Recreating the Wright R-1820 “Cyclone” (4)

The fins of the air-cooled cylinder heads are a state-of-art piece of metallurgy (Figure 86‑1):

Figure 86-1 Fins of the R-1820 cylinder head

At the first glance, it is hard to believe that they were cast as a single piece. But when you look closer, you will discover that these fins “grow up” from the solid parts of the head as naturally, as the hair from the head (Figure 86‑2):

Figure 86-2 Close-up of the fin details

Try to imagine the shape of molds used in the production of these parts, and the challenges faced by their manufactures! (There is an interesting post about this. It describes production of the R-1830 Twin Wasp cylinders). Basically, modern producers of the heads for the air-cooled aircraft engines use the same technology as eighty years ago.

In my model I will recreate these fins in a somewhat simplified form, as a few separate Blender objects. I will also skip some fine details of their shape (for example the small features that I marked in the figure above). Such a simplification conforms the moderate level of details that I assumed for this model. It is always possible to make a more detailed version of this object later.

Recreating the Wright R-1820 “Cyclone” (3)

One of the most prominent features of the R-1820 engine cylinders are their rockers. More precisely – their covers, cast as the part of the cylinder head (Figure 85‑1):

Figure 85-1 Cylinder valves and their rockers (a cutout)

The R-1820 was a classic four-stroke engine. Its cylinders had two valves: single intake valve, connected to the supercharger via a wide pipe, and single exhaust valve. Movements of these valves were controlled by cams, via pushrods and rocker arms mounted in the cylinder heads. The covers housing these valves and rocker mechanisms were placed on the right and left side of the cylinder head.