Headwind Strategy
jobst....@stanfordalumni.org
> This season I have had to do a lot of training/riding on days with a
> lot of headwind. Some wind gusts 20+ mph. What is the best strategy
> for riding in such conditions?
Excuse me for replying so off the cuff! After thinking about this
again, I realized I short cut the wind effect in that total wind
velocity squared constitutes drag. So the response should have read
as follows:
-----------------------------------------------------------------------
This can be assessed readily considering the effects.
Knowing power in still air in MPH used as a base value because that
can be assumed constant, speed in a head or tailwind and in between
can be accurately calculated. The following method was verified by
HPVA wind tunnel tests. Drag coefficient drops out since it is a
constant.
Road velocity (RV)
Wind Velocity (WV)
Wind Angle (WA)
Total wind (TW) [vector sum of RV and WV]
Total drag (TD)
Angle (DR) (DA)
For direct head- or tail-wind:
Power = (RV)* (RV + WV) ** 2
For winds at angles between zero and 180 degrees:
TW = SQRT((RV + (SIN(WA) * WV)) ** 2)
TD = TW**2
DA = ASIN(TW/RV)
Power = RV * COS(DA) * TD
The crux of this analysis that slipped by me (again) is that the
in-line component of total drag times rider velocity is the power
required. It's been a while since I wrote that article (Bicycle Guide
May 1992 and in an earlier Bike-Tech) mainly because this effect had
been previously overlooked. That article showed results for:
Power for winds at various angles at constant rider velocity
Speed for winds at various angles at constant power input.
Most interesting was the effect on an out and back TT for any fixed
wind velocity and direction, which I think was the initial question
here.
Using data plotting routines for this evaluation (power vs wind angle
for various speeds) will demonstrate graphically that one never gets
back what the wind takes out when turning around on a straight out and
back course, and that even winds up to about 12 degrees beyond 90
degree side wind cause increased drag depending on the ratio between
RV and WV. It occurs when WV and TW form a right angle.
Jobst Brandt <jobst....@stanfordalumni.org>
Marjan Sterk
>For winds at angles between zero and 180 degrees:
>
>TW = SQRT((RV + (SIN(WA) * WV)) ** 2)
TW = SQRT( RV ** 2 + (SIN(WA) * WV) ** 2 )
>DA = ASIN(TW/RV)
As it can be that TW > RV as well as TW < RV, this is incorrect. I
*think* it should be ATAN(WV/RV). Is this correct? It would make the
necessary power 1.4 times as great in the case of a sidewind of the
same speed as the rider is traveling.
Paul Alman
> This season I have had to do a lot of training/riding on days with a
> lot of headwind. Some wind gusts 20+ mph. What is the best strategy
> for riding in such conditions?
Is it best to ride out into the wind, or with the wind (if you have to make
that choice)? I can only assume the questioner is asking about training
effect, energy usage, etc. I personally prefer to go out into the wind, and
return with a nice tailwind. No reason other than the memory of a ride when
I got 40 miles from home,riding in the dead flat Thumb region of Michigan,
had to turn back into the wind (which had shifted and picked up), ran out of
water, no stores for 30+ miles, and a serious case of the bonk. I'd rather
not do that again.
"Marjan Sterk" <marjan...@ijs.si> wrote in message
news:3be808a4....@news.ijs.si...
jobst....@stanfordalumni.org
> There are still two mistakes.
>> For winds at angles between zero and 180 degrees:
>> TW = SQRT((RV + (SIN(WA) * WV)) ** 2)
> TW = SQRT( RV ** 2 + (SIN(WA) * WV) ** 2 )
>> DA = ASIN(TW/RV)
DA = ATAN(WV/RV)
I think it is the same as the above except that the former is more
indirect.
> As it can be that TW > RV as well as TW < RV, this is incorrect. I
> think it should be ATAN(WV/RV). Is this correct? It would make the
> necessary power 1.4 times as great in the case of a sidewind of the
> same speed as the rider is traveling.
You are correct. I'll pick that up. Thanks,
Jobst Brandt <jobst....@stanfordalumni.org>
jobst....@stanfordalumni.org
> This season I have had to do a lot of training/riding on days with a
> lot of headwind. Some wind gusts 20+ mph. What is the best strategy
> for riding in such conditions?
Excuse me for replying so off the cuff! After thinking about this
again, I realized I short cut the wind effect in that total wind
velocity squared constitutes drag. So the response should have read
as follows:
-----------------------------------------------------------------------
This can be assessed readily considering the effects.
Knowing power in still air in MPH used as a base value because that
can be assumed constant, speed in a head or tailwind and in between
can be accurately calculated. The following method was verified by
HPVA wind tunnel tests. Drag coefficient drops out since it is a
constant.
Road velocity (RV)
Wind Velocity (WV)
Wind Angle (WA)
Total wind (TW) [vector sum of RV and WV]
Total drag (TD)
Angle (DR) (DA)
For direct head- or tail-wind:
Power = (RV)* (RV + WV) ** 2
For winds at angles between zero and 180 degrees:
TW = SQRT((RV **2 + (SIN(WA) * WV) ** 2))
TD = TW**2
DA = ATAN(HV/RV)
ronde champ
<jobst....@stanfordalumni.org> wrote in message
news:dAYF7.1346$DD2....@typhoon.sonic.net...
jobst....@stanfordalumni.org
>> -----------------------------------------------------------------------
>> This can be assessed readily considering the effects.
>> Knowing power in still air in MPH used as a base value because that
>> can be assumed constant, speed in a head or tailwind and in between
>> can be accurately calculated. The following method was verified by
>> HPVA wind tunnel tests. Drag coefficient drops out since it is a
>> constant.
>> Road velocity (RV)
>> Wind Velocity (WV)
>> Wind Angle (WA)
>> Total wind (TW) [vector sum of RV and WV]
>> Total drag (TD)
>> Angle (DR) (DA)
>> For direct head- or tail-wind:
>> Power = RV * (RV + WV) ** 2
>> For winds at angles between zero and 180 degrees:
>> TW = SQRT((RV ** 2 + (SIN(WA) * WV) ** 2))
>> TD = TW ** 2
>> DA = ATAN (SIN(WA) * WV / RV)
>> Power = RV * COS(DA) * TD
>> The crux of this analysis that slipped by me (again) is that the
>> in-line component of total drag times rider velocity is the power
>> required. It's been a while since I wrote that article (Bicycle Guide
>> May 1992 and in an earlier Bike-Tech) mainly because this effect had
>> been previously overlooked. That article showed results for:
>> Power for winds at various angles at constant rider velocity
>> Speed for winds at various angles at constant power input.
>> Most interesting was the effect on an out and back TT for any fixed
>> wind velocity and direction, which I think was the initial question
>> here.
>> Using data plotting routines for this evaluation (power vs wind angle
>> for various speeds) will demonstrate graphically that one never gets
>> back what the wind takes out when turning around on a straight out and
>> back course, and that even winds up to about 12 degrees beyond 90
>> degree side wind cause increased drag depending on the ratio between
>> RV and WV. It occurs when WV and TW form a right angle.
> The above isn't correct, at least when using aerodynamically designed
> equipment, because the effective drag area (i.e., CdA, what you have
> termed "drag coefficient" in your equation) is NOT independent of relative
> wind direction (i.e., yaw angle). Thus, under the right conditions, you
> can not only "get back what the wind takes out", but will be faster than
> under no wind conditions.
As I said, the equations were used to compare drag for a wind rotated
about an actual bicyclist on the drops and correlated exactly with
HPVA wind tunnel tests. One of the HPVA outcomes was that a bicycle
and rider are effectively a "bluff body" having the same (drag
coefficient) cross section regardless of orientation with respect to
wind direction. Since nearly all drag arises from the rider, the
little bit that arises from a round tube bicycle in contrast to an
airfoil tubed bicycle is insignificant.
Even if there were a difference, the characteristic is exactly the
same and this is that side winds slow the rider. Even side winds from
as much as 12 degrees beyond a 90 degree side wind cause more drag. A
streamlined bicycle would not improve that condition.
The article I cite also shows how much time is lost in an out and back
TT with a pure side wind.
Jobst Brandt <jobst....@stanfordalumni.org>>
Bill Bushnell
jobst....@stanfordalumni.org wrote:
> Even side winds from as much as 12 degrees beyond a 90 degree side
> wind cause more drag. A streamlined bicycle would not improve that
> condition.
Depends on how "streamlined" is defined.
Back in late March 1999 I can recall one blustery late afternoon when I
was riding south along the Great Highway in San Francisco with the wind
blowing as best I can recall from the west-northwest. The highway was
closed to motor traffic due to blowing sand. On sections of the highway
that were not behind sand dunes and were fully exposed to the wind I could
stop pedaling and enjoy a free ride at speeds of roughly 18-22 mph,
depending on how hard the wind blew. I was able to get "lift" from the
wind because more than once I observed my speed increase without my
pedaling. The highway runs due south and is flat along this section.
--
Bill Bushnell <bush...@pobox.com>
Andrew Coggan
someone with experience regularly testing cyclists on aerodynamics bicycles
in wind tunnels, such as John Cobb. Alternatively, you can simply read the
scientific literature on the topic...both we and others have published data
showing a reduction in CdA with increasing yaw angle. I can send you
specific references if you don't want to take the time to look them up
themselves.
