Tap nutplates, 12iS/U-10 Step 3

[FlyingDiver]

Anyone know the reason for tapping the 2 nut-plates (out of 12) per this instruction?

 

[gasman]

Look ahead and see what connects there.

 

[FlyingDiver]

Look ahead and see what connects there.

It's the fiberglass tailcone fairing. Same screw in those two holes as in the 10 other ones that aren't getting tapped. I can't find anything different about those two.

 

[BobTurner]

It's the fiberglass tailcone fairing. Same screw in those two holes as in the 10 other ones that aren't getting tapped. I can't find anything different about those two.

Of course Vans is the ultimate authority here. But a pure guess: Those two nutplates are mounted on rather small tabs, and nutplates are often ‘tight’. If the builder really leans into the screwdriver he might bend those tabs. Making the first half easy to screw in - leaving a shorter length that needs to be pushed hard - might limit the bending tendancy???

 

[FlyingDiver]

Hmm. Maybe. Hopefully Scott M will chime in...

 

[MechaSteve]

I would assume it is to make it easier to get those screws started. If you can hand thread two screws, the cover is at least sorta held in place, and you can use both hands to fit the other screws.

 

[rvbuilder2002]

I can't remember anything specific regarding why that detail is there but my guess is its regarding how close those two screws are to the bottom of the stabilator. They are the most difficult to install and remove.
As someone else mentioned, brand new nutplates have a rather high prevailing torque.
That coupled with the close proximity to the bottom of the stabilator makes those screws even more difficult to install and remove.
Tapping the slightly will alleviate the initially high prevailing torque.