Overview:
Since beginning the process of rebuilding/refabricating the SBD's numerous electrical junction boxes last fall, the team at Pioneer Aero has made significant progress with this time-consuming aspect of the aircraft's restoration. Many of B-22's boxes suffered from significant corrosion issues, but Pioneer has been able to refabricate what they need to move forwards while also refurbishing as much original material as possible, including parts from donor airframes. This newly-updated article (3/28/2026) covers the work involved with completing the restoration and/or refabrication of the last of these boxes, which are now ready for painting and reintegration.
Rear Gunner's Electrical Distribution Panel:
The original rear gunner's electrical distribution sits about half way up the righthand fuselage wall towards the front of the rear gunner's cockpit (see image above). As the image below illustrates, several of this panel's knobs operate rheostats (variable resistors) which control the brightness levels of rear cockpit lighting (see image below). The panel also features a spring-loaded lid which covers the fuse and spare fuse box.
When Pioneer inspected the original SBD rear gunner's electrical distribution panel which came with B-22, they initially deemed it beyond salvage since the hinge which attaches the fuse box lid was literally riddled with corrosion that seemed to have also penetrated into the panel itself. Had the hinge been riveted to the panel, rather than spot welded, then inspecting the area beneath the hinge would have been relatively straightforward. However, removing spot welds is a more complex endeavor and almost always involves sacrificing one of the conjoined parts—since one usually has to grind down the welded 'nugget' fusing them together from one side of the join or the other. It is a time-consuming exercise, requiring significant skill and, even then, there is no guarantee that the adjoining part will escape the process undamaged.
And in this case, even if that operation concluded successfully, it was quite possible that the underlying structure was corroded beyond salvage anyway. As a result, Pioneer's Doug Brown began fabricating a replacement panel (as seen in Update 95), as this seemed like the most expeditious option. However, upon further reflection, Chief Engineer Martin Hedley decided that the panel could be saved after all. He worked out a repair plan, which his team has now carried out successfully. This is great news, as preserving original material, wherever possible/practical, is an important aspect of this project.
This image shows the original electrical distribution panel from B-22's rear cockpit after the hinge for the fuse box access lid has been removed—the lid is seen at image right. The spot weld ‘nuggets’ which once bound the hinge to the panel were milled away through the hinge, with care taken not to dig into the base material. Most of the detritus visible beneath where the hinge once sat is corrosion from the hinge along with accumulated dirt from having sat on the bottom of Lake Michigan for half a century. Bead blasting removed it all fairly easily, with the panel surface being well preserved, despite initial concerns. (image via Pioneer Aero Ltd.)
This image shows the original gunner's electrical distribution panel from B-22 in the process of being repaired. The area where the hinge for the fuse box access panel once sat was bead blasted to remove the remaining corrosion, with a layer of primer paint applied afterwards. Here a thin layer of body filler has been applied at various places on the panel to fill the shallow corrosion pitting. Note the orange masking tape; this is preventing the areas of etched lettering from being covered over with body filler. Once dry, the panel was sanded smooth to remove any excess body filler, then coated with another layer of primer paint. (image via Pioneer Aero Ltd.)
This image shows the original electrical distribution panel for B-22's rear cockpit after its repairs. The corroded hinge is also in view, having now been carefully removed from the fuse box access lid, saving that component as well as the panel itself. A replacement hinge and pin have also been cut to length, as seen to the left of the old component. Instead of being spot welded together, the new hinge will be riveted to the lid and the panel. (image via Pioneer Aero Ltd.)
Here we see a leaf from the fuse box access lid hinge in the process of being riveted to the gunner's electrical distribution panel. (image via Pioneer Aero Ltd.)
With the fuse box access lid hinge now firmly riveted in place on the gunner’s electrical distribution panel, it was time to drill out and rivet the fuse box access lid itself to the other side of the hinge, (image via Pioneer Aero Ltd.)
Electrical Distribution Panel Junction Box:
While the electrical distribution panel for the Dauntless rear gunner's compartment proved restorable, as demonstrated earlier in this article, the junction box it attaches to was corroded beyond repair. As a result, Doug Brown began the process of refabricating this box a couple of months ago and is now close to completing this task. More recently, he installed various fittings, like the anchor nuts for attaching the panel to the box, brackets for mounting an internal sub-panel, and a bracket for attaching the junction box itself to the airframe.
