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Offline Uiltjie

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Re: LC8 - How fast?
« Reply #80 on: January 24, 2008, 12:53:50 pm »
what engineering does your brother in law do?

I fear this is incorrect though , please do reseach again.

Lostdog , eish u go whichever way the wind blows my china

Confusion is being created between acceleration and top speed...it is important to bear in mind that at top speed no more acceleration is actually occuring ....

assuming identical machines with identical Cd's except one is heavier than the other ,the lighter one will certainly accelerate quicker ,the heavier one will take longer longer but the top speeds will remain pretty much unaffected.

pushing a mini or a bedford is about acceleration

He will reply, I'm too stupid to argue either way! ;)

OK, then you say that it requires the same energy to maintain a speed of say 30km/h for a Bedford and a Mini?  I beg to differ, I have pushed both in my time, and from actual experience can tell they do NOT require the same energy!

But I will let the clever people reply.

I am not argueing, I just find this fascinating!
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Offline SuperJuice

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Re: LC8 - How fast?
« Reply #81 on: January 24, 2008, 12:56:27 pm »
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Offline IceCreamMan

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Re: LC8 - How fast?
« Reply #82 on: January 24, 2008, 01:04:01 pm »
what engineering does your brother in law do?

I fear this is incorrect though , please do reseach again.

Lostdog , eish u go whichever way the wind blows my china

Confusion is being created between acceleration and top speed...it is important to bear in mind that at top speed no more acceleration is actually occuring ....

assuming identical machines with identical Cd's except one is heavier than the other ,the lighter one will certainly accelerate quicker ,the heavier one will take longer longer but the top speeds will remain pretty much unaffected.

pushing a mini or a bedford is about acceleration

He will reply, I'm too stupid to argue either way! ;)

OK, then you say that it requires the same energy to maintain a speed of say 30km/h for a Bedford and a Mini?  I beg to differ, I have pushed both in my time, and from actual experience can tell they do NOT require the same energy!

But I will let the clever people reply.

I am not argueing, I just find this fascinating!

Pushing a mini an pushing a bedford is not comparing apples with apples .. pushing a one ton mini and pushing a 500kg mini would be a fairer comparison..certainly to accerlate both from stadnstill it would be far easier to push the mini but one they are both at 5km's an hour at a constant speed no more acceleration is in effect .... no additional energy is needed
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Offline Uiltjie

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Re: LC8 - How fast?
« Reply #83 on: January 24, 2008, 01:05:34 pm »
I'm with ICM on this.

Read here: http://forum.physorg.com/index.php?showtopic=14909

Seems there is confussion amongst these okes too!  I thought it would a simple answer, but it seems not!

This is interesting, will watch in anticipation.....
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Offline LostDOG

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Re: LC8 - How fast?
« Reply #84 on: January 24, 2008, 01:14:38 pm »
what engineering does your brother in law do?

I fear this is incorrect though , please do reseach again.

Lostdog , eish u go whichever way the wind blows my china

Confusion is being created between acceleration and top speed...it is important to bear in mind that at top speed no more acceleration is actually occuring ....

assuming identical machines with identical Cd's except one is heavier than the other ,the lighter one will certainly accelerate quicker ,the heavier one will take longer longer but the top speeds will remain pretty much unaffected.

pushing a mini or a bedford is about acceleration

intuitively weight would play a big role , in reality it is a very very small role in top speed

Read reply # 58 again. I may not be elloquent but I sure as hell am not changing my tune.

For you to make a broad sweeping statement that topspeed is unaffected by mass you need the following:
1. Both bodies have exactly same aerodynamic properties (use Cd id you like)
2. They must have same power available
3. Each must be given enough time and road length to get to top speed (these will differ)
 
In the real world this is hard to get. Yes, racing on the salt flats in america, one could tweek them. A couple of okes racing bikes or even Formula 1 cars are very much effected by mass.

Dont call me china.
« Last Edit: January 24, 2008, 01:17:25 pm by LostDOG »
It's a friggen motorcycle, it's not supposed to be comfortable, quiet or safe. The windnoise is supposed to hurt your ears, the seat should be hard and riding it should make you shit your pants every now and then. Suck it up. -- Scary Gary MC
 

Offline IceCreamMan

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Re: LC8 - How fast?
« Reply #85 on: January 24, 2008, 01:18:36 pm »
what engineering does your brother in law do?

I fear this is incorrect though , please do reseach again.

