I started the vertical tailplane of the SBD by forming its root airfoil (Figure 35‑1). I had no description nor a direct photo of the airfoil used here. However, the reference photos reveal that it could have similar shape to the airfoil of the horizontal tailplane. Thus I copied that curve into this mesh.
Note that I used here a thin strip of the faces instead of a single curve (which I used in the case of the horizontal tailplane or the wing). The reason is simple: on the single subdivision curve I cannot mark a “sharp corner” at a control point (original mesh vertex). On the face “strip” I can mark the corresponding edge as sharp (increasing its Crease coefficient to 1). I marked in this way the edge at the split between the rudder and fin. Simultaneously I can form such a face strip in the top view as easily as a single curve. (I just have to remember to select its vertices using the group select commands (Border-select or Circle-select), instead of the simple mouse click). Why didn’t I use this method in the previous cases? Well, good ideas require some time to emerge…
Once the root airfoil was ready, I extruded it into the basic trapeze (Figure 35‑2):
Then I split this mesh into the rudder and fin (i.e. into separate objects, as in Figure 35‑3):
Note that I added additional “rib” edges to the mesh of the fin. They will be useful in forming the forward fragment of this part.
Initially, I extruded the first approximation of the dorsal fin from the bottom edges of the lower ribs (Figure 35‑4):
However, I decided that the resulting topology of this mesh differs too much from the original layout of the panel seams (and the original ribs and spars). To make a better approximation, I used the fin shaped in the previous step as the reference object (in Figure 35‑5 it is in red):
I cut out the forward part of the original fin, forming in this mesh the first vertical edge. Then I extruded it into next segment (Figure 35‑6):
The next segments were extruded in similar way (Figure 35‑7):
In each new segment the vertical cross section is significantly smaller than in the previous one. I had to compensate it by cutting out its bottom fragment (using the Knife tool — as in Figure 35‑7) and reducing the number of remaining faces.
Figure 35‑8 shows the resulting dorsal fin:
The tip of this fin was formed in an unusual way — it was stamped in the cover of a fuselage hatch (as you can see on the photo). I will form this cover later.
Figure 35‑9 shows the objects created in this posts:
You can examine them in this source *.blend file.
In the next post I will describe my work on the fairing of this fin (it seems quite simple, but occurred more difficult than I expected!).