Cancellara motorized attacks?

[cyclopeon]

Power = Force x Velocity
Force = Drag Constant x Velocity squared

therefore:
Power = Drag Constant x Velocity cubed.

Read more at wiki.

Ah, okay; thank you. But may I point out that that (at Wiki) is Drag at High Velocity. Which means approaching Mach 1 (ie approaching the speed of sound). Cyclists do not travel at anywhere near such speeds, not even with a motor-assist. Wrong conditions, wrong equation.

At cycling speeds power will vary roughly as the square of the velocity. 20kph, 100W; 40kph, 400W. On flat roads. (Uphill, less than the square: it depends on steepness but that's a whole nother issue)

 

[Frank Tuesday]

Ah, okay; thank you. But may I point out that that (at Wiki) is Drag at High Velocity. Which means approaching Mach 1 (ie approaching the speed of sound). Cyclists do not travel at anywhere near such speeds, not even with a motor-assist. Wrong conditions, wrong equation.

At cycling speeds power will vary roughly as the square of the velocity. 20kph, 100W; 40kph, 400W. On flat roads. (Uphill, less than the square: it depends on steepness but that's a whole nother issue)

Nowhere does it mention Mach is the description of 'High Velocity'. It defines high velocity as having a Reynolds number greater than 1000. Reynolds number is a non-dimension number relating inertial forces to viscous forces. For a high Reynolds number (Re), the inertial (drag) forces dominate, and the viscous forces can be neglected.

The Reynolds number is given by the equation:

Re=rho*V*L/mu

where:

Re is the Reynolds number
rho is the density of the fluid (air in our example)
V is the relative velocity of the fluid to the object (or vice-versa)
mu is the dynamic viscosity of the fluid.
L is the charactheristic length of the object (the bike in our example)

for Air at nominal sea pressure level and room temperature (25C):

rho = 1.184 kg/m^3
mu = 1.85E-5 N*s/m^2

source: Fundamentals of Fluid Mechanics Fifth Edition, Munson,2006, Appendix B, pg 763.

Assume a velocity of 13m/s (approx 29mph or 48kph).

It is difficult to calculate the characteristic length, so lets see what minimum characteristic length is necessary for the Reynolds number to be greater than 1000.

Solving the Reynolds Number equation for L:

L = Re*mu/(rho*V)

L = (1000*1.85E-5)/(1.184*13)

L = 0.001m or 1mm.

We can see from the equation that Re increases with increasing L, so any characteristic length greater than 1mm will qualify as 'high velocity'. I don't know the exact value, but the characteristic length of a bicycle is clearly greater than 1mm. Therefore, in this example, a bicycle travelling through air at 29mph is 'high velocity'.

FYI, the variance of density and viscosity are small over the ranges found in cycle racing.

at 0C, rho = 1.292, mu=1.71E-5
at 40C, rho = 1.127, mu = 1.84E-5

at 3000m, rho = 0.9093, mu = 1.694E-5

None of these are significant enough to change the fact that a bicycle in air at 29mph is 'high velocity', no matter the altitude and temperature.

Power is a function of velocity cubed, not velocity squared.

If you want to talk more fluid dynamics, let me know.

EDIT: I just noticed that in the wiki example, they use a car at 100mph, far from mach, and they state that double speed need 8 times the power.

 

[Oldman]

Nowhere does it mention Mach is the description of 'High Velocity'. It defines high velocity as having a Reynolds number greater than 1000. Reynolds number is a non-dimension number relating inertial forces to viscous forces. For a high Reynolds number (Re), the inertial (drag) forces dominate, and the viscous forces can be neglected.

The Reynolds number is given by the equation:

Re=rho*V*L/mu

where:

Re is the Reynolds number
rho is the density of the fluid (air in our example)
V is the relative velocity of the fluid to the object (or vice-versa)
mu is the dynamic viscosity of the fluid.
L is the charactheristic length of the object (the bike in our example)

for Air at nominal sea pressure level and room temperature (25C):

rho = 1.184 kg/m^3
mu = 1.85E-5 N*s/m^2

source: Fundamentals of Fluid Mechanics Fifth Edition, Munson,2006, Appendix B, pg 763.

