Road Helmet Aerodynamics

Discuss light weight issues concerning road bikes & parts.
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HammerTime2
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by HammerTime2

As I stated above, strong predominantly tail wind up a steep climb can put you at or near 180. There is continuum of possibilities from 180 all the way to zero.

natiedean24
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by natiedean24

180 degree angle of 'attack' is possible, but you have to stop and use some common sense to how that applies to aero design. If I'm riding 15 mph with a 30 mph tailwind, that is indeed a 15 mph 'wind' at 180 degrees.

But you would never want to consider such a silly scenario in a testing protocol, let alone try to consider in an aero design. Such extreme design conditions won't lend to a faster product and can thus be ignored.

by Weenie


justkeepedaling
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by justkeepedaling

Not only that, but you'd want the frontal area as high as possible. If the actual yaw really is 180 degrees, aero doesn't matter. You're going slow enough that weight would matter more with climbing, or you'd actually want the opposite of typical aero concepts. Just sit up onto the tops and get pushed along. Has NOTHING to do with low drag aerodynamics. In fact, it's such a small percentage of occurance that it can be considered negligible.

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HammerTime2
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by HammerTime2

People, I was correcting technically erroneous statements made on this thread. I was not stating the optimal way of optimizing for aero.

justkeepedaling
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by justkeepedaling

Well, obviously most comments are trying to refer to optimized aerodynamics. Stuff that makes you faster rather than pretty much negligible technicalities that have complete opposite results.

Roeboe
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by Roeboe

MajorMantra wrote:
Roeboe wrote:I think the main reason is for keeping the head wind and water free, since you lose most energy (heat) trough your head.


Myth!:

http://www.guardian.co.uk/science/2008/ ... nbehaviour" onclick="window.open(this.href);return false;


Well, if you leave you head uncovered, it is the only exposed body part so you will lose more heat there.

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MajorMantra
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by MajorMantra

Roeboe wrote:
MajorMantra wrote:
Roeboe wrote:I think the main reason is for keeping the head wind and water free, since you lose most energy (heat) trough your head.


Myth!:

http://www.guardian.co.uk/science/2008/ ... nbehaviour" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;


Well, if you leave you head uncovered, it is the only exposed body part so you will lose more heat there.


Exactly. But it is often stated that you lose a disproportionate amount of heat through your head which never been shown to be the case.

Valbrona
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by Valbrona

Epic-o wrote:Image


The Dandy only wore this helmet because it was more fashionable.

And lets not forget that most road racing is done in the slipstream/dirty air of the guys in front. There is no smooth air flow like you might get in a wind tunnel.

NGMN
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by NGMN

Valbrona, how can you continue to post about aerodynamics when we completely discredited your ideas about 360 degrees of yaw?

justkeepedaling
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by justkeepedaling

Oh, I see! Breakaways never succeed and sprints end in a single file line every time!

xyzgeoman
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by xyzgeoman

I want one that pops open a properly positioned sail when it senses a tailwind of any "yaw." Would that be legal?

SQ
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Joined: Tue Oct 14, 2008 7:39 am
Location: Melbourne

by SQ

The Bontrager claim the Oracle wind tunnel tests show it beats the comp, especially at angles of yaw.

Enticing, especially as the Previal test data was only at 0 deg, but what is "the comp"?

It has been said before but it never ceases to amaze that this isn't an area of focus or battle - spend $3K+ on a slightly new wheel shape but not worry about the drag on that massive blob that hits the wind...if I were making road helmets I would develop it in the tunnel and make a massive fuss about it.

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MajorMantra
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by MajorMantra

SQ wrote:It has been said before but it never ceases to amaze that this isn't an area of focus or battle - spend $3K+ on a slightly new wheel shape but not worry about the drag on that massive blob that hits the wind.


Maybe it's because, up until now at least, aero helmets have been really dorky whereas aero wheels look sweet. :)

HillRPete
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by HillRPete

Does anyone know which Helmet Rodriguez wore when winning La Fleche? It almost looked like a TT hemet from the side, with the prolonged tail. Is this the Radius model?

by Weenie


Privateer
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by Privateer

I'm also interested in the OP's question. I'm looking for a helmet for a very long, and hence very slow speed, TT i.e. one that will be most aero through a wide range of relatively high yaw angles.

I was thinking that something like the Giro that Miller wore in the final stage of the Tour last year (I don't care about being thought a "dandy") or the Kasks that Sky use would be ideal.
Image

I've not found any news about what happened to the Giro proto, and the Kasks won't be available until after the Olympics due to an exclusivity deal with Team GB (http://forum.slowtwitch.com/gforum.cgi?post=3455724).

The closest I can find is the Casco Warp track helmet:
Image

Does anyone have any other ideas?

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