I was looking at the photos of my newest pack I sewed together and posted in separate posting. From what I can tell from wearing and carrying it around loaded today the sewn in vertical strap works in vertical compression.
Making packs out ultra light weight fabrics like Cuben ,1.9 ripstop nylon or 210d dyeemna grid stop.
I was thinking how Xpac can be used as a sewn on top of ultra light fabric can be used as a exo skeleton frame compression/load stabilization system for load control instead of using nylon straps to save weight in the pack design.
You could sew vertical 1 to 3/4 inch wide straps at the center pull and each corner they all connect at the top draw string closer for the pack made out of Xpac. When you pull the draw string tight to close the top of the pack it chinches up the vertical straps .
Then sew two horizontal straps 8 to 12" around the circumference of the pack were nylon straps would be.
It would act as compression/Load stabilization system.
If you look at the photo of my pack you will see were the 210 dyeenma fabric bulges out from the vertical stringer so it works as compression.
Thanks for looking at my rambling thoughts on ultra light pack design.