Andy Coggan
<jobst....@stanfordalumni.org> wrote in message
news:B41G7.1402$DD2....@typhoon.sonic.net...
Paul Alman
HCT levels, we wouldn't ever need to ride our bikes to find out who is
goiing to win. And FUN, isn't that what it is all about for most of us?
"ronde champ" <ronde...@yahoo.com> wrote in message
news:9s9l2q$cuf$1...@suaar1ab.prod.compuserve.com...
Daniel Connelly
>
> Exactly! If bike racing was just about formulas, power generation, VO2 Max,
> HCT levels, we wouldn't ever need to ride our bikes to find out who is
> goiing to win. And FUN, isn't that what it is all about for most of us?
>
Don't be a luddite. This is about racing, and racing involves understanding
the factors which go into speed.
terry morse
> Exactly! If bike racing was just about formulas, power generation, VO2 Max,
> HCT levels, we wouldn't ever need to ride our bikes to find out who is
> goiing to win. And FUN, isn't that what it is all about for most of us?
To some of us, figuring out what's going on with our bodies on bicycles
IS fun.
--
terry morse
Palo Alto, CA
http://www.terrymorse.com/bike/
Stergios Papadakis
>
>
> Knowing power in still air in MPH used as a base value because that
> can be assumed constant, speed in a head or tailwind and in between
> can be accurately calculated. The following method was verified by
> HPVA wind tunnel tests. Drag coefficient drops out since it is a
> constant.
>
> Road velocity (RV)
> Wind Velocity (WV)
> Wind Angle (WA)
> Total wind (TW) [vector sum of RV and WV]
> Total drag (TD)
> Angle (DR) (DA)
>
> For direct head- or tail-wind:
>
> Power = (RV)* (RV + WV) ** 2
>
> For winds at angles between zero and 180 degrees:
>
> TW = SQRT((RV **2 + (SIN(WA) * WV) ** 2))
If I have understood your variables correctly,
I think this should be:
TW = SQRT((RV+WVcos(WA))**2 + (SIN(WA) * WV) ** 2))
Now it reduces properly to TW = RV + WV for WA = 0.
Stergios
Stergios Papadakis
> jobst....@stanfordalumni.org wrote:
> >
> > Power = (RV)* (RV + WV) ** 2
> >
> > For winds at angles between zero and 180 degrees:
> >
> > TW = SQRT((RV **2 + (SIN(WA) * WV) ** 2))
> > TD = TW**2
> > DA = ATAN(HV/RV)
> > Power = RV * COS(DA) * TD
Marjan Sterk writes:
> There are still two mistakes.
>> For winds at angles between zero and 180 degrees:
>> TW = SQRT((RV + (SIN(WA) * WV)) ** 2)
> TW = SQRT( RV ** 2 + (SIN(WA) * WV) ** 2 )
>> DA = ASIN(TW/RV)
> As it can be that TW > RV as well as TW < RV, this is incorrect. I
> think it should be ATAN(WV/RV). Is this correct? It would make the
> necessary power 1.4 times as great in the case of a sidewind of the
> same speed as the rider is traveling.
Stergios wrote:
> If I have understood your variables correctly,
> I think this should be:
>
> TW = SQRT((RV+WVcos(WA))**2 + (SIN(WA) * WV) ** 2))
>
> Now it reduces properly to TW = RV + WV for WA = 0.
>
> Stergios
Also, DA = atan(WVsin(WA)/(RV+WVcos(WA))
or DA = asin(WVsin(WA)/TW)
or DA = acos((RV+WVcos(WA)/TW).
These also reduce properly.
Stergios
Stergios Papadakis
> or DA = acos((RV+WVcos(WA)/TW).
>
> These also reduce properly.
>
> Stergios
OOPS
DA = acos((RV+WVcos(WA))/TW)
Stergios
ronde champ
"Stergios Papadakis" <papa...@physics.unc.edu> wrote in message
news:3BE964F7...@physics.unc.edu...
Kyle Legate
> Don't be a luddite. This is about racing, and racing involves understanding
> the factors which go into speed.
>
You guys get all excited about your numbers and unwieldy equations if you
must, but I never thought about calculus or physics while out training,
and I don't think it made me less effective in my training. And I don't
think any of those equations have answered the question of whether it
would be more effective to start your ride into the wind, or with the
wind. All you have accomplished is manufacturing long equations fit to
make most of our eyes glaze over, and pick apart each other's mistakes. Is
this all in attempt to answer the original poster's question, or is this
some kind of engineering soft porn?
... . . . . . . . . . . . . . . .
leg...@mcmaster.ca Kyle Legate leg...@hotmail.com
Tower of Tongues:Thursday PM:10:30-11:30 EDT:http://cfmu.mcmaster.ca
moon musick:ritual:IDM:experimental(electronica):minimalism:glitch
. . . . . . . . . . . . . . . ...
Dan Connelly
>
> On Wed, 7 Nov 2001, Daniel Connelly wrote:
>
> > Don't be a luddite. This is about racing, and racing involves understanding
> > the factors which go into speed.
> >
> You guys get all excited about your numbers and unwieldy equations if you
> must, but I never thought about calculus or physics while out training,
> and I don't think it made me less effective in my training. And I don't
> think any of those equations have answered the question of whether it
> would be more effective to start your ride into the wind, or with the
> wind. All you have accomplished is manufacturing long equations fit to
> make most of our eyes glaze over, and pick apart each other's mistakes. Is
> this all in attempt to answer the original poster's question, or is this
> some kind of engineering soft porn?
>
Some people like science and engineering, others like to be blissfully ignorant.
I have no problem with either approach, but don't ridicule the former because
you are among the latter.
jobst....@stanfordalumni.org
>> Thanks for taking all the fun out of bicycle racing.
> Exactly! If bike racing was just about formulas, power generation,
> VO2 Max, HCT levels, we wouldn't ever need to ride our bikes to find
> out who is goiing to win. And FUN, isn't that what it is all about
> for most of us?
You say that as though there were something wrong with understanding
the effects of wind on bicycling. How does knowing why and how winds
slow you down take the fun out of the sport. Your response seems to
define education and understanding of natural phenomena as an evil.
Jobst Brandt <jobst....@stanfordalumni.org>
ronde champ
<jobst....@stanfordalumni.org> wrote in message
news:fnfG7.1572$DD2....@typhoon.sonic.net...
> You say that as though there were something wrong with understanding
> the effects of wind on bicycling.
I may not know the effects of wind, but I know the effect that you, a
windbag, are having on me.
Paul Alman
might lead one to agree with Kyle without dismissing the fact that yes,
there is science involved in everything we do. Most of us live our lives
without obsessing on how our bodies work on the molecular level, or the
formula for wind resistance on a moving body, and also without dismissing
the existence of that science either.
Middle ground seems to work here.
"Dan Connelly" <djco...@ieee.org> wrote in message
news:3BE9817E...@ieee.org...
dvt
> I may not know the effects of wind, but I know the effect that you, a
> windbag, are having on me.
Never, and I mean NEVER, has the saying about "pot, kettle, black" been
more appropriate.
Dave
dvt at psu dot edu
Paul Alman
it is more fun to ride a bike than over analyze the science behind it. You
can do the latter without ever throwing a leg over a bike and enjoying the
unique feeling that brings.
"terry morse" <tmorse...@terrymorse.com> wrote in message
news:071120010737529232%tmorse...@terrymorse.com...
Paul Alman
understanding the effects of wind on bicycling, enjoy it if that is your
thing. Secondly, it might take the fun out of it for me if I focused more
on understanding the formulas etc., than I do on the reason I got into
cycling and racing in the first place. And finally, IMHO, education and
understanding of natural phenomena are "value neutral"; it is their
application that can puts some sort of moral/ethical value on them. Are you
saying that the love of education is therefor good and wonderful in all
cases, the opposite of evil.
Back to the point: the poster asked a simple question and we again turned
this into "whose slide rule is bigger" type discussion. You can answer this
poor guy without citing the formulas. Someone, maybe you (I lost track)
gave what I consider the appropriate "scientific answer" when he said "you
never gain back in a tail wind what you lose in a headwind". That is what
the formulas are for: an application of the principles and phenomena to a
"real world" question.
<jobst....@stanfordalumni.org> wrote in message
news:fnfG7.1572$DD2....@typhoon.sonic.net...
ronde champ
kettle, black" is people who feel the need to spell out their email address.
"dvt" <d...@nospam.psu.edu> wrote in message
news:20011107...@djvpc.arl.psu.edu...
ronde champ
"Paul Alman" <pa...@quickrelease.com> wrote in message
news:10051609...@axilla.wwnet.net...
> OK, just as it is fun fix the bikes or build wheels, etc., but I still say
> it is more fun to ride a bike than over analyze the science behind it.
It's even more fun to goof on the douches that participate in the sport.
Ted Bennett
Gay? You're seventeen, right?
Ted
Daniel Connelly
>
> You know something? The only thing more gay than people who say "pot,
> kettle, black" is people who feel the need to spell out their email address.
>
You forgot people who use "u" instead of "you". Yours I rank second
and third.
Henry Chang
<pa...@quickrelease.com> wrote:
>Ah the old either-or response. Appropriate use of the science involved
>might lead one to agree with Kyle without dismissing the fact that yes,
>there is science involved in everything we do. Most of us live our lives
>without obsessing on how our bodies work on the molecular level,
That's something that won't even happen in our lifetime because until
they figure out everything about quantum mechanics there is no chance
of figuring out exactly how the brain works.
