gotta do it this way cause the origional page, for some reason?, will not allow me to respond to others comments.
Thank you for the kind words about my lil project!
The covering is made of flashing material ( like one uses for roofs ) a roll like the one I used runs around 50 bucks and I used almost all of it.
The pieces are fastened to the strut units via U shaped clips with an oversize 1/4 inch hole in the center of the U and holes near the ends of the U (same size). Each strut ( you may be able to see'em in the pic ) has inlets cut into the plywood that resembles a T.
The bolt that holds the skin in place is locked into the T, and passes thur the U, with each unit held in place via a bolt passing thru the legs of the U and thru the strut..( took quite a while, probably lots of better ways to do it than with a lil do-mor grinder). a strip of aluminum 1&1/2" wide extends along the outside edge from the center to the tip (or nearly so) it is thrubolted to its strut unit and also contains a captive 1/4 x 1" bolt that also passes thru the outer covering.
Last but not least...I made aluminum V shaped pieces that cover the outer edge of the
sheet and are secured to each outer end of each strut for strength ( flashing matl is quite prone to flexing otherwise).
THe units have a thru bolt that fastens each hub to the tubing.
I made a crude indicator when I built the unit for the purpose of setting the tip to tip offset...a must!
It clamps to the shaft and has a10/24 stud pointed ahead and behind, offst to the amount of degrees I needed to make the helix shape.......after setting one unit, each succesive unit is set off the indicator...when all center units are set and checked, ya skin the thing.
my reply is too wordy,,sorry