Updating the Model of the SBD-1

As I described it in one of my previous posts, in parallel to the SBD-3 I build a SBD-1 model and a SBD-5 model. They are in the same Blender file, but in separate scenes. Since I completed the SBD-3 model for this project stage, now it is time to take care of these other versions. These models share all the common objects with the SBD-3, so I have to recreate a few different details. I already modified their NACA cowlings. In this post I will update the SBD-1, because there is just a single remaining difference: the ventilation slot in the side panel of the engine cowling.

The SBD-3 had this slot much wider than the SBD-1 and SBD-2 (Figure 54‑1):

Figure 54-1 Comparison of the ventilation slots in the SBD-3 and the earlier versions

(I used here an archival photo of the SBD-2, because it had the same side cowling as the SBD-1. There were only 57 SBD-1s ever built, so the photos of this version are not as numerous as the later ones).

Figure 54‑2 reveals the reason of this difference in the cowling shapes:

Figure 54-2 Internal differences between the engine compartments of the SBD-1, -2 and the SBD-3, -4

The SBD-1 and SBD-2 had special emergency device: pneumatic balloons, which automatically opened when the aircraft ditched on the water. They had to keep the airframe on the surface, giving the pilot and gunner more time to evacuate. These balloons and their trigger installations were stowed in boxes behind the ventilation slots (Figure 54‑2a).

In the SBD-3 the designers removed these balloons, creating more room for the air coming out from the oil radiator (Figure 54‑2b). In this version these ventilation slots are completely integrated into the side cowling panels.

Because of the frame around the balloon compartments (Figure 54‑2a), the side cowling of the engine had a slightly different shape in the SBD-1 and SBD-2. I modeled it by copying the corresponding cowling panel from the SBD-3, and inserting an additional edge loop in the middle (Figure 54‑3a):

Figure 54-3 A new version of the side panel, modified for the SBD-1, -2

I marked this edge as sharp and used it for the minor modifications of the panel shape (Figure 54‑3b).

It seems that the shape of the cutouts in the side view is identical in the SBD-1,-2 and SBD-3, thus I used the same auxiliary objects for its Boolean modifiers (Figure 54‑4a):

Figure 54-4 Forming the new inner panel for the side cutout

However, I had to create anew the inner panel, located inside this cutout. I started with the edge copied from the firewall. I extruded it forward (Figure 54‑4a), then inserted some additional edges in the middle (Figure 54‑4b).

I shaped this inner panel forming it as a smooth continuation of the fuselage shape (Figure 54‑5a):

Figure 54-5 Details of the inner panel

Then I concentrated all the inner edges of this mesh at the ventilation slot (Figure 54‑5b), and bent the forward edge of this panel toward this outlet (Figure 54‑5c).

In the effect I obtained the shape that closely resembles the original cowling (Figure 54‑6):

Figure 54-6 Details of the inner panel

You can compare this photo with the first figure in this post (Figure 54‑1).

It was the last element that I had to modify in this model. Figure 54‑7 shows the complete airframe of the SBD-1:

Figure 54-7 The SBD-1

It is ready for the next stage of this project (applying materials and textures).

In this source *.blend file you can evaluate yourself the model from this post.

In the next post I will start updating the model of another Dauntless version: the SBD-5. (There will be more differences than between this SBD-1 and the SBD-3).


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