On Thu, 11 Sep 2008 07:05:15 -0400, Pete Keillor
wrote:



Yikes! I hadn't been following this thread. Something will give. Dad
used this technique in 1949 or so to unstick some early tracked
combines cutting rice. He'd tie on with 100 ft. of 1" cable, take the
steel wheeled poppin' johnny out and spin it down at the end, then get
in the middle with another tractor and pull sideways. He later
realized that he could have been killed had something let go.

It's just trig. At 0 deg deflection, the load on the ends is
infinite. At 1 deg,you've moved sideways 1.7%, and decreased the
length by 0.015%, so mechanical advantage is already down to 114:1. At
0.1 deg, the mechanical advantage was 1145, and at 0.01 deg, 11,459
and so on. I used sin/(1-cos).
And something's gotta give!
Gerry :-)}
London, Canada