Lostdog , eish u go whichever way the wind blows my china

Confusion is being created between acceleration and top speed...it is important to bear in mind that at top speed no more acceleration is actually occuring ....

assuming identical machines with identical Cd's except one is heavier than the other ,the lighter one will certainly accelerate quicker ,the heavier one will take longer longer but the top speeds will remain pretty much unaffected.

pushing a mini or a bedford is about acceleration

intuitively weight would play a big role , in reality it is a very very small role in top speed

For you to make a broad sweeping statement that topspeed is unaffected by mass you need the following:
1. Both bodies have exactly same aerodynamic properties (use Cd id you like)
2. They must have same power available
3. Each must be given enough time and road length to get to top speed (these will differ)
 
In the real world this is hard to get. Yes, racing on the salt flats in america, one could tweek them. A couple of okes racing bikes or even Formula 1 cars are very much effected by mass.

Dont call me china.


so in essence u disagree, then agree ,then disagree then finally agree ... eish

formual 1 and racing bikes is about acceleration and time take to achieve top speed... top speed is not dependant on time taken
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Offline LuckyStriker

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Re: LC8 - How fast?
« Reply #86 on: January 24, 2008, 01:20:47 pm »
 

Offline SuperJuice

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Re: LC8 - How fast?
« Reply #87 on: January 24, 2008, 01:24:31 pm »
At the feast of ego everyone leaves hungry.
 

Offline LostDOG

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Re: LC8 - How fast?
« Reply #88 on: January 24, 2008, 01:25:14 pm »
what engineering does your brother in law do?

I fear this is incorrect though , please do reseach again.

Lostdog , eish u go whichever way the wind blows my china

Confusion is being created between acceleration and top speed...it is important to bear in mind that at top speed no more acceleration is actually occuring ....

assuming identical machines with identical Cd's except one is heavier than the other ,the lighter one will certainly accelerate quicker ,the heavier one will take longer longer but the top speeds will remain pretty much unaffected.

pushing a mini or a bedford is about acceleration

intuitively weight would play a big role , in reality it is a very very small role in top speed

For you to make a broad sweeping statement that topspeed is unaffected by mass you need the following:
1. Both bodies have exactly same aerodynamic properties (use Cd id you like)
2. They must have same power available
3. Each must be given enough time and road length to get to top speed (these will differ)
 
In the real world this is hard to get. Yes, racing on the salt flats in america, one could tweek them. A couple of okes racing bikes or even Formula 1 cars are very much effected by mass.

Dont call me china.


so in essence u disagree, then agree ,then disagree then finally agree ... eish

formual 1 and racing bikes is about acceleration and time take to achieve top speed... top speed is not dependant on time taken

In simple English:
Yes ICM, under ideal and controlled conditions the effect of mass, with all other properties being equal, is small, perhaps bordering on negligible.
There's a badge waiting for you somewhere.

So, a bunch okes okes once wanted to compare top speeds of similar bikes, is big fat LostDOG at a dissadvantage to his skinny ass mate Frankie?


It's a friggen motorcycle, it's not supposed to be comfortable, quiet or safe. The windnoise is supposed to hurt your ears, the seat should be hard and riding it should make you shit your pants every now and then. Suck it up. -- Scary Gary MC
 

Offline LostDOG

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Re: LC8 - How fast?
« Reply #89 on: January 24, 2008, 01:26:48 pm »
It's a friggen motorcycle, it's not supposed to be comfortable, quiet or safe. The windnoise is supposed to hurt your ears, the seat should be hard and riding it should make you shit your pants every now and then. Suck it up. -- Scary Gary MC
 

Offline Coala

Re: LC8 - How fast?
« Reply #90 on: January 24, 2008, 01:27:03 pm »
 ???so let me get this right, all things being equal (resistance, drive train strain, aerodynamics and power), weight make a negligible if any difference in top speed.  Now if I load me car with the cases of wine I bought down in the Cape during the December holidays, my car should be able to reach the same top speed as it would, without the wine.  Now, either the Cape wine has a drag factor (apart from me dragging myself to bed after having a bottle too many),  or its my imagination that the Landy was struggling uphills ?? and I??m not talking acceleration (I mean it??s a Landy ?? it does not accelerate ?? it reaches a certain velocity and tend to stay there).  
 

Offline SuperJuice

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Re: LC8 - How fast?
« Reply #91 on: January 24, 2008, 01:29:15 pm »
???so let me get this right, all things being equal (resistance, drive train strain, aerodynamics and power), weight make a negligible if any difference in top speed.  Now if I load me car with the cases of wine I bought down in the Cape during the December holidays, my car should be able to reach the same top speed as it would, without the wine.  Now, either the Cape wine has a drag factor (apart from me dragging myself to bed after having a bottle too many),  or its my imagination that the Landy was struggling uphills ?? and I??m not talking acceleration (I mean it??s a Landy ?? it does not accelerate ?? it reaches a certain velocity and tend to stay there).   

