Fan Testing Round 6, Potential Fan List/Methods

[Martinm210]

Hmm, how about doing what skinneelab guys do - several readings, dropping best and worst, averaging rest?

BTW, what different causes might cause different fan performance? If we theoretise/analise about it, maybe we can come up with better ideas how to counter those causes for more objective results?
Eg. how about ambient temp or humidity impact on fan rpm-s, storage circumstances (eg. storing time, vertical or horizontal) impact on bearing, bearing type specifics (eg. how do result repeatability looks for other ball bearing fans, do they fluctuate same as GTs?) and many other possible causes i forgot to imagine/think about ..

The big difference I see that I do have control over is warm up time (I noticed that back when I was testing rads on the crystalfontz, it's darn near impossible to hold a fixed RPM). There is a pretty dramatic change in the first few minutes where RPM increases with temperature, this is why I've been doing the whole 5 minute warm up thing. But I'm sure there are all sorts of variables that affect the result such as humidity, temperature, ambient noise level, altitude, and sample variance. Overall it seems noise levels are fairly controllable and repeatable, it's the air flow and fan RPM variances that's hard to pin down...but I've seen that by using the crystalfontz. Probably has alot to do with the temperature and run time and viscosity of the grease/oils used to lubricate the fans. In general I'm seeing more consistency is the sleeve or FDB sleeve like bearing systems that float on fluids. The fans like the GT with actual ball bearings and/or fans that have harmonic issues are the trouble makers for repeatability. I may try retesting some of the top fans, but I have no plan to retest them all many times...that would simply become "Work"..

I'm probably just being overly anal about repeatability, but I'm looking for some way of checking my setup as opposed to the actual fan. I want to make sure I'm comfortable with testing over multiple days that I'm getting the same thing. My anemometer is actually specified to read within 3% accuracy, so 1% repeatability (relative) is really good.

If you read fan specs, they all say +-10% on just about everything, that's probably about right if you started testing for sample variance.

I think we just need to accept the 10% spec and understand the limitations of testing one sample in a less than perfect environment. I could retest every fan 5 times, but then what have we done to test sample variance? You'd probably have to test 5 samples, 5 times, at sea level, in a fix ambient, fixed humidity, 0dBA anechoic chamber over 5 mounts to remove all the variables, but we have to be realistic at hobby/recreational level. This will be more than good enough I think and no I'm not retesting each fan 5 times.....I am going to use my fan check process though at least once per day run the D12SM12 to ensure nothing on the test rig has changed. This is also why I wanted to keep the fan testing rounds small, then they all get tested at relatively the same baseline, it's when you try to create a big database that all these little variables become very important. We'll see how it goes..I may have to break it up into several smaller rounds if I start seeing some check in variances I can't pin down...

Most of the fan testing/reviews I'm seeing on youtube is someone plugging in the fan sitting on a table feeling the air with the palm of their hand and subjectively saying "Wow, it's completely silent, and moving A LOT of air".

I'm not doing vertical though, I'm just not setup for that right now, but I might consider it later and run a few of the top picks after this round is complete.

I'm happy with the new anemometer, even with the GT +- 10 FPM is really not that bad, that's only about 1 CFM either way. With the old anemometer I had seen some variances as high as 4CFM, so this is a huge step in the right direction.

[Church]

BTW, with storing i meant exactly that - storing it on shelve, not mounting - afterall, unused fan for half a year might have some issues with lubricant gone bad, no? (i'm just recalling reading somewhere that for sleeve bearing fans it's bad not only run it horizontally mounted, but also storing, which many big shops ignore though, just piling them on shelves however it seems simplier to them, so even bought new sleeve bearing fan might have issues with flown out or dried out lubricant oil after months on shelves).

[Martinm210]

BTW, with storing i meant exactly that - storing it on shelve, not mounting - afterall, unused fan for half a year might have some issues with lubricant gone bad, no? (i'm just recalling reading somewhere that for sleeve bearing fans it's bad not only run it horizontally mounted, but also storing, which many big shops ignore though, just piling them on shelves however it seems simplier to them, so even bought new sleeve bearing fan might have issues with flown out or dried out lubricant oil after months on shelves).

Yeah I suppose...just not sure how you would know or determine that. Could be the same thing happening in the warehouse prior to the vendors or during shipping..etc.

