A view from last month showing the restored structure for the SBD's Wing Center Section aft of Spar #3 during its trial fitting. All of these components are now disassembled and in storage awaiting the time when everything is ready for riveting together. (image via Pioneer Aero Ltd.)
A view from last month showing the restored structure for the SBD's Wing Center Section aft of Spar #3 during its trial fitting. All of these components are now disassembled and in storage awaiting the time when everything is ready for riveting together. (image via Pioneer Aero Ltd.)

SBD Center Section Update:

Last month, Pioneer Aero wrapped up restoration of the primary SBD Wing Center Section components aft of Spar #3 (as shown in the image above). While these components still require painting and riveting together, that effort will await final assembly of the entire Wing Center Section. So in the meantime, all of these components are now safely in storage so that Pioneer can begin working on Spar #3 and the structure forward of it. 

Spar #3 about to be drilled off from the SBD’s Wing Center Section. The rib at image center is fuselage Frame #5 (righthand) which is riveted to the spar. The green-painted pieces are the restored/remanufactured lower angles for the ribs which sit on the aft face of Spar #3. They were temporally bolted in place to allow the trial-fitting of structure further aft of Spar #3. (image via Pioneer Aero Ltd.)
Spar #3 about to be drilled off from the SBD’s Wing Center Section. The rib at image center is fuselage Frame #5 (righthand) which is riveted to the spar. The green-painted pieces are the restored/remanufactured lower angles for the ribs which sit on the aft face of Spar #3. They were temporally bolted in place to allow the trial-fitting of structure further aft of Spar #3. (image via Pioneer Aero Ltd.)

Removing Spar #3:

Before Craig Cunha and his team could begin de-riveting Spar #3, they first had to remove the fuel tank bay structure between Spar #3 and Spar #2. These parts extend from the ribs at Station 15 (on either side of the fuselage center line) out to the bulkhead where the outer wing panels attach. Separating these items from the airframe provided full access to entire length of rivets attaching the upper spar cap for Spar #3 to the topside skin panel. Drilling out all of those rivets, along with the rib aft angles at Station #15, then allowed Cunha to lift Spar #3 from the airframe.

A section of internal structure removed from the lower side of the SBD’s Wing Center Section in the fuel tank bays between Spars #2 and #3. The top side attaches to the lower skin panel. (image via Pioneer Aero Ltd.)
A section of internal structure removed from the lower side of the SBD’s Wing Center Section in the fuel tank bays between Spars #2 and #3. The top side attaches to the lower skin panel. (image via Pioneer Aero Ltd.)

Spar #3 in the process of being de-riveted from the SBD’s Wing Center Section. This is the forward face of fuselage Frame #5 (top of the image) and the topside of the upper skin. The four horizontal rows of rivets are being drilled out to free the upper skin from Spar #3’s upper spar cap. Just the five upper skin rivets (seen in the shadow at the center of the image) will finish that work in this area. For reference, the wing leading edge is below the bottom side of this image. (image via Pioneer Aero Ltd.)

A different view of the same structure pictured in the previous image during the process of removing Spar $3 from the SBD’s Wing Center Section. (image via Pioneer Aero Ltd.)

Another view of Spar #3 during the process of removing it from the SBD’s Wing Center Section. The four horizontal rows of rivets just below the row of holes still needed to be drilled out at this point to free the upper skin from the upper spar cap. The row of rivets running vertically in the image across the Spar #3’s web plate also need drilling out; they attach to one of the inter-spar ribs linking to Spar #2. The topside skin seen here essentially forms the floor for the gunner's cockpit. (image via Pioneer Aero Ltd.)

Spar #3 during the process of drilling it off the SBD’s Wing Center Section, as seen from the topside towards the interface with the righthand outer wing panel. The double row of rivets running horizontally across image center still need removing to free the topside skin from the upper spar cap for Spar #3. As noted in previous images, the green piece is a restored lower angle for a rib which sits against the rear face of the web plate for Spar #3, temporally bolted in place to allow the trial-fitting of structure further aft. (image via Pioneer Aero Ltd.)

A view of the port side of the SBD’s Wing Center Section following the removal of Spar #3 and the fuel tank bay structure outboard of the rib at Station #15 (the lefthand inter-spar rib visible in this image). The fuel tank fills up the entire bay from Spar #2 (seen toward image bottom) and Spar #3 outboard of Station #15 on each side of the SBD center section. (image via Pioneer Aero Ltd.)

Another view of the SBD’s Wing Center Section underside following the removal of Spar #3 and the fuel tank bay structure. The central inter-spar rib linking Spar #2 and Spar #3 is visible at the heart of the image, with the ribs for Station #15 flanking it on either side. The fuel selectors are mounted in the space between these ribs, which is also where several systems from the cockpits enter the wing and route forward to the engine. (image via Pioneer Aero Ltd.)

A similar view of the structure depicted in the previous two images, but seen from further to the lower righthand side of the Wing Center Section. (image via Pioneer Aero Ltd.)

What's Next:

Work has now started on disassembling Spar #3 into its component parts, with each item cleaned and inspected to determine its future airworthiness potential. They have also begun restoring the lower stringer and stiffener assemblies for the lefthand fuel tank bay.

Craig Cunha holding Spar #3 of the SBD's wing center section.
A view of Craig Cunha holding Spar #3 from the SBD’s Wing Center Section. Craig and fellow engineer, Rod Hanson, had just finished removing it from the wing. The lower halves of fuselage Frame #5 (left and right) can be seen still riveted to the aft face of the spar web outboard of Craig's hands. The green-painted pieces visible along the spar are the restored/replaced lower angles for ribs which sit on the aft face of Spar #3; these were bolted temporally in place to permit trial-fitting of center section structure further aft. (image via Pioneer Aero Ltd.)