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+--- Thread: Weight of wheel (/showthread.php?tid=1331)
Weight of wheel - cologne - 08-07-2010
Where is the weight of the wheel and unsprung part of suspension and brake?
Before:
Code:
[ wheel-FR ]
mass = 19- NaN - 08-09-2010
It is calculated from tire dimensions. The densities are chosen to match real world tire/rim weight.
Code:
// calculate wheel inertia/mass
float tire_radius = tire.GetRadius();
float tire_width = tire.GetSidewallWidth();
float tire_thickness = 0.05;
float tire_density = 8E3;
float rim_radius = tire_radius - tire_width * tire.GetAspectRatio();
float rim_width = tire_width;
float rim_thickness = 0.01;
float rim_density = 3E5;
float tire_volume = tire_width * M_PI * tire_thickness * tire_thickness * (2 * tire_radius - tire_thickness);
float rim_volume = rim_width * M_PI * rim_thickness * rim_thickness * (2 * rim_radius - rim_thickness);
float tire_mass = tire_density * tire_volume;
float rim_mass = rim_density * rim_volume;
float tire_inertia = tire_mass * tire_radius * tire_radius;
float rim_inertia = rim_mass * rim_radius * rim_radius;- cologne - 08-09-2010
NaN Wrote:It is calculated from tire dimensions. The densities are chosen to match real world tire/rim weight.I didn´t follow the developers-discussion, but i worried about this result.
Not a good idea because:
- masses an inertia may vary between steel-wheels/normal tyre and cart wheels/slick and rally car or a formula car,
- the result of weight, inertia computation is completely intransparent (can´t add masses in .car-file to totalweight) and
- the unsprung parts of suspension/brakes are unconsidered!
Please allow:
Code:
[wheel-n]
mass = 20
inertia = 0.04- NaN - 08-10-2010
Added optional mass, inertia parameter to wheel declaration in rev 2847.
Quote:Not a good idea because:I'd avoid adjustments of wheel properties to get a certain handling. You would tune for the current implementation. And it has its own load of issues (like low inertia values).
- masses an inertia may vary between steel-wheels/normal tyre and cart wheels/slick and rally car or a formula car,
- the result of weight, inertia computation is completely intransparent (can´t add masses in .car-file to totalweight) and
- the unsprung parts of suspension/brakes are unconsidered!
I guess you've got some real-world wheel, unsprung parts mass and inertia values?
- cologne - 08-10-2010
Sorry, too slow, to catch Trulli´s rear wheel with unsprung masses in Hockenheim, :-(
NaN Wrote:I guess you've got some real-world wheel, unsprung parts mass and inertia values?
- NaN - 08-11-2010
Try to be faster next time, hehe.