Doug Brown refabricated the junction box for the rear gunner’s electrical distribution panel. The newly-made box is seen in the background of this image, while in the foreground, we see Brown’s hand holding one of the internal brackets for mounting a sub panel within the box—note the corner anchor nut on the bracket. (image via Pioneer Aero Ltd.)
Another view of the box from the previous image, following the installation of two small internal brackets for attaching an internal sub panel. (image via Pioneer Aero Ltd.)
Another view of the box from the previous image following the installation of various anchor nuts. Those arrayed around the upper edge will be used to secure the electrical distribution panel to the box. (image via Pioneer Aero Ltd.)
An external view of the junction box for the gunner’s electrical distribution panel following the installation of a mounting bracket which will eventually attach the box to structure in the rear cockpit. Note that the box has been partially sprayed in primer paint around the area where the bracket rivets to the box; this will help prevent corrosion where the parts meet one another. (image via Pioneer Aero Ltd.)
Baggage Compartment Junction Box:
The SBD's baggage compartment, which sits in the aft fuselage just behind the life raft storage tube, serves several purposes (outside the obvious). In addition to providing stowage for aircrew travel bags during repositioning flights, a tool kit and the manual crank handle for the engine's inertia starter, the space also serves as a convenient location for housing several important electrical components.
One of the latter items is referred to in Dauntless manuals simply as the 'Baggage Compartment Junction Box'. Attached to the back of the life raft storage tube, it hosts several switches which maintenance personnel use for diagnostic purposes. Its most prominent feature, however, is a large socket for connecting the Dauntless to an external power supply for various purposes such as engine startup. While the box for B-22's example was restorable, its lid was too badly deteriorated to refurbish. Thankfully, a donor airframe provided a lid in better condition which Pioneer's Doug Brown was able to restore. The following images cover that process.
A closeup view of B-22’s baggage compartment junction box prior to its removal from the airframe. The is significant evidence of extensive corrosion to the lid, especially around the steel fittings associated with the external power supply socket at its center. Note that the light bulb above the power socket appears to be partially filled with liquid… this turned out to be water from the bottom of Lake Michigan! (image via Pioneer Aero Ltd.)
One of the amazing things Pioneer’s Martin Hedley discovered during B-22’s disassembly was this intact light bulb—but even more surprising was that it was half fill of water. The bulb does not leak, so the water could only have entered it under immense pressure, which could only have occurred at the bottom of Lake Michigan during the decades after B-22’s crash—yet another fascinating aspect of the airframe's history. (image via Pioneer Aero Ltd.)
This is B-22’s original baggage compartment junction box lid following disassembly. There are clearly several areas of extensive corrosion. Unfortunately the damage around the hole for the "Circuit Voltage Test" bulb is beyond even cosmetic repair. (image via Pioneer Aero Ltd.)
This is the baggage compartment junction box lid from a donor airframe. It appeared to be in far better condition than the original example, thus meriting disassembly for further investigation regarding its airworthiness potential. (image via Pioneer Aero Ltd.)
The baggage compartment junction box lid from the donor airframe following removal of all of its components. Two areas of minor corrosion appeared during bead blasting, but they proved relatively easy to repair. (image via Pioneer Aero Ltd.)
The assembly drawing for the SBD's baggage compartment junction box cover showing the various lights, switches, lamps which mout to it, along with the external power recepticle.
The Douglas Aircraft factory drawing describing the cover for the SBD's baggage compartment junction box.
A view inside B-22’s original baggage compartment junction box. Some minor corrosion is present on the inside faces, but it was not so severe to render the part beyond airworthy restoration. (image via Pioneer Aero Ltd.)
A view of the baggage compartment junction box interior after corrosion removal and the application of an initial coat of primer paint. The areas of corrosion pitting were smoothed over with filler then sanded back level. Another coat of primer paint will return the box to airworthy condition. (image via Pioneer Aero Ltd.)
Gun Camera Switch Box:
Another of the electrical junction boxes which Doug Brown has been working on of late is the gun camera switch box which mounts to the ammunition canister straddling the aft face of the rear gunner's cockpit (see image below). When the switch is in the "on" position, this device activates the electrical circuitry controlling the 8mm gun camera attached to the flexible gun mount. Whatever the rear machine guns are pointed at, the camera will see. With a live circuit, film begins rolling whenever the rear gunner depresses the switch atop the righthand machine gun grip. While the camera was primarily intended for recording gunnery accuracy, it could also be operated without firing the guns.