Henry
Jon Isaacs
>it is more fun to ride a bike than over analyze the science behind it. You
>can do the latter without ever throwing a leg over a bike and enjoying the
>unique feeling that brings.
This is not an either/or situation. One can do both as both Andrew Coggan and
Jobst Brandt have amply demonstrated.
In my experience fast riders seem to be smart riders.
jon isaacs
Jon Isaacs
>must, but I never thought about calculus or physics while out training,
>and I don't think it made me less effective in my training.
You might realize you have apparently cross-posted to rec.bicycles.tech
Equations and understanding are what this newsgroup is about.
And while you may not want to understand these things, if you want to get the
most out of your effort, someone better be able to advise you on aerodynamic
issues.
Otherwise you will be just hung out to dry riding Spoxes or some such silly
thing.
jon isaacs
JRE
flying. Or...
JRE
jobst....@stanfordalumni.org
> OK, just as it is fun fix the bikes or build wheels, etc., but I
> still say it is more fun to ride a bike than over analyze the
> science behind it. You can do the latter without ever throwing a
> leg over a bike and enjoying the unique feeling that brings.
I don't see it as an either or situation but one that should interest
any bicyclist. Knowing why direct side winds retard progress is good
to know. In fact the out and back TT rider may be surprised at how
much slower his time is than in still air. In fact, that winds from
as much as 12 deg beyond a direct side wind also slow the rider was
not clear from anything I had read or heard from other riders.
The quantitative results may not interest you although the qualitative
ones should. I don't understand what the nay sayers get out of
attacking an analysis of wind effects on riding. I have ridden in all
sorts of winds pedaling and coasting (the effects are different). And
knowing how large the effects are helps on understand why pedaling
hard with a tailwind or downhill at high speed is not as ET productive
as uphill or into the wind.
I don't see how the awareness of these phenomena detracts from the sport.
Jobst Brandt <jobst....@stanfordalumni.org>
Fabrizio Mazzoleni
> I don't see how the awareness of these phenomena detracts from the sport.
Jobst, competitive cycling is a great sport, lets keep this eggheaded high brow
lame-o college kid gooby gop girly talk out of it.
jobst....@stanfordalumni.org
> Please take this to rec.bicycles.tech
It's too bad you are offended by an analytical approach to what winds to
to a competing bicyclist.
> please don't cross post.
I don't see how this does not belong in wreck.bike.racing, the place
of the original post, or is it that you don't want the tech group to
see your disdain for education.
Then Fabrizio Mazzoleni writes:
> I don't see how the awareness of these phenomena detracts from the sport.
Jobst, competitive cycling is a great sport, lets keep this eggheaded
high brow lame-o college kid gooby gop girly talk out of it.
I take this as tongue in cheek but it puts the right spin on the
aversion to understanding and learning.
Jobst Brandt <jobst....@stanfordalumni.org>
Jon Isaacs
>brow
>lame-o college kid gooby gop girly talk out of it.
>
>
I agree. Guys like Fabrizio and me can be ignorant and happy.
Leave the lame-o college kid gooby girly talk to riders like Lance and Jan.
Those guys know that understanding and riding smart is just as important as
being in good shape.
But for Fabrizio and me there is no hope anyway so we may as well just ride
stupid and use our meager brain cells for something more productive. :~)
Understanding the effects of wind is important for TT riders because it allows
them to better understand their actual state of conditioning.
If one event was done on a nice windless day at 80 degrees F and another one
was done on a windy winter day at 45F, there is no way to compare them without
some sort of understanding.
jon isaacs
Qui si parla Campagnolo
<< For winds at angles between zero and 180 degrees:
TW = SQRT((RV **2 + (SIN(WA) * WV) ** 2))
TD = TW**2
DA = ATAN(HV/RV) >>
are you sure???
Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl ST.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
Qui si parla Campagnolo
understanding
the factors which go into speed. >>
The biggest of which is human body performance which changes by the second and
cannot be predicted at all....
Jay W. Beattie
"Jon Isaacs" <joni...@aol.com> wrote in message
news:20011108091309...@mb-mb.aol.com...
By the way, the correct strategy to deal with a headwind is to ride
behind Jon, or a truck -- whichever is moving faster.-- Jay Beattie.
Kyle Legate
> That's something that won't even happen in our lifetime because until
> they figure out everything about quantum mechanics there is no chance
> of figuring out exactly how the brain works.
>
It all comes down to DNA methylation patterns. What's this about quantum
physics?
Phil Holman
> Back to the point: the poster asked a simple question and we again turned
> this into "whose slide rule is bigger" type discussion. You can answer this
> poor guy without citing the formulas. Someone, maybe you (I lost track)
> gave what I consider the appropriate "scientific answer" when he said "you
> never gain back in a tail wind what you lose in a headwind". That is what
> the formulas are for: an application of the principles and phenomena to a
> "real world" question.
Interesting is that simplified analysis shows that the speed increase
with a tailwind is greater than the loss into the headwind. But when
you add together the times for each direction the sum is greater than
the no wind situation.(I call it the inequality of time affect)
This is ignoring the situation that Andrew Coggan is talking about (a
side wind can be faster) which, possibly because of too many other
variables in a real life TT, is not widely seen or recognized by the
racing population.
Phil Holman
Henry Chang
<leg...@mcmail.cis.mcmaster.ca> wrote:
>On Thu, 8 Nov 2001, Henry Chang wrote:
>
>> That's something that won't even happen in our lifetime because until
>> they figure out everything about quantum mechanics there is no chance
>> of figuring out exactly how the brain works.
>>
>It all comes down to DNA methylation patterns. What's this about quantum
>physics?
You've got the way the brain works all figured out eh?
Absent an observer, at the subatomic level, matter and energy exists
in all states simultaneously. The huge promise of quantum computing
lies in the idea that one can perform calculations on variables that
occupy all possible states at once - massive parallel processing.
It's not much of a leap to imagine that billions of years of evolution
hasn't taken advantage of quantum characteristics in nature.
It's also a good explanation for how even the simplest of brains can
do image processing that outperforms teraflop-range (trillion
operations/second) supercomputers.
This is just a theory and no one has to buy into a theory when there's
no definitive proof. But to me it seems very logical that we can't
figure out how the brain works if we don't completely understand
subatomic physics. Just because we don't understand it yet doesn't
mean that nature hasn't gone there.
Henry
Philip Fink
Just a few comments that have nothing to do with bicycle racing, but you did
make a few comments that interest me due to the fact that I get paid to think
about them.
Physics has, for a long time now, held out the promise that all other
sciences can be derived from it. For example, if subatomic physics can be
understood, we can use that understanding to inform us about the function of
the brain. On the other hand, relatively little has been delivered on that
promise. A more typical situation is that other sciences describe a
phenomenon, and then physicists come in to explain the phenomenon (and often
make it seem like it was obvious). I'm not saying that the physicists
contribute nothing (in fact, I think those explanations are crucial), but I
will predict that, in the (in my opinion) unlikely event that the workings of
the brain are fully understood, it will probably be from the top down, rather
than from the bottom up.
But I think the more interesting question is about the similarities
between computers and brains. It is clear that today's computers and our
brains have almost nothing in common. Everything that computers do well, our
brains can't do very well, and vice versa. This is exactly what makes
computers so useful. In short, we should probably dump the computer metaphor
for the brain.
What to replace it with? My favorite metaphor would be a termite mound
(it would take to long to explain that one, but it has to do with self
organization), but it would be interesting to see how far a different type of
computer could get.
Phil Fink
Department of Cognitive and Linguistic Sciences
Brown University
Henry Chang
>
> Physics has, for a long time now, held out the promise that all other
>sciences can be derived from it. For example, if subatomic physics can be
>understood, we can use that understanding to inform us about the function of
>the brain. On the other hand, relatively little has been delivered on that
>promise. A more typical situation is that other sciences describe a
>phenomenon, and then physicists come in to explain the phenomenon (and often
>make it seem like it was obvious). I'm not saying that the physicists
>contribute nothing (in fact, I think those explanations are crucial), but I
>will predict that, in the (in my opinion) unlikely event that the workings of
>the brain are fully understood, it will probably be from the top down, rather
>than from the bottom up.
I disagree with that in this one particular instance.
If it turns out that the brain takes full advantage of the
what-are-now theoretical advantages inherent in quantum phenomena, how
are we to understand how it's workings if we don't understand the
quantum phenomena?
> But I think the more interesting question is about the similarities
>between computers and brains. It is clear that today's computers and our
>brains have almost nothing in common. Everything that computers do well, our
>brains can't do very well, and vice versa. This is exactly what makes
>computers so useful. In short, we should probably dump the computer metaphor
>for the brain.
It's true the metaphor isn't useful in the vast majority of cases.
What about savants though?
> What to replace it with?
Why replace it? How about shelving it temporarily? Whenever human
beings figure out how the brain functions, then it's going to have to
be brought back because then we're going to be able to make machines
that mimic what the brain does.
Henry
Kyle Legate
> It's not much of a leap to imagine that billions of years of evolution
> hasn't taken advantage of quantum characteristics in nature.
>
It has. The stunning activity of the enzyme alcohol dehydrogenase is
explained by hydrogen tunnelling, a quantum phenomenon.
> It's also a good explanation for how even the simplest of brains can
> do image processing that outperforms teraflop-range (trillion
> operations/second) supercomputers.
