ok, well i think i figured out why bikes have poor drag coefficients, if you would like to call it that.

well this is how i see it. bikes cut threw less air, and cuts threw it pretty well (i think) but sense a bike doesnt bring the air back together it is just leaving a pocket of low pressure, and sense a bike is very light the low pressure will obviously pull alot more on the bike than it would a car. and so the faster the bike gets going obviously the pocket will get bigger and suck harder, thus making it harder for the bike to excellerate at higher speeds.

please correct whats wrong

 

Your spelling!!

 

ha, ass.

i honestly dont pay attention to my spelling on the net. its not a term paper and i find no reason to be uptight about it.

 

Well, I wasn't being uptight about it which is why I put a next to my comment. I(Most of the people) don't pay attention when I'm typing on the net or treat it as a term paper either, but still I don't misspell the easiest words. Anyways, my comment was meant as a joke so don't be offended. I've read plenty of your posts before.

 

I'd say that's fairly accurate on one level. I think we would probably find that this is the result of a bike NOT "cutting through it well".

The frontal area of a bike is small compared to a car, but it's so goofy that it's hard for air to move around. I've never seen wind tunnel data on a bike. ...That said I'm willing to bet the flow goes turbulent before it gets too far past the front turn signals. Once you lose laminar flow (nice smooth air flow) you're screwed. You've got a tangled mess of air that's leaching off the energy you're motor is supplying. This I think is ultimately the cause of the large region of low pressure behind the bike, so you have two slowing factors caused by one phenonmenon.

Next time you're watching a race pay attention to the riders' postures as they run the longer straights. Many of them will keep their butts off the seat a little to help the air flow down their backs and onto the tailsection (more) cleanly. I tried this at Road America a few year ago and It seems to have merit. I also found that it made me tired so I stopped. ...those are long straights!

 

ditto.

 

Doesn't the coefficient of drag take into account the frontal area? If so, that would give lower numbers to big vehicles, but they would have to push more air out of the way. Anybody interested in finding a description on the internet somewhere of how the coefficient of drag is computed?

 

Wait has nuthing to due w/ arrowdynamics. Pleeze excuze my speling...it sucks almost as hard as the air pockit behind my bike!

 

[QUOTE]Originally posted by Chris S
[B]Wait has nuthing to due w/ arrowdynamics.

 

The coefficient of drag doesn't have anything to do with frontal area - to find the actual drag, multiply the coefficient by the area. No does it have anything to do with weight.

http://www.projectbasketcase.com/info/airdrag.html
http://www.teknett.com/pwp/drmayf/tbls.htm