Assume a velocity of 13m/s (approx 29mph or 48kph).

It is difficult to calculate the characteristic length, so lets see what minimum characteristic length is necessary for the Reynolds number to be greater than 1000.

Solving the Reynolds Number equation for L:

L = Re*mu/(rho*V)

L = (1000*1.85E-5)/(1.184*13)

L = 0.001m or 1mm.

We can see from the equation that Re increases with increasing L, so any characteristic length greater than 1mm will qualify as 'high velocity'. I don't know the exact value, but the characteristic length of a bicycle is clearly greater than 1mm. Therefore, in this example, a bicycle travelling through air at 29mph is 'high velocity'.

FYI, the variance of density and viscosity are small over the ranges found in cycle racing.

at 0C, rho = 1.292, mu=1.71E-5
at 40C, rho = 1.127, mu = 1.84E-5

at 3000m, rho = 0.9093, mu = 1.694E-5

None of these are significant enough to change the fact that a bicycle in air at 29mph is 'high velocity', no matter the altitude and temperature.

Power is a function of velocity cubed, not velocity squared.

If you want to talk more fluid dynamics, let me know.

EDIT: I just noticed that in the wiki example, they use a car at 100mph, far from mach, and they state that double speed need 8 times the power.

Thanks again for saving me research. And thus...Cancellara used his own powerful legs to drop Boonen. All done.

 

[nvpacchi]

source: Fundamentals of Fluid Mechanics Fifth Edition, Munson,2006

My least favorite textbook

 

[Oldman]

My least favorite textbook

Try reading the legal patent law books related to engineering.

 

[tidean]

I have serious doubts about Cancellara's performance at Flanders and Roubaix. I have seen a lot of races, but I can't remember a rider doing something like that in the classics. The guy absolutely dropped Boonen like a stone.

The Cassani video raises a lot of questions. I hate to be a conspiracy theorist, but those two Cancellara performances just don't smell right.

Didn't O'Grady break away for 20 or so km's when he won his Paris Roubaix title, & definitely not by motor or by any other illegal means.?????

 

[tidean]

I'm just not buying this yet. Come on, it's not as if Cancellara's some mug. Is it that suspicious that the time trial world champion (by a mile) should put out huge watts while in the saddle?

Yeah the time trial world champ against a sprinter on a hill????

 

[online-rider]

No doubt about the performances but too many people would know about his bike.

Not true It only takes one pair of hands slide the battery in and assemble everything look how quickly they did it on the video! Cancellaras riding this spring 2 me looks ridiculous, never seen anything like it. and im more suspicious of that worlds TT where he beat most by like 5 mins

He may be innocent but i dont care cos hes on peds anyway so he dont deserve pity

 

[SpartacusRox]

Not true It only takes one pair of hands slide the battery in and assemble everything look how quickly they did it on the video! Cancellaras riding this spring 2 me looks ridiculous, never seen anything like it. and im more suspicious of that worlds TT where he beat most by like 5 mins

He may be innocent but i dont care cos hes on peds anyway so he dont deserve pity

This would rank as one of the dumbest posts. FC wins because he is the best, end of story. He is doing nothing this season that he has not done in the past. At PR, Boonen toasted himself and by dropping back left himself wide open to an attack, which is exactly what happened. He then buried himself trying to catch up while the others sat on him like a bunch of novice girls and hardly took a turn.

This thread is the biggest waste of time ever and should be locked before it encourages more morons to come out of the woodwork.

 

[Notso Swift]

This would rank as one of the dumbest posts. FC wins because he is the best, end of story. He is doing nothing this season that he has not done in the past. At PR, Boonen toasted himself and by dropping back left himself wide open to an attack, which is exactly what happened. He then buried himself trying to catch up while the others sat on him like a bunch of novice girls and hardly took a turn.