>
Absolutely, but you're talking about information processing whereas I was
talking about information storage. One theory is that this is accomplished
in part by patterns of DNA methylation. Before anyone chimes in to tell me
how wrong I am, I said _in part_. There's also a lot to be said for
reinforcement of synaptic firing patterns, remodelling of synapses, etc.
These patterns are one explanation as to why certain smells can take you
back to early childhood memories. How you process these memories may very
well have something to do with quantum processes.
> This is just a theory and no one has to buy into a theory when there's
> no definitive proof. But to me it seems very logical that we can't
> figure out how the brain works if we don't completely understand
> subatomic physics. Just because we don't understand it yet doesn't
> mean that nature hasn't gone there.
>
Completely understanding subatomic physics is something akin to completely
understanding human cell biology. I don't think it will happen in our
children's children's children's lifetimes...
Henry Chang
<leg...@mcmail.cis.mcmaster.ca> wrote:
>>
>Completely understanding subatomic physics is something akin to completely
>understanding human cell biology. I don't think it will happen in our
>children's children's children's lifetimes...
I agree with that because, if past history is any indicator, as soon
as humans figure out the current set of problems, the new insight will
unmask yet another layer of unknowns that will need to be worked upon.
And so on and so on and so on.
Henry
Andrew Coggan
> Daniel-<< Don't be a luddite. This is about racing, and racing involves
> understanding
> the factors which go into speed. >>
>
> The biggest of which is human body performance which changes by the second and
> cannot be predicted at all....
You know not of which you speak.
Andy Coggan
Andrew Coggan
> Jobst writes-
>
> << For winds at angles between zero and 180 degrees:
>
> TW = SQRT((RV **2 + (SIN(WA) * WV) ** 2))
> TD = TW**2
> DA = ATAN(HV/RV) >>
>
> are you sure???
Of course he is. ;-/
Andy Coggan
Benz OuYang
"Paul Alman" <pa...@quickrelease.com> wrote:
> Exactly! If bike racing was just about formulas, power generation, VO2 Max,
> HCT levels, we wouldn't ever need to ride our bikes to find out who is
> goiing to win. And FUN, isn't that what it is all about for most of us?
Actually, it sort of does. Racing, at least in Lance Armstrong's case,
is pretty much about formulas, and power generation. Chris Carmichael,
in fact, was reported to have predicted Armstrong's wins because of the
numbers that he crunched out of Armstrong's measured performance. It
takes a specific output to win Le Tour and apparently, Armstrong hit
that and was thus predicted to win. We all know what he did, of course.
I guess at the pro level with a certain amount of determination, humans
are like machines. Given certain conditions, the outcome is quite
predictable for the most part.
Cheers,
Benzzoy
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warren
<Pine.SOL.4.33.011108...@mcmail.cis.mcmaster.ca>, Kyle
Legate <leg...@mcmail.cis.mcmaster.ca> wrote:
> On Thu, 8 Nov 2001, Henry Chang wrote:
>
> > That's something that won't even happen in our lifetime because until
> > they figure out everything about quantum mechanics there is no chance
> > of figuring out exactly how the brain works.
> >
> It all comes down to DNA methylation patterns. What's this about quantum
> physics?
Too cold and dark to ride, eh?
Henry Chang
<REMOVEbe...@hotmail.com> wrote:
>In article <10051428...@axilla.wwnet.net>,
> "Paul Alman" <pa...@quickrelease.com> wrote:
>
>> Exactly! If bike racing was just about formulas, power generation, VO2 Max,
>> HCT levels, we wouldn't ever need to ride our bikes to find out who is
>> goiing to win. And FUN, isn't that what it is all about for most of us?
>
>Actually, it sort of does. Racing, at least in Lance Armstrong's case,
>is pretty much about formulas, and power generation. Chris Carmichael,
>in fact, was reported to have predicted Armstrong's wins because of the
>numbers that he crunched out of Armstrong's measured performance.
The problem with this method is: even if you can control the output of
your rider, the output of the opponents is an unknown quantity.
How about trying to make a TdF winner out of someone less talented
than Armstrong?
Henry
Qui si parla Campagnolo
After I said-<< The biggest of which is human body performance which changes by
the second and
> cannot be predicted at all. >>
Well, I've seen lots of info and data about what some bike thing will do to
performance, but when you put a human on the bike, the performance may be
better, may be worse, not 'predictable' at all....
Kyle Legate
> Too cold and dark to ride, eh?
>
Damn right. Even on the nice days (high of 10C) it's dark by 5pm. What's a
brother to do?
Alan J Bishop
Henry Chang wrote:
> On Thu, 08 Nov 2001 16:23:27 -0500, Philip Fink <fi...@sfsu.edu> wrote:
> >
None of you have both oars in the water.
--
Sue and Alan Bishop
PO Box 156
Exmouth WA 6707
Ph/fax 08 9949 2950
Benz OuYang
henrichang....@home.com (Henry Chang) wrote:
> The problem with this method is: even if you can control the output of
> your rider, the output of the opponents is an unknown quantity.
>
> How about trying to make a TdF winner out of someone less talented
> than Armstrong?
Unfortunately, someone less talented than Armstrong won't be able to
produce the kind of absolute power and power-to-weight ratio that he
does.
John Albergo
Stergios Papadakis wrote:
> > jobst....@stanfordalumni.org wrote:
> > >
>
> > > Power = (RV)* (RV + WV) ** 2
> > >
> > > For winds at angles between zero and 180 degrees:
> > >
> > > TW = SQRT((RV **2 + (SIN(WA) * WV) ** 2))
> > > TD = TW**2
> > > DA = ATAN(HV/RV)
>
> > > Power = RV * COS(DA) * TD
>
> Marjan Sterk writes:
>
> > There are still two mistakes.
> >> For winds at angles between zero and 180 degrees:
> >> TW = SQRT((RV + (SIN(WA) * WV)) ** 2)
> > TW = SQRT( RV ** 2 + (SIN(WA) * WV) ** 2 )
> >> DA = ASIN(TW/RV)
> > As it can be that TW > RV as well as TW < RV, this is incorrect. I
> > think it should be ATAN(WV/RV). Is this correct? It would make the
> > necessary power 1.4 times as great in the case of a sidewind of the
> > same speed as the rider is traveling.
>
>
> Stergios wrote:
> > If I have understood your variables correctly,
> > I think this should be:
> >
> > TW = SQRT((RV+WVcos(WA))**2 + (SIN(WA) * WV) ** 2))
> >
> > Now it reduces properly to TW = RV + WV for WA = 0.
> >
> > Stergios
>
> Also, DA = atan(WVsin(WA)/(RV+WVcos(WA))
> or DA = asin(WVsin(WA)/TW)
> or DA = acos((RV+WVcos(WA)/TW).
>
> These also reduce properly.
>
> Stergios
Okay, here's my crack at this. I was so delighted to see that someone
had proven that a wind with tailwind component can still slow you down.
I always thought it was just ME. I found this interesting enough to want
to see it graphically. I ended up blowing 20 years of dust off of my
physics and math texts, so I apologize in advance if I'm totally in left
field here...
My conclusions agree with yours for TW
(without the cosine argument you only get the 90deg component of the
wind)
For DA, I ended up with:
DA=90-atan((rv+cos(wa)wv)/sin(wa)wv)
same as your first example, I think... but uglier
This is similar to working out dead reckoning in flying, though we always
used a "whiz wheel" (probably dating myself there). Never did the actual
calculations until now. I am all mathed out!
Anyway, here's what I ended up with after arguing with Excel for a
while...
http://home.pacbell.net/lososos/bikewind.jpg
http://home.pacbell.net/lososos/bikewind.xls
If correct it certainly illustrates Jobst's assertion that the wind takes
away much more than it gives back.
John Schreiber
>
> Okay, here's my crack at this. I was so delighted to see that someone
> had proven that a wind with tailwind component can still slow you down.
> I always thought it was just ME. I found this interesting enough to want
> to see it graphically. I ended up blowing 20 years of dust off of my
> physics and math texts, so I apologize in advance if I'm totally in left
> field here...
>
> My conclusions agree with yours for TW
> (without the cosine argument you only get the 90deg component of the
> wind)
> For DA, I ended up with:
> DA=90-atan((rv+cos(wa)wv)/sin(wa)wv)
> same as your first example, I think... but uglier
> This is similar to working out dead reckoning in flying, though we always
> used a "whiz wheel" (probably dating myself there). Never did the actual
> calculations until now. I am all mathed out!
> Anyway, here's what I ended up with after arguing with Excel for a
> while...
>
> http://home.pacbell.net/lososos/bikewind.jpg
> http://home.pacbell.net/lososos/bikewind.xls
>
> If correct it certainly illustrates Jobst's assertion that the wind takes
> away much more than it gives back.
I don't claim to follow the math in any more than a general way, but
that graph is an excellent illustration of the discussions above. Much
easier to understand.
When you mention flying it seems obvious that 90 degree side wind is
going to require a higher air speed to maintain the same ground speed.
After all if you are having to crab into the wind to maintain your
ground track, you have to go through more air to get to the same
place.
When I was learning to fly we used what was called (if I remember
correctly) an E-6B which could plot your vectors. Using the E-6B makes
it clear too.
Isn't science beautiful.
