#43 A glitch in the biplan2.ac object

[steelman]

There seem to be a glitch in the biplane2.ac object causing a black vertical "line" to be drawn (see atachments). I run crrcsim on Debian stretch, the version of the package is 0.9.12-6.2+b1. I tried fixing the problem by loading the model into AC3D and running "Optimise Vertices" and "Optimise Surfaces" operations without any noticeable effect.