This thread is the biggest waste of time ever and should be locked before it encourages more morons to come out of the woodwork.

Add the Ronde, where Boonan said he was cramping

 

[Ripper]

This would rank as one of the dumbest posts. FC wins because he is the best, end of story. He is doing nothing this season that he has not done in the past. At PR, Boonen toasted himself and by dropping back left himself wide open to an attack, which is exactly what happened. He then buried himself trying to catch up while the others sat on him like a bunch of novice girls and hardly took a turn.

This thread is the biggest waste of time ever and should be locked before it encourages more morons to come out of the woodwork.

And yet, you posted

 

[skippy]

APRIL FOOLS DAY was 2mths ago! BP are polluting the Gulf of Mexico and the Media are short of ideas so even here in Austria this nonsense is surfacing!
Pascal the mechanic sticks his head out of the sunroof of the team car and we have sensationalism! Boonen gets his derriere kicked and there is "Conspiracy"! Lance has even been tied to this in some articles as some "jokers" reckon he lent the bike out!" Correct me but doesn't Radio Shack ride Trek and didn't "Specialized" stop supplying a team because they want Kids to respect thier body and avoid "Substance abuse"?
Athletes train for events and F C trained for this with Stewie & co pulling him to the point where he could use all his energy to get the desired result, Victory. Basso didn't win the Giro alone Silvo Smyzd pulled him , Nibali & Evans et al up the climbs to the point that Liquigas were able to determine the result.
Yesterday after 140k i jumped on the back of a family group of 3 and they towed me 30k at over 40+kph, it was sad they were not going the rest of the way as i went thru 2 speed signs at 37 & 38 after they heded west to Innsbruck and i went south to Zillertal.
Robbie McEwen reported 68kph on twitter training recently and Cippo was booked on the SuperStrada at 90+ behind a M/bike!

SILLY SEASON IS OVER! Back to the real world PLEASE?

BY THE WAY my take on the CHEATING RACERS

FACT is these UN CONSCIENABLE CHEATS deserve to be locked and tagged in their homes for the full period of their suspension and NOT allowed to work in any "CYCLING related activity" whether with teams or travel or speaking engagements.

IN ADDITION on return from Suspension they must only race in a league 2 steps below their departure point, thus we will not see the PROTOUR polluted by the poison that they were infected with! Professionals faced with this situation will think about "Short cuts" to success when they forsee the consequences!

Pat Mc Quaid may be Irish and be portrayed as a lightweight but i am sure he is "SAVVY enough "to make the CHEATS sweat at night when he uses the power that is at his disposal more effectively!

DO THE CRIME , SERVE THE TIME ! Tired of hearing how some of these adults were misled !

 

[Buffalo Soldier]

This doesn't make sense. The only way to get the equivalent of an extra 100W is to add an extra 100W. You can't add 23W and get the equivalent of 100W. They say it is the equivalent of an extra 100W because the motor generates significantly more power, but losses in the system reduce that to an extra 100W at the chain.

So what is the effect of 100W? It is dependent upon speed. The drag force acting upon a rider is proportional to the velocity squared. At steady state, the power required is proportional to the velocity cubed. What this means in general terms is that if you want to double your speed, it takes 8 times the amount of power. That is why my economy car can easily exceed 100mph, while it takes 500+hp to break 200mph.

Lets compare the same rider at different power outputs. The jump from 100 to 200 W is pretty significant. Double the power, so 2^(1/3), or 1.26 times the velocity. The jump to 200-300 is still pretty good: 1.5 times the power, 1.14 times the velocity. What about the difference between 500 and 600W? A 20% increase in power only gives a 6% increase in velocity. Still not too bad. What about what we are looking at in this case. A short burst of max power to get away from your companions. Lets assume that Cancellara can achieve a peak output of 1400W during a break. Obviously I don't know his numbers, but I've hit 2200 on the Powertap before, and I have a significant bulk advantage over him, so I think this is reasonable. I think Cozy Beehive calculated approx 1400 in his analysis as well. Even if it is completely wrong, it still illustrates the physics. FYI: At 1000W, you'd see a 3% increase in speed, and at 2000W, 1.6% increase.