Now, if you could, I'd like to see another graph. What speed do I
travel if I maintain a constant power level through your range of wind
speeds and directions? For instance at the power level to maintain 15
or 20 MPH in calm air, how fast would I be going with a 40 MPH
quartering tail wind or a 20 MPH side wind. I've always thought tail
winds should speed me up more than they really do and that in a 40 MPH
head wind I should be reduced to a stop rather than able to continue
at six MPH.
--
Thanks John Schreiber
Andrew Coggan
> Anyway, here's what I ended up with after arguing with Excel for a
> while...
>
> http://home.pacbell.net/lososos/bikewind.jpg
> http://home.pacbell.net/lososos/bikewind.xls
>
> If correct it certainly illustrates Jobst's assertion that the wind takes
> away much more than it gives back.
Unless you accounted for the fact that CdA varies with yaw angle (as well as
non-aerodynamic power losses), then it isn't correct. This was my point to
Jobst originally.
As for anybody who thinks that this discussion should NOT be on r.b.racing,
in the best Brian Trdina tradiation, I say "fuck off" - the conclusions of
such an analysis have a direct bearing upon equipment selection for
competition. (Although people can not read this and remain ignorant if they
want to...just makes it that much easier to beat them in races.)
Andy Coggan
Andrew Coggan
> Now, if you could, I'd like to see another graph. What speed do I
> travel if I maintain a constant power level through your range of wind
> speeds and directions? For instance at the power level to maintain 15
> or 20 MPH in calm air, how fast would I be going with a 40 MPH
> quartering tail wind or a 20 MPH side wind. I've always thought tail
> winds should speed me up more than they really do and that in a 40 MPH
> head wind I should be reduced to a stop rather than able to continue
> at six MPH.
It is EXCEEDINGLY rare for wind speeds to reach 20 mph at ground level, much less 40 mph. The
wind speeds you hear cited on weather reports are measured at 10 m off the ground, and there is
a considerable dimunition as you descend to a cyclist's level.
When we did our validation study at the Texas A&M wind tunnel and adjacent airport, the flags
were snapping in a very strong wind resulting from a cold front passing through (what Texans
call a "blue norther"). Although I don't recall the weather report for that day, I'm sure that
gusts of over 35 mph were expected/recorded (as 10 m). Yet, the highest gust of wind we
measured all day at 1 m of the ground was around 10 mph.
Andy Coggan
jobst....@stanfordalumni.org
> Okay, here's my crack at this. I was so delighted to see that
> someone had proven that a wind with tailwind component can still
> slow you down. I always thought it was just ME. I found this
> interesting enough to want to see it graphically. I ended up
> blowing 20 years of dust off of my physics and math texts, so I
> apologize in advance if I'm totally in left field here...
> My conclusions agree with yours for TW
> (without the cosine argument you only get the 90deg component of the
> wind)
> For DA, I ended up with:
> DA=90-atan((rv+cos(wa)wv)/sin(wa)wv)
> same as your first example, I think... but uglier This is similar to
> working out dead reckoning in flying, though we always used a "whiz
> wheel" (probably dating myself there). Never did the actual
> calculations until now. I am all mathed out! Anyway, here's what I
> ended up with after arguing with Excel for a while...
> http://home.pacbell.net/lososos/bikewind.jpg
> http://home.pacbell.net/lososos/bikewind.xls
> If correct it certainly illustrates Jobst's assertion that the wind
> takes away much more than it gives back.
That is what I presented in the article in Bike Tech and Bicycle
guide. To make the curves useful to differing points of view, I chose
to plot the curves at both constant speed and constant power, the
latter being reality for bicycle riders and the former for a motorized
rider who just turns up the motor to maintain the same speed.
I is on that basis that the other curves were drawn. I suggest the
plot be in 2D rather than 3D, labeling wind velocities on the curves
because fore and aft displacement is difficult to discern on the 3D
graph.
Since you have the data, could you re-plot that in 2D and show the
constant power curve based on a 25MPH power, which it a good one for
strong bicyclists.
The curves for straight line, out and back, TT for winds from 0 to 90
degrees is probably the most important one for the practical rider but
the one you plotted is the one that raises the most interest since it
shows something that has made riders feel weak when they think they
should be going faster.
The basis for all this is that it HAS been misrepresented often by
writers who did not separate drag from the equation and apply the
in-line component of it to rider speed to get power. It was this
point that originally prompted me to write a rebuttal to one of these
articles that was presented in Bike Tech and received no criticism.
Jobst Brandt <jobst....@stanfordalumni.org>
jobst....@stanfordalumni.org
>> If correct it certainly illustrates Jobst's assertion that the wind
>> takes away much more than it gives back.
> Unless you accounted for the fact that CdA varies with yaw angle (as
> well as non-aerodynamic power losses), then it isn't correct. This
> was my point to Jobst originally.
As I said, the equations were validated by mapping HPVA curves of data
measured in a wind tunnel of an unfaired rider onto the computed
results with excellent correlation. The conclusion was that a bicycle
and rider can be treated as a "bluff body". The HPVA did not know
that I would write an article citing their work nor did I alter the
equations to make their results fall closely along the computed
curves.
> As for anybody who thinks that this discussion should NOT be on
> r.b.racing, in the best Brian Trdina tradiation, I say "fuck off" -
> the conclusions of such an analysis have a direct bearing upon
> equipment selection for competition. (Although people can not read
> this and remain ignorant if they want to...just makes it that much
> easier to beat them in races.)
I take it you don't want to know what effects winds have on rider
speed. I have been at enough races where know-nothing riders
explained these effects at great length to others, relying heavily on
myth and lore. I am aware of this attitude and am still surprised how
it prevails in this time where technology has advanced into our lives
as much as it has.
Jobst Brandt <jobst....@stanfordalumni.org>
Andrew Coggan
the trigger without thinking?
1) As *I* said before, numerous measurements of riders using modern aero
equipment have demonstrated that CdA *does* change as a function of yaw
angle (c.f. Martin JC, Milliken DL, Cobb JE, McFadden KL, Coggan AR.
Validation of a mathematical model for road cycling power. J Appl Biomech
1998; 14:276-291). IOW, the data you relied upon to write your article, and
to defend your statements here, are out-of-date, or at least incomplete.
2) As for the relevance of this discussion to r.b.racing, I thought that I
made it crystal clear that I thought that it *did* belong here...but
apparently even my use of an expletive failed to make that obvious to you.
What more do you want me to do?
The irony of this all is that while you're busy making fun of "know
nothings" who do not fully understand the physics involved, your own
appreciation of the topic at hand has failed to keep pace with the times....
Andy Coggan
<jobst....@stanfordalumni.org> wrote in message
news:ZWAH7.3406$DD2....@typhoon.sonic.net...
Philip Holman
> Since you have the data, could you re-plot that in 2D and show the
> constant power curve based on a 25MPH power, which it a good one for
> strong bicyclists.
The most dominant effect of time lost in an out and back TT is simply due to
the fact that the time spent with an advantage (tailwind) is always less
than with the disadvantage (headwind).
Considering only aerodynamic drag and based on .4hp (220ft lb/sec) @ 25mph
and a 10fps (6.82mph) wind with 0 yaw.
Velocity into the wind is 20.67 mph (-4.37)
Velocity with the wind is 29.73 mph (+4.73)
The amount of velocity lost is less than the amount gained.
But for the same power outputs:
Time to do a 25mile TT no wind @25mph is 60 minutes
Time to do a 25mile TT with 10fps wind is 61minutes 30 sec. (36.28 + 25.22)
Phil Holman
Henry Chang
<alanj...@bigpond.com> wrote:
>None of you have both oars in the water.
If you're saying that because it's off topic, it is an appropriate
flame.
If you're saying that because you think that those who engage in the
silicone intelligence vs. computer intelligence debate are nuts, then
it just demonstrates that you label as 'crazy' what you don't
understand.
As Mr. Fink has posted, that's what he gets paid for and in the future
as computers get more and more sophisticated (especially if an
understanding of DNA brain function is realized), it is a topic that
will become more and more relevant.
Henry
Philip Holman
"Andrew Coggan" <andya...@erols.com> wrote in message
news:3BEECDCA...@erols.com...
> John Albergo wrote:
>
> > Anyway, here's what I ended up with after arguing with Excel for a
> > while...
> >
> > http://home.pacbell.net/lososos/bikewind.jpg
> > http://home.pacbell.net/lososos/bikewind.xls
> >
> > If correct it certainly illustrates Jobst's assertion that the wind
takes
> > away much more than it gives back.
>
> Unless you accounted for the fact that CdA varies with yaw angle (as well
as
> non-aerodynamic power losses), then it isn't correct. This was my point to
> Jobst originally.
The most dominant effect of time lost in an out and back TT is simply due to
the fact that the time spent with an advantage (tailwind) is always less
than with the disadvantage (headwind).
For your findings to work (varying CdA) and contention that this could
result in a faster time, it would have to be in a situation where the speeds
in both directions were fairly close. Are there any real life TT experiences
to relate.
Phil Holman
Andrew Coggan
> For your findings to work (varying CdA) and contention that this could
> result in a faster time, it would have to be in a situation where the speeds
> in both directions were fairly close. Are there any real life TT experiences
> to relate.
Chet Kyle performed essentially the same calculations that Jobst keeps crowing
about, but taking into account the effects of aero equipment. The results of
these calculations indicated that, under the right conditions, you can be faster
in and out-and-back or loop TT. Kyle went on to relate anecdotal evidence
(self-timed TTs) supporting his calculations. However, I cannot confirm this
based on personal experience, since I choose (based on the physics) to always
race w/ the most aero stuff I can lay my hands on...IOW, I don't have the
non-aero condition for comparison.
