Obio has already posted a file called "s55_rotor_sound_update.zip" in the library here . . .
but perhaps you already know that . . .
To be honest I didn't know until I went looking after Jorge's post yesterday. Popped it into the sim, a vast improvement, so a massive thank you due to Obio.
I've got all the permissions I need for the Flettner set, just want to do a little tweaking & then it'll be up in the Library. After which I shall take a look at the Fa 223 (although I've got few repaints ahead of that which I want to finish), that setup deserves something better than an alias to the B206B.
I almost sound as though I know what I'm doing ....