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A view of the SBD's wing center section from December 2023 showing the skin panel between Spar Web Nos.2 & 3 still in place. This is the panel assembly immediately beneath the rearmost panel, already removed in this image. Spar-web No.2 spans the airframe just above the wheel wells visible at the bottom of this photograph. (image via Pioneer Aero Ltd.)

Skin Panel Removal Process:

To remove one of the major skin panel assemblies from the SBD's lower wing center section, the restoration team at Pioneer Aero Ltd. first has to detach any components overlapping adjacent panels. They first employed this procedure in December 2023 when removing the skin panel assembly straddling Spar Web Nos. 3 and 5.

The team recently repeated this same process during the extraction of the skin panel assembly between Spar Web Nos.2 and 3. With the intersecting components removed, the restoration team could then de-rivet the panel (Douglas Part #5093218) from the airframe. After removing this panel from the airframe, the team then detached the internal components beneath it.

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The skin panel between Spar Web Nos.2 and 3 (part #5093218) is highlight in red in this illustration of the SBD's wing center section from the type's Erection & Maintenance Manual.

Skin Replication:

The restoration team then disassembled the skin panel into its component parts. The largest of these items, the skin itself (#5093218-34), sadly suffered from too much impact damage and corrosion to reuse. Even so, the skin was sufficiently intact to serve as a template for manufacturing its replacement. Pioneer Aero's Mark Lamborn described how the restoration team effected this effort, stating: "The next step was to lay the removed skin as flat as possible onto a new sheet of aluminum. Once these two sheets were held together firmly, I drilled through most of the original rivet holes, excluding any which were too distorted or not sitting flat."

The team essentially traced out the hole patterns from the original skin onto its replacement. Any hole locations which could not be replicated in this manner will be ascertained once the new skin is trial-fitted to the wing center section structure.

Once Mark finished back-drilling the new skin, he then traced the original component's outline and access portal apertures onto the new material (using the manufacturing drawings to confirm any missing/compromised details). He then trimmed the new material to its appropriate shape, and cut out the demarcated access holes as well.

Following its removal from the airframe, the skin panel between Spar Nos. 2 & 3 was fully disassembled into its component parts. This image shows the skin itself, viewed from its interior side. Unfortunately, corrosion and impact damage rendered this component beyond airworthy repair. However, it was sufficiently intact to serve as an excellent pattern for the manufacture of its replacement. Lying it flat over new aluminum sheet enabled the direct transfer of most rivet holes and various access holes to the replacement skin. (image via Pioneer Aero Ltd.)
The replacement skin during the remanufacturing process. Note that most of the rivet holes and access points have already been cut into the new material, using the original skin as a template. Those holes which this process could not reliably locate will be confirmed once the skin is trial-fitted onto the original wing structure. (image via Pioneer Aero Ltd.)

Parts Evaluation:

In addition to the skin section remanufacture, Mark went through the process of evaluating the potential serviceability of the ancillary components removed from panel #5093218. While several parts were too damaged to sufficiently repair, a good number were overall excellent condition, and will undergo refurbishment in due course.