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Lighter Carbon Back Stay - version 2
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Kevin Egelhoff
(kegelhoff) - F

Locale: Southern Cal
Re: Ideas for v5 on 04/01/2009 08:40:39 MDT Print View

Huzefa,
If I only had the time .....

I had wanted to make a cuben pack to try it out with this stay but I really need to make another cuben shelter for the summer/fall and that will be taking up most of my time in the next few months.

I think you have some very interesting ideas here. Why don't you make this bag and I will make sure that we test it with the carbon stay!

Kevin

Derek Goffin
(Derekoak)

Locale: North of England
Lighter Carbon Back Stay - version 2" on 04/01/2009 10:13:22 MDT Print View

Hello Kevin,
I just saw this thread. It looks very interesting. In my view you need some moveable adjustment. Would it be possible to make a minimal wing version and 2 curved more flexible wing extensions and attach them together in some variable way. For example a big patch of velcro. Now the wing extensions could be shaped and positioned so their top edges perfectly follow the crest of the users hips for about 100mm to the point at the front of the hips where the crest falls away. When a non padded flexible hip belt is attached to the top edge and front of this structure it would pull in and cradle the hips perfectly. I am imagining the extensions being small, only big enough for fine adjustment.
Note this has some parallels to, but might be a big improvement on an Aarn belt.

Edited by Derekoak on 04/01/2009 10:19:28 MDT.

Huzefa Siamwala
(huzefa) - M
Re: Re: Ideas for v5 on 04/01/2009 10:16:19 MDT Print View

Thanks Kevin, I would love to make a pack for this stay. Right now I am playing with some 1.5oz cuben for another project. Very cool stuff! But it isnt puncture proof. With some pressure I can poke a pen tip through. I think puncture proofness isnt really required or can be expected from SUL gear. What is important is that punctures/tears donot spread and this weight of cuben is very good at that.

I have limited quantity of the fabric and can order more for the pack only next month.

Huzefa Siamwala
(huzefa) - M
Re: Lighter Carbon Back Stay - version 2" on 04/01/2009 10:57:14 MDT Print View

Hi Derek,

>Would it be possible to make a minimal wing version and 2 curved more flexible wing extensions and attach them together in some variable way.

Why? Kevin says in an earlier post >Yes, the wings are flexable and they flex more as you get closer to the tips.>


>Now the wing extensions could be shaped and positioned so their top edges perfectly follow the crest of the users hips for about 100mm to the point at the front of the hips where the crest falls away.
>>Note this has some parallels to, but might be a big improvement on an Aarn belt.

note that both mchale and Aarn donot use any stiffeners in the belt. Best to keep carbon wings to minimum and as flexible as possible.

You will not find plastic stiffeners in our hip belts either. The belts wrap so effectively that they create their own firm structure. Belt stiffeners are the current hallmark of high-tech packs. It is really too bad real people are not as insensitive as mannequins because we think the new crop of belts on the market are a step backward in comfort. mchale packs

I am not sure can one improve on aarn hipbelt. There is so much attention to the details on aarn packs that it is mind boggling. Lately, I have been drooling over aarn packs. Now if they made packs using cuben fiber and pack weighed under a pound... but thats not going to happen.

Kevin,

Similar idea can be used here:
ss

Edited by huzefa on 04/02/2009 07:20:53 MDT.

Derek Goffin
(Derekoak)

Locale: North of England
"Lighter Carbon Back Stay - version 2" on 04/02/2009 07:58:01 MDT Print View

Huzefa,
Aarn belts have wings that are attached at the stay right by the spine with a big Velcro patch for maximal adjustment.
I believe the aim is to bring the curved edge of the stiff part of the belt in line with the ischial crest. The part of the belt infront is made from flexible mesh. I have not taken a belt apart to see why it is stiff but I assure you it is thin and stiff
Under heavy load I can feel the stiff part of the belt at the back distorting. I think it must improve things for a really stiff (in elevation only) carbon stay to carry the load round to the sides. I think you would then not need the belt so tight to get good load transfer. This would be more comfortable. I think a CF shape like Kevins is a probably lighter way to carry load forwards. I personally would still add front pockets to balance the load front to back and give access during walking.
Arrn is just sending me a pre production MM 55 to try.
As I see it this carbon stay would be most help for really heavy loads. But might well help the whole range.

