Overview:

Pioneer Aero’s restoration team has made great progress with the restoration of Spars #2 and #3 in the past couple of months, along with several associated components. The latter includes such elements as Fuselage Frames #3 and #5, the lower halves of which rivet onto Spars #2 and #3 respectively. We will discuss this work in detail with the following...

The web plate from Spar #3 awaiting a coat of primer in the paint booth at Pioneer Aero. (image via Pioneer Aero Ltd.)
The web plate from Spar #3 awaiting a coat of primer in the paint booth at Pioneer Aero. (image via Pioneer Aero Ltd.)

Spar #3: Rebuild Update

In a previous restoration update featuring Spar #3, we described how Craig Cunha's team were able to restore the subassembly's original spar cap extrusions using approved, wartime battle damage repair techniques. With that work now completed, and most other items from the spar either refurbished or remanufactured, it was time to coat the components in primer paint and begin reassembly. Pioneer still awaits the arrival of some new extrusion material to complete the spar, but the progress they have made with the rest of it looks magnificent! They have also more or less completed the restoration of the lower left and righthand sections of Fuselage Frame #5.

Components from Spar #3 and Fuselage Frame #5 in the paint booth at Pioneer Aero prior to receiving a coat of primer. (image via Pioneer Aero Ltd.)

An original component from the lower, lefthand section of Fuselage Frame #5 (top) and its replacement, which awaits a coat of primer paint. The original part proved unsalvageable due to corrosion beyond allowable limits. (image via Pioneer Aero Ltd.)

The components which form the lower, left and righthand sections of Fuselage Frame #5 clecoed together following primer-painting, and now ready for final-riveting. Only the tapered element at the top right (with numerous, pre-existing rivet holes) is original; the others being remanufactured. The narrower sections mount directly to the web plate in Spar #3.(image via Pioneer Aero Ltd.)

The forward face of Spar #3 following the reassembly of its primer-painted components. A few stiffeners remain to be fabricated; a task which will occur once the correctly profiled extrusions arrive at Pioneer Aero. (image via Pioneer Aero Ltd.)

The aft face of Spar #3 following the reassembly of its primer-painted components. Again, several stiffeners have yet to be refabricated, but this task will occur once the correctly profiled extrusions are on hand. (image via Pioneer Aero Ltd.)
The aft face of Spar #3 following the reassembly of its primer-painted components. Again, several stiffeners have yet to be refabricated, but this task will occur once the correctly profiled extrusions are on hand. (image via Pioneer Aero Ltd.)

Spar #2: Stripping Down

After removing Spar #2 from the SBD's Wing Center Section jig, the restoration team stripped this major subassembly down into its component parts. They then media-blasted each part to remove any old paint, dirt and corrosion, thus enabling an inspection to determine their future airworthiness potential. While the upper spar cap and web plate were beyond salvage, the lower spar cap and numerous original brackets and angle sections were all repairable.

A closeup showing the forward face of Spar #2 prior to its disassembly. Note that the lower, lefthand section of Fuselage Frame #3 is still attached at this point, jutting through the spar cap, bottom center. There is also evidence (whitish areas at right) of significant corrosion on the spar web plate. (image via Pioneer Aero)
A closeup showing the forward face of Spar #2 prior to its disassembly. Note that the lower, lefthand section of Fuselage Frame #3 is still attached at this point, jutting through the spar cap, bottom center. There is also evidence (whitish areas at right) of significant corrosion on the spar web plate. (image via Pioneer Aero)

A closeup view of Spar #2, this time showing the reverse side to that on view in the previous image. (image via Pioneer Aero)

Another closeup view of Spar #2 immediately adjacent to the area depicted in the previous image. The whitish bands running along the web plate’s length illuminate areas of corrosion where strips of fabric and felt once sat, holding a fuel tank shell in place. (image via Pioneer Aero)

Another closeup showing the forward face of Spar #2 just adjacent to that shown in the previous image. The ragged hole in the spar’s web at left resulted from other components, torn loose during the wartime crash, being driven through the aluminum plate by the force of the water. This alone rendered the spar web unsalvageable for airworthy use. Even so, the areas of deep corrosion (whitish specking) also visible in this image would have yielded a similar result. Note also the highly corroded pulley bracket sitting between the circular production holes. (image via Pioneer Aero)

Another closeup showing the forward face of Spar #2 prior to its disassembly. Towards the left side of this image, we can see lower righthand section of Fuselage Frame #3, which has a pair of pulley brackets mounted to it. The control lines for the undercarriage locking mechanism pass through these pulleys. (image via Pioneer Aero)

Spar #2: Rebuild Under Way

As with each of the other spars in the SBD’s Wing Center Section, Pioneer Aero’s engineers had to manufacture a new web plate for Spar #2. The SBD’s original web unit had suffered impact damage during the dive-bomber’s WWII crash, not to mention significant corrosion following several decades submerged in Lake Michigan. Even so, it was sufficiently intact to serve as a template for refabricating its replacement. The team also built new internal brackets for the bomb mount hard points, replacing corroded originals. They had to perform similar tasks for various doublers and angle brackets on the spar as well.

