I have completed a major step toward completing the tank bay modification. After a bunch of trial and error (heavy on the error) I got the cables, guides, tank straps, and tank mock-up just right. I designed my own holder for the fairleads using material used for cutting boards. I made a bunch of different designs until I got the holder right. I need to be able to remove the fairlead so the cable could be removed and changed if necessary. The final design simply holds the two halves of the fairleads tightly against the plywood surface using a couple AN3 bolts. Removing the bolts releases the fairlead for removal opening up a 3/4" opening for the cable ends to fit through. I also had to add an extra pulley to pull the cable the correct distance from the face of the front spar. I might have been able to do this with a fairlead but felt the amount of re-alignment necessitated a pulley vs the fairlead.
This is the pulley positioned to locate the cable correctly. I used a pulley with a ball bearing center for ease of movement of the pulley.
Here you can see the angle change of the cable. The cable at the bottom of the pulley shows the angle change. I needed to bring the cable closer (about 3/4") to the face of the spar to place the cable between the tank straps.
This is the holder I finally settled on. You can see a shallow shoulder inside the 3/4"hole. The shoulder holds the large flange of the stock piper fairlead up against the plywood surface of the rib.
This shows the fairlead set inside the the holder. The two AN3 bolts (over kill, I know) hold everything in place.
Here are the fairleads bolted in place by the holders I designed. They will be easy to remove to replace a cable if needed. Next was to fit everything together to see how it all works when assembled.
This shows the tank mock-up positioned. in the bay. The cables are clear of all structure and clear of the tanks. Success!
This is a close up of the upper fairlead and the cable running past the lower tank strap. The strap is covered in rubber further protecting the cable from any wear. The cable is about 3/8" fron the strap.
I also placed a fairlead on the center brace for the lower cable. I moved the position just a bit after gluing to better center the fairlead on the cable.
Ready to move forward, paint the tank straps, and prepare the 1/8" ply for the bottom shear plate. I also have to complete these steps on the other wing.