Overview:
While the team at Pioneer Aero has been making great strides with the SBD's larger structural components, they have also focused on some of the myrad smaller components which fit into the fuselage. This update highlights some of these accomplishments, which we hope you enjoy learning about.
Forward Upper Fuselage Progress:
In addition to the stringers, Pioneer’s team has worked on fitting the lefthand upper longeron to the fuselage frames and skins. To begin this process, they trial-fitted the replacement lefthand upper engine mount to the corresponding longeron. As with the righthand longeron, this involved adjusting the angles for the inner and outer folds, then trimming and locating it in the correct spot before drilling. The longeron is now drilled-off against Fuselage Frames #1, #3, #4, #5 and #6. The replacement for Fuselage Frame #2 has also been fitted, and progress has been made fitting and drilling each of the parts which comprise the gun mount structure and instrument panel sides. Some of these parts came from a donor airframe, while the rest are replacements. The replacement lefthand forward skin section has also been drilled-off against the matching frames and stringers.
The original lefthand fuselage skin (in blue paint) which sits between the upper longeron, the fuselage split, the firewall and Fuselage Frame #3 alongside its partially completed replacement. For reference, the left edge of the skin points towards the front of the aircraft. The large rectangular hole provides access for loading/unloading the ammunition box feeding the lefthand forward .50 cal machine gun, whilst the smaller opening serves as a foothold for climbing into the cockpit. William Lowen will cut these openings into the new aluminum sheet once he has transferred all of the holes into the structure, ensuring that this narrow skin section remains in the correct location until all of the rivets holes have been drilled. (image via Pioneer Aero Ltd.)
The original righthand fuselage skin (in blue paint) which sits between the upper longeron, the fuselage split, the firewall and Fuselage Frame #3 alongside its partially completed replacement. Barring its lack of a foothold opening, this skin section is essentially the mirror image of that described in the previous photograph. (image via Pioneer Aero Ltd.)
The replacement lefthand upper engine mount and longeron are seen here during test-fitting. The lefthand longeron which came with the project needed some final flange angle adjustments to ensure that it fitted correctly. The longeron is now drilled to Fuselage Frames #1, #3, #4, #5 and #6. Replacement Fuselage Frame #2 has also been fitted. (image via Pioneer Aero Ltd.)
The instrument panel supports located between the top of Fuselage Frame #2 and the longerons both needed replacing due to corrosion damage. These parts also comprise the aft-most elements in the mounting structure for the fixed machine guns. The vertical ribs (lefthand example shown in place) which sit between Fuselage Frames #1 and #2 form the inboard elements of the gun mounting structure and also hold the upper instrument panel mounts. (image via Pioneer Aero Ltd.)
This view of the fuselage is looking aft into the area where the lefthand forward .50 caliber machine gun sits. The lefthand vertical rib for the machine gun mounting structure described in the previous image is also seen in this image; it was salvaged from a donor airframe. (image via Pioneer Aero Ltd.)
Looking aft into the area where the righthand .50 caliber machine gun sits. The front face of the replacement instrument panel support (located between the top of Fuselage Frame #2 and the longerons) is visible to the right in this image. The vertical rib running between the left edge of the image and Fuselage Frame #2 is also part of the gun mounting structure (and riveted to the longeron). The original component was corroded beyond re-use, so a replacement was fabricated - hence the shiny aluminum surface. (image via Pioneer Aero Ltd.)
Fuselage Frame #1 (Lower Section):
Fuselage Frame #1 comprises three primary sections (upper, middle and lower) with the bottom two being integrated within the SBD's Wing Center Section (see illustration below). The aircraft's firewall mounts within the central ring formed by these three subassemblies.
The lower section of our SBD's original Fuselage Frame #1 was too badly buckled and corroded to be of much use, even as a pattern, however an example from a donor airframe was available to the project. As the image below reveals, even this component was beyond economic repair for airworthy use, however, it did provide several reusable parts.
The restoration team refabricated the frame section. After it returned from heat treating, they inked reference lines onto the aft face before positioning angle stiffeners in the appropriate spots and drilling them off. Two of these stiffeners are restored donor components, while three others are replacement parts remade on site.
