Bushwalk Australia

This is the new award-winning Yeti Fever Zero sleeping bag, which weighs just 280g and is, says the brand, the world's lightest sleeping bag - the previous holder of that title was also made by Yeti and was a colossal 40g heavier at 320g...
http://www.outdoorsmagic.com/gear-blog/ ... 11492.html

Amazing stuff.
Mind you the Fusion (the 320g version) was rated at 15c comfort so I expect this to be in the same range.

Kinda pointless isnt it?
At a 15c comfort rating why wouldn't i just sleep in my clothes which would also keep me warm at those sort of temperatures. That would save me a whole 280g!

But with some layering you can get a lot lower than that.
Take a look at the size :

Franco I detect your credit card finger twitching;)

No, not me.
The previous version was already about $600 , so I'll stick with the WM Summerlite..

For the dimensions it's pretty light on down. I had a quilt that was 50" wide tapering to 36" @ the foot end with sewn through construction, that had a similar amount of fill to this (5oz 800 fill). Very little loft, around 15mm maybe at the center of each baffle.
Great warm weather quilt but it was purely summer only.

Good to see the envelope being pushed.
I have to laugh at the image for the bag though. Looks fit to burst with loft......
From my experience with similar fill on a smaller quilt, IMO the one in the image looks to be overstuffed to make it look extra puffy. In real life I don't think that would be the case.

wayno, you seem to stay abreast of the lastest gear. Has anyone proposed an inflatable, baffled top quilt? It could be like a Neoair except made out of less durable material since it wouldn't have to support your weight or be as resistant to puncture. Maybe it could even be filled with argon?

There was, years ago, a sort of sleeping bag bivy combo that used air beams.
But it was heavy even for the intended temperature.
I'll see if I can remember a key word of sort to find it on Google.

The fabric of the new Yeti bag is 20g for a square meter. Hard to do that with a somewhat puncture resistant material.

Orion wrote:wayno, you seem to stay abreast of the lastest gear. Has anyone proposed an inflatable, baffled top quilt? It could be like a Neoair except made out of less durable material since it wouldn't have to support your weight or be as resistant to puncture. Maybe it could even be filled with argon?

ferrino of Italy showed some inflatable sleep systems at Friedrichshafen show 1 or 2 years back. Not sure if they were adopted/commercialised, all I could see just now was the integrated bag/sleep mat, but sniff them out perhaps?

i havent come across anything like that,
only inflatable insulation jackets

blacksheep wrote:

Orion wrote:wayno, you seem to stay abreast of the lastest gear. Has anyone proposed an inflatable, baffled top quilt? It could be like a Neoair except made out of less durable material since it wouldn't have to support your weight or be as resistant to puncture. Maybe it could even be filled with argon?

ferrino of Italy showed some inflatable sleep systems at Friedrichshafen show 1 or 2 years back. Not sure if they were adopted/commercialised, all I could see just now was the integrated bag/sleep mat, but sniff them out perhaps?

I have wondered extensively about this.

*The first obvious hurdle is breath ability. If an object is air tight then it won't have any ability to be moisture permeable. So it could be quite sweaty, but potentially very warm.
*The next hurdle would be comfort due to the rigidity of the the cocoon/sleepingbag.
* Alot of air would be need to inflate the entire cocoon.


My thoughts though about overcoming some of this is for the cocoon the cocoon to be a combination of technologies. The base would be the same as a Neo Air. However, the upper would be a combination of inflated rings and welded to more traditional sleeping bag fabrics. This would ensure the bag maintains loft. The rings would need to have foil inside like a Neo Air. The inflated rings would be end around the foot, the hips and the shoulders.

This is a very complicated way of improving the capacity of down to expand. So I don't think this would be worth it....

However, what if...

The un-inflated sections had foil inside of them in them the same as the inflated pad. Then there might be many benefits in doing it. But you also return to the first hurdle of Breathability due to the foil.

I wonder if the foil would still reflect as much heat if it were perforated with millions of tiny holes??


If you could achieve this then the the other opportunities are enormous. It would be possible to have super light insulated tents. Imagine if the roof and walls of an inner tent were baffled could be baffled a reflective foil liner.


