Any updates on reclassification?
#31
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The effect isn't directly dependent on speed - its dependent on acceleration (which in an automobile usually diminishes as speed increases). The faster you must accelerate the wheel (or the car) the more torque required (I know, that's obvious). If you know the acceleration rate and the MoI, you can calculate required wheel torque to accelerate just the wheel/tire combo.
In a vacuum the relative percentage of available torque required would remain the same as you went through the gears - you accelerate slower in each successive gear, so less torque is required to accelerate the wheel/tire, but available torque is also reduced thanks to gearing changes. But in the real world, the increased aero drag means the torque devoted to accelerating rotating masses becomes less significant at higher speeds because acceleration decreases faster than a pure wheel thrust to weight calculation would dictate.
UL
In a vacuum the relative percentage of available torque required would remain the same as you went through the gears - you accelerate slower in each successive gear, so less torque is required to accelerate the wheel/tire, but available torque is also reduced thanks to gearing changes. But in the real world, the increased aero drag means the torque devoted to accelerating rotating masses becomes less significant at higher speeds because acceleration decreases faster than a pure wheel thrust to weight calculation would dictate.
UL
#33
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Windscreen,
Believe it or not - I've only run my bar from 50% of full stiff to full soft (last hole). I haven't had any problems.
What I have had happen is have one of the bolts that hold the bottom of the heim joint to the car (not sure what that piece is) work itself loose and then get some play - but that was because it wasn't tight enough to begin with. Since I've tighted it down it hasn't happened again.
I believe that Bill is giving you guys bolts with threads that are closer together to prevent this from happening.
According to Bill I might have some interference running the bar at the 75% setting (when you have to move heim joint to the front of the attachment point - but haven't tried that yet.
Since mine is the prototype I might get some revisions during the off-season.
Etgar
Believe it or not - I've only run my bar from 50% of full stiff to full soft (last hole). I haven't had any problems.
What I have had happen is have one of the bolts that hold the bottom of the heim joint to the car (not sure what that piece is) work itself loose and then get some play - but that was because it wasn't tight enough to begin with. Since I've tighted it down it hasn't happened again.
I believe that Bill is giving you guys bolts with threads that are closer together to prevent this from happening.
According to Bill I might have some interference running the bar at the 75% setting (when you have to move heim joint to the front of the attachment point - but haven't tried that yet.
Since mine is the prototype I might get some revisions during the off-season.
Etgar
#34
ultimate lurker,
All of what you say is also true of weight added to the car: a "fixed" fraction of the torque that goes toward acceleration is used to accelerate the ballast, therefore the higher the acceleration the more net torque goes towards the ballast; and with aerodynamic drag, the faster you're going, the less difference the ballast makes because most of the torque goes towards fighting drag.
Assuming that I've done my physics right and Andrew Trevitt did his physics right, our predictions should be identical and they're just different ways of looking at the same thing. I personally feel it's a lot more natural to think of it as just acting like added weight, but if Trevitt's treatment is more intuitive for you, then feel free to imagine extra weight in the car to act just like heavier wheels
All of what you say is also true of weight added to the car: a "fixed" fraction of the torque that goes toward acceleration is used to accelerate the ballast, therefore the higher the acceleration the more net torque goes towards the ballast; and with aerodynamic drag, the faster you're going, the less difference the ballast makes because most of the torque goes towards fighting drag.
Assuming that I've done my physics right and Andrew Trevitt did his physics right, our predictions should be identical and they're just different ways of looking at the same thing. I personally feel it's a lot more natural to think of it as just acting like added weight, but if Trevitt's treatment is more intuitive for you, then feel free to imagine extra weight in the car to act just like heavier wheels
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