scsmith
Well Known Member
I had two problems with the flap pushrod attachment to the flaps on my -8. The main problem was that the geometry was such that I would have had to cut a bigger hole in the fuselage than I wanted. I tried spacing the rod end out (inboard actually) from the face of the end rib on the flap, and that helped, but I was running out of length on the threaded post of the integral rod-end and post. It also meant that the threaded portion of the post was bearing on the flap rib.
The second problem is that the integral rod-end and post arrangement does not have any positive capture feature that rod end bearings are supposed to have in case the bearing fails. This is probably very rare, but what the heck, follow AC 43-13 when you can. So here is what I did:
I used a normal rod-end bearing, and made a spacer sleave to fit over the AN3 bolt, plus the appropriate washers, including an AN970 washer to act as a positive retainer in case the bearing fails. The spacer is roughly 0.300 long, so it improves the geometry of the pushrod passage through the fuselage, allowing a smaller hole.
In case someone is worried about the signs of paint wear on the pushrod, don't worry, its not touching the fuselage during flap operation, I triple-checked. Those are paint scrapes from the initial installation, which had to be done a few times to get the fuselage hole right. I need to touch up that paint, because these are 4130 steel pushrods.
The second problem is that the integral rod-end and post arrangement does not have any positive capture feature that rod end bearings are supposed to have in case the bearing fails. This is probably very rare, but what the heck, follow AC 43-13 when you can. So here is what I did:
I used a normal rod-end bearing, and made a spacer sleave to fit over the AN3 bolt, plus the appropriate washers, including an AN970 washer to act as a positive retainer in case the bearing fails. The spacer is roughly 0.300 long, so it improves the geometry of the pushrod passage through the fuselage, allowing a smaller hole.
In case someone is worried about the signs of paint wear on the pushrod, don't worry, its not touching the fuselage during flap operation, I triple-checked. Those are paint scrapes from the initial installation, which had to be done a few times to get the fuselage hole right. I need to touch up that paint, because these are 4130 steel pushrods.