car's trajectory

[Rodan]

Rodan wrote:

The steering linkage rotates the front wheels at two different
angles. The geometry is designed so that the extended
centerlines of the two front axles always meet the extended
centerline of the rear axle at a common point. The sharper
the turn, the nearer this point is to the car.

The trajectory of every point on the car is a circle, centered
at that common point, whether going forward or backward.
__________________________________________________

:

Does the steering configuration truly provide a single center
of rotation?
__________________________________________________

The geometry is designed so that the extended centerlines
of the two front axles always meet the extended centerline
of the rear axle at a common point.

Rodan.

 

[JosephKK]

Exactly the issue at hand. JKK doesn't believe it.


For some definitions of "faster". ;-)


Tell it to the physics non-believer.

You missed my question and went off a tangent. Take an object of
dimensions of reasonable size moving circularly about a point. The
velocity in Cartesian coordinates varies by location within the
object, due primarily to the fact that the object itself is rotating.
Even the magnitude of velocity varies by location within the object in
polar coordinates in ratio to the radius value.

This does not even address side force distortion of the tires or
sideways slip.

Do, please, continue your commentary on the physics of cornering in
cars.

 

[JosephKK]

Rich did answer but in his way and it was basically correct.

let me try....
If the tires do not have a slightly different turning angle,
they will not follow the correct path and will squeal
and start to tear apart stuff the longer you let it go.
(slowly but surely)
anyways...
The outside tire follows a long path,
The inside one a shorter path.
making 2 circles.
The outer circle has a smaller angle of turn
than the inner circle has.
Most cars do make the steering axles do such by changing the camber angle
http://en.wikipedia.org/wiki/Camber_angle and a
http://en.wikipedia.org/wiki/Caster_angle
You can change the angle at which the wheel is turning
compared to equal instead.

Alignment is the key word.
and BTW:
alignment will pretty much never cause a shake while
going straight.
that is of course the balancing.

You do not even understand the content of your links.

 

[JosephKK]

Rodan wrote:

The steering linkage rotates the front wheels at two different
angles. The geometry is designed so that the extended
centerlines of the two front axles always meet the extended
centerline of the rear axle at a common point. The sharper
the turn, the nearer this point is to the car.

The trajectory of every point on the car is a circle, centered
at that common point, whether going forward or backward.
__________________________________________________

:

Does the steering configuration truly provide a single center
of rotation?
__________________________________________________

The geometry is designed so that the extended centerlines
of the two front axles always meet the extended centerline
of the rear axle at a common point.

Rodan.

Merely restating that it is so does not answer the question. Show us
the math or go away.

 

[Rodan]

Rodan wrote: The sun always rises in the east.
_________________________________________

JosephKK asked: Does the sun truly always rise in the east?
_________________________________________

Rodan wrote: The sun always rises in the east.
_________________________________________

JosephKK wrote: Merely restating that it is so does not answer
the question. Show us the math or go away.
_________________________________________

Your question did not ask for math. What sort of math would
enlighten or satisfy you? Who is "us"?

Rodan.

 

[krw]

You missed my question and went off a tangent. Take an object of
dimensions of reasonable size moving circularly about a point.

You were arguing that a car didn't (move about a point), but thanks
for playing.

The
velocity in Cartesian coordinates varies by location within the
object, due primarily to the fact that the object itself is rotating.
Even the magnitude of velocity varies by location within the object in
polar coordinates in ratio to the radius value.

Totally irrelevant.

This does not even address side force distortion of the tires or
sideways slip.

So what?

Do, please, continue your commentary on the physics of cornering in
cars.

Do wake up.

 

[JosephKK]

You were arguing that a car didn't (move about a point), but thanks
for playing.


Totally irrelevant.


So what?


Do wake up.

You had claimed that the tracks of the tires all pointed to a single
point. Put up the math (including the geometry), 'cause i do not
think it can be done.

 

[Rodan]

:

You claimed that the tracks of the tires all pointed
to a single point. Put up the math (including the
geometry), 'cause i do not think it can be done.
__________________________________________

It's not TRACKS. It's AXLE centerlines that all meet at a single point.

The geometry is established by drawing two lines, both originating
from any common point on the extension of the fixed axle centerline.
Terminate the lines at the centers of the two turnable wheels.
Rotate each turnable wheel until its axle coincides with its respective
drawn line. Note that the wheels are not parallel with each other.
The vehicle will rotate around the common junction.

Each steering wheel position requires a different pair of axle angles to
set a new common junction. This is accomplished by connecting
the turnable axles to each other with a mechanical linkage that will
constrain the wheel centerlines to always meet at a common point on
the fixed wheel centerline as the steering wheel is turned.

The math is the easiest part. A book of standard 4-bar mechanical
linkage formulas will allow you to plug in the wheelbase and tread
measurements for the particular vehicle. The resulting numbers
will describe the linkage required.

Rodan.

 

[Androcles]

| "JosephKK" wrote:
|
| You claimed that the tracks of the tires all pointed
| to a single point. Put up the math (including the
| geometry), 'cause i do not think it can be done.
| __________________________________________
|
| It's not TRACKS. It's AXLE centerlines that all meet at a single point.

Nonsense. When the car is travelling straight the axle centerlines
are parallel and therefore do not meet (by definition of parallel).


--
Why did Einstein say
the speed of light from A to B is c-v,
the speed of light from B to A is c+v,
the "time" each way is the same?

