lot in the A/C, my legstraps will work loose a little bit. If it is asymmetric, then it may cause some issue.


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I hear you, and agree that it's a lack of symetry somewhere - but I'm insistant that I and others were looking for it for the whole day - and didn't find it.



Well, another few jumps on it might reveal it.

I have also noticed some slight differences when I have had one sleeve 'turned back' a bit more than the other. The air didn't seem to inflate the wing as well. A little bit of wiggling, and I could get the sleeve rotated back in place (symmetric).

j

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If you accidentally route the cable through the hip ring, it is not noticeable at once the wing is sewn up, unless you closely examine it from the inside. But if you're certain that it was done right, than I believe you.

Wind won't change your heading. It affects your flight the same way it affects everything else. It will change your position in relation to the ground, but not heading. The only difference is that flying at very low velocity ("floaty" or stalled) in a crosswind, you can feel one side of the suit pushing up a little bit, or near clouds, you can experience turbulence (only at very low velocities).

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Could a too tight suit cause this?



It could, but only according to a wild theory I just thought up. Is it possible that one leg is slightly longer than the other? It wouldn't affect anything until you put on a tight suit. It's not uncommon (in fact, my right leg is about 1/5" longer than my left). In this case, it's possible to encounter a suit that fits in a way where only one leg can fully extend and the other one either needs a slight bend in the knee or doesn't fully stretch out the bootie. Seems crazy, but not impossible. It's the last thing I can think of before blaming the pilot.

Turn issues are almost ALWAYS feet. I've videoed people that swore up and down that their feet were symmetrical and on level, but the video showed otherwise. It's usually instability, though (assymetrical heels). If your feet aren't on level, it causes a slide. If one foot is pushed back further than the other, it causes a turn. You have a subtle and almost unnoticeable combination of these going on that results in a "built-in" turn.

And I seriously doubt it's the suit itself. If others have flown it straight, then that's not the issue. If you looked at how they're made, assymetrical construction is pretty much ruled out.
"¯"`-._.-¯) ManBird (¯-._.-´"¯"

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With a wing suit that gets done on the ground. No way am I undoing my suit on jump run to adjust legstraps.Done as in sewn up or put on? If you need to adjust leg straps, just unzip the double zippers. I do it all the time. Being that it's very difficult to adjust leg straps under canopy, I pay extra attention to leg strap symmetry and adjust, if needed -- even in the plane.

As a side note, I always don my suit while standing. :)
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I have also noticed some slight differences when I have had one sleeve 'turned back' a bit more than the other. The air didn't seem to inflate the wing as well. A little bit of wiggling, and I could get the sleeve rotated back in place (symmetric).



Good call. A very plausible cause. I have experienced that before (can be fixed in freefall with a few shakes of the arm), and have since always checked that the end of the zipper is in the same place on each hand.
"¯"`-._.-¯) ManBird (¯-._.-´"¯"

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It could, but only according to a wild theory I just thought up. Is it possible that one leg is slightly longer than the other? It wouldn't affect anything until you put on a tight suit. It's not uncommon (in fact, my right leg is about 1/5" longer than my left). In this case, it's possible to encounter a suit that fits in a way where only one leg can fully extend and the other one either needs a slight bend in the knee or doesn't fully stretch out the bootie. Seems crazy, but not impossible. It's the last thing I can think of before blaming the pilot.



Believe it or not, I think this might be happening with me. I have a GTI that I've jumped 12 times (only 2 jumps on other wingsuits). I personally think it is a bit too tight - if I stand on the ground on tiptoes I can feel the material from toe all the way to shoulder stretching tight just as my toes get pointed all the way. It happens with both legs.

However, in the air, when I go to point my toes and max out, many times I feel the material on the left half of the suit ONLY get very tight and then I start turning left slowly. I told Jari about this and he was sure it was pilot error, and at my experience I don't want to disagree - it's very possible I'm doing something wrong.

But here's the kicker:

On my last wingsuit jump I had a cutaway and hurt my back, the reason I haven't jumped in 6 weeks... but that's not the point. The point is I went to a chiropractor for my back and he found out something about me from looking at x-rays. My right leg is effectively 3/4" shorter than my left! I say effectively because the leg isn't actually shorter, but my pelvis is "clocked" permanently, for some reason or other, he said it's probably been like this for years. He said up to 0.2" is normal in most people, but 0.75" is a fuck of a lot!

So... my left leg gets tight when I try to max out the suit. My left leg is 3/4" longer. Coincidence? I still don't know, and I'm sure it's possible I'm still doing things wrong up there. I know from looking at video of myself sitflying my legs are not symmetrical when I think they are (sitflying, at least). But I'm thinking of getting both the booties extended a bit...
www.WingsuitPhotos.com

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If you accidentally route the cable through the hip ring,



No hip rings on my rig...

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Could a too tight suit cause this?



