The Cessna 120-140 Association Forum

I've been working with my mechanic to fine tune the rigging on my airplane recently. After doing the flight controls and still encountering a heavy wing, we attempted today to lengthen the rear strut on the light wing per the service letter in the document library.

We hit a snag - try as we might we could not get the bolt holes to align so we could reattach the strut. In the end we gave up and reverted to the original configuration so I could fly home.

Is there a trick to doing this? Do we need lifting straps for the wing? We only unbolted the rear strut, is it necessary to do either the front strut or even the attach points to allow the wing to rotate up?

Do you have metalized wings? I ran into that problem with my metalized wings.

2356 wrote: ↑Sun Aug 02, 2020 11:02 pm Do you have metalized wings? I ran into that problem with my metalized wings.

Yes, my wings are metalized.

Metalized wings are nearly inflexible. You can try lengthening the light wing as much as possible, then finishing it by shortening the other one. Otherwise, you're stuck.

6643 wrote: ↑Mon Aug 03, 2020 10:27 am Metalized wings are nearly inflexible. You can try lengthening the light wing as much as possible, then finishing it by shortening the other one. Otherwise, you're stuck.

Would loosening the rear attach point allow the wing to pivot enough to make it work?

Can't hurt, but that's a pretty rigid connection. The fabric wing will warp pretty easily whereas the metalized one doesn't want to twist. It's not moving the whole wing, rather putting a bit of a twist in it. You are introducing a progressive change in the angle of incidence from the wing root to the tip (wash-in or wash-out).

6643 wrote: ↑Mon Aug 03, 2020 4:16 pm Can't hurt, but that's a pretty rigid connection. The fabric wing will warp pretty easily whereas the metalized one doesn't want to twist. It's not moving the whole wing, rather putting a bit of a twist in it. You are introducing a progressive change in the angle of incidence from the wing root to the tip (wash-in or wash-out).

In that case it sounds like my options are to attempt shortening the length on the heavy wing, or failing that bandaid the issue with an aileron trim tab.

Turn it as far as you can, then fly for a while, then try to turn it some more. Eventually, the skin will start to buckle...