In our last restoration update, the team at Pioneer Aero Ltd. had just separated the upper fuselage subassembly from the airframe. In the intervening weeks, they have further disassembled the fuselage into its major component parts and begun mounting them in purpose-built jigs for their rebuild. The lower image is reproduced here as a reference.
Separating the lower aft fuselage:
With the upper half of the fuselage removed, it was now time to separate the lower aft section from its forward counterpart. To complete this task, it was necessary to remove several skin panels and the underlying stringers and joiners overlapping Frames 8 and 9. The image immediately below captures this effort part way through the process, engineers having already de-riveted most of the skin sections falling between Frames 8 and 9 on the right side of the fuselage. Longeron 6, which straddled the join between the upper and lower fuselage subassemblies, has already been detached from the right side. All that remained to permit the aft fuselage's separation at this point was for the team to drill out the remaining rivets linking the stringers together.
(Note the Cleco fasteners holding the stringer joiners together along the bottom of the fuselage. This was a temporary measure, to keep everything in alignment whilst the team drilled off the final rivets holding the fuselage subassemblies together.)
This image shows the lower rear fuselage (mounted on trestles) following its separation from the rest of the airframe. (photo Via Pioneer Aero Ltd.)
A view of the lower rear fuselage following its separation. The bulkhead in the foreground is mounted at Frame 9. (photo Via Pioneer Aero Ltd.)
Wing Center Section: Fuselage Remnant Removal
The remaining lower fuselage pieces mounted to the wing center section had to be de-riveted, piece-by-piece, since they are integral to the latter subassembly.
Looking aft, with the front face of the Frame 4 bulkhead in the foreground, and the radar equipment rack and gunner's cockpit floor structure behind that. The gunner’s cockpit floor structure was removed first, followed by the rack and the bulkhead diaphragm. (photo Via Pioneer Aero Ltd.)
The wing root fairings, stringers and skins in the process of being dismantled. The lower forward section of the fuselage is built integrally with the wing center section so each item is removed individually. (photo Via Pioneer Aero Ltd.)
The wing center section, with the lower forward section of the fuselage now completely removed. The eight fuselage frames which still poke out from the top of the wing are riveted directly onto the respective front faces of the four wing spars. The lower engine mount attachments were located at the end of the longerons which run along the top side of the wing. Unfortunately, they were torn off during the SBD’s crash into Lake Michigan during WWII, with only the now very jagged stumps of the attaching longerons remaining (covered under blue cloth at the ride edge of the image). (photo Via Pioneer Aero Ltd.)
Fuselage and wing jigs:
Pioneer Aero has built jigs to hold the fuselage and wing center sections secure during the restoration process. The jig for the upper half of the fuselage holds it perfectly level, with the fin remaining vertical. The jig's numerous attachment points to the various fuselage frame ends and empenage structure will allow sections of the fuselage to be removed, restored and refitted in the correct position. The jig will also hold the upper engine mounts in the correct location.
Meanwhile, the team has constructed an elaborate new jig for the wing center section, which will be held vertically with the leading edge facing down. This will allow Pioneer's engineer's to dismantle and restore the major subassembly in the most practical way possible, since they will have easy and equal access to either side of the wing. The jig will also hold the lower engine mounts in the correct location.
. (photo Via Pioneer Aero Ltd.)
The top half of the fuselage is now is its correct position relative to the main jig frame. The ends of each frame are being securely attached using packers, as required to ensure they remain in exactly their current location. (photo Via Pioneer Aero Ltd.)
The left hand lower end of Frame 3 in the process of being securely attached to the jig. (photo Via Pioneer Aero Ltd.)
The left hand lower end of Frame 3, following the completion of the alignment process, now securely attached to the jig. (photo Via Pioneer Aero Ltd.)
The aft end of the upper fuselage half securely attached to the jig, with each frame end having been fastened in place. The unpainted three-legged frame visible in the image is attached to the horizontal stabilizer mounting point, while the tall frame on the right locates the rudder’s upper hinge point, ensuring that the fin remains vertical. This section of the jig has additional attachments lower down which connect to the aft face of Frame 17 and the horizontal stabilizer mounts. (photo Via Pioneer Aero Ltd.)
Another vantage point of the jig structure from the previous image, show where it attaches to Frame 17 and the horizontal stabilizer. (photo Via Pioneer Aero Ltd.)
A view of the jig structure which holds the SBD’s rollover frame securely in the correct position. (photo Via Pioneer Aero Ltd.)
This image shows the process of installing the forward attachment plate in the jig. This will hold the upper engine mounts, the forward ends of the longerons and Frame 1, all in the correct location relative to the airframe’s vertical and horizontal center lines. (photo Via Pioneer Aero Ltd.)