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It could, but only according to a wild theory I just thought up. Is it possible that one leg is slightly longer than the other?



That may be it. My right leg is a half inch longer than my left as the result of a broken left femur many years ago...

t
It's the year of the Pig.

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[replyThat may be it. My right leg is a half inch longer than my left as the result of a broken left femur many years ago...

A longer right leg on a very tight suit could very likely be the culprit to a slight left turn. By pushing your left heel out, you are stretching the tail to even out the trailing edge between your legs (since it's above your heels on the GTi), and therefore removing the turn. I think we may have found the problem. One more reason to avoid to tight of a suit. :)
"¯"`-._.-¯) ManBird (¯-._.-´"¯"

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My right leg is effectively 3/4" shorter than my left! I say effectively because the leg isn't actually shorter, but my pelvis is "clocked" permanently, for some reason or other, he said it's probably been like this for years. He said up to 0.2" is normal in most people, but 0.75" is a fuck of a lot!



I think you answered your own question. Most people have some difference in leg length, but the rest of their skeletal frame/musculature compensates. The only way to really measure this is to sit legs straight, and measure from hip to toe. Sure, one is longer. But, your hips are cocked, which equalizes this.

Thus, standing, you are no more taller on one side than the other. Otherwise you would be leaning to one side. ;)

Even when laying down, the musculature keeps this cock in your hips (for the most part), so I don't see this as being the cause.

I know more than one flyer that was having problems with suit fit on a new suit, including suits that 'seemed too tight'. Pretty much the suit fit was actually caused by doing up their rig too tight or improperly.

Once they loosened their rigs a little bit, the suit started fitting (and flying) better.

j

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Slow reply here.

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Thus, standing, you are no more taller on one side than the other. Otherwise you would be leaning to one side



Actually, when I walk (or stand straight) I have a subconscious (at least it used to be, now I am very aware of it) bend in my left leg. If I straighten both legs all the way one *does* extend longer than the other. I can't lean to one side (because of gravity), but I can pick my right foot up off the ground while keeping both legs straight (can't do the opposite). It's so noticeable the doc wants me to wear a 9mm in my shoe under my right heel, to put equal stress distribution in my back.

So, on the ground I can get along normally (even without the insert, which I haven't decided on yet) since my left leg bends a bit to compensate (which puts more stress on my right knee which explains partly why it sucks). But in the air, I believe it is my instinct to straighten both legs all the way since I don't have the constraint of the ground, and then the left leg DOES extend further.

Only think I don't fully understand now is that the left leg is tight and the turn is also left. I'm not sure if that makes sense to me - I've never tried leg turns in the suit - but ManBird implied the opposite - that a tight RIGHT leg could cause a left turn. I know in normal RW freefall I can turn (rotate) left by bending my right leg slightly.
www.WingsuitPhotos.com

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I thought about this, but the bottom line is I've used 5 different suits - and have had no heading control issues, except for the 3 dives done on this one. I've solved the problem by simply not jumping it.

t
It's the year of the Pig.

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I jumped a Classic once, a GTI once, and then bought a different GTI. I've jumped it 12 times. It's only happened on this GTI, which I own, so not jumping it is not a solution. But this suit is tighter than the other two were I think. I'm thinking of getting 1" or so added to the booties.
www.WingsuitPhotos.com

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Actually, when I walk (or stand straight) I have a subconscious (at least it used to be, now I am very aware of it) bend in my left leg. If I straighten both legs all the way one *does* extend longer than the other. I can't lean to one side (because of gravity), but I can pick my right foot up off the ground while keeping both legs straight (can't do the opposite). It's so noticeable the doc wants me to wear a 9mm in my shoe under my right heel, to put equal stress distribution in my back.



Most people (according to what I have read), end up shifting their hips. This is usually what is seen in x-rays. Certainly large differences are compensated differently.

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So, on the ground I can get along normally (even without the insert, which I haven't decided on yet) since my left leg bends a bit to compensate (which puts more stress on my right knee which explains partly why it sucks). But in the air, I believe it is my instinct to straighten both legs all the way since I don't have the constraint of the ground, and then the left leg DOES extend further.

Only think I don't fully understand now is that the left leg is tight and the turn is also left. I'm not sure if that makes sense to me - I've never tried leg turns in the suit - but ManBird implied the opposite - that a tight RIGHT leg could cause a left turn. I know in normal RW freefall I can turn (rotate) left by bending my right leg slightly.



Not sure if 9mm would make a difference or not. [:/]

As for tightened suit, if you say you extend both fully (no more compensating knee drop), then the long leg is tight, and the short leg is loose. If you instinctively tried to tighten the short side, you may be inducing a turn that way.

Modifying the suits are a pretty big pain in the a$$. I would make yourself a 'block' and tape in on the bottom of your short legs shoe. If that fixes it, then you could consider mods.

I can't remember, has others jumped your suit and deemed it fine?

j

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