Sadly, B-22's original gun camera switch box was corroded almost beyond recognition. Although the project was able to acquire a better example from a donor airframe, it also had too much corrosion for airworthy rehabilitation, however, it was sufficiently intact to serve as a template. Doug Brown was able to refabricate all of the parts necessary for creating a new box, which is now ready for primer painting and integration with its electrical components.
This image shows the donor gun camera switch box sitting beside its partially completed replacement, with a newly-made mounting bracket in the process of being trial-fitted to a new junction box. (image via Pioneer Aero Ltd.)
Another view of the newly-made bracket being trial-fitted to the replacement gun camera switch box. The original example from the donor airframe is in the background. (image via Pioneer Aero Ltd.)
In Update 95, Doug Brown had just begun remanufacturing the lid for the gun camera switch box, cutting the holes and engraving the requisite text into a fresh aluminum blank. He has now completed forming the lid to the correct shape, and it is seen here placed beside a non-airworthy donor lid for comparison. (image via Pioneer Aero Ltd.)
Here is a closeup view of the completed replacement lid for the gun camera switch box, which reveals the engraved text more effectively. (image via Pioneer Aero Ltd.)
The new mounting bracket for the refabricated gun camera switch box is seen here following its completion, ready for riveting to the box itself. Note that an initial coat of primer paint has also been sprayed onto the box where the mount will attach. (image via Pioneer Aero Ltd.)
This view shows the mounting bracket after it has been riveted to the gun camera switch box; the lid for the latter is sitting on the bench behind it. This is the final fabrication step for this box, which is now ready for painting and integration with its electrical components. (image via Pioneer Aero Ltd.)
Throttle Position Switch Box:
This particular junction box connects to the throttle lever on the left side of the cockpit wall. It houses a microswitch which, when triggered by part of the throttle lever which protrudes through a slot in its side, sounds an alarm if the undercarriage has not been lowered alerts the pilot that protrudes through a slot in its side to rest against the throttle lever. The microswitch will trigger an alarm if the throttle position is below the necessary setting when the landing gear are deployed. B-22's original example was beyond salvage, so Pioneer fabricated a new one from scratch. Interestingly, unlike most of the other SBD's electrical junction boxes, the box for this component was welded together, rather than stamped—as the original factory drawing seen below describes.
This is the newly-fabricated lid for the throttle position warning switch box. It comprises two sections of sheet aluminum riveted together, each with the same outer profile, but with the lower one (out of view here) slightly smaller than the other so it fits snugly into the box opening. (image via Pioneer Aero Ltd.)
A view of the newly-fabricated throttle position warning switch box. Note that there is a slot cut into the body. This will an arm from the throttle leaver to slip through into the box so it can depress a microswitch whenever the throttle is retarded beyond a certain point. Should the pilot fail to lower the undercarriage during the landing approach, the microswitch closure will activate a warning horn alerting them to that fact—hopefully allowing them to avoid an accidental gear-up landing! (image via Pioneer Aero Ltd.)
An end-on view of the throttle position warning switch box during fabrication, with Doug’s hand holding the lid in place—and providing a scale regarding box size. A multi-pin electrical socket will eventually be mounted into the circular opening. (image via Pioneer Aero Ltd.)
A view of the newly-manufactured throttle position warning switch box, with its lid in place. This was the smallest and final junction box which Doug Brown had to complete. (image via Pioneer Aero Ltd.)
Miscellaneous Junction Boxes:
As already intimated, Pioneer's Doug Brown has continued working on the smaller electrical junction boxes and their lids, being able to refurbish several original components. Oddly, some of the serviceable boxes needed new lids fabricated for them, and vice versa. Some of these are depicted in the images below.
This little electrical box is an original, airworthy example from a donor aircraft, but it didn’t have a serviceable lid, so a replacement was fabricated. (image via Pioneer Aero Ltd.)
A different view of the original electrical box from the previous image seen here with its replacement lid sitting in place. The holes for the retaining fasteners will be located and drilled next. (image via Pioneer Aero Ltd.)
This house-shaped electrical junction box lid is an original from a donor aircraft, however it did not come with a serviceable box, so a replacement has been fabricated. (image via Pioneer Aero Ltd.)