Without the adjustable wing extensions we are in DIY land where people have to cut and file the CF stay to their own hips and then buy a new stay if their waist increases at Xmas.

Edited by Derekoak on 04/02/2009 08:10:11 MDT.

Huzefa Siamwala
(huzefa) - M
Re: "Lighter Carbon Back Stay - version 2" on 04/03/2009 22:12:40 MDT Print View

I understand what you are saying.

I have an idea which can eliminate the need of velcro: elastic 3D mesh. I am not sure whether aarn uses "elastic" 3D mesh but this would be perfect material for hipbelt, shoulder straps, and back panel. Elastic would automould to any hip shape. What is important is dual buckles. This allows adjustment of top and bottom separately eliminating the distorting you speak of. Also 3D mesh will give great ventilation, so it is MUCH better alternative to cuben straps and CCF hipbelt.

Edited by huzefa on 04/04/2009 05:06:09 MDT.

Derek Goffin
(Derekoak)

Locale: North of England
"Lighter Carbon Back Stay - version 2" on 04/06/2009 04:41:59 MDT Print View

Thinking about this CF stay. It is totally rigid and people's hips, (especially but not only, women) rock their hips as they walk. Most packs either specifically have a joint between the hip belt and the back stays or are so poorly fixed that there is no problem. This inverted T stay is either going to restrict hip movement or make the pack tend to swing from side with the hips.

Huzefa,
On the Natural balance Aarn uses 3D mesh in different thicknesses for:
the shoulder straps,
the surface between the pack and the user's back just for ventilation
and the hip belt from hip crest to hip crest across the belly, infront of the stiffer part of the hipbelt from hip crest round the back to the other hip crest. His hip belt has a fabric hinge at the back so the natural hip movement is allowed without moving the pack

Huzefa Siamwala
(huzefa) - M
Re: "Lighter Carbon Back Stay - version 2" on 04/08/2009 04:09:02 MDT Print View

Derek, you have a point.

Kevin, for V5 why not make stay and hip portion separate and then connect them with a pivot?

Ammon Manning
(ammonmanning) - F
Progress? on 08/03/2010 10:20:31 MDT Print View

Did anything ever come from this? I would be very interested in purchasing one of these stays!!

Steven Evans
(Steve_Evans) - MLife

Locale: Canada
Re: Progress? on 08/03/2010 21:36:06 MDT Print View

It was good reading through this thread again. I've been doing longer trips in the winter and with the heavier loads, this stay appeals to me even more. I communicated with Kevin via e-mail a few days ago - he has been very busy at work so I am not sure if he made any more progress. Of course, I'll let him answer...

drowning in spam
(leaftye) - F

Locale: SoCal
Re: Re: Progress? on 08/10/2010 05:18:16 MDT Print View

I would love to see this as an external frame. It would weigh a little more, but it'd allow different size bags to be installed for different types of trips. Either way, I greatly admire what has been done with this pack already.

Kevin Egelhoff
(kegelhoff) - F

Locale: Southern Cal
Re: Re: Re: Progress? on 08/12/2010 21:50:29 MDT Print View

Hey Guy,
Been a BUSY year! I quit working on this project as I felt the carbon just ended up being too stiff and didn't flex enough side-to side. After attending the OR show for the first time this year it was cool to see several companies with almost the same type of back stay system, although much cheaper and heavier. I tried on a few of these new pack designs and the Black Diamond felt good as well as the new Sierra Designs. After seeing these two very similar designs I think this project could have worked better if it had a low pivot point and if the wings were made more flexible to maybe try and carry less load. So .... if things slow down enough at work I may try and make some adjustments to this and see if it feels a little better and more natural. Or ... it might be time to finally make that new 2-man cuben fiber shelter I have wanted to make for a few years!