So what is the effect of an extra 100W at 1400W rider output? a 2% increase in velocity. So if he was able to go 50kph, with the motor assist, he could do 51kph.

First of all: an extra 1kph is enough to win a race

Second: i don't know much about mechanics et all. but this is how someone explained it to me (i hope my translation is decent):

"Don't focus on the power. A battery that fits in the tube can not possibly deliver 100W! But they say it's comparable to 100W extra and this is a big difference ...

Suppose you're on your bike, uphill, what would you desire? And let's be realistic: a motor that fits in a tube won't make a winner of any of us. You're hungry for a push! And this is precisely what costs a lot of force, or torque. The power still comes from Cancellara but the force comes from the engine.

Torque is force or, to-put-in-motion. Power is the number of times you can transfer that force to the ground. You can say that one man can make more torque than a regular car but not the power or speed.

You can also calculate it. Someone from 80kg can deliver up to 800N on a bike with gear of about 20cmn so it delivers a torque of 160Nm (800N * 0.2M). With all your transfer this decreases, but this is not important to us. A good cordless drill can produce from the smallest to the largest 10Nm or 30 Nm. So let's take 20Nm. This means that that person suddenly delivers 180Nm. As a benefit of 10%.

For us, this wont be a difference because we can not fully transfer force to the road, our power is far too little. But Cancellara who delivers 800W of power .."

 

[Frank Tuesday]

First of all: an extra 1kph is enough to win a race

I never said it was. I never said it wasn't. I posted this so that people could really see what effect the motor could have on a rider. Honestly, I figures that those who are convinced one way or the other would find the bits that supported their already held belief.

Second: i don't know much about mechanics et all. but this is how someone explained it to me (i hope my translation is decent):

"Don't focus on the power. A battery that fits in the tube can not possibly deliver 100W! But they say it's comparable to 100W extra and this is a big difference ...

I'll say it again. You can't have the effect of 100W without adding 100W. It just isn't physically possible. It violates the conservation of energy principle.

Suppose you're on your bike, uphill, what would you desire? And let's be realistic: a motor that fits in a tube won't make a winner of any of us. You're hungry for a push! And this is precisely what costs a lot of force, or torque. The power still comes from Cancellara but the force comes from the engine.

Torque is force or, to-put-in-motion. Power is the number of times you can transfer that force to the ground. You can say that one man can make more torque than a regular car but not the power or speed.

I don't think you understand what power is. Power is the rate of doing work or energy transfer. The amount of work done is the applied force times the distance it moves, or the applied torque times the rotation.

Once you have the amount of work done, to find the average power, you divide by the time. You can't have power without some applied force or torque. The only way to have force but not power is if the applied force is unable to overcome friction and no motion occurs. If the "force comes from the engine", and the bike is moving, the engine is developing power.

You can also calculate it. Someone from 80kg can deliver up to 800N on a bike with gear of about 20cmn so it delivers a torque of 160Nm (800N * 0.2M). With all your transfer this decreases, but this is not important to us. A good cordless drill can produce from the smallest to the largest 10Nm or 30 Nm. So let's take 20Nm. This means that that person suddenly delivers 180Nm. As a benefit of 10%.

Actually an 80kg rider can deliver significantly greater than 800N of force on the pedals. That is why we use the upper body. If you pull up on the bar you increase the applied force at the pedal. You can do this with your bathroom scale if you don't believe me. Stand on it, get your weight, and then grab ahold of something and pull yourself down. I went from 250lbs to maxing the scale out (over 400lbs).