I've also heard routinely that running sleeve bearing fans in horizontal is bad. That seems to make sense, but I'm finding that most of the fancy FDB and other named bearings are also basically a sleeve type bearing. Very few fans actually use ball bearings....most are sleeve types with various modifications to that...but still a sleeve bearing.

Also most sleeve bearing fans have some sort of o-ring on the shaft which I assume is to help prevent lubricants from leaving?

Anyhow, I'm a bit lost when it comes to bearing naming convention. It seems fluid dynamic bearings and Nano bearings are all basically sleeve bearing fans with a twist. The Gelid Wing 12 and the Silverstone AP121 both had what I would call a sleeve bearing, neither one had any sort of conventional ball bearings inside.

I guess the only indicator we have is the lubricant itself, and I can't say I've ever had a fan that "Leaked" at the shafts. I would think if there was some sort of storage/leakage problem it would show up under the stickers or something along those lines.

[Church]

Nano bearings imho are plain sleeve bearings with fancy name, kind of like Feser Admiral rad nano surface threatment .
FDB, while technically one of sleeve bearing types, differs from it, that it's not just lubricant put between tension surfaces at assembling of bearing, but due to bearing design lubricant gets artifcially 'pumped/forced' between those surfaces by bearing rotation, and it's more so then in sleeve 'floating' upon layer/film of fluid lubricant, then sliding between surfaces. Hydrodynamic bearings might be more effective and with potentially much longer life at always on usage scenarios, but with extra wear on starting up/stopping, also usually have a little bit higher minimum startup current (because of extra still friction). Friction is way smaller then that of sleeve bearing, but there is energy loss on 'pumping' fluid lubricant.

[Martinm210]

Nano bearings imho are plain sleeve bearings with fancy name, kind of like Feser Admiral rad nano surface threatment .
FDB, while technically one of sleeve bearing types, differs from it, that it's not just lubricant put between tension surfaces at assembling of bearing, but due to bearing design lubricant gets artifcially 'pumped/forced' between those surfaces by bearing rotation, and it's more so then in sleeve 'floating' upon layer/film of fluid lubricant, then sliding between surfaces. Hydrodynamic bearings might be more effective and with potentially much longer life at always on usage scenarios, but with extra wear on starting up/stopping, also usually have a little bit higher minimum startup current (because of extra still friction). Friction is way smaller then that of sleeve bearing, but there is energy loss on 'pumping' fluid lubricant.

Ok, I'll look for that. The few fans I have completely taken apart just didn't seem like they had any way to really pump a fluid, some had a notch in the sleeve where lubricants can be stored, but it seemed like they all had roughly the same ability at retaining the lubricant.

I'm really happy with sleeve bearing, I guess I just assumed anything that wasn't called a sleeve bearing would be a lot more different. To me they all look like sleeve bearing with a fancy name with the exception of the few with ball type bearings. I'm also really not seeing any noise differences..seems like noise comes down to the blades and motor...all the bearing types seem to do just fine although you can hear ball bearings a bit.

[Church]

Simpliest type of FDB looks Very much like sleeve (Fig.25.1). Rotating shaft + specificly to working temps selected viscosity-wise fit lubricant .. shaft kind of climbs/lifts up on that lubricant film resulting in not touching bearing at all. But such seems to work only in vertical position, in horizontal it will work like normal sleeve bearing? Big pile of theory. Mention of complex selection of lubricant.

Of course there are other types of fluid bearings like in hard disks or other devices with other means of pumping lubricant between surfaces, but that seems not the case for fans (2nd pic in this article)?

Hmmm. Hmmm? I wonder then why i've heard many times that FDB bearing fans are as good as ball bearing in horizontal position aswell, unlike sleeve bearing fans?

EDIT
I'm kind of lost. I'd love to hear comments from some engineer with more in depth knowledge to describe main principles/differences of sleeve vs FDB into simple words. And especially i'm interested in practical results of FDB fans in horizontal mount position. I wonder also if many spec-ed fans as 'sleeve bearing' ones are in reality with hydrodinamic bearings?

[Martinm210]

Simpliest type of FDB looks Very much like sleeve (Fig.25.1). Rotating shaft + specificly to working temps selected viscosity-wise fit lubricant .. shaft kind of climbs/lifts up on that lubricant film resulting in not touching bearing at all. But such seems to work only in vertical position, in horizontal it will work like normal sleeve bearing? Big pile of theory. Mention of complex selection of lubricant.

