This is something which is probably of more interest to the dragracer,
but, since Jaguar used this on their early C-Types, I would urge those who are running a
RWD beam axle car on road courses to consider this information.
This is an asymmetric trailing 3 link arrangement which, during
forward acceleration, completely cancels driveshaft torque, thereby providing equal rear
tire loading for maximum acceleration. There are 2 symmetrically situated links (in plan
view) and a third "odd" link which is offset from the car's centerline (to the right). All
links, in plan view, are assumed to be parallel to the long axis of the car (i.e.,
parallel to the SAE X-axis).
In the dragracing application, it is generally desirable to have the
antisquat at or near 100%. In a road racing application, however, this high value of
antisquat commonly causes wheel hop during braking. The spreadsheet allows the user to
specify the percent antisquat. The default value is 100%.
Jaguar placed the odd link above the axle, but it can be either above
or below. When placed below, the situation becomes more favorable with a "tubbed" car.
The drawback is that the single lower link is carrying a very large compressive load.
Care should be taken to use tubing with sufficient wall thickness and diameter for safety.
The user
has the freedom to use different rear pivot locations for the links.
The spreadsheet assumes the rear pivots to be in essentially the same side
view location. If, however, the locations of the front pivots are to be controlled, it is
only necessary that the appropriate values be input as "rear" values and a negative sign
be placed before the link length value.
It is assumed that the symmetrical links, in plan view, are arranged symmetrically about
the car's centerline and that the center of gravity is on or near that same centerline.
It should be noted, however, that the spreadsheet equations assume the odd link offset to
be measured from the midpoint of the transverse spacing of the symmetrical links. In
other words, it is not required that the "symmetrical" links be truly symmetrical. The
two links, themselves, could be offset from the car's centerline. If the link pair were
offset, say, 2 inches to the left of the car's centerline and the odd link 4 inches to
the right of the car's centerline, the true odd link offset would be 6 inches and it is
this number that should be inserted in the spreadsheet. This might be considered if a
packaging problem exists.
