Overview:

An upcoming museum exhibit has consumed a fair amount of our energy of late, so we apologize for the delay in bringing you reports on progress with our Dauntless restoration. Pioneer Aero has accomplished a lot with the SBD in the interim, so we appreciate your patience while we bring you all up to speed on their progress. This, our 100th SBD restoration update, will focus upon Nigel Lowen's work with the historic dive-bomber's lower rear fuselage.

A graphical drawing from page 15 of the Dauntless Illustrated Parts Manual depicting a section of the SBD's lower rear fuselage. The inset at the lower left highlights the area where the arrestor hook attaches, with part 01 being the righthand forging for the arrestor hook mount.
A graphical drawing from page 15 of the Dauntless Illustrated Parts Manual depicting a section of the SBD's lower rear fuselage. The inset at the lower left highlights the area where the arrestor hook attaches, with part 01 being the righthand forging for the arrestor hook mount.

Arrestor Hook Mount:

Nigel Lowen took apart B-22's arrestor hook mounting assembly several months ago. This mostly involved cleaning and inspecting each part before returning his energy to refurbishing the lower rear fuselage's frames and stringers. However, with that effort mostly completed, he has been able to devote time to various ancillary parts in this section of the airframe, including the arrestor hook mount.

The arrestor hook itself pivots around a heavy-duty bolt which straddles two sturdy aluminum forgings bolted to the keel stringers leading forwards from Fuselage Frame #13. After media blasting most of the dirt and old paint from these components, Lowen discovered corrosion near the main pivot holes. Even though it seems highly unlikely that this SBD will ever make an arrested landing again, these parts are integral to the airframe's structure and also help bear the arrestor hook's mass, not to mention the aerodynamic pressure against it during flight, so Pioneer Aero must factor these issues in when deciding whether the corrosion issues are beyond amelioration for airworthy use or not. Thankfully, a second set of forgings was available in a chunk of fuselage salvaged from a donor Dauntless. After cleaning, these parts were found to be in excellent condition. However, after trial-fitting them into their appropriate, original keel stringers (#15R and #15L), only the righthand forging fitted its stringer properly, with the lefthand unit, rather frustratingly, being misaligned. As a result, Pioneer must decide whether to manufacture a new #15R keel stringer, or refurbish B-22's original righthand arrestor hook mount.

These are B-22's original arrestor hook mounting brackets; they attach to the keel stringers (#15L and #15R) at Fuselage Frame #13. Initial inspection following partial blasting revealed some corrosion around the main pivot holes. Pioneer has yet to decide whether these parts can be rendered airworthy again. (image via Pioneer Aero Ltd.)
These are B-22's original arrestor hook mounting brackets; they attach to the keel stringers (#15L and #15R) at Fuselage Frame #13. Initial inspection following partial blasting revealed some corrosion around the main pivot holes. Pioneer has yet to decide whether these parts can be rendered airworthy again. (image via Pioneer Aero Ltd.)

The same section of SBD fuselage depicted in the previous image, albeit from its lefthand side. (image via Pioneer Aero Ltd.)

A lump of fuselage from a donor aircraft as seen from its righthand side. This section includes the arrestor hook strut and the arrestor hook mount fittings (hard to see below the stringers). Note: the aircraft's nose would have been towards image right. (image via Pioneer Aero Ltd.)

Here are two sets of forged aluminum arrestor hook mounts. The lefthand set is original to B-22, whilst that on the right is from a donor airframe. The original pair suffered a degree of corrosion but (obviously) they both fit the original keel stringers (#15L & 15R). The donor pair are in good condition, however, only the righthand unit fits B-22’s original, airworthy keel stringer (#15R). This type of misalignment was quite common for aircraft of the WWII era, since even those manufactured on production lines were essentially hand made. While this does not affect the airworthiness of any individual component, it can complicate its ability to mate up with components from another aircraft. A decision will be made soon regarding which mounting fittings will be used. (image via Pioneer Aero Ltd.)
Here are two sets of forged aluminum arrestor hook mounts. The lefthand set is original to B-22, whilst that on the right is from a donor airframe. The original pair suffered a degree of corrosion but (obviously) they both fit the original keel stringers (#15L & 15R). The donor pair are in good condition, however, only the righthand unit fits B-22’s original, airworthy keel stringer (#15R). This type of misalignment was quite common for aircraft of the WWII era, since even those manufactured on production lines were essentially hand made. While this does not affect the airworthiness of any individual component, it can complicate its ability to mate up with components from another aircraft. A decision will be made soon regarding which mounting fittings will be used. (image via Pioneer Aero Ltd.)
To demonstrate how the two arrestor hook mount fittings from the donor airframe do not properly mesh with B-22’s original components, we can see them here during their trial-fitting to original keel stringers #15L & #15R. While the righthand example (closest to the camera) fits, the lefthand unit does not due to a drilling misalignment on stringer #15L. Note how the arrestor hook attachment bolt, slipped through the righthand mount, but cannot pass through the bushing on the lefthand fitting across from it. (image via Pioneer Aero Ltd.)
To demonstrate how the two arrestor hook mount fittings from the donor airframe do not properly mesh with B-22’s original components, we can see them here during their trial-fitting to original keel stringers #15L & #15R. While the righthand example (closest to the camera) fits, the lefthand unit does not due to a drilling misalignment on stringer #15L. Note how the arrestor hook attachment bolt, slipped through the righthand mount, but cannot pass through the bushing on the lefthand fitting across from it. (image via Pioneer Aero Ltd.)

