Modeling the Rear Part of the Engine Cowling

In this post I will create the next section of the engine cowling. I copied its forward edge from the rear edge of the inner cowling panel. Then I extruded it toward the firewall (Figure 48‑1):

Figure 48-1 Initial shape of the engine cowling behind the NACA ring

I am going to split this object into individual panels, thus I already marked their future edges as “sharp” (as you can see in the figure above). It allowed me to preserve continuity of the tangent directions around these future panel borders from the very beginning.

In the next step I created the space necessary for the covers of the gun barrels (Figure 48‑2):

Figure 48-2 Cutting out the area for the gun barrel covers

Then I split this object into separate cowling panels (Figure 48‑3):

Figure 48-3 Splitting the cowling into separate panels, and cutting out their openings

I also used auxiliary “boxes” and the Boolean modifiers to cut out various openings in the side and bottom panel.

To keep the mesh topologies as simple as possible, I decided to model the inner part of the air outlet in the side cowling as a separate object (Figure 48‑4):

Figure 48-4 Forming the inner panels along the side air outlets (SBD-3)

(In the real SBD-3 it was also a separate piece of sheet metal). Its vertical contour was rounded to fit the fuselage behind the firewall (as you can see in Figure 48‑4), thus to shape it in this way I added three additional edge loops in the middle of this mesh.

The initial version of the gun cover was copied from the reference object, then I adjusted its shape fitting it to the adjacent panels (at least to their contours — see Figure 48‑5):

Figure 48-5 Forming the gun covers

Note that it is possible to have a corner in the middle of the border of a 3D surface that was carefully fit at its front and the rear contour (see Figure 48‑5)! In this case this is an intended effect, recreating the effect visible on the reference photos.

The last element of this cowling is the adjustable scoop (Figure 48‑6), directing the air into the oil radiator (hidden inside engine compartment). It seems to have thick walls, but I suppose that they were empty inside (however, I am not sure — I cannot see any seams there):

Figure 48-6 Adjustable oil radiator scoop (SBD-3)

I started forming this element by fitting its bottom surface into the fuselage contour (Figure 48‑7):

Figure 48-7 Forming the oil radiator scoop (1)

Then I formed the side walls of this object. As the reference I used an auxiliary circle, centered at the scoop pivot point (Figure 48‑8a):

Figure 48-8 Forming the oil radiator scoop (2)

Then I created the thick walls of this scoop using a Solidify modifier (Figure 48‑8b).

Initially I was going to round the edges of this object using a multi-segment Bevel modifier, placed after the Solid modifier. However it occurred that the Solid modifier created in some corners of this mesh dynamic faces that cause problems in the result generated by the Bevel modifier. Thus I had to “fix” the results of the Solid modifier before using the Bevel tool. You can see the rounded, thick edges of this scoop in Figure 48‑9a), while Figure 48‑9b demonstrates the complete cowling panels:

Figure 48-9 Forming the oil radiator scoop (3)

Figure 48‑10 shows the complete engine cowling, compared to an original aircraft:

Figure 48-10 Complete engine cowling (SBD-3)

Note that the model in the picture above uses different lighting than in the photo. It results in different shadows and reflections from the curved surfaces of the fuselage.

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

In the next post I will create the last panel of this fuselage: the hinged doors in the front of the windscreen.


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