A proper 5-blade fan

[rhs856]

I needed a 5-blade fan for a build, but I noticed that all of them looked the same... ridiculous. Every fan in my parts bin had disproportionately spaced blades. This would not do, so I decided to make the 7-blader in my kit into a 5-blade with appropriate spacing.

First, I cut all but one of the blades off. I did this so I could line the tilt of the other four up with one of the originals. Cut the blades off as close to the center hub as possible without marring up either the blade or the hub. I sanded the nubs off of the hub and cleaned up the four best-looking blades.

I then measured the distance around the hub with a piece of tape, and divided by 5. My hub was roughly 35/64" around, so I made a mark on the tape every 7/64".

On each mark, I piloted a hole with the hobby knife and drilled it using the smallest bit I had. I drilled another hole in the end of each blade, where it would align with the hub.

I used a bit of wire in the hole on each fan blade to pin it to the hub.

Finally, I used CA glue to attach everything, making sure the angle on each blade was close to the original one that I had left on.

I hope this helps!

Edited February 14, 2012 by rhs856

[pharr7226]

Very nice tutorial. Well written, easy to understand, and great pictures.

[Foxer]

Nicley done. This is the kind of tips needed here for those not having done this type of modification before. It all seems simple once you see it, but you hit all the right techniques along the way.

[Casey]

Many fans were designed with unevenly spaced blades, such as this early '70s Mopar fan:

Not sure if that's correct for your application or not, but since most kits tend to get the top of the line engines and options, they usually get heavy duty fans, too.

[rhs856]

Thank you to the people posting pictures of fans with different blade placement. It is definitely important to do your research to recreate what is correct for the subject you're building.

I love this place! So much information!

[62rebel]

the reasoning behind spacing them out of phase was to disrupt the droning fan noise evenly spaced blades make. even four bladed fans have the blades out of phase. the swept blade design on electric fans negates the need for phasing, so they don't do it on electric fans. trucks and heavy usage vehicles ( ambulances, police cars, high performance engines) would not bother trying to cut noise down, so they tend to have evenly spaced blades (often in odd numbers) on their fans.

[Deathgoblin]

the reasoning behind spacing them out of phase was to disrupt the droning fan noise evenly spaced blades make. even four bladed fans have the blades out of phase. the swept blade design on electric fans negates the need for phasing, so they don't do it on electric fans. trucks and heavy usage vehicles ( ambulances, police cars, high performance engines) would not bother trying to cut noise down, so they tend to have evenly spaced blades (often in odd numbers) on their fans.

That answers that question. I was just wondering about the odd spacing on the fans a couple of days ago. Thanks!