Using the calculator this forum kindly provides and working through various fairing shapes and real world testing is interesting .
For instance this Royal Enfield Dreamliner from 1953 that I've posted before works out at a cd of .66 from the published speed and fuel consumption figures .
Not a bad figure for something built primarily as a weather protection shield with some consideration of drag . When we come to something like Craig Vetter's fairing though things have really improved !
At the moment it seems Mr Vetter's fairing is about as good as it is possible to get bearing in mind the problems with a perfect NACA foil ....ie side lift in traffic and disturbed air . The openings at the sides seem sufficient to spoil the side lift but still provide a good airflow .
Does anyone know the cd of the Vetter fairing ?