Engine Nacelles (1/3)
| Comet 4, version 0.3, for X-Plane 8.15, with nacelles within the ACF. |
The project started in X-Plane 8.15, with nacelles as four individual “miscellaneous bodies” within the main aircraft file, or “ACF”. Several problems had to be overcome. This page illustrates one point, which is the scale of the break-through that X-Plane 8.40 was for projects like this:
Plane Maker assumes that all bodies will be symmetrical in cross-section, which is fine for the vast majority of fuselages, engine nacelles, weapons and pinion tanks. For the Comet, it wouldn’t do. I soon discovered that this limitation only applied to Plane Maker, in fact the ACF contained separate co-ordinates for all vertices on either side of Plane Maker’s “mirror”. I created the nacelle shapes in 3D, then wrote a program to load the data into the right hex-addresses in the ACF.
It worked, but there were still problems with the symmetry. The shape no longer had to be symmetrical, but the left-right split had to lie on a
| Comet 4, version 0.6, for X-Plane 8.60, with nacelles as a 3D object. |
flat plane, like a tree trunk in a saw-mill. By rotating one nacelle 45 degrees and the other 90 degrees, the shape was reasonable in plan, but not accurate in side elevations.
When joined together, the nacelles had a hard-edge, which looked wrong, and attempting to fare-in the heat exchanger (effectively a third mini-nacelle between the intakes) was challenging.
Finally, the shininess of the skin was not consistent with the shape of the object. This was because I had not calculated the correct vector normals for the nacelles, which is usually done invisibly by Plane Maker.
Just at the point where it all looked too difficult, Austin Meyer released X-Plane 8.40, which allowed me to design a proper, complex shape in 3D and attach it to the ACF. All the problems I had been struggling with on the nacelles vanished overnight.