Dragging the wheel sucker

Is there a table of measurement-verified values of energy saved at
varying speeds from close following?

But, I'm as much interested in the Subject, the cost to the lead
rider. I know speed records set behind lead vehicles are always posed
as though the only action of that lead vehicle is to reduce drag, as
if making the air thinner, less viscous. The truth is otherwise,
whether you view this is a partial vacuum pulling the trailing cyclist
or the closing backwave pushing him forward.

So, what is the energy penalty on the leading rider, at varying
speeds?

Harry Travis

On Sep 23, 8:55 pm, "
wrote:

So, what is the energy penalty on the leading rider, at varying
speeds?

There is none. In principle the leading rider would have a slight
gain because the reduced pressure in the air behind him is partially
filled by the trailing rider so he has less drag. This has been
observed in closely drafting race cars where there's a big speed gain
by the trailing car and a slight gain for the lead car. I doubt that
the benefit for the lead rider would be measurable for cyclists.

wrote:
Is there a table of measurement-verified values of energy saved at
varying speeds from close following?

http://www.ncbi.nlm.nih.gov/pubmed/10589873

On 2008-09-24, peter wrote:
On Sep 23, 8:55 pm, "
wrote:

So, what is the energy penalty on the leading rider, at varying
speeds?

There is none. In principle the leading rider would have a slight
gain because the reduced pressure in the air behind him is partially
filled by the trailing rider so he has less drag. This has been
observed in closely drafting race cars where there's a big speed gain
by the trailing car and a slight gain for the lead car.

Indeed and I just saw an Indy Car race in which I wondered if that might
have been happening. Castroneves won it at the last minute by a couple
of inches, but at the point that he was edging past the other chap he
had his teammate right behind him, possibly giving him the tiny
advantage he needed.

On Sep 24, 3:18*am, Ben C wrote:
On 2008-09-24, peter wrote:

On Sep 23, 8:55 pm, "
wrote:

So, what is the energy penalty on the leading rider, at varying
speeds?

There is none. *In principle the leading rider would have a slight
gain because the reduced pressure in the air behind him is partially
filled by the trailing rider so he has less drag. *This has been
observed in closely drafting race cars where there's a big speed gain
by the trailing car and a slight gain for the lead car.

Indeed and I just saw an Indy Car race in which I wondered if that might
have been happening. Castroneves won it at the last minute by a couple
of inches, but at the point that he was edging past the other chap he
had his teammate right behind him, possibly giving him the tiny
advantage he needed.

Top speed for a displacement hull boat is a function of the boat
length - the longer the boat, the faster it will go. I would suppose
that top cycling speed might also be dependent on the length of the
train. I doubt a longer train would have a much higher speed without
pacelining, but it would be interesting to see how a longer train
affected the overall group's speed.

R

On 9/24/2008 6:14 AM RicodJour wrote:

On Sep 24, 3:18 am, Ben C wrote:
On 2008-09-24, peter wrote:

On Sep 23, 8:55 pm, "
wrote:
So, what is the energy penalty on the leading rider, at varying
speeds?
There is none. In principle the leading rider would have a slight
gain because the reduced pressure in the air behind him is partially
filled by the trailing rider so he has less drag. This has been
observed in closely drafting race cars where there's a big speed gain
by the trailing car and a slight gain for the lead car.
Indeed and I just saw an Indy Car race in which I wondered if that might
have been happening. Castroneves won it at the last minute by a couple
of inches, but at the point that he was edging past the other chap he
had his teammate right behind him, possibly giving him the tiny
advantage he needed.

Top speed for a displacement hull boat is a function of the boat
length - the longer the boat, the faster it will go. I would suppose
that top cycling speed might also be dependent on the length of the
train. I doubt a longer train would have a much higher speed without
pacelining, but it would be interesting to see how a longer train
affected the overall group's speed.

R

B-but a paceline isn't composed of a single, long "hull," the cyclists
aren't connected together so that the reduced drag behind the leader helps
push the leader along. It's more like a bunch of little unconnected boats.

--
Mike "Rocket J Squirrel"

In article
,
" wrote:

Is there a table of measurement-verified values of energy saved at
varying speeds from close following?

There are some. I would think that the IHPVA would be a good resource
for this kind of information.

But, I'm as much interested in the Subject, the cost to the lead
rider. I know speed records set behind lead vehicles are always posed
as though the only action of that lead vehicle is to reduce drag, as
if making the air thinner, less viscous.

That's not how it works.

The truth is otherwise, whether you view this is a partial vacuum
pulling the trailing cyclist or the closing backwave pushing him
forward.

That's not precisely accurate.

So, what is the energy penalty on the leading rider, at varying
speeds?