Of course there are other types of fluid bearings like in hard disks or other devices with other means of pumping lubricant between surfaces, but that seems not the case for fans (2nd pic in this article)?

Hmmm. Hmmm? I wonder then why i've heard many times that FDB bearing fans are as good as ball bearing in horizontal position aswell, unlike sleeve bearing fans?

EDIT
I'm kind of lost. I'd love to hear comments from some engineer with more in depth knowledge to describe main principles/differences of sleeve vs FDB into simple words. And especially i'm interested in practical results of FDB fans in horizontal mount position. I wonder also if many spec-ed fans as 'sleeve bearing' ones are in reality with hydrodinamic bearings?

Interesting, sounds like Hydrodynamic and Sleeve are used synonymously. Sort of what I figured...

Regardless, I'm going to give the assumed horizontal + sleeve bearing = fail myth a try myself. I've run Yates for 2+ years in vertical without any problem, and I just installed 3 horizontally in my kids budget build pushing up through an MCR320 mounted in the top of the case. Not a huge sample, but I do plan to run them this way for as long as they last...

One week down, two years to go.

Anyhow, I guess I'm not generally too concerned with sleeve bearings, they seem to work just fine at least vertically, although some fans with ball bearings do seem to have lower resistance as indicated by their lower power consumption.

It almost seems like power consumption per CFM is actually a pretty good indicator of noise. If it's not energy is not lost through heat, it must be noise or vibration.

I think I'm going to look at power consumption more closely this next round.....thinking CFM per Watt is more important than we've been giving it credit.

Anyhow, looking forward to starting in on some testing. I'm going to probably do this in mini groups of 6-8 fans at a time (depending on how smooth/quickly the tests go), each of which will include the D12SM12 as a calibration check.

Not sure which ones will show up first, but the first at the door get tested.. and I'll retest the old fans as I have time or gaps in new fans coming in. I'm also going to do the MCR 120 scenario first, then the others depending on how it's going.

[Martinm210]

FYI, received two shipments in today...felt like Christmas...

Special thanks to Shazza for 6 new fans...she even let me pick them out myself..

Also Gabe for the brand new MCR120, going to use the Swiftech MCR120 radiator for all the new fan testing..It is wider and should represent the optimal low resistance radiator test..
The RS120 is a bit narrow so the edges of the fan get slightly obstructed. The extra width of the MCR provides a cleaner mount and larger area should mean very low air pressure drop.

And for the first two retested fans, I've selected the Yate Loon D12SM12 and GT15.

Going to start testing these this weekend, but in the mean time I'll work on some unboxing pics..

[Martinm210]

Got the MCR120 all unboxed and ready for testing. This should provide some good improvements to lowering the air pressure drop and minimizes the shroud conflicts with the air flow path.

It's been a while since I had a new MCR, and I like the new changes. The packaging is very performance/business style. Everything is there for a performance purpose with no waste in fancy packaging printing...I like that. Also like the logo imprint on the sides and more satin black paint finish.

Got it all mounted up...ready to roll..

[Brodholm]

Great stuff Martin!

Really looking forward to the new testing with this equipment!

[BrokenArrow]

I never understood why manufacturers could not shift the screw hole locations over just 1/8" more in either direction to avoid puncturing.

[Martinm210]

I never understood why manufacturers could not shift the screw hole locations over just 1/8" more in either direction to avoid puncturing.

I think it's because the copper folds are standardized and meant to fit between flat tubes that are spaced at 1CM increments, and if you want the same number of pass 1 channels as the return pass 2 channels, you get a nearly perfect alignment with screw holes.

So it's a trade off, balanced channels vs potential water channel conflict and most choose to make the rad evenly balanced and centered on the fan as would I. About the only practical option is to include some sort of protector like Koolance does, but then again that's blocking a little air flow so it's trading a little bit of performance for protection. Then you have the added cost.

I'd leave them as is, and provide the right screw lengths...which most do.

After making the mistake once, I am very careful anytime I'm using custom screw lengths..

[the finisher]

Just got home
San Aces shipped tomorrow

[Martinm210]

No rush, take your time...very much appreciate all the support...

I'll start a new working thread on this, this thread was more of a fan list thread and I'm sure now that I'll go ahead and retest everything I have on hand.

[shazza]

Glad the fans made it safely, Martin!