Originally Posted by
BillyBob58
Well, I have not seen quilts/bags rated for R-value, but that makes sense. Or if you use the higher figure of 12 ( maybe even a bit over 12 ) r= 4.16.
But I'm not sure how exact the figures are on this. For instance, Younblood - the designer of the Speer SPE - had a table that showed some "observed" workable temps using his SPE with various pads.
He showed that a 1/8" CCF pad @ r 0.5 was "good" to 63 , or 70-63=7, and 7 divided by R0.5= 14F per R!
While a 1/2" pad with R 2.2 worked at 43. So 70-43= 27 . 27 divided by R2.2= 12.272 per R.
1" pad at R 4.3 good to 17F. So, 70 minus 17 = 53 divided by R4.3 = 12.325 per R.
BUT, with an inflatable 1" pad rated at R 2.3 he showed 47. 70 - 47 = 23/2.3= 10F per R! Several other inflatables only show about 10F per R unit.
So I guess we have a ball park of 10-14F per R, with the thinner CCF pads being a little higher on the R per inch scale. But mostly about 10 for the inflatables ( based on their R rating ) and about 12.5 for most of the CCF pads.
But here is where a monkey wrench gets thrown into the machinery: a lot of folks are cold in a hammock even at 75. Would these observed temps still work for them, or do we need to move the "good to" temps up 5F? But, if we need to move those workable termps up, it does not change the degrees per r value guestimate.
But if the "75F" folks are still good with a 1/8" pad @ 63F, or with a 1" pad to 17F, then the degrees of protection per R value are even higher than the above calculations indicated.