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Discussion Starter #1
One of my first posts, so I'm gonna take a flyer. Hey, it's late and I'm a bit manic . . .

Those wrinkles in the top buttresses: seems to me an effective, low-cost solution for GM to implement would be to employ a little tensioned-fabric-architecture theory here. That is, make the trailing edge of the buttress (the peak or ridge, if you will) a paraboloid (curved). To eliminate wrinkles, we're after even tension throughout the fabric of the buttress. To quote from http://fabricarchitecture.co.uk/ :

"True tensile fabric structures are those in which every part of the fabric is in tension. The fundamental rule for stability is that a tensioned fabric structure must curve equally in opposite directions, this gives the canopy stability. This is known as an anticlastic form and mathematically as a hyperbolic paraboloid."

I think that the curved ridge of the buttress would also enhance the look.

So what does anyone think? Brilliant, right? Just a thought . . .
 

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js_euler said:
One of my first posts, so I'm gonna take a flyer. Hey, it's late and I'm a bit manic . . .

Those wrinkles in the top buttresses: seems to me an effective, low-cost solution for GM to implement would be to employ a little tensioned-fabric-architecture theory here. That is, make the trailing edge of the buttress (the peak or ridge, if you will) a paraboloid (curved). To eliminate wrinkles, we're after even tension throughout the fabric of the buttress. To quote from http://fabricarchitecture.co.uk/ :

"True tensile fabric structures are those in which every part of the fabric is in tension. The fundamental rule for stability is that a tensioned fabric structure must curve equally in opposite directions, this gives the canopy stability. This is known as an anticlastic form and mathematically as a hyperbolic paraboloid."

I think that the curved ridge of the buttress would also enhance the look.

So what does anyone think? Brilliant, right? Just a thought . . .
I was thinking of something similar, but since I haven't actually seen the car in person, I don't know whether it would be possible
 

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Yeah, I haven't seen one in person either, but it does seem from the pics that the ridge is currently dead straight - don't see how a little hyperbolic paraboloid action could NOT help. Bet the phone starts ringing off the hook tomorrow; those crazy GM engineers, ya know . . . :lol:
 

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Sounds like a worthwhile idea for GM to give a try. My guess is that the wrinkles are there because the added fabric is needed as slack for when the buttresses are released and folded. If GM could add a bit of a curve to flatten the material out, and yet retain the extra slack so it can fold ok it would be very nice!

I almost expected this post to be a humorous post and not serious. I was prepared to click on it and see a picture of an ironing board and iron! :lol:
 

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Spray can?

Don't they still make that spray starch in a can? :cool:
 

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:lol: Not sure spray starch would really work. They are not the kind of wrinkles you get like when you leave a dress shirt wadded up in a ball after washing it, instead of putting it on a hanger.

They are more like waves or ripples. I pushed on the material there and there is a lot of lateral give too, before the material gets tight. There is certainly a lot of extra material in the butress which is what is causing these waves. Unfortunately, I didn't get to see exactly how the top retracts in my hands on experience, so I cannot say whether all that extra slack is necessary. I just assume it is, because it would make no sense to have it otherwise.

Although, maybe starch spray is worth a shot.
 

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wrinkled or not

My top isn't wrinkled but it does have light areas on the black fabric. Also, it is a pain to put the top back up. The latch doesn't fit into the receptor unless you stick your finger up there and pull the tip of the latch down. It is taking two people to close it so far. Once the weather stripping breaks in it may close easier. :willy:
 

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Bleacherman said:
My top isn't wrinkled but it does have light areas on the black fabric. Also, it is a pain to put the top back up. The latch doesn't fit into the receptor unless you stick your finger up there and pull the tip of the latch down. It is taking two people to close it so far. Once the weather stripping breaks in it may close easier. :willy:
I would expect it to get easier. The weather stripping is one element, the other is the fabric. The fabric has to start out tight because over time it will stretch.
 

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Discussion Starter #9 (Edited)
Thought I was being funny . . .

That's the story of my life - try to be serious, and people laugh; try to be funny, and people frown and shake their heads! :rolleyes:

But yeah, I was serious. Might be interesting to try as a retro-fit; have an interior shop cut and re-sew the buttresses. :eek: It seems to be a perfect candidate for the tensioned fabric approach. It seems to be the same issue as trying to keep a square sheet taut by holding only at the corners - you get those slack wrinkles. The paraboloid curve along the edges distributes the tension evenly throughout the piece.

That being said, I tend to believe those who have said the whole issue is no big deal. Just some late night madness last night.
 

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Fformula88 said:
Sounds like a worthwhile idea for GM to give a try. My guess is that the wrinkles are there because the added fabric is needed as slack for when the buttresses are released and folded.
:agree:
The butresses are a special application. I don't believe there are any wrinkles seen on the rest of the top, which is more conventional. I am calling the butress wrinkles "character" and leave it at that. Who is going to be looking at the buttresses while they are drooling over the looks of the rest of the car, especially in motion?
 

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From the pictures Excelsior posted it looks like the bottom edges of the buttresses are not fitting tight to the lid which appears to be the cause of the wrinkles.
 
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