[Av8torTom]

The directions for building the trim tab say to:

"...countersink the spar and leave the holes in the hinge un-modified"

Surely the holes in the hinge get countersunk but I don't see mention of it further on in the directions.

Anyone?

T.

 

[Av8torTom]

OK, I see...

I see what's going on. I did not machine countersink the spar, I dimpled it so I will need to countersink the holes in the hinge... hummmmm

 

[miko38]

The hinge does not get countersunk. It attaches under the top of the trim tab spar, which is also flat because you countersunk the top of the trim tab spar.
I hope this makes sense

 

[Av8torTom]

Thanks

Mike, I dimpled the spar so I also needed to dimple the hinge holes - presumably this is OK; I figure less material removed from the parts this way anyway.

 

[mcencula]

Doubler strip

This has been discussed before. In the past, when someone has dimpled the spar and countersunk the hinge, Van's has recommended fabricating a doubler strip to go behind the hinge with just drilled holes (not dimpled nor countersunk). This will be the 4th layer of material (i.e. skin / spar / hinge / doubler). Without the doubler, the hinge will be likely to curve during riveting because the aluminum is soft.

Good luck,