Thread Number: 9862
Kirby Fan Question
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Post# 107541   9/3/2010 at 09:34 (3,558 days old) by eurekastar (Amarillo, Texas)        

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I have vacuums both with the older aluminum fan and the newer lexan/kevlar fan. The aluminum fan certain has a distinctive sound, reminiscent of a jet. However, I'm just curious if there is a difference in suction/airflow produced by each fan. Is one greater than the other? This is the fan that came out of my Model 515.

Post# 107543 , Reply# 1   9/3/2010 at 10:17 (3,558 days old) by joe22 ()        

i hope you put the metal fan back in the 515, ;-))

Post# 107545 , Reply# 2   9/3/2010 at 10:31 (3,558 days old) by eurekastar (Amarillo, Texas)        

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I did. If the metal fan is in good shape, I re-install it. That 515 fan was in perfect condition. Not even a little nick on it anywhere. I think the previous owner didn't have children, who will vacuum up anything -- coins, rocks, nuts, BBs.

Post# 107549 , Reply# 3   9/3/2010 at 11:28 (3,558 days old) by electrolux~137 ()        

Well, a Kirby man told me that the kevlar fan actually creates more suction power. That's because it's lighter in weight than the aluminum one and puts less "drag" on the motor, so the motor runs faster. And, presumably, that's also better for the motor.

Post# 107554 , Reply# 4   9/3/2010 at 12:55 (3,558 days old) by kirbysthebest (Wichita, KS)        

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I had a debate with a now former member a year or so ago about this same subject.

When I worked for Kirby, I was told that the plastic model being eleven blade and aerodynamicly designed moved more air than the 10 blade aluminum, however, the former member had data that suggested the aluminum fan with deeper fins moved the greater amount of CFM.

Your observations are the same as mine, the aluminum fan give the Kirby a more low pitched growl, where as the plastic fan is higher pitched, presumed from the higher motor revs.

I was told, and have no data to support the heresay, but was told that the plastic fan was better balanced and easier on the motor in high speed operation. Again I have no proof.

Post# 107556 , Reply# 5   9/3/2010 at 13:51 (3,558 days old) by joe22 ()        

there has to be a way to measure the airflow through a kirby, some sort of a meter thing

Post# 107559 , Reply# 6   9/3/2010 at 14:21 (3,558 days old) by kirbysthebest (Wichita, KS)        
there has to be a way to measure the airflow through a kirby

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And there is. I know there is a Barid meter that measures CFM, I don't have one; but am sure others here may.

Just remember there are variables, and this is where the former member and I got into it. The type and condition of your bag is one that I can think of.

In some cases, but don't feel it applies here since you would probably use the same machine and measureing solely airflow. But temperature, humidity, and foot traffic are variables to consider if one is measuring amounts of "dirt" picked up.

Post# 107560 , Reply# 7   9/3/2010 at 15:03 (3,558 days old) by kirbfan94 ()        

The metal fan moves more air, The weight diffrence isint enough to make the motor spin that much slower.
Deeper, Straighter blades=more airflow.

Post# 107561 , Reply# 8   9/3/2010 at 15:17 (3,558 days old) by kirbymodel2c (Nottingham, England)        

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To be honest I think the newer type of fan is better from a performance angle.Please bear in mind that the plastic fans on the newer models was designed by kirby with help from NASA with the help on computer programs like CAD etc and the metal ones were not.

So I think its unlikely that the metal fan will out perform the new style fan.
But I do like the metal fan on the older kirby's. by the way.


Post# 107566 , Reply# 9   9/3/2010 at 16:50 (3,558 days old) by electrolux~137 ()        

I prefer the metal fans as well, and all my Kirbys have them. There is a distinct difference in the sound.

Post# 342604 , Reply# 10   2/1/2016 at 11:01 (1,581 days old) by KirbyCollector (Columbus Ohio USA)        
My perspective on Kirby fans

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I have done many tests and comparisons between ten blade aluminum fans and eleven blade polymer fans and from what I've seen and experienced, the aluminum fan creates just a little more suction and airflow. When I did a comparison between a D50 with a newer fan and a D80 with older fan, the D80 won the baking soda test. I then switched the fans so the D50 had the older fan and the D80 had the newer fan. The D50 won that time. I even did my own unique metal fan retro fit in my G4. I did a baking soda test between the retro fit G4 and a Diamond Edition. The G4 cleaned up way better than my Diamond. I switched the fans. That time the Diamond won. I believe the deeper, and straighter blades are what creates more airflow and suction.

Post# 342608 , Reply# 11   2/1/2016 at 12:19 (1,581 days old) by sptyks (Skowhegan, Maine)        

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Kirby teamed up with NASA to produce a new fan which is both stonger
and with better airflow performance. NASA did wind tunnel tests to prove it.
This article proves why the new polymer fans perform better than the
old metal fans which are so susceptible to breakage.

Post# 342656 , Reply# 12   2/2/2016 at 04:26 (1,581 days old) by tolivac (Greenville,NC)        

Vacuum fan speed vs jet engine--remember the fans and compressor blades in jet engines are larger than in the vacuum cleaner motor.In a typical GE widebody twin spool engine-the secondary spool or rotor-the one that drives the engines propulsion fan-is running up 4,000RPM.That fan assembly could be 8Ft dia and weigh almost a ton.And with it running at speed-it moves over a ton of air per second!!!The stresses on the tips of those fan blades is a few hundred TONS!So the vacuum fan is nothing compared to what is in a jet gas turbine engine!Oh yes-look at cloesup pictures of jet engine fans and you will see small nicks on them just like a direct air vacuum fan!Engine techs file these nicks out by hand and rebalance the fan.This can be done a few times before the blades have to be replaced.And a good reason why runways have to be cleaned.Like a direct air vacuum fan engine fans can ingest so much before something BAD happens!In the engines its the primary rotor that contains the compressor and turbine blades that can run to 10,000RPM.This is largely sheilded by the fan blades-so objects aren't as likely to damage the blades on the primary spool or rotor.

Post# 342768 , Reply# 13   2/3/2016 at 12:43 (1,579 days old) by sptyks (Skowhegan, Maine)        

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I didn't know you were such an expert on jet engines.


Post# 342950 , Reply# 14   2/6/2016 at 03:56 (1,577 days old) by tolivac (Greenville,NC)        

Learned about it from reading and visiting a YouTube website 0f "Agent JZ".Gas turbines appeal to my "Motorhead" other folks like piston engines-I like turbines!On the Agent site they show MANY test runs of engines.Including variable nozzle adn afterburner ones!They do a great job of explaining the tests and how the features on the engines work-you find out what goes on underneath the engine cowels!

Post# 343018 , Reply# 15   2/6/2016 at 15:10 (1,576 days old) by wyaple (Pickerington, OH)        
CFM Tests of Vacs From 1980-2013

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Here's the link to my extensive CFM tests using a GM8901 anemometer.


Post# 343019 , Reply# 16   2/6/2016 at 15:12 (1,576 days old) by wyaple (Pickerington, OH)        
Water Lift Tests

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Here's the link to my extensive water lift tests.


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