Andy Coggan
warren
<andya...@erols.com> wrote:
> The irony of this all is that while you're (jobst) busy making fun of "know
> nothings" who do not fully understand the physics involved, your own
> appreciation of the topic at hand has failed to keep pace with the times....
It's all he's got Andy-this time, and many others.
-WG
Qui si parla Campagnolo
> > >
> > > For winds at angles between zero and 180 degrees:
> > >
> > > TW = SQRT((RV **2 + (SIN(WA) * WV) ** 2))
> > > TD = TW**2
> > > DA = ATAN(HV/RV >>
<< TW = SQRT((RV + (SIN(WA) * WV)) ** 2)
> > TW = SQRT( RV ** 2 + (SIN(WA) * WV) ** 2 )
> >> DA = ASIN(TW/R >>
<< TW = SQRT((RV+WVcos(WA))**2 + (SIN(WA) * WV) ** 2))
> >
> > Now it reduces properly to TW = RV + WV for WA = 0 >>
<< Also, DA = atan(WVsin(WA)/(RV+WVcos(WA))
> or DA = asin(WVsin(WA)/TW)
> or DA = acos((RV+WVcos(WA)/TW).
>
> These also reduce properly. >>
This is comical....
Fabrizio Mazzoleni
> > > >
> > > > For winds at angles between zero and 180 degrees:
>On 13 Nov 2001 14:17:08 GMT, vecc...@aol.com (Qui si parla Campagnolo) wrote:
> This is comical....
>
>
>
Actually I find totally USELESS mumbo jumbo lame crap
like that shit to be really very sad. Garbage like that has
no reason to exist.
Dave Mackey
Sure it does, it's math masturbation. Nothing wrong with that.
Engineers are made to solve problems. Without them, cycling wouldn't
have progressed since Karl von Drais's 'Swiftwalker'. While Jobst and
company's discussion may have 0% relevance to you when you're actually
on your bike, that's not really the point. It's just a puzzle to solve.
--
Dave Mackey
usenetATmirrorcageDOTcom
Mechanical Engineers build weapons, Civil Engineers build targets.
Bob G
"Dave Mackey" <sp...@spam.spam> wrote in message
news:MPG.165b16b4391e8eb898969e@news...
> Mechanical Engineers build weapons, Civil Engineers build targets.
Q: What do engineers use for birth control?
A: Their personalities.
Bob
Philip Holman
>
>
>
>Actually I find totally USELESS mumbo jumbo lame crap
>like that shit to be really very sad. Garbage like that has
>no reason to exist.
"Bob G" <bob...@removenospamyahoo.com> wrote in message
news:9ss3fc$5p4$1...@bob.news.rcn.net...
Hey, how about a bunch of us, Fabrizio and such who don't like all this
calculation crap, form a separate NG. We could figure all this stuff based
on our own superior perceptions. Seat of the pants figuring is plenty good
enough. I've even come up with a good name for the NG.
It's ....rec.bike.shitforbrains. Let me know what you all think .....oh
sorry I forgot........you don't do you.
Phil Holman
Fabrizio Mazzoleni
> Hey, how about a bunch of us, Fabrizio and such who don't like all this
> calculation crap, form a separate NG. We could figure all this stuff based
> on our own superior perceptions. Seat of the pants figuring is plenty good
> enough. I've even come up with a good name for the NG.
> It's ....rec.bike.shitforbrains. Let me know what you all think .....oh
> sorry I forgot........you don't do you.
>
Good idea there number two. Tell me when the NG is online. I don't know
anything about that stuff and I don't want to learn ( computer stuff is FEM ).
One problem you will have to look into, how are we going to keep old daddy
pants Jobst from spamming us with all his lame-o troll posts that he bombards
this group with.
I didn't have time to spell check this post.
John Schreiber
> > > John, Jobst and Stergios farted out a bunch of lame useless shit
> > > > > >
> > > > > > For winds at angles between zero and 180 degrees:
> >
> >
> > >On 13 Nov 2001 14:17:08 GMT, vecc...@aol.com (Qui si parla Campagnolo) wrote:
>
> > > This is comical....
> > >
> > >
> > >
> > Actually I find totally USELESS mumbo jumbo lame crap
> > like that shit to be really very sad. Garbage like that has
> > no reason to exist.
>
> Sure it does, it's math masturbation. Nothing wrong with that.
> Engineers are made to solve problems. Without them, cycling wouldn't
> have progressed since Karl von Drais's 'Swiftwalker'. While Jobst and
> company's discussion may have 0% relevance to you when you're actually
> on your bike, that's not really the point. It's just a puzzle to solve.
"comical" "USELESS mumbo jumbo" "math masturbation"
Do you guys make fun of people who speak different languages than you
do? Do you make fun of people who understand more than you? When
you're left in the dust by a better rider do you make fun of them to
make up for your inadequacy?
If you don't care about this stuff, ignore it. It certainly has more
to do with bicycle racing than most of what I see on this news group.
I think you've been left in the dust by smarter (or at least better
educated on this topic) people and all you can do is make fun of them.
--
Thanks John Schreiber
Philip Holman
"Fabrizio Mazzoleni" <chip...@xxyahoo.com> wrote in message
news:1104_1005709234@pent...
Good to see you have a sense of humor............ er, you were jo........nah
never mind.
Here's my first stab at figuring.
Say you want to do 27mph for your TT and its windy.
You go out with a tail wind at 30 mph so what do you have to do on the way
back into the head wind to get your 27mph average. 3mph faster on the way
out is 10% of 30 mph. So with 27mph equivalent to 110% then 100% is 24.5mph
which is the speed you need to go on the return.
Is that easier to understand than:
Vs = Vf x Va / (2Vf -Va)
where
Vs = Slow leg velocity
Vf = Fast leg velocity
Va = Average target speed
Or do you just put your head down and go at a familiar level of effort (eye
balls out) in each direction and get what you get.
My opinion is that most people do the latter.
Phil holman
Fabrizio Mazzoleni
> I think you've been left in the dust by smarter (or at least better
> educated on this topic) people and all you can do is make fun of them.
To inject the odd fact into your rant:
People like you and others that go around farting out lame-o stuff
like m+x = (cx2) are as easy to exploit and abuse as someone who
rides around on some hybrid thingy bike.
(and even more so since most of you suffer from the delusion that you are smarter
than everybody else. LOL)
I bet you could stand to lose a few pounds of body fat.
Dave Mackey
> "comical" "USELESS mumbo jumbo" "math masturbation"
>
> Do you guys make fun of people who speak different languages than you
> do? Do you make fun of people who understand more than you? When
> you're left in the dust by a better rider do you make fun of them to
> make up for your inadequacy?
>
> If you don't care about this stuff, ignore it. It certainly has more
> to do with bicycle racing than most of what I see on this news group.
>
> I think you've been left in the dust by smarter (or at least better
> educated on this topic) people and all you can do is make fun of them.
Woah there, cowboy. If you look at my post, I'm hardly making fun of
anybody. In fact, I did say 'Nothing wrong with that' and credited this
type of critical thinking for technological advances.
As for calling it 'math masturbation', well, it is, isn't it? You're
solving what amounts to a physics equation, why? For your own personal
satisfaction. I don't mean it derogatorily, it's just a lame ass joke,
I guess.
I get a big kick out of deriving formulas and especially physics models.
Math is easily my favourite subject. Seriously. I think it's all
pretty interesting. But that's just me. If you look hard at my
signature down there, you can probably deduce what I'm going to
university for.
So if you took offence, all apologies. But if you're still going to
call me stupid, I'll gladly take that apology back.
jobst....@stanfordalumni.org
> You go out with a tail wind at 30 mph so what do you have to do on
> the way back into the head wind to get your 27mph average. 3mph
> faster on the way out is 10% of 30 mph. So with 27mph equivalent to
> 110% then 100% is 24.5mph which is the speed you need to go on the
> return. Is that easier to understand than:
There is a basic example of this in the scenario where the rider rides
into a steady stiff headwind on the first half of his out-and-back TT
going 12.5MPH. How fast does he have to ride on the return leg to
average 25MPH, assuming that he has the power to go that fast?
You can get all sorts of answers to this because most riders don't do
the math and don't understand the concepts.
Jobst Brandt <jobst....@stanfordalumni.org>
Mark Hickey
>"Fabrizio Mazzoleni" <chip...@xxyahoo.com> wrote in message
>> Good idea there number two. Tell me when the NG is online. I don't know
>> anything about that stuff and I don't want to learn ( computer stuff is FEM ).
>> One problem you will have to look into, how are we going to keep old daddy
>> pants Jobst from spamming us with all his lame-o troll posts that he bombards
>> this group with.
>>
>> I didn't have time to spell check this post.
Absolutely classic!
>Good to see you have a sense of humor............ er, you were jo........nah
>never mind.
>Here's my first stab at figuring.
>Say you want to do 27mph for your TT and its windy.
>You go out with a tail wind at 30 mph so what do you have to do on the way
>back into the head wind to get your 27mph average. 3mph faster on the way
>out is 10% of 30 mph. So with 27mph equivalent to 110% then 100% is 24.5mph
>which is the speed you need to go on the return.
