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Turbine fans by Aerocool
Posted: Sun Apr 10, 2005 11:05 pm
Posted: Mon Apr 11, 2005 5:32 am
The marketing people clearly didn't think of SPCR when they wrote the product description.
The following is from the linked page:
new fan are engineered with a Double layer fan blade design for improved air pressure. These totally new fans feature a stylish turbine design
and a detachable turbine fan head.
new fans use 16 Fan blades, more fan blades then any other 12cm fans
in the market!
That being said, the actual details look pretty good:
Speed : 950+ - 10%RPM
Bearing : Sleeve
But I'm wondering, would this 16 blade design improve airflow? It only suggests "improved air pressure". And also would it shift the noise frequency to higher more noticable frequencies?
Posted: Mon Apr 11, 2005 5:35 am
Airflow is about 35 CFM which is close to the Nexus, which has about the same RPM.
Posted: Mon Apr 11, 2005 5:47 am
cansan wrote:But I'm wondering, would this 16 blade design improve airflow? It only suggests "improved air pressure". And also would it shift the noise frequency to higher more noticable frequencies?
More pressure is good
Fans have a P-Q curve like all fluid pumps, and can move more air through a restrictive environment (such as a heatsink) with a higher pressure impellor.
ie more air for your dB dollar, assuming the specs are honest of course.
Posted: Mon Apr 11, 2005 6:02 am
Sounds like something Fry's would carry, you think?
*schedules a visit to Fry's* ;P
Posted: Mon Apr 11, 2005 9:36 am
here's the official site
. sure are ugly (to me anyway).
eh, if they ever go under $10 i'll get one.
Posted: Mon Apr 11, 2005 9:37 am
I just noticed the fan at a review here: www.mikhailtech.com review
and dropped by here to see if anyone had posted it. I think I found the link to the review from TechReport, but I don't remember.
A pic of the chrome version:
Yeah, I was thinking pressure too. Imagine if they came out with a 38mm version. :drool: Small hub, high blade count, <1000rpm, looks like this could be a really nice heatercore fan, much less case fan. They look pretty cool too. The Al Evercools just got some serious competition in the bling, quiet sector.
Resellers here: http://www.aerocool.us/where.htm
Posted: Mon Apr 11, 2005 10:03 am
The interleaved fan blades *MAY* allow for sound waves to cancel each other (the tail rotor of the Apache uses the technique).
The new Turbine is available in the UK at Tekheads, listed specification:
Rated Voltage: 12 VDC
Operating Voltage: 10.2-13.8 VDC
Air Flow: 37.44 CFM
Static Pressure: 0.035 Inch-H2O
Input Current: 0.25A (max)
Input Power: 3.0W
Speed: 950+ - 10%RPM
Noise: 19.66 dBA (Condition: background noise lower than 17.0dBA)
Operating Temperature: -10C to +70C
Notice you can't undervolt it much, I wonder why?
Posted: Mon Apr 11, 2005 10:30 am
Remember the rule for fan specs. They can be untrustworthy. Even Panaflo, which has reasonable fan specs lists their fans as only going down to 7v.
Posted: Mon Apr 11, 2005 12:16 pm
sthayashi wrote:... Even Panaflo, which has reasonable fan specs lists their fans as only going down to 7v.
Hmm? None of my 12 Panaflo 12L 80mm fans go below 7V... This is using a sunbeam 5.25" fan controller. However, my 1 92mm M1BX goes down to about 5V.
Posted: Mon Apr 11, 2005 12:37 pm
I got in a stock of 10 Japanflos from Jab-tech a while back and of about 5 that I tested, they all ran at 5v. :shrug:
Anyway, looking forward to hearing some personal testimonies of this Aerocool fan.
Posted: Mon Apr 11, 2005 12:44 pm
I've never had an L1A that doesn't start at 5v, and I've had plenty. Tiamat, are you sure about the voltage, there's no real accurate way to judge just from the knob on the controller.