None. Wind tunnel testing was conducted at the Kirsten Wind Tunnel at
the University of Washington of drafting riders on 2008 (Bicycle
Quarterly, 6, 3, pp. 45-7). They found that the rear rider saw a
reduction in wind resistance up to 38% and that the leading rider also
saw a reduction in wind resistance of up to 3%. Thus being the leading
rider has no penalty and may even have benefit from drafting.

The authors' explanation was that the following rider creates a "push"
although I was unconvinced of this explanation of the observed data.

Travis Harry wrote:

Is there a table of measurement-verified values of energy saved at
varying speeds from close following?

But, I'm as much interested in the Subject, the cost to the lead
rider. I know speed records set behind lead vehicles are always
posed as though the only action of that lead vehicle is to reduce
drag, as if making the air thinner, less viscous. The truth is
otherwise, whether you view this is a partial vacuum pulling the
trailing cyclist or the closing backwave pushing him forward.

So, what is the energy penalty on the leading rider, at varying
speeds?

Where do yo9u suppose the energy goes? The leading rider can only
gain from a closely following body. A slight pressure wave of
insignificant magnitude precedes a bicyclist. It does not extend far
ahead, but is possibly detectable with careful instrumentation. The
work of a lone rider in still air (for simplicity) puts the air into
forward motion just as trash on a road is swirled forward when a motor
vehicle passes.

I hope in you bicycling you have had the opportunity to sit in behind
a moving van. Whether anyone gets into that slipstream or not does
not make the power required to make the slip stream any
different... unless it is a large blunt moving van closely following.
That would be much like the semi trailer behind the wind deflector
above the tractor cab. When not puling a semitrailer, the tractor
must drive harder but, on level ground with a trailer it reduces
eddies behind the cab.

Jobst Brandt

aka Jobst Brandt wrote:
Travis Harry wrote:

Is there a table of measurement-verified values of energy saved at
varying speeds from close following?

But, I'm as much interested in the Subject, the cost to the lead
rider. I know speed records set behind lead vehicles are always
posed as though the only action of that lead vehicle is to reduce
drag, as if making the air thinner, less viscous. The truth is
otherwise, whether you view this is a partial vacuum pulling the
trailing cyclist or the closing backwave pushing him forward.

So, what is the energy penalty on the leading rider, at varying
speeds?

Where do yo9u suppose the energy goes? The leading rider can only
gain from a closely following body. A slight pressure wave of
insignificant magnitude precedes a bicyclist. It does not extend far
ahead, but is possibly detectable with careful instrumentation. The
work of a lone rider in still air (for simplicity) puts the air into
forward motion just as trash on a road is swirled forward when a motor
vehicle passes.

However, a large trailing vehicle can produce a significant "bow wave"
which is why support motor homes and chase vehicles are not allow to
follow the cyclist too closely in endurance events and speed record
attempts, respectively.

I hope in you bicycling you have had the opportunity to sit in behind
a moving van.[...]

The best draft I ever had was a pick-up truck pulling a wagon full of
hay bales at 40 to 50 kph, which I followed at a spacing of about 1
meter for several kilometers at low effort. I doubt I had any effect on
the farmer's fuel economy.

--
Tom Sherman - Holstein-Friesland Bovinia
“the bacteria people tuned in-as to bioengineering at the correct wave
Point” - gene daniels

aka Jobst Brandt wrote:
Travis Harry wrote:

Is there a table of measurement-verified values of energy saved at
varying speeds from close following?

But, I'm as much interested in the Subject, the cost to the lead
rider. I know speed records set behind lead vehicles are always
posed as though the only action of that lead vehicle is to reduce
drag, as if making the air thinner, less viscous. The truth is
otherwise, whether you view this is a partial vacuum pulling the
trailing cyclist or the closing backwave pushing him forward.

So, what is the energy penalty on the leading rider, at varying
speeds?

Where do yo9u suppose the energy goes? The leading rider can only
gain from a closely following body. A slight pressure wave of
insignificant magnitude precedes a bicyclist. It does not extend far
ahead, but is possibly detectable with careful instrumentation. The
work of a lone rider in still air (for simplicity) puts the air into
forward motion just as trash on a road is swirled forward when a motor
vehicle passes.

However, a large trailing vehicle can produce a significant "bow wave"
which is why support motor homes and chase vehicles are not allow to
follow the cyclist too closely in endurance events and speed record
attempts, respectively.

I hope in you bicycling you have had the opportunity to sit in behind
a moving van.[...]

The best draft I ever had was a pick-up truck pulling a wagon full of
hay bales at 40 to 50 kph, which I followed at a spacing of about 1
meter for several kilometers at low effort. I doubt I had any effect on
the farmer's fuel economy.

--
Tom Sherman - Holstein-Friesland Bovinia
“the bacteria people tuned in-as to bioengineering at the correct wave
Point” - gene daniels