Why are the fan blades uneven? - Page 3 - PeachParts Mercedes-Benz Forum

okto · #31 07-07-2011, 08:17 PM

Quote:

Originally Posted by tbomachines

Except, regardless of how many blades it has, if they are all equal in length and spaced out evenly they will amplify like crazy. That's because each one would have the same wavelength relative to the last and following blade, they would all be generating identical pulses.

Good point. I was thinking purely in terms of mechanical oscillation, not the pulse each blade makes as it cuts through the air.

You can make physics say anything is possible if you leave out the right bits from your theoretical system.

lutzTD · #32 07-07-2011, 10:17 PM

Quote:

Originally Posted by tbomachines

Except, regardless of how many blades it has, if they are all equal in length and spaced out evenly they will amplify like crazy. That's because each one would have the same wavelength relative to the last and following blade, they would all be generating identical pulses.

yes but at only one frequency, if it is a 12 blade it will amplify like crazy at 5 frequencies. think of it this way, a 12 blade fan has 6 2 blade fans, 3 4 blade fans, 4 3 blade fans and 2 6 blade fane buried inside of it, each of these produces its own amplified noise frequencies.

scottmcphee · #33 07-07-2011, 11:06 PM

I'm a big fan of the question that started this thread.

vstech · #34 07-08-2011, 08:57 AM

isn't jimmyL a fan expert?...

leathermang · #35 07-08-2011, 09:00 AM

JimmyL is an antique fan collector...