A Pig in the Wind: Part whine, part math (physics?) question.

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I hate math and I never took physics.

Dumpster would probably relish the opportunity to dig his teeth into this problem, though. There's probably some sort of equation that can be compiled.

I thought there was some kind of rule regarding aero bars and kick stands and how the two should never come into contact on the same bike.  Similiar to matter/anti-matter.

I am not an expert, but I believe that wind resistance is really not a factor until about 15mph.  At 10mph., there would seem to be minimal benefit from aero position, even on the pig.  Therefore, I would be upright.
Headwind is a different story.  Wind resistance increases by squares.. eg..20mph has 4x greater wind resistance than 10mph, 30mph 9x etc..

Aerodynamics affect any body that is in motion, from .01 mph up to supersonic speeds .........

"So say we all!"

...sorry, huge Battlestar Galactica fan and I dig your avatar.

Aero position would be faster, you still to overcome the drag.

Hahaha!  That's what I was thinking as well, but to hear you put it so articulately, I actually laughed out loud at my comp screen.  I may have gotten a strange look from a co-worker. 

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With the tail wind you'd have a lot less wind resistance to cut through so I think the aero position would be of relatively less benefit. Sitting upright creates a sail effect. So, I have 2 votes towards upright being faster in a tail wind.

Dude - did you steal my bike?  I've commuted on that bike, in those conditions.  Only difference is no kickstand and my 1000 is a WSD. 

Normally, I would say that if you've got a tailwind you may as well sit up.

However... knowing what the rear panniers feel like, I found aero to be more comfortable overall and more "powerful."  It felt like having all of the weight to my rear (including me, half the bike, my pannier, etcs) it's unnatural and I always wanted to lean forward to distribute my weight in any condition.

I think you should do hill repeats in those conditions and let us know.  Don't you love that afternoon wind around here?  Hah.

Edited by BikerGrrrl 2009-04-22 3:15 PM

OK, here is my two cents.
Without getting into a diagram...It depends on the net airspeed over the bike.

So, if you had a little airspeed meter on your bike, and I am assuming you wouldn't mind the additional weight, and it said that the net airspeed was in the direction you were traveling, sit up.

If the net airspeed is the other direction, then aero would be better, as it would reduce your resistance. However, this doesn't take into account that in general, you generate less power from the aero position.

I have also read that the effect of aero on a hill is less important than the effect of weight when on a hill. This is becuase you are slower on a hill, and the effect of wind resistance is much more pronounced at higher speeds (power of 2).

OK, this is starting to confuse me.

Maybe if two swallows gripped it by the husk?

Eli

I think we all failed to factor in that it is a 7:00 relative wind rather than direct tailwind. Of course this means Aces should be slightly aero on the left side while completely upright on the right. This presents the largest surface area for the aiding wind while still maintaining some aero-ness.

Alternately, you could remove the completely useless areobars and fashion them into some sort of keel to maximize the simulation of your bicycle as a sailing vessel.

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I climb out of Palo Duro Canyon about once a week.  It is about an 18% grade.  If the wind is blowing up the hill I can climb at 8mph.  If it's not I climb at 6mph.  I am upright when I do it.

I waited to weigh in on this one... physics major/engineer here.

What matters is the speed of the wind relative to the speed of the rider. So we have two situations, both where the wind speed is faster than the rider in the given plane of motion.

When sitting, the rider's net coefficient of resistance let's call C0.
When in aero position, C1.

I think everyone would agree that sitting up will provide greater drag, so C0 > C1.

This effect will be most pronounced the greater the difference between the rider speed and the wind speed.

Once the rider begins to approach the wind speed, or if the wind changes its relative angle and the component of the wind pushing you drops, this benefit is lost and we encounter the opposite situation, where the wind is not helping you move forward at all. In this situation, you definitely want to be in aero.

I would only sit up if the wind was very steady, or if the wind is very strong relative to my current speed. Otherwise gusty wind or a change of angle in the wind could easily negate any of the gains from sitting up.