I've heard those 6-bladed ones on the Hercs are money. Don't they automatically feather? I heard one start up once and actually sounded really cool.
Yeh they are pretty awesome and they definately have a noticeable noice to them. They do autofeather but it depends on certain criteria. I can get into more scenarios then are worth talking about on this forum. Basically when you want them to feather, they will and when you want them to windmill to power the hydraulic system they will do that as well.