>Is that easier to understand than:
>
>Vs = Vf x Va / (2Vf -Va)
>where
>Vs = Slow leg velocity
>Vf = Fast leg velocity
>Va = Average target speed
Some advice, Phil... never try to teach a pig to sing. It wastes your
time and annoys the pig. ;-)
>Or do you just put your head down and go at a familiar level of effort (eye
>balls out) in each direction and get what you get.
Well, yes.
Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $695 ti frame
Mark
>
> There is a basic example of this in the scenario where the rider rides
> into a steady stiff headwind on the first half of his out-and-back TT
> going 12.5MPH. How fast does he have to ride on the return leg to
> average 25MPH, assuming that he has the power to go that fast?
This was actually a bonus question on a quiz in a transportation class I
took (slightly varied, of course).
Qui si parla Campagnolo
no reason to exist. >>
Not useless I guess but the utility escapes me, for the guy that just wants to
ride their bike...
Particularly when ya ride outside and 'predicting' the wind direction and speed
only occurs after the fact...
terry morse
> Not useless I guess but the utility escapes me, for the guy that just wants to
> ride their bike...
> Particularly when ya ride outside and 'predicting' the wind direction and
> speed only occurs after the fact...
Some of us actually check the wind speed and direction before going out
for a ride, and adjust our rides to avoid stiff headwinds. Here's what
I use:
http://sfports.wr.usgs.gov/wind/
--
terry morse
Palo Alto, CA
http://www.terrymorse.com/bike/
Philip Holman
<jobst....@stanfordalumni.org> wrote in message
news:W%nI7.4133$DD2....@typhoon.sonic.net...
I tend to agree, I wonder if it warrants an inclusion into FAQ. It does come
up often enough.
I purposely posed the problem starting out with a tailwind to avoid the
scenario you have mentioned. The effect is dominant for linear (hill
climbing) as well as exponential resistance functions (wind) for cycling.
The formula I derived is limited for Vs > 1/2 Va.
Phil Holman
Philip Holman
"Mark Hickey" <ma...@habcycles.com> wrote in message
news:3bf2745a....@netnews.att.net...
> "Philip Holman" <phi...@earthlink.net> wrote:
>
> >"Fabrizio Mazzoleni" <chip...@xxyahoo.com> wrote in message
>
> >> Good idea there number two. Tell me when the NG is online. I don't know
> >> anything about that stuff and I don't want to learn ( computer stuff
is FEM ).
> >> One problem you will have to look into, how are we going to keep old
daddy
> >> pants Jobst from spamming us with all his lame-o troll posts that he
bombards
> >> this group with.
> >>
> >> I didn't have time to spell check this post.
>
> Absolutely classic!
Do I take it that you do not attach some level of sophistication to the
above answer.
>
> >Good to see you have a sense of humor............ er, you were
jo........nah
> >never mind.
> >Here's my first stab at figuring.
> >Say you want to do 27mph for your TT and its windy.
> >You go out with a tail wind at 30 mph so what do you have to do on the
way
> >back into the head wind to get your 27mph average. 3mph faster on the way
> >out is 10% of 30 mph. So with 27mph equivalent to 110% then 100% is
24.5mph
> >which is the speed you need to go on the return.
> >Is that easier to understand than:
> >
> >Vs = Vf x Va / (2Vf -Va)
> >where
> >Vs = Slow leg velocity
> >Vf = Fast leg velocity
> >Va = Average target speed
>
> Some advice, Phil... never try to teach a pig to sing. It wastes your
> time and annoys the pig. ;-)
There are enough of us here who provide irrefutable evidence to the fact
that you can educate pork.
>
> >Or do you just put your head down and go at a familiar level of effort
(eye
> >balls out) in each direction and get what you get.
>
> Well, yes.
This gives some insight into your personality type. Funny, I never rated you
as a feeling type.
So much for amateur psychology.
Phil Holman
Mark Hickey
>"Mark Hickey" <ma...@habcycles.com> wrote in message
>news:3bf2745a....@netnews.att.net...
>> "Philip Holman" <phi...@earthlink.net> wrote:
>>
>> >"Fabrizio Mazzoleni" <chip...@xxyahoo.com> wrote in message
>> >> I didn't have time to spell check this post.
>>
>> Absolutely classic!
>
>Do I take it that you do not attach some level of sophistication to the
>above answer.
Fabrizio has become an artful troll - he's created quite an on-line
persona (a virtual caricature of riders we all know). The beauty is
in the finely tuned LACK of sophistication...
>> >Vs = Vf x Va / (2Vf -Va)
>> >where
>> >Vs = Slow leg velocity
>> >Vf = Fast leg velocity
>> >Va = Average target speed
>>
>> Some advice, Phil... never try to teach a pig to sing. It wastes your
>> time and annoys the pig. ;-)
>
>There are enough of us here who provide irrefutable evidence to the fact
>that you can educate pork.
More often they just end up bacon sandwiches.
>> >Or do you just put your head down and go at a familiar level of effort
>(eye
>> >balls out) in each direction and get what you get.
>>
>> Well, yes.
I should point out that my ability to do any math at all during a time
trial is, well, minimal. I've been astonished at what I can't
calculate when I'm deep in oxygen debt.
"*pant* *pant* it took *pant* 30 minutes *pant* to the *pant*
turnaround.... *pant* *pant* how long *pant* is the whole *pant* ride
gonna *pant* take? *pant* *pant* Duuuuhhhhh"
>This gives some insight into your personality type. Funny, I never rated you
>as a feeling type.
>So much for amateur psychology.
Actually, not my strong suit. I was once tested for "spiritual
gifts", and was told they'd never seen anyone score that low on
"mercy". Henceforth, I was known as Merciless Mark. Hey, if the shoe
fits...
Doug Milliken
(Long, but imo this thread needs some historical context)
The "HPVA" data that Jobst is quoting is almost certainly ours, published in
"Second International Human Powered Vehicle Scientific Symposium Proceedings".
The symposium was in 1983 and my paper is titled, "Moulton Bicycle Aerodynamic
Research Program", December 1980. The book of papers is still available
(afaik) from <http://www.ihpva.org> and along with the other IHPVA Proceedings
is recommended reading for anyone interested in hpv development and
aerodynamics.
Alex Moulton <http://www.alexmoulton.co.uk> funded our test work because he
was curious to (1) know if there were any major differences between his bikes
and a conventional bike and, (2) find out if any sort of aerodynamic
assistance (fairing) would be useful for general riding--_not_ racing.
I believe that we were the first to test a bicycle in the wind tunnel at yaw
angles (to simulate cross winds). I had access to a low speed tunnel (CALSPAN
ASF, Buffalo, NY) and built my own measuring equipment that rotated with the
bike on the turntable. This meant that we were measuring the "x-force"--the
air drag along the axis of the bike that the rider must overcome. The
published paper includes a subset of the data that we measured, including drag
data at yaw angles of 0, 10, 20, 30, 40, 50, 60 & 90 degrees to the wind. As
well as various fairing configurations tested on a Moulton MkIII, I had a very
standard Gitane 10-speed (early 1970's vintage) that we used as a baseline
case for comparison. Perhaps Jobst remembers which data he used, it would
have made sense to use the data on the Gitane as representative of the bikes
of that era.
In this very early test work my riding position, my clothes, as well as the
bike itself are far from duplicating the positions and equipment available
to bike racers _today_. I sat on the test bikes in three different positions
with a small back brace to partially fix my position and I wore street shorts
(not bike shorts), a tight T-shirt and a watch-cap to keep my hair from
blowing around. I also tried loose clothes and noted an immediate increase in
air drag of over 10%.
Our analysis of the data (not all included in our paper) made use of the
actual data points that were measured and plotted on paper. For our purposes,
we compared various different configurations against each other with different
cross plots. We did not look at the out-and-back performance on a time trial,
since the research program was not directed toward racing.
Contrasted to that, Jobst worked the time trial problem (out and back) and
published in "Bike Tech". He took a look at the shape of our data for the
unfaired bike and determined that he could fit it quite well if he assumed
that the rider and bike was replaced with a vertical cylinder, symmetric with
respect to yaw angle. Thus his equations do not require any kind of table
look-up or other type of empirical curve fit. For the unfaired bikes that I
tested, this is probably a safe assumption, although the data does not fit
perfectly.
Since those early days, I've been back to the wind tunnel many times with
different groups including another project on my own sponsored by the
original Schwinn Company (1981), Hed/BicycleSports (Texas A & M tunnel) and
Project '96 (US Olympic Team at General Motors tunnel). Each test session had
a different purpose and test plan. Andrew Coggan refers (below) to the
work that resulted in our joint paper with lead author Jim Martin.
In general, the cylindrical assumption for the rider loses accuracy as soon as
the bike picks up an increase in side area from, for example, streamlined
tubing, faired wheels and/or disk wheels. This is pretty easy to see in a
general way--once there are planar surfaces on the bike it reacts differently
as the air attaches and separates from these surfaces, at different yaw
angles. Also, the modern time-trial and triathlete riding positions (with a
very flat back and careful tuning of position) have a great deal of attached
flow around the rider--when compared to the positions (and clothing) that I
tested over 20 years ago, and this also moves the test results away from the
cylindrical assumption.
-- Doug Milliken <bd...@bfn.org>
Day job ---> <http://www.millikenresearch.com>
On Sun, 11 Nov 2001, Andrew Coggan wrote:
> Do you ever read the posts you're responding to, Jobst, or do you just pull
> the trigger without thinking?
