Center Wing - Finishing

Temporary Assembly of Wing in Shop

The left wing panel is resting in place next to the Center Wing. After trimming, the taper pins will be installed in the Main Spar. Then after careful adjustment and measuring, the holes will be drilled into the Rear Spar Angle.

Front view of Center Wing and Left Wing Panel

Note hold-down jig on the main spar.

Under view of Left Wing Panel

Temporary hold-down jig

A short angle has been fashioned to hold the center of wing to the table. Two construction screws into the workbench. Cleco's through the spar rivet holes; plus, a drift punch on the center hole.

Temporary Hold-Down jig

Right Side of Center Wing - Counter Weights - hard to see

In addition to the hold-down jigs, a shot-bag and sledge hammer head on the right side of the Center Wing will keep the wing from tipping off the table when the left wing panel is installed.

Wing joint between Left Wing Panel and Center Wing

Need to cut access holes for wing assembly and trim skins. Note: doubler for wing step at far right. I'm going for the full size doubler due to the age of the pilot.

Pivoting Center Wing on top of work bench

Temporary Handle

Used scrap angle ... Cleco's and C-Clamp hold in place.

Back Drilling holes into rib and lower skin

Drill guide with 3-inch hole spacing. Drill easily bends to properly align with the hole.

Sharp Edge of Rear Spar Angle

Needs rounding to allow flush fit.

Grinding the Rear Spar Angle

A 3-M grinding/polishing wheel is used to properly round the rear spar angle to ensure flush fit the bend in the .016 lower rear wing skin at the top of the Z-bend. A router was tested on scrap. Also, using hand files was tested. This is the best but not the fastest.

Rounding Edge of Rear Spar Angle

Using magnifying lenses clipped to billed cap to determine if enough rounding on the rear spar angle has been achieved.

Center Wing Rear Spar Angle

Nice flush fit on sample bend of .016 aluminum.

Center Wing Panel

Two diagonal measurements to the center point of the Rear Spar Angle must be equal for the Rear Spar Angle to be centered. The angle has only 1/4-inch excess length ... so accuracy is a must.

Striking a line perpendicular to the main spar.

A similar line will be struck on the opposite side. These must be equal distance from the center point ... they were.

Bulkhead C1 (top center)

Just for the heck of it, I laid Bulkhead C1 in place. Good view of temporary handle ... see next image.

Center Wing Panel - Handle

The section of angle cut from the upper spar cap was temporarily installed as a handle. Cleco's and a C-clamp (not installed yet) hold it in place. Lower skins are long enough to slide under the bottom fuselage rails ... but will be trimmed back as necessary. Note: the rear spar doesn't need rounding in the center section.

Fitting rear upper skin to fuselage.

More trimming required.