Jul 13, 2011 at 4:41 am #1276649
Martin RyeBPL Member
I had a look recently at Terra Nova's new two man 920g the Ultra 2. Info on my blog at: http://summitandvalley.blogspot.com/2011/07/terra-nova-day-out-part-two.html Also they are doing a range of UL packs made of cuben and DyneemaJul 13, 2011 at 8:26 am #1758832
Nice overview. Looks like Terra Nova is stepping the bar up again. I don't agree with their use of a .51oz flysheet or that the tent will be made in China but I do like the new design. The price is a bit nuts though. The pack is also nice with more of a "normal" price.Jul 13, 2011 at 9:41 am #1758854
Yuri RBPL Member
Even if i twas on 50% off sale for only £600 – i wouldn't touch it. Especially since they have some basic design issues (one of them is the long zipper on the exit. Half of the tent manufacturers make this mistake and do not understand why their sales are not as high as they hoped. Trying to reach all the way into a an extended corner (especially after chilly night when water condensed on the inside of a fly) is not the most pleasant exercise for a sleepy hiker and an invitation for an impromptu cold shower. They should have reduced the weight and made it easier to reach by moving it to the side and making it vertical (thus shortening the zipper, making it super easy to reach and pull.
It's a small thing, but if one is paying that much money, why buy something that isn't 100% user friendly?Jul 13, 2011 at 9:48 am #1758858
. .BPL Member
@biointegraLocale: Puget Sound
I am pleased to see more flies being made out of Cuben and hope to see others getting into it, such as Big Agnes (wink, nudge).Jul 13, 2011 at 10:16 am #1758870
I also think the translucent cuben is a mistake for a fully enclosed shelter. They should be using an opaque or reflective version of the material. The translucent cuben acts like a greenhouse in a fully enclosed shelter because it doesn't block the suns radiation. I measured an olive drab cuben mid to be 20 degree's hotter inside then outside.. Outside it was 92 degrees with 75% humidity, Inside the fully zipped up shelter was 112 degrees with 95% humidity. It wasn't even a really sunny day so I imagine in some situations there could be even more a temp. differential. I think these compaines are forgetting that shelters are intended to shelter you from all the elements not just certain ones. When 90% of the people, backpack in the summer this is a major issue I have never heard anyone talk about and is the reason I switched to a reflective cuben fiber material.Jul 13, 2011 at 10:31 am #1758879
Lawson, you must live in Florida or something.
There are many parts of the country where it gets cold at night. Even in the middle of summer, it dips below freezing along the John Muir Trail. Sometimes it is well below.
If my cuben fiber shelter raises the inside temperature by _anything_, then that is a good thing.
–B.G.–Jul 13, 2011 at 10:44 am #1758884
Greenhouse effect would be nonexistant in the dark.Jul 13, 2011 at 10:49 am #1758888
"Greenhouse effect would be nonexistant in the dark."
It works pretty good before sundown. That gets everything dried out and warmed up inside, and then the shelter can be closed up. That results in it being more comfortable by dawn.
–B.G.–Jul 13, 2011 at 10:51 am #1758890
I bought the Brooks Range Rocket tent, which is the reflective cuben. Set it up in the yard the day I got it (a bit over a month ago?). It was a warm day. It was a whole lot hotter in the tent (good thing it's my winter tent).
For many of us, though, we don't use our shelters until dark anyway. I'm never in my shelter when there's sun shining or daylight present, not even in the rain.Jul 13, 2011 at 11:08 am #1758900
It would of been much hotter if the material was translucent.
The greenhouse effect would only raise the temp. during the day when the suns radiation is at full power and this would only apply to fully enclosed shelters, not tarps. Its the same reason the inside of your car gets really hot during the day but not at night. With that said, at night a fully enclosed shelter built from this same translucent material could actually yield a colder shelter then one built with opaque or reflective materials because the material cannot reflect your bodies radiation.
LawsonJul 13, 2011 at 11:24 am #1758905
"The greenhouse effect would only raise the temp. during the day when the suns radiation is at full power"
No, actually the greenhouse effect would raise the temperature during the day regardless of whether the sun is at full power or not.
This greenhouse effect works pretty good before sundown. During this time, the heat gets everything dried out, and the inside air is warmed up. It prepares the shelter for a cool night.
–B.G.–Jul 13, 2011 at 11:41 am #1758911
"No, actually the greenhouse effect would raise the temperature during the day regardless of whether the sun is at full power or not."
That's completely true, especially if the shelter is set up low enough to keep the draft out. Even a tarp pitched in an A-frame, if it's pitched low, would build up a bit of a temperature differential before convection got the air moving. With the sun veiled by clouds or near the horizon, it will just be slower.
I'd guess that a reflective coating would reduce that effect, by letting less of the heat through the fabric.
Venus, however, is evidence that you don't have to let a lot of heat through the fabric in order to warm it up. All you have to do is keep a small amount more than you lose, since it has an insanely high albedo, and ends up absorbing a lot less energy into its atmosphere than Earth does, yet it's a tad warmer ;)
Then again, this is one of the selling points behind tarps. You don't have to pitch it that low when it's hot, in which case even a slight breeze will keep the interior cool(er) by constantly recycling the air inside, and thereby circumventing the greenhouse effect.Jul 13, 2011 at 12:07 pm #1758922
I think you two are missing the point and trying to argue over semantics. No matter how you slice it, a fully enclosed translucent shelter is going to be hotter in the middle of the day then one made from an opaque or reflective material. Period.