>
> 1) As *I* said before, numerous measurements of riders using modern aero
> equipment have demonstrated that CdA *does* change as a function of yaw
> angle (c.f. Martin JC, Milliken DL, Cobb JE, McFadden KL, Coggan AR.
> Validation of a mathematical model for road cycling power. J Appl Biomech
> 1998; 14:276-291). IOW, the data you relied upon to write your article, and
> to defend your statements here, are out-of-date, or at least incomplete.
>
<snipped
> Andy Coggan
>
>
> <jobst....@stanfordalumni.org> wrote in message
> news:ZWAH7.3406$DD2....@typhoon.sonic.net...
> > Andrew Coggan writes:
> >
> > >> If correct it certainly illustrates Jobst's assertion that the wind
> > >> takes away much more than it gives back.
> >
> > > Unless you accounted for the fact that CdA varies with yaw angle (as
> > > well as non-aerodynamic power losses), then it isn't correct. This
> > > was my point to Jobst originally.
> >
> > As I said, the equations were validated by mapping HPVA curves of data
> > measured in a wind tunnel of an unfaired rider onto the computed
> > results with excellent correlation. The conclusion was that a bicycle
> > and rider can be treated as a "bluff body". The HPVA did not know
> > that I would write an article citing their work nor did I alter the
> > equations to make their results fall closely along the computed
> > curves.
> > <more snipped>
> > Jobst Brandt <jobst....@stanfordalumni.org>
Andrew Coggan
Thanks for the information. As always, you prove yourself to not only be an
excellent scientist, but also a great diplomat. ;-)
Andy
"Doug Milliken" <bd...@bfn.org> wrote in message
news:GMvJx...@freenet.buffalo.edu...
Philip Holman
> Doug,
>
> Thanks for the information.
Yes thanks, "historical context" is key here.
>As always, you prove yourself to be a great diplomat. ;-)
We could all take a page out of Doug's and Jim Martin's book here.
The comparison I'm interested in is between 0 wind and a wind with a
range of yaw angles that would more than compensate for the losses from a
large speed differential (with aero equipment).
Tooling around on Tom Compton's website, with a disc wheel, I find that
wind conditions at or around a 90 yaw result in a faster time than a 0 wind
condition but slower when using a regular wheel. I'm looking at saving 40
secs in a 40K
TT.
The closest conditions I've experienced was at Masters Nats this year in
Spokane.
There was a strong side wind that resulted in a very even time split. The
course is reasonably flat but what grades there are in combination with
local directional changes did result in speed fluctuations from low 20s to
low 30s for me.
Looking at the finishing times of the dozen or so riders I know very well, I
would say that their times were a little on the slow side. My point here is
that any gains from a side wind were overshadowed by losses from speed
fluctuations due to changes in relative wind direction and slope.
Phil Holman
Philip Holman
> >> time and annoys the pig. ;-)
> >
> >There are enough of us here who provide irrefutable evidence to the fact
> >that you can educate pork.
>
> More often they just end up bacon sandwiches.
What's this "they" stuff. I was talking about "us".
> Actually, not my strong suit. I was once tested for "spiritual
> gifts", and was told they'd never seen anyone score that low on
> "mercy". Henceforth, I was known as Merciless Mark. Hey, if the shoe
> fits...
Are you sure they weren't dissing you for your lack of riding ability
and saying Merckxiless Mark.
puh.....puh, puh.....that all folks.
Phil Holman
Andrew Coggan
> >As always, you (Doug Millikent) prove yourself to be a great diplomat.
;-)
>
> We could all take a page out of Doug's and Jim Martin's book here.
Never heard of the "hackpack", have you, Phil? ;-)
Andy Coggan
Philip Holman
Sure, thats the bunch over in rbr aka the "Panties in a Wad" brigade.
Phil Holman
John Albergo
jobst....@stanfordalumni.org wrote:
> John Albergo writes:
>
> .... Anyway, here's what I
> > ended up with after arguing with Excel for a while...
>
> > http://home.pacbell.net/lososos/bikewind.jpg
> > http://home.pacbell.net/lososos/bikewind.xls
>
> > If correct it certainly illustrates Jobst's assertion that the wind
> > takes away much more than it gives back.
>
> That is what I presented in the article in Bike Tech and Bicycle
> guide. To make the curves useful to differing points of view, I chose
> to plot the curves at both constant speed and constant power, the
> latter being reality for bicycle riders and the former for a motorized
> rider who just turns up the motor to maintain the same speed.
>
> I is on that basis that the other curves were drawn. I suggest the
> plot be in 2D rather than 3D, labeling wind velocities on the curves
> because fore and aft displacement is difficult to discern on the 3D
> graph.
Portion of the same chart in 2D:
http://home.pacbell.net/lososos/bikewind2.jpg
Still-air power falls within the checkered region
>
> Since you have the data, could you re-plot that in 2D and show the
> constant power curve based on a 25MPH power, which it a good one for
> strong bicyclists.
Haven't solved this one yet.
>
> The curves for straight line, out and back, TT for winds from 0 to 90
> degrees is probably the most important one for the practical rider but
> the one you plotted is the one that raises the most interest since it
> shows something that has made riders feel weak when they think they
> should be going faster.
>
> The basis for all this is that it HAS been misrepresented often by
> writers who did not separate drag from the equation and apply the
> in-line component of it to rider speed to get power. It was this
> point that originally prompted me to write a rebuttal to one of these
> articles that was presented in Bike Tech and received no criticism.
>
> Jobst Brandt <jobst....@stanfordalumni.org>
>
John Albergo
Qui si parla Campagnolo wrote:
While some of this is merely illustrating a curiosity, in a real sense the
topography of drag is the land we are all riding. Conversely, hills can be
conceptualilzed in terms of drag also. Without drag all of the uphill effort
would be regained as speed on the downhill. So drag is everything. Knowing the
"lay of the land" helps in deciding how to spend your energy -- you can plot your
course through that topography. True you don't have constant knowledge of
windspeed and velocity but you do have an overall knowledge before you start,
whenever you stop and you also know how the "relative wind" is going to change as
you go up and down hills. You can see grass or tree leaves/limbs moving, debris
scudding across the road. You can feel the changes in power required and relate
them to the slope of the roadway. There's lots of information available. I hope
I'm not making Fabrizio even sadder.
John Albergo
Fabrizio Mazzoleni wrote:
In the future you may find it more enjoyable to avoid threads with the word
"Strategy" in the subject.
Andrew Coggan
masterpiece) to a hack pack email missive is like comparing what gets written
on a high school boy's bathroom wall to fine literature.
For a small taste of the hack pack style, go read a few of Max Kash Agro's race
reports on Truesport.com...
Andy Coggan
Henry Chang
<andya...@erols.com> wrote:
>Comparing what gets posted on r.b.r. (excepting the occasional Dave Bailey
>masterpiece) to a hack pack email missive is like comparing what gets written
>on a high school boy's bathroom wall to fine literature.
>
>For a small taste of the hack pack style, go read a few of Max Kash Agro's race
>reports on Truesport.com...
MKA is an excellent writer, but if the reader doesn't know who the
nicknames refer to, it start to look like spam really fast.
Henry
Doug Milliken
Slow newsfeed here, sorry for delay.
I don't think I have any data on "regular" TT bikes here (not my personal
research interest). Lots of this has been collected by others--maybe
Andrew knows where there is a good set? I think Tom Compton has done
a good job of integrating existing data into his calculations.
I do have good data on one of the fully faired AM bikes (hpv) that I built.
Pics here:
<http://www.interq.or.jp/cool/yutakais/gallery/index2.htm>
In the left frame click on "Bicycle" and then on "Aero IV".
I think Andrew was around when we tested some of these fairings.
Not only does the data show that this fairing generates "x-thrust" when on
a "reach" (in sailing terms) but I've ridden it for long periods on the
flat at 15+ mph with no pedaling at all.
A second example -- given a big parking lot and a steady wind, lay out an
oval course with the wind running at 90 deg to the long axis of the oval.
On this course I was able to sail around as long as the wind kept up, no
pedaling after I got up to speed initially. It is a handful when "coming
about" and if there are gusts or passing trucks...so small boat warnings
apply<grin>!
-- Doug Milliken
John Albergo
Paul Alman wrote:
> Nothing wrong at all about
> understanding the effects of wind on bicycling, enjoy it if that is your
> thing. Secondly, it might take the fun out of it for me if I focused more
> on understanding the formulas etc., than I do on the reason I got into
> cycling and racing in the first place. And finally, IMHO, education and
> understanding of natural phenomena are "value neutral"; it is their
> application that can puts some sort of moral/ethical value on them.
Consider a hunter.
A true hunter knows his prey. He knows its habits, where it lives, where it
eats. He knows where it goes for water. He knows the lay of the land. He
knows the plants that grow there in use; in seed and leaf and flower. He knows
his weapons and his traps. He knows how fast he can run and how far and in
what conditions. He knows the world and he knows himself. His understanding
does not dull the beauty of his world.
Philip Holman
I also looked up some old threads in Google "Sail effect of disk wheels"
from 1998 which was good reading and explains some of the agro in this
thread.
Thanks again
Phil Holman
"Doug Milliken" <bd...@bfn.org> wrote in message
news:Gn2w...@freenet.buffalo.edu...