These house-shaped electrical junction boxes and their matching lids are all serviceable originals from a donor aircraft. After bead blasting and inspected, they are now ready for primer painting. (image via Pioneer Aero Ltd.)
One of the SBD’s electrical junction boxes has a lid held on by wing nut-style, quick release Dzus fasteners. This image shows the box with the layout for the rivets which will hold the Dzus spring in place drawn onto the box exterior. Doug is holding one of these Dzus springs up to the box side to confirm the rivet layout. The spring will, of course, be mounted to the box side’s interior face. (image via Pioneer Aero Ltd.)
A view of the box after each Dzus spring has been riveted to its interior. This was the final step in the fabrication of this particular box. (image via Pioneer Aero Ltd.)
The Last Batch:
Doug Brown has begun building up the final batch of electrical junction boxes for the SBD. This section will show the steps involved in this effort for two of these boxes. Originally, the Douglas Aircraft Company (or one of its subcontractors) would have manufactured the boxes by stamping them out with a hydraulic press or possibly a drop hammer. However, such an endeavor requires a set of dedicated dies and molds to shape each type of junction box. Since the original tooling for these junction boxes was most likely scrapped soon after WWII, a new set would have to be made if the original manufacturing technique were to be applied. However, this would require expensive, non-recurring engineering fees and considerable lead time to set up, which seemed an excessive approach for producing such a small number of units.
Therefore, Brown opted to manufacture the boxes by cutting out a flattened version of the box from a sheet of weldable aluminum, folding up the edges into the appropriate box shape, then welding the seams shut. Next, the welded joints would be ground smooth to the correct profile. With the basic shape for each box completed, Brown marked out and cut the various mounting holes and entry/exit points into the body, then attached the various fasteners and mounting brackets each box required. The following sequence of images shows this process in action.
Here we see one of the boxes after Doug Brown has smoothed down its welded seams to the correct, rounded profile. He has also begun marking out some of the holes which the box needs to have cut into its base. Note that the factory drawing for this junction box is visible in the background. (image via Pioneer Aero Ltd.)
These are the same boxes from the previous images. One of them has had six mounting holes drilled into it, plus a central pilot hole. The latter will guide a circular cutter in the next stage of fabrication. (image via Pioneer Aero Ltd.)
The junction boxes are seen here after having had a large opening cut into each of their bases. (image via Pioneer Aero Ltd.)
One of the junction boxes is seen in the background here, having had all of its various holes cut into it. Most SBD junction boxes have lids which are held on by Douglas-designed anchor nuts like the one Doug Brown is holding in this image. These cube-shaped nuts, threaded through the middle, have a small cylinder on one face which protrudes through a mounting hole on the side of the box. Brown will use a rivet squeezer to flare out the end of this cylinder which protrudes through the box, locking it in place in much the same way as a hollow tail rivet. Note that a screw is used to prevent the lock nut’s thread from being distorted during the squeezing process, as demonstrated here. (image via Pioneer Aero Ltd.)
This is the rivet squeezer (with a custom set) which Doug Brown used to install the lock nuts on each of the electrical junction boxes. (image via Pioneer Aero Ltd.)
A view of the electrical junction box after having had one of the anchor nuts installed. Note how the tail of the lock nut’s mounting cylinder has been flared tightly against the box’s outer face. (image via Pioneer Aero Ltd.)
Junction Box Completion:
As alluded to earlier, Doug Brown has now completed the restoration/fabrication stages for all of the SBD's electrical junction boxes. The images below show the entire collection of boxes after their mechanical completion. All that remains now is to repaint the boxes and install their various electrical components. While, to some, this may seem insignificant in comparison to the major structural elements involved in this project, it is, never-the-less, an essential stage in getting the SBD flying again!
Another view of the now mechanically complete set of SBD electrical junction boxes, plus two skinny arms which hold one of the boxes to an engine bearer tube. This shot shows the range of sizes, shapes and hole patterns involved. Note how some boxes share the same the size and shape, but feature different hole patterns, while others have the same plan-form but differ in height. Others, of course, are completely unique. (image via Pioneer Aero Ltd.)
Another view of the complete set of SBD electrical junction boxes showing their variety of shapes, sizes and configurations. The example in the lower righthand corner is the one featuring the quick-release Dzus fasteners attaching its lid. They are now ready for painting. Mechanically complete, each box is now ready for painting and then fitting out. (image via Pioneer Aero Ltd.)