Rear Fuselage Lift Points:

Nearly every WWII-era American military aircraft with a tail wheel features a hardened lifting point on the rear fuselage to both make it easy (and safe) to hoist the airframe onto a ship or vehicle, or for mechanics to raise the aircraft into a horizontal attitude for maintenance-related issues. These lifting points usually allow a hoisting strap or bar to pass clean through the fuselage without causing damage to it. Such is the case for the Dauntless, which has two beefy aluminum forgings (with circular apertures) mounted on opposite sides of the lower rear fuselage–see the item highlighted by callout #12 in the illustration at the beginning of the article.

B-22's original lifting points suffered from significant corrosion, as the images below reveal. Thankfully, we were able to source replacements from a donor airframe, and these proved to be in airworthy condition after media blasting and inspection. Pioneer trial-fitted them successfully to the fuselage, while replacing the sections of stringer #7 which pass between the lift points and the skin on both sides of the aircraft as well. These parts were then painted with primer, ready to be riveted into the fuselage later.

An image from inside the righthand side of B-22’s lower rear fuselage prior to its disassembly. The heavily corroded item with the large circular hole running through it is one of the SBD’s original fuselage lifting points. Sadly this significant aluminum forging was damaged beyond airworthy repair. For reference, the right side of the image points aft. (image via Pioneer Aero Ltd.)
An image from inside the righthand side of B-22’s lower rear fuselage prior to its disassembly. The heavily corroded item with the large circular hole running through it is one of the SBD’s original fuselage lifting points. Sadly this significant aluminum forging was damaged beyond airworthy repair. For reference, the right side of the image points aft. (image via Pioneer Aero Ltd.)

This image shows the replacement lefthand lifting point from a donor airframe clecoed into position within B-22’s rear fuselage; the original skin is being used for jigging purposes. The lifting point forging has been bead blasted, inspected, and determined to be airworthy. Note that the stringer between the lifting point forging and the skin has been replaced too. For reference, the rear fuselage is upside down on the jig, with the aircraft’s tail being towards image right. (image via Pioneer Aero Ltd.)

This image shows the righthand lifting point from the donor airframe clecoed into position within B-22’s rear fuselage––in the same manner as for the lefthand lifting point shown in the previous image. For reference the rear fuselage is upside down on its jig, with the aircraft’s tail being towards image left. (image via Pioneer Aero Ltd.)

A view of the lifting points from the donor airframe and related replacement stringers following trial-fitting and primer-painting. They are now ready for riveting to the lower rear fuselage later in its restoration. (image via Pioneer Aero Ltd.)
A view of the lifting points from the donor airframe and related replacement stringers following trial-fitting and primer-painting. They are now ready for riveting to the lower rear fuselage later in its restoration. (image via Pioneer Aero Ltd.)

Skin Refabrication:

Along with rebuilding internal components for the SBD's lower rear fuselage, Nigel Lowen has also begun refabricating some of its skins as well, beginning with those sitting between Fuselage Frames #13 and #17. These skins were fabricated from different thicknesses of aluminum sheet to match the originals (and the manufacturer's drawings). All of them have been rolled to match the fuselage profile, then drilled to match its refurbished original frames and stringers. To ensure the replacement skins were precisely located, neighboring original skins were temporally clecoed to the aircraft's internal structure to ensure it remained fixed in its original positions.

