Why are fan blades not evenly spaced?

[XT700]

Was looking at the fan today and realized the blades are not evenly spaced. Why? Will it make a difference when the fan is reinstalled. Hope not%) .

 

[72Sport]

I have heard that it makes them run quieter.

 

[Smarty6]

I know it makes it easier to get at some of the bolts.....

 

[Wes harden]

No it won't make any diff a quality fan should have been balanced on it's own. the odd spacing is to break up wind patterns and noise.

 

[iwlbcnu]

Harmonics

 

[broncow72]

Harmonics

HHmmm.. Might be fun to sound like an airplane. I used to make that sound as a kid.;D

 

[Eoth]

Count the blades... Stock fan is SEVEN... Uneven number of blades means spacing has to be uneven to balance it out. Now why did they choose seven and not an even number? Everyone has a theory.

 

[68 Broncoholic]

My stock fan is a 5 blade and is off set. A six blade is equal. My other Bronco has a seven which is off set. I can see the harmonics problem but how come a 6 blade is equal?

 

[Devin]

I have always been told that it is done to reduce noise.

 

[DirtDonk]

Harmonics/Noise.
I'm not sure I agree with you Eoth. Can't any number can be spaced evenly around a circle? 6 blades is spaced every 60° and seven would be spaced every 51.4°
just like a 5-pointed star is generally evenly spaced.
Uh, that's right isn't it?
Geometry wasn't exactly my strong point, but that just stood out and made me think.
I do like the gap the odd number leaves though. Sure makes getting to those PITA bolts easier. A little...

Paul