rec.autos.simulators

Also, the spring axis can be mounted outside of the strut axis apparantly.  I'm
having a tough time visualizing how this can be done.

Thanks for any input!

Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://www.racesimcentral.net/

My little car sim screenshots:
http://www.racesimcentral.net/

This page shows the modified McPherson strut front suspension of a Ford
Mustang, which has separate spring and strut axes.  It also has a little
animation demonstrating the suspension movements of McPherson strut and
double wishbone suspension types.

Of course, that's MacPherson strut (forgive me, it's late!).  Anyway, here's
another page with a downloadable animation.

http://203.67.17.176/adams/adams_example/19/suspension.htm

In common strut suspensions the wheelhub is fixed rigidly to the lower
portion of the strut.  Sometimes the hub-to-strut joint is bolted so that a
small static camber adjustment is possible.

Time to visit some car dealers on Sunday (when no one is there) and
start crawling around under a variety of cars & trucks.

...

Unfortunately it looks to me like the strut rod (upper portion) and body
(lower portion) are bending/kinking in this animation.  I tried to hold a
straight edge on the picture but it's hard to really see at that animation
rate.  In reality, the rod runs in tight fitting linear bearings...

Of course when lateral tire forces are added, the strut will bend a certain
amount.

The strut is usually installed an "angle" yes. But this really makes the
king pin inclination axis and scrub radius first. I does also help with
camber gain  because the strut is telescoping. As the suspension moves up,
the strut gets shorter as the shock moves down into the main strut body. The
top of the strut where it attaches to the body is a joint (or *** for
most cars) and that (a long with the lower ball joint ) allows the strut to
compress and extend. As the lenght changes so does the installed angle of
the strut and hence the camber. The angle of the lower a-arm has alot to do
with it, too, as the wrong angle on that will kill camber gain. Execessive
lowering of a car with out relocating mounting points will cause this
problem...

  Is this how it works?  I've looked through

The 89-up 911's (C2's / C4's & 993's) have this situation . Instead of the
strut being bolted directly in-line (looking in at the wheel well) with the
hub it is moved rearward about 7 degrees or so with extensions off the back
side of the hub. They do this to clear the 4WD's front axle. The spring axis
is at this angle. The ball joint, however is still more or less in the
normal place, and if you were to draw a line from the lower ball joint thru
the top *** strut mount that would be what the car "sees" as the strut
axis.......about 12 degrees different from the spring axis becuase of the
aforementioned 7 dgrees inclination plus 5 degrees of caster.....

Hope that helps

--Doug Arnao

Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com

My little car sim screenshots:
http://performancesimulations.com/scnshot4.htm

Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://PerformanceSimulations.Com

My little car sim screenshots:
http://performancesimulations.com/scnshot4.htm

Thanks, Doug.  I can see now how the strut axis change could be
drawn/calculated when the strut axis goes through the lower arm ball joint, but
am having a tough time seeing how this could be solved when the axis is not in
line properly.  I was thinking that the strut axis was fixed relative to the
car, but it's obviously not.  

If the strut axis went through the lower arm joint, a circle describing the
motion of this joint would intersect a line going from the upper joint (strut)
through the arm/strut joint.  The top and bottom of the strut would lie on this
line and could be found by drawing circles starting at the lower arm joint, if
I'm seeing this right.

If the axis is not on this line though, then this falls apart.  Haven't quite
figured that out yet.

Todd Wasson
---
Performance Simulations
Drag Racing and Top Speed Prediction
Software
http://www.racesimcentral.net/

My little car sim screenshots:
http://www.racesimcentral.net/