Originally Posted by karlik
Thank you -
I've been using a spectrum analyzer to get the headspeeds on 450's for quite a while, but I've never been able to verify it on a slower head or with more than 2 blades because I didn't know what the actual speed was.
Yours is at 61 hz.
61 x 60 seconds is 3660 hz divided by 3 blades is 1220 rpm. It works
Sounds like it. That 1250 I'm quoting is not set in stone...it is a best guess as I have an Eagletree sensor/logger, which gives some 50 rpm of noise range in the speed reading, so I do my best to decipher the chart setting this up