Horizontal Stab incidence (twist?)

[Clifford]

This last weekend the threaded fitting at the top of the HS Lift Strut (connecting to the HS leading edge) broke. I've got the new fitting installed but cannot find anywhere what to adjust these to.
I'm seeing a lot about avoiding HS dihedral; no problem. But this forward facing lift strut doesn't address dihedral; it adjusts HS twist and incidence.

The good part of the story is that this happened at the Hood River fly-in and it couldn't have happened at a better place. They have a nice restoration hangar and they let me loose to weld the broken fitting so I re-installed it and flew home.

 

[bumper]

Each side fo the horizontal stab wants to be at 90 degrees with the vertical, and wants to have no twist (as you stated. The MKI Eyeball is used for part of this. Stand at the trailing edge of the wing and sight down to the leading edge of the horizontal stab at the root. Move your head up/down to get in-line with it at the root. Now, without moving your head, look to the outboard edge - you should see no twist.

A good eye and a digital level (or a bubble level if you raise the tail) is nice to have.

 

[Clifford]

Each side fo the horizontal stab wants to be at 90 degrees with the vertical, and wants to have no twist (as you stated. The MKI Eyeball is used for part of this. Stand at the trailing edge of the wing and sight down to the leading edge of the horizontal stab at the root. Move your head up/down to get in-line with it at the root. Now, without moving your head, look to the outboard edge - you should see no twist.

A good eye and a digital level (or a bubble level if you raise the tail) is nice to have.

Got it. Thanks a ton Bumper. Steve @ Aviat got back to me and said essentially the same thing.
Something I found that made it a little easier to eyeball was placing a straight piece of aluminum angle (0.75x0.75x48) on top just aft of the leading edge and this gave a better sight reference to the trailing edge.

It's all back together with new terminal fittings on both sides (just being extra cautious) and rigged using the MK1 Eyeball and flies great.
Thanks again Bumper and Snowbirdxx !!!!

 

[bumper]

Something I found that made it a little easier to eyeball was placing a straight piece of aluminum angle (0.75x0.75x48) on top just aft of the leading edge and this gave a better sight reference to the trailing edge.

Cliff,

Not sure how that would work? With my eye in-line looking at the leading edge, the leading edge is going to be "bigger" in my view as it's closer. To make sure the trailing edge is centered, I'll move my head up a bit so I can just barely see the fabric extending aft, then move my head down a bit to make the same check on the under surface. I'll want to confirm, through that head movement, that both inboard and outboard ends of the stab are in line with each other. I would think that the aluminum strip might make that harder to do, though I haven't tried it.

BTW, On the Huskys that I've found that were "out of line", they were well out of line and enough to be obvious. Maybe it was a period in time when the final inspection/rigging was a bit sloppy. On my 2005 ship, there was a trim tab on the right aileron, with a lot of bend correction dialed in! They'd slapped that on there instead of rigging the plane properly, cause the controls were "crossed up" to compensate. When I was finished adjusting things, after removing that tab and making some other, um, changes, it flew as nice as can be.