Posted: Mon Apr 11, 2005 12:54 pm
Well after wasting an hour driving back and forth, Fry's doesn't have it.
ALTHOUGH i got a spiffy firewire/usb enclosure to test out, bwahahah...
Posted: Mon Apr 11, 2005 1:38 pm
sthayashi wrote:... Even Panaflo, which has reasonable fan specs lists their fans as only going down to 7v.
Hmm? None of my 12 Panaflo 12L 80mm fans go below 7V...
I believe sthayashi was referring to the fact that on Panaflo's spec sheets, their P-Q / N-Q plots typically have curves from 13.8V, 12V, 10.2V, and down to 7V (or double those values for 24V fans). The operating voltage in their Basic Data table is 7-13.8V.
Posted: Mon Apr 11, 2005 4:36 pm
I was referring to that and the fact that all my Panaflos have hit 5v with no problem (much like Rusty's experience). Tiamat's experience is a first for me.
Posted: Mon Apr 11, 2005 6:38 pm
is, by definition, pretty much the opposite of a fan
Posted: Tue Apr 12, 2005 12:29 pm
Yeah, it is a little bit of an misnomer. When I first saw the reference to it, I thought it was a perhaps a screamer or a blower. I guess they are trying to appeal to the silent freeks in the know, while at the same time attract the dude browsing though the computer retail store.
Posted: Tue Apr 12, 2005 10:08 pm
To my cynical mind, these look
like they are designed mainly to look like the turbine fans on a jet engine (mass market appeal) rather than for any silencing benefit (niche market appeal). Particularly when you see a "features" list like this:
2. Stylish turbine design. - the bling factor appeal
3. detachable turbine fan head - it's only there in the first place to look good!
5. 16 Fan blades! More fan blades then any other 12cm fans in the market! - so what?
But if it actually performs well too I'll be pleased!
Tzupy wrote:(the tail rotor of the Apache uses the technique)
I certainly hope it's quieter though!
Posted: Wed Apr 13, 2005 12:04 am
The noise reduction may work if the two blade layers are at a certain angle. This applies to air noise, not motor or bearings noise anyway. Don't ask which angle, I don't know, but I have thought about this configuration more than a year ago. I wanted to experiment with two 120x25 mm fans and see what happens at various angles. But I couldn't think of a way to synchronize the fans (to maintain the angle at operation, since the two fans wouldn't spin at exactly the same speed) and the two fan combo would be 50 mm thick and unusable in any case I know, so I dropped the idea.
It will be interesting to see if these fans can maintain good air pressure at low speed, this seems to be a problem with most conventional fans.
Posted: Wed Apr 20, 2005 11:38 pm
So, anyone get any and have comments?
Posted: Sun Apr 24, 2005 6:45 am
I wish I understood "fan dynamics" so I knew the tradeoffs of blade count, blade size, and blade angle.
This fan will have a base motor noise frequency of about 16 hz (950 rpm = 15.8 rps). 16 blades at 950 rpm will generate some kind of sound at 253 hz. A 7 blade fan at the same speed will generate some kind of sound 111 hz.
The point is that this fan, because it is slow, will generate a very low frequency vibration from the motor. 16hz is generally considered subsonic and in a range that we can't hear. We can feel those sounds but not hear them. The higher blade count will generate a higher frequency noise than a fan with fewer blades. 253 hz is in a very audible range, probably more so than 111hz. I can't predict whether this fan is noisier or not. If the air flow is indeed better as Aerocool claims - the fan could be slowed down to reduce motor noise even more.
I don't know about the noise cancellation ideas. My first thought is there is no reason to expect cancellation. Cancellation (ala Bose headphones) occurs when sounds of opposite phase are present. They will cancel each other out. I'm not sure how this fan blade design can achieve that.
Definitely seems like a fan worth testing.
Zipzoomfly.com has them for $18.99.
Posted: Sun Apr 24, 2005 7:43 am
hofffam wrote:This fan will have a base motor noise frequency of about 16 hz (950 rpm = 15.8 rps). 16 blades at 950 rpm will generate some kind of sound at 253 hz. A 7 blade fan at the same speed will generate some kind of sound 111 hz.