How does the inflateble jacket from Klymit breath? are there panels around the arm pit that are different?

thy are like puffy jackets, its not inflated all over the garment, it broken down to small inflated compartments, you can have the garment breathe in the narrow gaps between the inflated compartments

I think the 280g Yeti corresponds to the L size in PHD, that would make the PHD 260g (more or less)
Given that the Yeti fabric is 40% lighter per square meter, I would think that the Yeti has a bit more down inside making it a bit warmer.
Both brands claim to be using 900+ down.

Orion wrote:wayno, you seem to stay abreast of the lastest gear. Has anyone proposed an inflatable, baffled top quilt? It could be like a Neoair except made out of less durable material since it wouldn't have to support your weight or be as resistant to puncture. Maybe it could even be filled with argon?

Yes -- The Enlightened Equipment Epiphany. Inflatable cuben fibre quilt. You could adjust the warmth by adjusting the loft!

Tim over at EE keeps saying that he might bring it back. Check out reviews of it here.

They should make it without a hood, that would save them another 20-30 grams.

iGBH wrote:Kinda pointless isnt it?
At a 15c comfort rating why wouldn't i just sleep in my clothes which would also keep me warm at those sort of temperatures. That would save me a whole 280g!

This makes so much sense!

Strider wrote:

iGBH wrote:Kinda pointless isnt it?
At a 15c comfort rating why wouldn't i just sleep in my clothes which would also keep me warm at those sort of temperatures. That would save me a whole 280g!

This makes so much sense!

yeah but ultralighters know that if you sleep in your clothes as well, you'll get a lower comfort temperature out of the bag and they'd factor that in.. plus some ultralighters will really push a bags rating and use it well below its comfort rating, especially if they know they sleep warm....

wayno wrote:

Strider wrote:

iGBH wrote:Kinda pointless isnt it?
At a 15c comfort rating why wouldn't i just sleep in my clothes which would also keep me warm at those sort of temperatures. That would save me a whole 280g!

This makes so much sense!

yeah but ultralighters know that if you sleep in your clothes as well, you'll get a lower comfort temperature out of the bag and they'd factor that in.. plus some ultralighters will really push a bags rating and use it well below its comfort rating, especially if they know they sleep warm....

Lol wayno I have a feeling Strider was making the same point as you but rather more sarcastically

Franco wrote:The fabric of the new Yeti bag is 20g for a square meter. Hard to do that with a somewhat puncture resistant material.

Joomy wrote:The Enlightened Equipment Epiphany. Inflatable cuben fibre quilt. You could adjust the warmth by adjusting the loft!

http://web.archive.org/web/20111003143429/http://enlightenedequipment.webs.com/epiphanyk.htm/

Cool concept. I hadn't heard about that. It was available in 0.33 oz/yd² (0.11 11 g/m²) and 0.48 oz/yd² (0.17 17 g/m²) Cuben fabric.
You have to wonder how puncture resistant they were. Their 4°C rated bag weighed about 380g.

I think I'd rather have soft breathable nylon against my body than a VBL. Just my preference.


edit: ooopsie

Neither that quilt nor that Cuben fabric are air tight...

Oh, I see. The quilt isn't sealed tight and brand new Cuben has some finite air permeabiity as well.
So the inflation can only be sustained to the loft that the down is capable of supporting in the first place.

In terms of sewing the "world's lightest" bag, is the 0.11 g/m² Cuben the lightest down proof fabric available?

is the 0.11 g/m² Cuben the lightest down proof fabric available?
Maybe but would you really want Cuben against your skin ?

Franco wrote:...would you really want Cuben against your skin ?

Orion wrote:I think I'd rather have soft breathable nylon against my body than a VBL. Just my preference.

It's a good point though. It's not really apples to apples if the fabric isn't breathable.
I've slept warm enough under an 85g emergency space blanket well below the 15°C rating of the "world's lightest" bag.

i've seen cuben fibre products that have been coated with polyester

Franco wrote:is the 0.11 g/m² Cuben the lightest down proof fabric available?
Maybe but would you really want Cuben against your skin ?

That sounds much too light.

icefest wrote:

Franco wrote:is the 0.11 g/m² Cuben the lightest down proof fabric available?
Maybe but would you really want Cuben against your skin ?

That sounds much too light.

11gm/m2 ?

http://www.zpacks.com/materials.shtml

I auto corrected (in my head...) that weight to 11g per square meter

What about this one...

http://www.phdesigns.co.uk/product_info ... cts_id=366

From personal experience making box wall sleeping bags, the lightest shell I've made is about 200g....

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