This drawing from the SBD's Illustrated Parts Manual depicts the airframe's lower fuselage, with each callout number representing a specific section of skin on the airframe. Each of the items depicted has the root Douglas Aircraft part number 5063493, with a dash number representing the specific component. Note that each plate has two callout numbers associated with it, an odd number for the right side of the airframe and an even number representing its mirror image on the opposite side.
This drawing from the SBD's Illustrated Parts Manual depicts the airframe's lower fuselage, with each callout number representing a specific section of skin on the airframe. Each of the items depicted has the root Douglas Aircraft part number 5063493, with a dash number representing the specific component. Note that each plate has two callout numbers associated with it, an odd number for the right side of the airframe and an even number representing its mirror image on the opposite side.
Here Nigel Lowen is seen refabricating the fuselage skin #112 for the lower rear fuselage. He has already rolled the new skin to its correct profile and is in the process of drilling off some of its rivet holes. This skin is represented by callout #25 in the illustration above. (image via Pioneer Aero Ltd.)
Here Nigel Lowen is seen refabricating the fuselage skin #112 for the lower rear fuselage. He has already rolled the new skin to its correct profile and is in the process of drilling off some of its rivet holes. This skin is represented by callout #25 in the illustration above. (image via Pioneer Aero Ltd.)
Replacement belly skin #112 is seen here being trial-fitted to the SBD’s lower rear fuselage. The original skins #37 (closest to the jig’s base) and #39 are temporally fitted to ensure the frames and stringers are precisely fixed in their original positions. The newly-fabricated skin #37 is visible atop a pile of original skins awaiting replacement in the foreground. Note that one of the refurbished lifting points mentioned earlier in this article is shown poking out from beneath the new skin #37 towards image left. (image via Pioneer Aero Ltd.)
Replacement belly skin #112 is seen here being trial-fitted to the SBD’s lower rear fuselage. The original skins #37 (closest to the jig’s base) and #39 are temporally fitted to ensure the frames and stringers are precisely fixed in their original positions. The newly-fabricated skin #37 is visible atop a pile of original skins awaiting replacement in the foreground. Note that one of the refurbished lifting points mentioned earlier in this article is shown poking out from beneath the new skin #37 towards image left. (image via Pioneer Aero Ltd.)

A closeup view of replacement belly skin #112 during its trial-fitting. The aft ends of original skins #37 (lower) and #39 (upper) each overlap the new skin panel, and show visible signs of significant, unrepairable surface corrosion. (image via Pioneer Aero Ltd.)

A view of the port side of the lower rear fuselage in the process of having replacement skins #112 and #36 trial-fitted. The original skin #38 is temporally fitted to help ensure that the underlying fuselage frames and stringers are in their correct positions. Note that the original skin #36 is seen sitting beside the fuselage, its circular cutout being the opening for the port-side lifting point. (image via Pioneer Aero Ltd.)

A closeup of the port side of replacement belly skin #112 during its trial-fitting. The aft ends of the original skin #38 and the replacement skin #36 are also visible. (image via Pioneer Aero Ltd.)

Another view of replacement skins #112 and #36 during their trial-fitting. (image via Pioneer Aero Ltd.)

A tail-end view of the SBD’s lower rear fuselage in the process of having replacement skins trial-fitted. (image via Pioneer Aero Ltd.)
A tail-end view of the SBD’s lower rear fuselage in the process of having replacement skins trial-fitted. (image via Pioneer Aero Ltd.)

Another view of the lower rear fuselage in the process of having the replacement skins refabricated. Here we see the replacement belly skins #42 and #112 and the right side replacement skins #37 and #39 during their trial-fitting. The original belly skin #44 is temporally fitted to help align the new skins. The original skin #42 is visible sitting beside the fuselage, its interior face being visible. Under that is the original skin #35. (image via Pioneer Aero Ltd.)

Another view of the lower rear fuselage in the process of having the replacement skins refabricated. Here we see the replacement belly skins #42 and #112 and the left side replacement skins #36 and #38 are being test fitted. The original belly skin #44 is temporally fitted. Furthermore, replacement skins #42 and #34 are visible sitting beside the fuselage awaiting their trial-fitting. (image via Pioneer Aero Ltd.)

A tail-end view of the lower rear fuselage in the process of having the replacement skins fabricated. This image shows replacement belly skins #42 and #112 and side replacement skins #36, #37, #38, #39 all being trial-fitted. The original belly skin #44 is temporally fitted to help correctly align the fuselage structure. (image via Pioneer Aero Ltd.)
A tail-end view of the lower rear fuselage in the process of having the replacement skins fabricated. This image shows replacement belly skins #42 and #112 and side replacement skins #36, #37, #38, #39 all being trial-fitted. The original belly skin #44 is temporally fitted to help correctly align the fuselage structure. (image via Pioneer Aero Ltd.)