why 2 U-joints?

[centerhill condor]

pulled the motor for some summer fun and with a 3 point mount why does the system have 2 U-joints? just curious

[inwo]

One joint can compensate for angular misalignment only. Two can make up for axial error. ie. up-down, side to side.
Some dual joints are also constant velocity. Maybe all of them. It's been a while since school. :)
Just reread your post, sorry! Did you mean: why two when there is NO misalignment?