The center section leading edge pocket cutouts were also marked out and cut into the frame; the pockets themselves (refurbished originals from the donor airframe) were then positioned and drilled off. Holes for two sets of system control connections were also marked out and cut into the frame. The team also fabricated and drilled off the bomb aiming window support bracket and its associated hinge. The cowling attach brackets were also fabricated, located and drilled off. The upper edge and holes for the lower engine mounts were then marked out and trimmed to their final size and shape.
This image shows the lower section of Fuselage Frame #1 (aft face) with the stiffeners positioned and match drilled. Various holes have also been cut into the frame. The two D-shaped holes mark where the pockets for the wing leading edge are located, whilst the other two holes are for mounting hydraulic and electrical system connection blocks. (image via Pioneer Aero Ltd.)
A view showing the frame’s forward face after a stiffener and the leading edge 'D' pockets have been positioned and match drilled. The two pockets and stiffener are refurbished originals from a donor airframe. (image via Pioneer Aero Ltd.)
The forward face of the replacement lower section of Fuselage Frame #1 is seen here being trial-fitted to the middle section from a donor airframe. The large, circular design inked onto the new metal closest to the camera marks where the righthand engine mount will eventually be located. (image via Pioneer Aero Ltd.)
Another view of the forward face for the replacement lower section of Fuselage Frame #1 being trial-fitted to a donor middle section. The series of angled brackets arrayed along the Frame’s lower edge (uppermost in the image) will hold the Dzus springs used to hold the aft edge of the engine cowls in place. Note also the caste aluminum component sitting near the center of the image. This is a refurbished hydraulic connection block from a donor aircraft. (image via Pioneer Aero Ltd.)
A closeup image showing the bomb aiming window mounting bracket (including the hinge) being trial-fitted to the lower section of Fuselage Frame #1 (aft face). (image via Pioneer Aero Ltd.)
Another view of the newly-fabricated lower section of Fuselage Frame #1 (forward face) as components are being trial-fitted. (image via Pioneer Aero Ltd.)
Related to the lower section of Fuselage Frame #1, the restoration team has also worked on elements of the structure attaching to its aft face. The drawing above depicts this structure, part of which serves as the mount for the Bomb Displacing Gear we described in a previous article. The mounting structure for this equipment also includes a support assembly for the bomb-aiming window beneath the pilot’s feet. While the original component (part #14 in the drawing above) was too badly damaged to refurbish for airworthy use, Pioneer’s Craig Cunha fashioned a replacement from new metal, as shown in the images below. This component sits aft of the bomb window, supporting its rear edge.
These are parts from the original assembly used to support the rear edge of the bomb aiming window. As can be seen, there is both impact and corrosion damage visible on these parts. (image via Pioneer Aero Ltd.)
The original support assembly alongside its partially completed replacement. (image via Pioneer Aero Ltd.)
Pilot's Armor Plate:
The SBD has several areas with armored protection, the most important of these being mounted behind the pilot’s seat against the rollover structure (see illustration below). The plate comprises several sections, with the lower element recently receiving treatment from Pioneer Aero’s William Lowen. The original component salvaged from our Dauntless had a heavy layer of corrosion, with significant pitting. Even so, it was still salvageable for use in the aircraft, given that it is not part of the load-bearing structure, nor will it be required - we hope - to withstand enemy bullets!
The front face to the lower section of the pilot's seatback armor plate seen here in as-removed condition. As is evident, it is heavily pitted with rust in some areas. (image via Pioneer Aero Ltd.)
The aft face of the armor plate shown in the previous image in as-removed condition. (image via Pioneer Aero Ltd.)
William Lowen removed the bulk of the rust using a composite stripping disc, and then bead-blasted the plate to clean out the pitting. It was then etch-primed and hi-build primed (a spray-on coating which helps fill in the corrosion pitting). Once this is dry and hard, Lowen will sand it back then add further layers of hi-build until the required surface finish is achieved.
The aft face of the armor plate during the cosmetic restoration process. Is has been painted with etch primer and then hi-build primer. This will then be sanded back and further layers added until the required surface finish is achieved. (image via Pioneer Aero Ltd.)
The front face of the armor plate during the cosmetic restoration process. (image via Pioneer Aero Ltd.)