Which brings us to the point about Cancellara attacking seated. While standing, a rider can put more force through the pedals. You might think this automatically means more power. Unfortunately, Force is only one-half the power equation. The other part of power is velocity. In this case we are talking about the rate of motion of his pedals.

Remember that P=F*V or P=T*w, where w is the rotational velocity. To increase the power you can do two things: increase the applied force at the pedal or increase the rotational velocity of the pedal, or to use bike talk, the cadence.

If we think back to the ole' Lance v. Jan days, Lance used less force and higher cadence. Jan used more force, less cadence. Each was able to produce similar power.

Standing and applying high force does not necessarily equate with higher power generation compared to sitting and spinning. The point where one is more gives more power will depend upon the individual rider. We might remember that Cancellara is pretty good at time trials which require creating power while seated.

For us, this wont be a difference because we can not fully transfer force to the road, our power is far too little. But Cancellara who delivers 800W of power .."

Sorry, I don't even know what this means.

 

[online-rider]

This would rank as one of the dumbest posts. FC wins because he is the best, end of story. He is doing nothing this season that he has not done in the past. At PR, Boonen toasted himself and by dropping back left himself wide open to an attack, which is exactly what happened. He then buried himself trying to catch up while the others sat on him like a bunch of novice girls and hardly took a turn.

This thread is the biggest waste of time ever and should be locked before it encourages more morons to come out of the woodwork.

Well im sorry mr spartacus fan.
Youre right fabian is probably innocent, he's just an innocent victim of the pathological hate i bear towards the CSC/Saxo bank team

 

[Oldman]

Well im sorry mr spartacus fan.
Youre right fabian is probably innocent, he's just an innocent victim of the pathological hate i bear towards the CSC/Saxo bank team

Well at least you and Spartacus finally put this thread into perspective. Ignoring science makes it easier to burn the witches. Until someone actually produces a schematic of a motor that works as people have suggested Cancellara could have applied it, save the silly conspiracy films showing a small drive turning the pedals all by itself. It's like taping fireworks to a saddle...

 

[Polish]

Well at least you and Spartacus finally put this thread into perspective. Ignoring science makes it easier to burn the witches. Until someone actually produces a schematic of a motor that works as people have suggested Cancellara could have applied it, save the silly conspiracy films showing a small drive turning the pedals all by itself. It's like taping fireworks to a saddle...

Taping fireworks to saddle....little advantage
Ultra Smooth Ceramic BB Bearings....a little more
Hyper Low Resistance Ceramic Hub Bearings....a little more
Push From a Fan.....a little more
Power Assist crankset....a little more

all these littles can add up

 

[Ripper]

Well at least you and Spartacus finally put this thread into perspective. Ignoring science makes it easier to burn the witches. Until someone actually produces a schematic of a motor that works as people have suggested Cancellara could have applied it, save the silly conspiracy films showing a small drive turning the pedals all by itself. It's like taping fireworks to a saddle...

LMAO! Vroom vroom vroom .... BOOM.

That would be unpleasant

On that note, I think I'll turn up at the next pro-1/2 crit with a lawnmower engine in a backpack and wires hooked to my bike. No one will notice anything when I take off at 60 kph

 

[Oldman]

LMAO! Vroom vroom vroom .... BOOM.

That would be unpleasant

On that note, I think I'll turn up at the next pro-1/2 crit with a lawnmower engine in a backpack and wires hooked to my bike. No one will notice anything when I take off at 60 kph

I want to see your wattage output...

 

[Ripper]

I want to see your wattage output...

Well, my output will likely be 300 to 400, the engine will simply add another 1000 (and lots of smoke)

 

[cyclopeon]

[Fluid mechanics 101]
Power is a function of velocity cubed, not velocity squared.

If you want to talk more fluid dynamics, let me know.

EDIT: I just noticed that in the wiki example, they use a car at 100mph, far from mach, and they state that double speed need 8 times the power.

Okay, 40 years is longer than that stuff will stick around with precision in my head unused.

