VF-17 had a system of distinguishing flights with prop color. Red was for Blackburn's, white for Hedrick's and so on. The system was soon abandoned as it was impossible to keep that kind of order with aircrafts in the area. My sources say 18'' but I think it depends where You start to count . In the end the photographs show different configuration of prop colors - only the cup painted, the cup and the blade roots construction in color and so on.
Blackburns Coirsair is my second beloved plane, so it is a great pleasure for me to see good model of her, even if some details are missing like the patches covering the holes done by Hedrick's burst Nov.11th 1943.
Good Job!