For those who need a modeling tool, there's one in the files section
of the subaruvanagon yahoo group.  In the upper left is a rollout
calculator.

Accuracy:  Measured two revolutions will be about 160-170 inches.
Accurate to 1/4 inch using a 20 foot metal rule gives about a 1 in 500
accuracy or 0.2%. or a wobbly 4 sig digs.

Now back to your regularly scheduled programming.

Pensionerd.