But, in the more mundane practical sense:
and using the Bicylce Power and Speed Calculator found at http://www.noping.net/english/

For a given set of constants*, 30mph requires 502W, while 15mph requires 94W, which I suggest is closer to 4:1 than it is to 8:1 Of course it is even closer to 5:1 but what the heck.

Obviously an approximation based on an "average body shape"....

*(height 70.5", weight 205lb, bike weight 20.9lb, slope 0%, cad 90rpm, temp 68F, alt 25ft; triathalon bike)

 

[Frank Tuesday]

Okay, 40 years is longer than that stuff will stick around with precision in my head unused.

But, in the more mundane practical sense:
and using the Bicylce Power and Speed Calculator found at http://www.noping.net/english/

For a given set of constants*, 30mph requires 502W, while 15mph requires 94W, which I suggest is closer to 4:1 than it is to 8:1 Of course it is even closer to 5:1 but what the heck.

Obviously an approximation based on an "average body shape"....

*(height 70.5", weight 205lb, bike weight 20.9lb, slope 0%, cad 90rpm, temp 68F, alt 25ft; triathalon bike)

I don't know what to tell you about that page. If you look at the equation he uses, it is the same as what I've been saying. With no wind velocity, no gradient, the equation reduces to a constant times velocity cubed. I don't know what else he has going on in the background. He does say that he used actual power meter data, but not how he used it. He doesn't say how he used cadence in his calculations, nor how he calculates the various coefficients: Cw, Cr, Cm.

I'm not saying what he has done is incorrect, but there isn't enough information on his site to validate his method.

Things I can think of:

Drivetrain frictional losses are related to the cadence, but not the velocity of the bicycle. But then you'd have to look at gear selection and the amount of rotation within individual chain links as well.

Energy losses through flex of various bicycle components.

 

[Oldman]

I don't know what to tell you about that page. If you look at the equation he uses, it is the same as what I've been saying. With no wind velocity, no gradient, the equation reduces to a constant times velocity squared. I don't know what else he has going on in the background. He does say that he used actual power meter data, but not how he used it. He doesn't say how he used cadence in his calculations, nor how he calculates the various coefficients: Cw, Cr, Cm.

I'm not saying what he has done is incorrect, but there isn't enough information on his site to validate his method.

Things I can think of:

Drivetrain frictional losses are related to the cadence, but not the velocity of the bicycle. But then you'd have to look at gear selection and the amount of rotation within individual chain links as well.

Energy losses through flex of various bicycle components.

Our team is sponsored by Specialized and wouldn't you know it? The seat tube is hollow all the way to the bottom bracket. We didn't have the option for after market parts but we'll check on that and get back to you.

Also, someone said 1 kph is enough to win a race. Really? Maybe a TT with constant contribuiton but who is going to ride away from another rider by merely going another 1 kph? Careful with your response because 1 kph on the flat with no wind, friction from drive or pavement doesn't translate into 1 kph on a 20% Alpe de Huez switchback.

 

[Frank Tuesday]

[/color]

Our team is sponsored by Specialized and wouldn't you know it? The seat tube is hollow all the way to the bottom bracket. We didn't have the option for after market parts but we'll check on that and get back to you.

Also, someone said 1 kph is enough to win a race. Really? Maybe a TT with constant contribuiton but who is going to ride away from another rider by merely going another 1 kph? Careful with your response because 1 kph on the flat with no wind, friction from drive or pavement doesn't translate into 1 kph on a 20% Alpe de Huez switchback.

Sorry, I don't understand what you are getting at. I don't see any relation from my post that you quoted and what you have typed here.

 

[Archibald]

LMAO! Vroom vroom vroom .... BOOM.

That would be unpleasant

On that note, I think I'll turn up at the next pro-1/2 crit with a lawnmower engine in a backpack and wires hooked to my bike. No one will notice anything when I take off at 60 kph

lol!!
the cycling version of that Darwin Award winner with the JATO cannister attached to his car (if that was real)...