A view of Spar #2 during the restoration process. The myriad holes and openings in the replacement web plate were transferred from the original component, which served as a template. The lower cap (at left) and the cross pieces of extrusion are all original, refurbished components shown here following cleaning, inspection, and the remediation of minor corrosion; they are now ready for primer-painting. The raised square bracket (with four copper-colored clecos holding it in place against the web) will eventually serve as a mount for an electrical junction box. (image via Pioneer Aero)
A view of Spar #2 during the restoration process. The myriad holes and openings in the replacement web plate were transferred from the original component, which served as a template. The lower cap (at left) and the cross pieces of extrusion are all original, refurbished components shown here following cleaning, inspection, and the remediation of minor corrosion; they are now ready for primer-painting. The raised square bracket (with four copper-colored clecos holding it in place against the web) will eventually serve as a mount for an electrical junction box. (image via Pioneer Aero)

These replicated brackets are being trial fitted to Spar #2, with a heavily corroded original component being offered up to demonstrate why it was unsalvageable. The brackets will form part of a hard point for holding an ordnance mount to the wing. (image via Pioneer Aero)

Some of the original, heavily corroded mounting angles from Spar #2, along with their newly-manufactured replacements. Once painted with primer, the new parts will have anchor nuts fitted to them. (image via Pioneer Aero)

Here is a closeup of the refabricated electrical junction box mounting bracket shown in the previous image. (image via Pioneer Aero)

At right is a heavily corroded pulley mounting block for Spar #2, as removed from our SBD, along with its replacement retrieved from a donor airframe. (image via Pioneer Aero)

The pulley brackets which form part of the undercarriage locking mechanism (following refurbishment). The original parts for B-22, shown still mounted to Fuselage Frame #3 in an earlier image, proved beyond salvage, but these examples, recovered from a donor airframe, were of sufficient quality to reuse. They are located within the SBD's righthand wheel well. (image via Pioneer Aero Ltd.)

Spar #2: Fuselage Frame #3

As mentioned earlier in this article, the lower left and righthand sections of Fuselage Frame#3 are fastened to Spar #2 with rivets. Pioneer’s engineers, led by Craig Cunha, drilled off these assemblies from the spar, then disassembled, bead-blasted and inspected each of their component parts. While they had to replace all but one of the four web plates involved, it proved the opposite for the extruded sections, with just one of these needing remanufacture. New pulley brackets (which attach to the lower, lefthand section of Fuselage Frame #3) were also refabricated to replace the corroded originals.

A closeup of the lower lefthand section of Fuselage Frame #3 following its removal from Spar #2 showing where it once attached to the frame’s upper half (note the change in paint where the joiner plate once sat). This is the forward face of the frame, prior to its disassembly. The light grey area in the middle of the web plate indicates where deep corrosion set in, rendering it beyond airworthy use. (image via Pioneer Aero)
A closeup of the lower lefthand section of Fuselage Frame #3 following its removal from Spar #2 showing where it once attached to the frame’s upper half (note the change in paint where the joiner plate once sat). This is the forward face of the frame, prior to its disassembly. The light grey area in the middle of the web plate indicates where deep corrosion set in, rendering it beyond airworthy use. (image via Pioneer Aero)

The left and right lower sections of Fuselage Frame #3 following their removal from Spar #2, but prior to their disassembly. The aft faces are visible here. The corroded pulley mounts will need replicating. (image via Pioneer Aero)

Another view of the lower sections of Fuselage Frame #3, showing the aft faces prior to disassembly (the righthand frame is at the top). Note the light grey area at the middle of the extrusion at the bottom of the image; this represents corrosion which rendered part beyond airworthy limits. (image via Pioneer Aero)

The lower left and righthand sections of Fuselage Frame #3 part way through their restoration. Here we see original parts (following bead-blasting and inspection) being trial-fitted with newly-fabricated examples of those components which proved beyond salvage. The lefthand section (at left) is all original to B-22, except for the upper web, which has been replaced with a newly-fabricated part (note shiny new aluminum sheet). For the righthand section, only the outer extrusion is original too B-22, sadly; the inner extrusion is set for replacement due to excessive corrosion. Sitting at image right are the three web sections for Fuselage Frame #3 which needed replacing. (image via Pioneer Aero)

A closeup showing where the pulley mounts (replacements) attach to the lower lefthand, section of Fuselage Frame #3 that is attached to spar #2. Both extrusions and the web plate seen here are all original to B-22. (image via Pioneer Aero)

The lower left and righthand sections of Fuselage Frame #3 part way through their restoration. Here we see original parts (following bead-blasting and inspection) being trial-fitted with newly-fabricated examples of those components which proved beyond salvage. The lefthand section (at left) is all original to B-22, except for the upper web, which has been replaced with a newly-fabricated part (note shiny new aluminum sheet). For the righthand section, only the outer extrusion is original too B-22, sadly; the inner extrusion is set for replacement due to excessive corrosion. Sitting at image right are the three web sections for Fuselage Frame #3 which needed replacing. (image via Pioneer Aero)
The lower left and righthand sections of Fuselage Frame #3 part way through their restoration. Here we see original parts (following bead-blasting and inspection) being trial-fitted with newly-fabricated examples of those components which proved beyond salvage. The lefthand section (at left) is all original to B-22, except for the upper web, which has been replaced with a newly-fabricated part (note shiny new aluminum sheet). For the righthand section, only the outer extrusion is original too B-22, sadly; the inner extrusion is set for replacement due to excessive corrosion. Sitting at image right are the three web sections for Fuselage Frame #3 which needed replacing. (image via Pioneer Aero)