Earp 0 #1 January 13, 2015 So I ran across this wind chill chart geared towards motorcycle riders: http://3.bp.blogspot.com/-HrbLdfclw8U/TbIcYRsqC2I/AAAAAAAAAZQ/UrNjSInoXts/s1600/motorcycle+wind+chill+chart.jpg Studying that chart, I notice that the faster you drive, the lower the temperature feels. All as expected. Then I notice that the hotter it gets, driving faster feels less cool. For example, at a 50-degree air temp and at 30 mph, the wind chill drops the felt temp to 28, a decrease of 22 degrees. But at 90 degree air temp and that same 30 mph, it only drops the felt temp by a 1 degree to 89. Hmm. Okay... And then it gets really weird. At 95 and 100 mph, this chart claims that anything above 5 mph actually makes you feel HOTTER, rather than cooler. Now I'm skeptical. How can that be? I wouldn't think it possible for the wind chill temperature to get higher than the actual temperature. So driving fast on a really hot day through the desert isn't going to make you feel any cooler? At least not temperature-wise, according to this chart. But of course, driving fast on a motorcycle makes you "cool" in another sense. Can any of you thermodynamic geniuses out there explain this? Quote Share this post Link to post Share on other sites
quade 3 #2 January 13, 2015 There are two basic factors in wind chill; evaporation and replacing the air next to the body. The air immediately surrounding the body acts as an insulator. Assuming the body isn't being cooled by evaporation, pumping hotter air around the body will heat it up. None of this happens in a linear fashion.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
pchapman 261 #3 January 13, 2015 Interesting. Earp And then it gets really weird. At 95 and 100 [degrees F I think you meant to type], this chart claims that anything above 5 mph actually makes you feel HOTTER, rather than cooler. ... with the wind is replacing the relatively cooler air around your body with more and more even hotter air. That's why they have convection ovens! Quote Share this post Link to post Share on other sites
GD64 1 #4 January 13, 2015 Earp......I don't know. From a personal experience point of view all I can say is Sturgis heat in August, running 90 mph plus in a pack of air cooled V-twins feels hot from crotch to ankles (motor heat) but cooler on rest of body vs frying the whole body in downtown stop and go traffic. Quote Share this post Link to post Share on other sites
Earp 0 #5 January 13, 2015 quadepumping hotter air around the body will heat it up. So maybe the magic "zero number" is 98.6 - the temperature of a human body. If the air is cooler than 98.6 then the body is cooled. The lower you get from 98.6, the more cooling effect. If the air is hotter than 98.6 the body is heated. If the air is exactly 98.6, you feel no change, no matter how fast you drive. So if you graphed it, it would produce a bell curve with the peak at 98.6 degrees. This make sense to me. Quote Share this post Link to post Share on other sites
quade 3 #6 January 13, 2015 Earp***pumping hotter air around the body will heat it up. So maybe the magic "zero number" is 98.6 - the temperature of a human body. If the air is cooler than 98.6 then the body is cooled. The lower you get from 98.6, the more cooling effect. If the air is hotter than 98.6 the body is heated. If the air is exactly 98.6, you feel no change, no matter how fast you drive. So if you graphed it, it would produce a bell curve with the peak at 98.6 degrees. This make sense to me. It's not that exactly, but close enough for understanding.quade - The World's Most Boring Skydiver Quote Share this post Link to post Share on other sites
ryoder 1,380 #7 January 13, 2015 http://www.slate.com/articles/health_and_science/science/2007/02/wind_chill_blows.html"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones. Quote Share this post Link to post Share on other sites
JohnnyMarko 1 #8 January 14, 2015 The title of this thread gave me the chills...because it made me think of all the people who call wind chill the "wind shield" Quote Share this post Link to post Share on other sites
Niki1 1 #9 January 14, 2015 JohnnyMarkoThe title of this thread gave me the chills...because it made me think of all the people who call wind chill the "wind shield" Is that the calculation of a bug impact?Most of the things worth doing in the world had been declared impossilbe before they were done. Louis D Brandeis Where are we going and why are we in this basket? Quote Share this post Link to post Share on other sites
JohnMitchell 14 #10 January 14, 2015 Niki1 ***The title of this thread gave me the chills...because it made me think of all the people who call wind chill the "wind shield" Is that the calculation of a bug impact? Nope, it's the calculation of how much you wish you had a windshield when jumping in the winter time. Quote Share this post Link to post Share on other sites
Niki1 1 #11 January 14, 2015 JohnMitchell ******The title of this thread gave me the chills...because it made me think of all the people who call wind chill the "wind shield" Is that the calculation of a bug impact? Nope, it's the calculation of how much you wish you had a windshield when jumping in the winter time. I have a "gloves" rule. If it's cold enough to wear gloves, it's too cold to jump. I'm from Fla.Most of the things worth doing in the world had been declared impossilbe before they were done. Louis D Brandeis Where are we going and why are we in this basket? Quote Share this post Link to post Share on other sites
sfzombie13 307 #12 January 15, 2015 does friction play into this at all?_________________________________________ Si hoc legere scis nimium eruditionis habes Quote Share this post Link to post Share on other sites
stayhigh 2 #13 January 15, 2015 That's also a 1000 jumps rule. Once you hit 1000 jumps, wearing glove is just not worth 25 bucks. I only jump in between 70-80 degree, ground temperature. You have be able to stay in your jumpsuit without sweating inside the airplane or other wise, just not worth it.Bernie Sanders for President 2016 Quote Share this post Link to post Share on other sites
saibat 0 #14 May 13, 2015 Hello everyone. Sale Shorts darim24.com/1738/shorts Large selection and good prices guaranteed. So if you are interested, write to the PM Quote Share this post Link to post Share on other sites
FlyingRhenquest 1 #15 May 13, 2015 stayhighThat's also a 1000 jumps rule. Once you hit 1000 jumps, wearing glove is just not worth 25 bucks. I only jump in between 70-80 degree, ground temperature. You have be able to stay in your jumpsuit without sweating inside the airplane or other wise, just not worth it. That's a pretty narrow window. 60 ground here is usually reasonably comfortable as long as you're not doing a high pull. 50's about as low as I'll go anymore. I hate getting under canopy and not being able to feel my fingers. First year I'd jump if the plane was flying. I think it was -22 at altitude one time. I'm so not doing THAT again!I'm trying to teach myself how to set things on fire with my mind. Hey... is it hot in here? Quote Share this post Link to post Share on other sites
BillyVance 34 #16 May 13, 2015 FlyingRhenquest***That's also a 1000 jumps rule. Once you hit 1000 jumps, wearing glove is just not worth 25 bucks. I only jump in between 70-80 degree, ground temperature. You have be able to stay in your jumpsuit without sweating inside the airplane or other wise, just not worth it. That's a pretty narrow window. 60 ground here is usually reasonably comfortable as long as you're not doing a high pull. 50's about as low as I'll go anymore. I hate getting under canopy and not being able to feel my fingers. First year I'd jump if the plane was flying. I think it was -22 at altitude one time. I'm so not doing THAT again! Coldest I ever jumped was 32F on the ground. Yeah, fuck that. Once was enough."Mediocre people don't like high achievers, and high achievers don't like mediocre people." - SIX TIME National Champion coach Nick Saban Quote Share this post Link to post Share on other sites