The way I see it that's the effect of gravity.
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Offline SuperJuice

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Re: LC8 - How fast?
« Reply #92 on: January 24, 2008, 01:32:40 pm »
So, a bunch okes okes once wanted to compare top speeds of similar bikes, is big fat LostDOG at a dissadvantage to his skinny ass mate Frankie?

Fat = bigger/wider = more wind resitance

Skinny = slimer/smaller (prettier?  ;D) = less wind resistance

So yes in those circumstances the skinnier riders top speed would be higher than yours.

Nothing to do with weight though.
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Offline Coala

Re: LC8 - How fast?
« Reply #93 on: January 24, 2008, 01:33:29 pm »
ja gravity is a real bitch
 

Offline LostDOG

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Re: LC8 - How fast?
« Reply #94 on: January 24, 2008, 01:36:57 pm »
So, a bunch okes okes once wanted to compare top speeds of similar bikes, is big fat LostDOG at a dissadvantage to his skinny ass mate Frankie?

Fat = bigger/wider = more wind resitance

Skinny = slimer/smaller (prettier?  ;D) = less wind resistance

So yes in those circumstances the skinnier riders top speed would be higher than yours.

Nothing to do with weight though.

Jip, if you isolate all other factors out. I agree, and tried to right from the start. In this discussion thread, is it reasonable to isolate all other issues out?

Appology: ICM I agrued on other issues, I'm sorry. Power cuts and other factors are affecting my mood.
It's a friggen motorcycle, it's not supposed to be comfortable, quiet or safe. The windnoise is supposed to hurt your ears, the seat should be hard and riding it should make you shit your pants every now and then. Suck it up. -- Scary Gary MC
 

Offline Uiltjie

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Re: LC8 - How fast?
« Reply #95 on: January 24, 2008, 01:38:50 pm »
OK guys, don't get upset, this fun remember?

So, I spoke to my clever swaerie in Pretoorsdorp, who is a civil engineer BTW.

It takes energy to move mass, end of story.  Not acceleration, just maintaining speed, be it top speed or any speed.  You need energy for that.  The more the mass, the more the energy.

2 simple examples:

1.  A Bugatti Veyron has a 750Kw engine to move its 2.5t body to a topspeed of 400km/h.  If it weighed 500kg, the motor needed would have been say 300Kw.
2.  If you take a Citi golf, powered by a VW 1600 motor, driving at say 100km/h, takes X amount of energy. If you build the same car from styrofoam, same shape, same drag, and you power it with a Yammie XT500 motor, and travel next to the real golf, and you could quickly swap the engines, do you think the XT motor will maintain the speed on the real Citi Golf?

Does this simple arguement make sense?
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Offline Butch

Re: LC8 - How fast?
« Reply #96 on: January 24, 2008, 01:40:14 pm »
I did 220 on my KTM once...
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Offline Uiltjie

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Re: LC8 - How fast?
« Reply #97 on: January 24, 2008, 01:44:04 pm »
I did 220 on my KTM once...


Ja Boet, just the right comment! ;D ;D ;D ;D ;D
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Offline Uiltjie

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Re: LC8 - How fast?
« Reply #98 on: January 24, 2008, 01:45:01 pm »
I did 220 on my KTM once...


BTW, you started all this, being skinny and all! ;D ;D
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Offline IceCreamMan

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Re: LC8 - How fast?
« Reply #99 on: January 24, 2008, 01:45:49 pm »
OK guys, don't get upset, this fun remember?

So, I spoke to my clever swaerie in Pretoorsdorp, who is a civil engineer BTW.

It takes energy to move mass, end of story.  Not acceleration, just maintaining speed, be it top speed or any speed.  You need energy for that.  The more the mass, the more the energy.

2 simple examples:

1.  A Bugatti Veyron has a 750Kw engine to move its 2.5t body to a topspeed of 400km/h.  If it weighed 500kg, the motor needed would have been say 300Kw.
2.  If you take a Citi golf, powered by a VW 1600 motor, driving at say 100km/h, takes X amount of energy. If you build the same car from styrofoam, same shape, same drag, and you power it with a Yammie XT500 motor, and travel next to the real golf, and you could quickly swap the engines, do you think the XT motor will maintain the speed on the real Citi Golf?

Does this simple arguement make sense?

yes, the argument makes sense however it is incorrect ... the air resistance of the vehicle in question either the golf or the bugatti is the limiting factor not the weight thereof.  

again your swaar is bringing in too many variables , we are not comparing a xt500 motor with a citigolf motor , we are comapung a citigolf motor with a citigolf motor, we are comparing a citigolf weighing 1 ton with a citigolf weighting fora rguments sake 2 tons ...in this scenario the top speed owuld be the same , the time taken to reach top speed would be vastly different ..the negligible topspeed owuld be due to additonal friction caused by the wheels an bearings but it would be tiny
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