Overview:
Over the past several months, Pioneer Aero’s Hadon Smith has made great strides restoring the leading edges for the SBD’s Wing Center Section. He started with the righthand side, bringing that subassembly close to completion before, more recently, initiating work on the lefthand side. The latter endeavor is now well advanced, as this report will reveal.

Moving Forwards:
Smith’s last report saw the lefthand nose spar essentially complete, with the opening stages of the leading edge reassembly process underway. With the leading edge skin located accurately in the jig, Smith positioned the nose ribs against it. He then drilled mounting holes along each rib’s forward flange and through the skin, temporarily securing the components in position with clecoes. This allowed the nose spar to be drilled into positioned and secured (again with clecoes) against the rear flange of each nose rib.


Wheel Cutout and Remaining Stringers
Smith was then able to position and drill the fore-most stringer against the leading edge skin. With the locations for the nose ribs and nose spar now firmly established (by drilling them against the skin), Smith could then calculate the precise position and orientation for the wheel axle. Using this information, he rigged up a cardboard template outlining the wheel clearance so he could trim away excess leading edge skin to properly define the wheel cutout. He then carefully shaped the remaining leading edge stringers to align perfectly with the skin contours and secured them in place.

The lefthand leading after the wheel well cutout in the skin had been trimmed to the correct size. (Image via Pioneer Aero Ltd.)
With locations for the forward stringer and the nose ribs having been fixed against the lefthand leading edge skin, it was now possible to determine the exact positions for the remaining stringers. This view shows the structure after the temporary removal of most internal components, which allowed the stringers to be positioned and curved to match both the leading edge skin profile and rib cutouts. (Image via Pioneer Aero Ltd.)
A follow-on from the previous image showing how the stringers on either side of the foremost stringer have been shaped properly and drilled against the leading edge skin. (Image via Pioneer Aero Ltd.)
Primer Painting And Reassembly
After drilling the nose ribs and stringers to the leading edge skin to formalize their positions, it was time to take the temporarily-assembled structure apart to coat each component in primer paint. With the paint set, Hadon Smith then re-clecoed the parts back in place for the next stage, forming the fresh air ductwork.


Fresh Air Ductwork
With the nose ribs, stringers and leading edge skin clecoed together, Smith could then begin forming components for the fresh air duct to match the leading edge structure. The duct snakes its way from a port in the SBD’s lefthand leading edge through the ribs into the cockpit, providing fresh air to the pilot. This duct comprises several sections of 2” diameter aluminum pipe, flared at each end to allow adjoining sections to slip together during installation.
Smith began the process of making this duct by creating the necessary bends in a single piece of pipe. Due to the nature of the machine used to bend the pipe, however, it was not possible to produce consecutive bends with the required length of straight pipe between them (i.e. the straight sections were too long). As a result, Smith cut away these excess lengths of straight pipe and welded the bends together to form the appropriately sized part.


For the duct’s interface with the leading edge, Smith had to weld an appropriately curved flange to the section of pipe which attaches to the interior face of the skin. He then fashioned a matching exterior flange for riveting the duct to the leading edge skin, rolling its inner edge to provide a smooth transition for the air entering the duct. Smith then trial-fitted the duct to the leading edge, and fabricated specialized clamps for holding each section of ductwork together or to the nose ribs they passed through.
As already noted, the port for the fresh air duct is mounted in the left hand leading edge. This image shows the trial-fitting of the exterior duct interface, clecoed to the mounting ring at the end on the duct inside the wing.
A view inside the lefthand wing leading edge structure showing where the fresh air duct terminates. This image was captured during the trial-fitting of a clamp where the duct passes through the rib. (Image via Pioneer Aero Ltd.)
Here are various pieces of the fresh air duct following their completion. They will be fitted once the nose ribs are riveted into place. (Image via Pioneer Aero Ltd.)
Here are some of the clamps fabricated to hold the various sections of fresh air duct to the ribs. (Image via Pioneer Aero Ltd.)
Riveting
After forming the fresh air duct, its parts went into the paint booth for a coat of primer. It was then time to rivet together the leading edge structure comprising the skin, nose ribs and stringers. The video below shows Hadon Smith on the rivet gun (closest to camera) working with Craig Cunha on the bucking bar to form up the rivets which hold one of the nose ribs to the skin. Listen in to the call and response between these two engineers; it really reveals how well an experienced rivet team collaborates.
An interior view of the lefthand leading edge structure during the process of riveting in the ribs. The tube at the right is a fully-assembled, newly-painted section of fresh air duct; note how it is clamped against the ribs it passes through. (image via Pioneer Aero Ltd.)
Final-Fitting the Nose Spar
It was now time to final-fit the nose spar into the leading edge structure. Hadon Smith had already drilled off this subassembly against the rear flanges of each nose rib. Smith had permanently riveted these ribs in place against the leading edge skin, so he could now drill off the spar against the skin too.

An exterior view of the lefthand leading edge during the process of drilling off the nose spar cap against the skin. The row of silver-tinted clecos are holding the spar in place. (image via Pioneer Aero Ltd.)
Trial-Fitting the Inter-spar Ribs:
Now that the nose spar had been drilled off against the leading edge ribs, Smith could begin using these holes to trial-fit the inter-spar ribs linking the nose spar to Spar #1. He had formed the basic shapes for each of these ribs some time earlier, but Smith used this opportunity to trim and fit each of them into the correct position against the nose spar. With that work completed, these interspar ribs were ready for the paint booth and primer painting!
The nose spar for the lefthand leading edge during the process of fitting the inter-spar ribs linking the nose spar to Spar #1 ribs. Note: the far right edge of the spar in this image mates up with the outboard wing bulkhead. (image via Pioneer Aero Ltd.)