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#21
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helmet ventilation?
wrote in message ... Dear Chris, Actually, the thin metal domes amplify the weak signal sufficiently to be received by our instruments at a muc greater distance and allow us in turn to reach and control a much wider audience. Kang & Kodos ....and always whirling...WHIRLING!!!! *Bob Dole spinning around furiously in slightly off-center orbits* |
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#22
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helmet ventilation?
Just zis Guy, you know? wrote:
On Wed, 13 Jul 2005 08:58:53 -0400, "C.J.Patten" wrote: When you spend 5 times as much to get something like a Giro Atmos (i gather they use it on the tour?) is the ventilation that much better? Would you notice your head staying that much cooler? I don't think it's anything to do with cost (most properties of helmets are not, as far as I can tell - some very cheap Chinese helmets are Snell certified, no Bell helmet is) but there was some research I heard of recently. A headform was heated to 42C, and a fan was then blown over it for 4 minutes. Temperature drops were 10.5C for the bare head, 9.1C for the best helmet, 2.5C for the worst helmet. So I'm sure there is a big difference in cooling effect, as you surmise. Finding out where on the scale between, as it were, 13% and 76% reduction in cooling effect any one particular helmet lies, is likely to be problematic! It is probably a function of the size and number of vents, but maybe not, and of course these might have a consequent effect on structural integrity as well. It's a good question, actually - I don't know to what extent the body is able to compensate for the reduced cooling. As far as I understand it the scalp plays the major part in cooling the head, and there is evidence in respect of cricketers that helmet-induced heating impairs reactions. I think there are probably as many unknown unknowns as known unknowns here. IOW, possibly. :-D |
#23
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helmet ventilation?
Just zis Guy, you know? wrote: A headform was heated to 42C, and a fan was then blown over it for 4 minutes. Temperature drops were 10.5C for the bare head, 9.1C for the best helmet, 2.5C for the worst helmet. Of course, there isn't always a fan handy when you are stopped at traffic lights. Or crawling up a hill. James |
#24
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helmet ventilation?
On 13 Jul 2005 23:11:03 -0700, "James Annan"
wrote: Just zis Guy, you know? wrote: A headform was heated to 42C, and a fan was then blown over it for 4 minutes. Temperature drops were 10.5C for the bare head, 9.1C for the best helmet, 2.5C for the worst helmet. Of course, there isn't always a fan handy when you are stopped at traffic lights. Or crawling up a hill. James Dear Guy and James, Of course, if our heads actually reached 107.6 degrees Fahrenheit, it probably wouldn't matter whether we were stopped, crawling up a hill, or doing 90 mph. Irrelevantly, Carl Fogel |
#25
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helmet ventilation?
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#26
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helmet ventilation?
On 13 Jul 2005 23:11:03 -0700, "James Annan"
wrote: A headform was heated to 42C, and a fan was then blown over it for 4 minutes. Temperature drops were 10.5C for the bare head, 9.1C for the best helmet, 2.5C for the worst helmet. Of course, there isn't always a fan handy when you are stopped at traffic lights. Or crawling up a hill. Unless you are Ivan Basso, in which case you have no shortage of fans, mostly female (but they are not looking at your head). Oh, /that/ sort of fan. As you were, then... Guy -- http://www.chapmancentral.co.uk "Let’s have a moment of silence for all those Americans who are stuck in traffic on their way to the gym to ride the stationary bicycle." - Earl Blumenauer |
#27
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helmet ventilation?
On Thu, 14 Jul 2005 05:12:06 GMT, "Bill Sornson"
wrote: IOW, possibly. Yep, or possibly not. But I don't think cost is going to be a particularly reliable indicator. Guy -- http://www.chapmancentral.co.uk "Let’s have a moment of silence for all those Americans who are stuck in traffic on their way to the gym to ride the stationary bicycle." - Earl Blumenauer |
#28
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helmet ventilation?
I had a solid helmet I broke in a fall last year. The replacement is a Bell
with vents. I don't notice it's any cooler. -- Bob Burns Mill Hall PA (email is spamtrap) "C.J.Patten" wrote in message ... I won't get in to a helmet debate. I wear one, reasons irrelevant for this thread. My question has to do with vents. My current helmet is a Giro Indicator. This wasn't an expensive helmet but it fits well. When you spend 5 times as much to get something like a Giro Atmos (i gather they use it on the tour?) is the ventilation that much better? Would you notice your head staying that much cooler? Any other extremely vented helmets? (don't say "bare head" smart-asses) Thanks, Chris |
#29
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helmet ventilation?
Bob Burns wrote: I had a solid helmet I broke in a fall last year. That's what you get for wearing a helmet. |
#30
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helmet ventilation?
snipped
Oh, /that/ sort of fan. As you were, then... Guy -- Wow...."As you were" ...I haven't heard that expression since Camp Pendleton! Semper Fi! John ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
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