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The fin's leading edge, primer painted and riveted together, is trial-fitted to the fuselage to ensure its proper alignment . (image via Pioneer Aero Ltd.)

Fin Reassembly Continues:

SBD Update No.29 from February described Pioneer Aero engineer William Lowen's efforts rebuilding the aircraft's tail fin. Using refurbished parts he had salvaged from both B-22 (BuNo.36175) and an as yet unidentified donor airframe, Lowen had begun reassembling the SBD's vertical stabilizer; a fair number of parts also required refabricating.

Lowen has made great progress with this project in the interim. He began by riveting the components from the fin's forward section together and trial-fitting the subassembly to B-22's fuselage with clecos to ensure everything lined up correctly, as shown in the leading, and lower two images. 

Assembling in the Jig:

Lowen then placed the forward fin subassembly, along with other key components, in the vertical stabilizer's purpose-built jig. With these items in place, it was possible to begin lining up the interconnecting skin sections, ribs, stiffeners and bulkheads (both of original and new manufacture). Lowen then back-drilled rivet holes in the new material using the original components as a guide.

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The fin leading edge components mounted in the vertical stabilizer's purpose-built reassembly jig along with the lower section of Frame #17, the SBD's rearmost fuselage bulkhead. (image via Pioneer Aero Ltd.)

Small Parts:

In addition to the reassembly work, Lowen has continued refurbishing and refabricating numerous smaller parts for the SBD's fin. This has included the restoration of four control cable pulley mounts and two cable guides associated with the aircraft's 'tail feathers'. Each of these came from the donor fin, as the examples on B-22 had irredeemable corrosion issues.

A good number of angled aluminum tabs for attaching stringers to the ribs where they intersect were also salvaged from the two tail units. The majority of these items proved reusable and they have now been stripped, inspected, fettled and primed.

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A selection of vertical stabilizer pulley mounts recovered from both B-22 and the donor fin. Lowen selected the best of these for refurbishing. (image via Pioneer Aero Ltd.)
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Four pulley mounts retrieved from the donor fin and refurbished. Once they have each received a replacement pulley, these components will be riveted back on to Frame #17. (image via Pioneer Aero Ltd.)

Getting Close:

As Lowen stated: "The new skins were a good opportunity to integrate the donor parts with the original B-22 internal parts, as the holes through the skins were all drilled free hand at the factory and differ slightly from aircraft to aircraft."

The trial-fitting process continues. Once that is completed, the tail fin will undergo partial disassembly so that unpainted parts can receive a coat of primer. Final riveting will likely start soon after!


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The fin structure, part way through the process of back-drilling the new skin panels. (image via Pioneer Aero Ltd.)
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The replacement skins undergoing back-drilling against the fin’s internal structure and trial fitting. This step is now complete. (image via Pioneer Aero Ltd.)