Vertical rudder tube issue

[Turbo 162]

Come to think of it, I too have seen and wondered about this fabric wrinkle.  A couple of light tubes from the post close to where that diagonal joins, forward to the tubing clusters on the sides would provide lots of stiffening.  Deficient design for sure.  Thanks, SuberAvid, for the explanation.

Edited 11 Jan 2019 by Turbo

[SuberAvid 617]

It is actually plumb.  I think the photo is at a bit of an angle.  I fabbed up the mounting block out of wood then had it milled out of aluminum but the angle was a little too positive and I wanted to keep the tail as low as possible to get the max angle of attack so added some shims in the front to bring it plumb.