Thought I bent my fan blade but.....

[danoscooter]

Turns out the fan blades are not symmetrical. Why would they be that way? Wouldn't they be unbalanced. For the past couple days I had been trying to source a fan blade that would work with a clutch. Most of the aftermarket ones were symmetrical that's why I thought I had a bent blade. Then I ran into an AC Delco one that look exactly like my bent blade!

 

[K9Vic]

You did not know this, they are asymmetrical by design.

http://www.madsci.org/posts/archives/aug98/899326517.Eg.r.html

 

[doghead]

Good old Google!

 

[danoscooter]

So its to prevent an annoying humming noise at high rpm's. Don't really buy that considering these motors arent meant for high rpm's. Plus they aren't quiet either.

 

[doghead]

Who really cares why?

They work just fine.

 

[danoscooter]

I just think its funny and stupid. Stupid because I spent time looking for a replacement.

 

[Anubis8472]

So its to prevent an annoying humming noise at high rpm's. Don't really buy that considering these motors arent meant for high rpm's. Plus they aren't quiet either.

If the blades were evenly spaced they would "chop" like .. well a "chopper".

They are not specific to CUCV's. All full size fans are made like that, since well like the 50's.

Now they wouldn't go and redesign an entirely new type of fan blade for these trucks just because they're already loud.

That link mentions that electric fans don't move enough air to need this treatment, but that isn't true. Even electric fans have similar measures, just usually not the offset blades. Sometimes it's as small as a few holes in the shroud to prevent the pressure pulsing.