You guys should check out Phil Werner's (sectionhiker.com) review of the the MLD cuben duomid. http://sectionhiker.com/mountain-laurel-designs-doumid-cuben-fiber/
The author addresses this issue in the unexpected section. He says "Cuben Fiber transmits a lot of light through the walls to the interior of the shelter." he then talks about how this is beneficial for bugs at night but "The downside of this is that the Duomid becomes an oven when it is warm and sunny. So much so, that you can't remain in the shelter when you want to lie around in the afternoon and read. It's for this reason, that I probably won't use the Duomid in summer conditions and will opt instead for a flat tarp."Jul 13, 2011 at 12:51 pm #1758930
Martin RyeBPL Member
Interesting comments. Having never used a cuben shelter I would not know or comment on the effects of weather on them. Yuki comments like yours are noted by Terra Nova. One thing I found out on my visit and talking to the design team, and staff. Was how much they read on the web about views, comments and reviews of their products. So maybe some ideas like yours will filter through to them.
I think the use of cuben is a small thing still with Terra Nova. But as they learn more about using it we will see more and more tents from them made with it. Cost will come down I am assured as they master making tents with it and reduce the time they take to make kit.
My friend Terry made a video of the Ultra 2 http://terrybnd.blogspot.com/2011/07/terra-nova-voyager-ultra-2-solar.html
Also views form another friend at the preview http://backpackingbongos.wordpress.com/2011/07/13/terra-novas-new-range-for-2012-a-sneak-preview/Jul 13, 2011 at 1:51 pm #1758952
"During this time, the heat gets everything dried out, and the inside air is warmed up. It prepares the shelter for a cool night"
Ahh, good point/idea, though this sounds like a condensation trap trap to me.Jul 13, 2011 at 1:59 pm #1758957
"…could actually yield a colder shelter then one built with opaque or reflective materials because the material cannot reflect your bodies radiation."
This is only true if the material is "translucent" with respect to radiation with frequency in the Infrared band (thats what our bodies emit at night…unless we are really hot). You cannot tell if something is translucent/opaque/reflective with respect to IR by looking at it under visible light.
Important fact though for during daylight hrs (seems like a pro in the cooler days and a con in hotter…).Jul 13, 2011 at 2:10 pm #1758964
"Ahh, good point/idea, though this sounds like a condensation trap trap to me."
If the shelter space is still cool and moist during the day, then often there is a lot of condensation inside during the night. However, if the shelter space is warmed up and dried out during the day, there isn't much moisture left inside for night. The moisture of exhaled breath doesn't take much air movement to eliminate.
–B.G.–Jul 13, 2011 at 2:34 pm #1758972
Daryl and DarylBPL Member
@lyrad1Locale: Pacific Northwest, USA, Earth
I only use a tent for warmth and appreciate the greenhouse effect when it happens.
I recall one trip in particular where it was snowing off and on with brief shots of sun poking through the clouds. I was very cold and wet. I set up the tent and a brief period of sun brought the temps up to about 70F. It felt wonderful!Jul 13, 2011 at 4:29 pm #1759019
"I think you two are missing the point and trying to argue over semantics. No matter how you slice it, a fully enclosed translucent shelter is going to be hotter in the middle of the day then one made from an opaque or reflective material. Period."
I'm pretty sure that no one is disagreeing with that. I even asserted that I expected you to be correct, but I haven't experienced it myself (yet), because it won't transmit as much energy into the shelter from the sunlight.
I actually noticed it even when tooling around with a Trailstar. I put it up when I was camping in the desert, but I pitched it low and without a door in order to make seam-sealing easier, and when I lifted an edge to climb inside the difference in temperature was easily noticeable.
On the side of curiosity, have you found it to make a significant difference in warmth in colder conditions? I ask because I so rarely end up with heat being the problem, since I do most of my trekking in the Cascades and Olympics.Jul 13, 2011 at 5:14 pm #1759028
Translucent cuben fiber shelters are especially good for passive melting of snow. You simply fill up a plastic sack with clean snow and put it inside the shelter. It beats burning up all of that fossil fuel.
–B.G.–Jul 13, 2011 at 5:20 pm #1759031
@thomdarrahLocale: Southern Oregon
Hike from dawn to dark and not worry about solar gain.Jul 13, 2011 at 5:50 pm #1759039
@robertm2sLocale: Lake Tahoe
Douglas Ide said: “I bought the Brooks Range Rocket tent, which is the reflective cuben.” Douglas, have you formed an over-all impression of the Rocket?
P.S. I heard of one owner who thought the breathability could be better, so he removed the cardboard-tube part of a peanut can, leaving a metal ring that was light yet strong. He sewed one spot on the ring up to the eyebrow of the vent, allowing him to flip the ring down to keep the vent open, or up to allow the vent to fall flat.Jul 13, 2011 at 6:03 pm #1759044
"have you formed an over-all impression of the Rocket? "
I have not. I haven't had a chance to use it yet. I bought it as a solo winter tent, but got it recently, so I won't actually use it til November/December.Jul 13, 2011 at 6:33 pm #1759059
Eugene SmithBPL Member
@eugeneiusLocale: Nuevo Mexico
"Hike from dawn to dark and not worry about solar gain."
Nailed it.Jul 13, 2011 at 8:01 pm #1759095
What I was getting at was using a shelter as dryer for wet gear in the evening.
You'll set up the shelter and the air inside will be equal to outside in terms of temp and humidity (relative and absolute) and you'll put you're wet gear inside.
B/c of the greenhouse effect the inside will heat up (air and wet gear). Air's relative humidity drops. Both of these act to evaporate water from the the wet gear (increasing humidity).
Some air exchange happens as a result of convection (as already described) but an elevated temperature and absolute humidity is obtained (elebated relative to what it would have been with no greenhouse effect).
The sun goes down and the temperature drops (approaching ambient — and dropping below if the conditions are right) resulting in an increaing relative humidity and probably condensation). The way I am seeing it the condensation will be greater by using the tent as a dryer b/c the humidity was made greater.
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