This is bad news if you ask me. 250hz is pretty close to the speech range where human hearing is much better. For the same dB
at 111Hz and 250Hz the one at 250 would translate to a higher dBA
If this fan had to run at a lower speed to give the same airflow as a 7 blade fan, it would be great. But look at the specs:
Nexus 1000 rpm 37cfm
Turbine 950 rpm 37cfm
The difference is very marginal, in my opinion. Worth a look, I think; but I very much doubt 16 blades will do anything significant.
Posted: Sun Apr 24, 2005 8:36 am
this is something from biology, but the ear has special ability to hear voice levels that arent at all as easily impaired when compared to bass and treble levels of sound. So, anything in the talking range is difficult to not hear even at lower levels. I duno if anyone ever heard of this. pun intended
Posted: Sun Apr 24, 2005 10:29 am
The higher blade count will generate a higher frequency noise than a fan with fewer blades. 253 hz is in a very audible range, probably more so than 111hz.
Wouldn't that mean that thicker fans with fewer blades, I'm guessing 38mm and 5 blades, or 50mm and 3 blades, would be a dead easy way to make a fan, any size fan, much quiter?
Posted: Sun Apr 24, 2005 2:30 pm
sthayashi wrote:Remember the rule for fan specs. They can be untrustworthy. Even Panaflo, which has reasonable fan specs lists their fans as only going down to 7v.
I wouldn't say 'untrustworthy', rather that the fan is guaranteed
to work at X volts, anything lower is a bonus. If the fan won't run at 6V it may be cause to moan, but not cause to RMA.
Interesting spec - I've found Aerocool honest on noise numbers as far as I can judge (though they do tend to go for the bling factor rather than quality IMO) so look forward to comments on the real thing.
Posted: Sun Apr 24, 2005 2:41 pm
el jefe - not exactly sure what you said. I think you meant that humans hear midrange better than bass and treble. If so - that is correct. This non-linear effect changes for different volume levels. We hear bass and treble even worse when the levels are lower.
I tend to agree with cansan. 250 hz is a worse frequency range than 111 Hz.
Mathias - you might be right about a thicker fan with fewer blades. 5 blades probably doesn't work well in a 25mm fan because they would probably be angled relatively flat and have low movement of air. A 38 mm fan would allow a steeper angle with a much larger blade.
Posted: Sun Apr 24, 2005 3:46 pm
mathias wrote:Wouldn't that mean that thicker fans with fewer blades, I'm guessing 38mm and 5 blades, or 50mm and 3 blades, would be a dead easy way to make a fan, any size fan, much quiter?
I think so too. Maintaining the same airflow numbers with a thicker fan, either reduce the number of blades OR reduce the speed of the fan.
Posted: Sun Apr 24, 2005 4:26 pm
Reduce the fan speed? I think if thicker fans gave much better CFM's, then they'd be much more common. Since they hardly ever make 25mm thick fans with more than 7 blades, or 38mm fans with more than 5 blades, I'm assuming they don't benefit much from anything more. 50mm and 3 blades is just a guess, maybe a 50mm fan would need to have four blades / maybe a 3 blade fan's optimum thickness would be more.
BTW, does anyone know why PC fans never have an even number of fins?
Posted: Sun Apr 24, 2005 9:25 pm
i've read it is for acoustic reasons... when there are blades directly opposite sides then the tendency to beat with the surroundings is increased - eg. if there was a vertical obstruction nearby then both the top and bottom blades would sweep past it at the same time
probably if the frame geometry was triangular and not square then an even number of blades would be preferable (but if you look at, say, a panaflo then the hub is held onto the frame by FOUR bars)
Posted: Mon Apr 25, 2005 12:30 am
These do look interesting fans - I have one on order and will report back once I get hold of it - currently I am running a Nexus 120mm and a Panaflo 38mm 120mm so will be good to compare this fan with these two highly regarded fans.