Right on, that is really similar to Cody's Super Shelter from _Dual Survival_...I admit it blew my mind when I first saw it.
(Cody throws in the "long-wave radiation" terminology for extra survival credibility points)
21st Century Baker's Tent
21–30 of 172 posts
Re: 21st Century Baker's Tent
#22Those emergency blankets don’t work like normal blankets - by trapping air and preventing it from moving - but by reflecting heat and keeping it in.
> Those emergency blankets don’t work like normal blankets - by trapping air and preventing it from moving - but by reflecting heat and keeping it in.
This reads as if to imply emergency blankets vent air freely, that's obviously not true.
Re: 21st Century Baker's Tent
#23Those emergency blankets don’t work like normal blankets - by trapping air and preventing it from moving - but by reflecting heat and keeping it in.
And they are not comfortable, as this post shows:
https://www.reddit.com/r/CampingandHiking/comments/4wtetp/im...
Re: 21st Century Baker's Tent
#24Those emergency blankets don’t work like normal blankets - by trapping air and preventing it from moving - but by reflecting heat and keeping it in.
> Those emergency blankets don’t work like normal blankets - by trapping air and preventing it from moving - but by reflecting heat and keeping it in. This reads as if to imply emergency blankets vent air freely, that's obviously not true.
Thermal insulation, whether we're talking about a blanket, a winter jacket, or the foam stuff in your walls, generally involves a layer of some thickness within which there are many tiny spaces full of trapped air. It's difficult for heat to propagate across those spaces. The author's point is that mylar emergency blankets do not provide this thick layer of "trapped air". It's true that they prevent air from crossing, but only for the very thin layer of the blanket.
I'm not sure exactly how effective the mylar blankets are and under what circumstances, but this is what "trapped air" refers to.
Re: 21st Century Baker's Tent
#25Those emergency blankets don’t work like normal blankets - by trapping air and preventing it from moving - but by reflecting heat and keeping it in.
I'm not a physicist but wouldn't this reflective effect be tiny compared to the prevention of convective heat loss?
Considering average human body area is around 2 square meters and body temperature is around 37 degrees Celsius I get around 1000 W of radiation from the human body according to this calculator: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/radfrac.h...
Re: 21st Century Baker's Tent
#26"It's said that Henry David Thoreau lived alone in a Bakers tent on Walden Pond." Who says this? Thoreau lived in a cabin and had his mother bring him food every day.
Thoreau says this, in The Maine Woods[0]. (EDIT: Thoreau says that he lived in a tent in Maine, not at Walden Pond.) The author of TFA got it a little wrong. Note to those wanting to replicate this: I'm pretty sure Thoreau's tent catches fire at some point. I'd have to re-read to confirm or deny if it had anything to do with setting the tent in front of the fire, as the author of TFA does.
Re: 21st Century Baker's Tent
#27Earlier quoted context omitted.
I'm not a physicist but wouldn't this reflective effect be tiny compared to the prevention of convective heat loss?
I spent a night in the woods (on purpose, not a real emergency) sleeping with an emergency blanket. It was not at all comfortable, but the blanket seriously worked. I would wake up whenever it moved to stop covering me because it would instantly become cold, then feel much warmer as soon as the blanket is back in place. The reflective action is impressive. They also act as a wind break and turn whatever clothes you a…
A long time ago I similarly tested a (non-heat-reflective) orange plastic survival bag, sleeping overnight behind some rocks on exposed moorland (something like https://www.military1st.eu/cs037-highlander-emergency-surviv...).
The poor thermal insulation and condensation were predictable. I hadn't predicted the shifting wind which chose to balloon my orange cocoon with cold air every 20 mins no matter which orientation I chose to lie in. I finished the night with a bungie cord around the sack, under my armpits. That of course left my head, shoulders and arms exposed but kept the wind out. Not recommended.
After this experience I upgraded to reflective mylar survival bags. NB "bag". These are a little harder to find than survival blankets but if a bag can be so badly affected by moderate wind, a blanket would be so much worse.
Re: 21st Century Baker's Tent
#28Earlier quoted context omitted.
I'm not a physicist but wouldn't this reflective effect be tiny compared to the prevention of convective heat loss?
Considering average human body area is around 2 square meters and body temperature is around 37 degrees Celsius I get around 1000 W of radiation from the human body according to this calculator: http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/radfrac.h...
Or to put that in terms of net heat loss, in the 0-30C range you're looking at about 10 watts for every degree of difference between your skin and the environment.
Re: 21st Century Baker's Tent
#29What happens if the tent catches fire? Does it burn?
I'm guessing it'll burn, but perhaps not very well/too dangerously... But I'm sure there's a way to weld yourself in molten plastic if you're unlucky?
Not certain which exact model is used - doesn't look like they're advertised as flame retarded? (most modern tents are)
https://www.surviveoutdoorslonger.com/shelters/heat-reflecti...
Re: 21st Century Baker's Tent
#30[deleted]