The sound is the clay jugs, or "buzios" on the rigging. The sound helped the miller know what kind of adjustment was needed to the sails or direction the rigging pointed. Varying buzio tuning setups also helped a miller distinguish between his mill and a nearby one, as there were often several...
@AlexTrc Don't know about the pilot, but there is a Gee Bee Racer on display at the Springfield Museums in Springfield, MA. It's in the same building where they have the Indian Motocycle exhibit. Also, you must need balls of steel to strap yourself into that flying engine and take off!
The sound is the clay jugs, or "buzios" on the rigging. The sound helped the miller know what kind of adjustment was needed to the sails or direction the rigging pointed. Varying buzio tuning setups also helped a miller distinguish between his mill and a nearby one, as there were often several...