Toprudder
Tried it. It only made 1/2 a db difference. 94.5db.
I have just bought a beautiful 3 blade true turn spinner for my 2.6 Extra and I can it use it at the field because it takes the noise over 96db!!
Buzz
ORIGINAL: toprudder
ORIGINAL: Buzz Lightyear
First test 94.9db at 3m on grass with aluminium spinner
Second test 90.9db at 3m on grass without aluminium spinner!!!
I've heard of pattern guys spraying the inside of the aluminum spinners with exapandable foam, then carving out enough room for the prop/shaft/nut etc. Would be an easy experiement.