3/4" hole in 0.032 center ribs and false ribs

[N3UW]

There is a 3/4" hole below the large oval hole in the center and false ribs. is it better to cut out that hole when you build the ribs or after the ribs are installed to the spar?

[Gavin Chester]

Cut out when you build the ribs, Along with the Cable hole above.
Be sure to reference the rib and wing root drawings for the correct location.

[X'N]

FYI a step drill work great for drilling them.

[Enewton57]

I made the hole after assembly since it's location changes between the wing root and the aileron. I used a step drill bit and a 90 degree drill and drilled before the final wing skin was riveted in place. Here is the way I determined where to drill the holes in each rib location: (link removed due to URL change)

[Gavin Chester]

There seems to be a difference between Kit wings and plans build.
By the looks of the kit built wings there is only one size oval hole (small).
On plans build there are two.
The big one in the .025 "ribs allows for the angle of cable to the first .032" rib guide bushing, then parallel to wing root.

[Phil]

Gavin; I bought a set of the avipro ribs, and you are correct. All the center ribs have the smaller size "D" hole at the back of the rib. I'm debating whether or not to cut the 0.025" ribs out to the larger hole or not.

Phil