1/2[tau(A)+tau(A')]= tau(B)
where
A = (0,0,0,t)
A' =(0,0,0,t+x'/(c-v) +x'/(c+v))
B = (x',0,0,t+x'/(c-v))
x' = x-vt

Ref: http://www.fourmilab.ch/etexts/einstein/specrel/www/figures/img22.gif

"Easy: he did NOT say that." - cretin [email protected]

Androcles

 

[Rich Grise]

Wrong again. Done deal. Alignment fixed everything balancing didn't.

How is this supposed to be parsed?
A: "fixed everything that balincing didn't",
B: "fixed everything, balancing didn't."

They're almost opposites, you see.

Thanks,
Rich

 

[Rodan]

"Rodan" wrote:

It's not TRACKS. It's AXLE centerlines that all meet at a single point.
_________________________________________________________


Nonsense. When the car is travelling straight the axle centerlines
are parallel and therefore do not meet (by definition of parallel).
_________________________________________________________

Your email suggests that you are a student of physics. Ask your
instructor to explain the concept of the limiting case of an arc's
trajectory as its radius approaches infinity.

Rodan.

 

[Rich Grise]

On Fri, 23 May 2008 15:32:41 -0700, Mark-T wrote:

This has been going on for a very long time; perhaps this will
help:
http://mysite.verizon.net/richgrise/images/TURNING_CAR.gif

Now, go do your own damn homework! ;-)

Good Luck!
Rich

 

[Rich Grise]

What part did you fail to comprehend? Each front wheel issteered at a
slightly different angle relative to the car, but the centerlines of each
front wheel's axis of rotation cross each other at some distance from the
car. If the steering geometry is correct, that crossing point is ALSO
where the lines drawn through each front wheel's center axis cross the
line that extneds through both rear wheels.

Show us
Correctly read and understand the above, and the math is shown. QED.

Math? What math?
http://mysite.verizon.net/richgrise/images/TURNING_CAR.gif

Well, geometry is math, right?

Hope This Helps!
Rich

 

[krw]

You had claimed that the tracks of the tires all pointed to a single

You're a liar too. I claimed no such thing.

point. Put up the math (including the geometry), 'cause i do not
think it can be done.

Your reading skills are right up there with your understanding of
physics.

 

[Androcles]

| "Rodan" wrote:
|
| It's not TRACKS. It's AXLE centerlines that all meet at a single point.
| _________________________________________________________
|
|
| Nonsense. When the car is travelling straight the axle centerlines
| are parallel and therefore do not meet (by definition of parallel).
| _________________________________________________________
|
| Your email suggests that you are a student of physics. Ask your
| instructor to explain the concept of the limiting case of an arc's
| trajectory as its radius approaches infinity.
|
| Rodan.

See this first:
http://www.androcles01.pwp.blueyonder.co.uk/Steering.gif

Now read this:
Your reply clearly indicates you are fucking stupid. Ask your
keeper to put you back in your padded cell.


--
Why did Einstein say
the speed of light from A to B is c-v,
the speed of light from B to A is c+v,
the "time" each way is the same?

1/2[tau(A)+tau(A')]= tau(B)
where
A = (0,0,0,t)
A' =(0,0,0,t+x'/(c-v) +x'/(c+v))
B = (x',0,0,t+x'/(c-v))
x' = x-vt

Ref: http://www.fourmilab.ch/etexts/einstein/specrel/www/figures/img22.gif

"Easy: he did NOT say that." - cretin [email protected]

Androcles

 

[JosephKK]

:

You claimed that the tracks of the tires all pointed
to a single point. Put up the math (including the
geometry), 'cause i do not think it can be done.
__________________________________________

It's not TRACKS. It's AXLE centerlines that all meet at a single point.

The geometry is established by drawing two lines, both originating
from any common point on the extension of the fixed axle centerline.
Terminate the lines at the centers of the two turnable wheels.
Rotate each turnable wheel until its axle coincides with its respective
drawn line. Note that the wheels are not parallel with each other.
The vehicle will rotate around the common junction.

Rodan.

Cut the kak and bring the math. Not some book of tables.

 

[JosephKK]

You're a liar too. I claimed no such thing.


Your reading skills are right up there with your understanding of
physics.

Your response is so obviously deficit. Put up the math or shut up.

 

[JosephKK]

What part did you fail to comprehend? Each front wheel issteered at a
slightly different angle relative to the car, but the centerlines of
each front wheel's axis of rotation cross each other at some distance
from the car. If the steering geometry is correct, that crossing point
is ALSO where the lines drawn through each front wheel's center axis
cross the line that extneds through both rear wheels.

Show us

Correctly read and understand the above, and the math is shown. QED.

What math where? I do not see any math. Bring the math, if you can.
Not engineering / mechanics tables, the math (solid geometry and ODE
or better).

 

[JosephKK]

Math? What math?
http://mysite.verizon.net/richgrise/images/TURNING_CAR.gif

Well, geometry is math, right?

Hope This Helps!
Rich

Almost clear as mud. How does it track with changes in turning angle?
How does it do it? Does this represent the results of an actual
steering/suspension geometry?

 

[Rodan]

Your reply clearly indicates you are fucking stupid.
Ask your keeper to put you back in your padded cell.
____________________________________________


I do not see any math. Bring the math, not some
book of engineering/mechanics tables. Show us the
math or go away. Your response is obviously deficit.
_____________________________________________

You may have meant "deficient". If the explanation
of vehicle steering geometry design was deficient in
clarity, I can gladly provide a detailed mathematical
analysis for your complete satisfaction. Please
identify the type and rigor of the analysis you need.

When you say "show us", I hope "us" does not include
the person above who makes the obscene posts.

Thank you for your continued interest in learning.

Rodan.