New fan blade design - owl like

spookmineer · Post by **spookmineer** » Tue Mar 13, 2007 3:43 pm

According to this article, a new fan blade design, based on the wings of an owl, booked very good results.

The blades are developed by engineers from KÃ¼nzelsau (Germany).
Joachim Dietle: "The owl is the bird with the least wing noise" (this is true, mice can't even hear them approaching).

I have no idea how they incorporated the shape or other parameters into a fan blade.
The fan blade does have toothed sides.

Claimed results of the 80 cm (!) fan: 10% higher efficiency, and half as loud as the competition.
The fan was built with climate control and cooling technique (general) in mind, but could ofcourse be reduced in size to fit a PC.

I'm very sceptic but it sounds interesting.

thejamppa · Post by **thejamppa** » Tue Mar 13, 2007 4:12 pm

I am affraid those small tooths might create higher pitch sounds which is worst kind of noise for me... But that really looks intresting concept. I hope guys talk is not just commercial talk.

Fan blades look bit mean though, let's hope they're as effective as they are claimed. And I think, owl's silent flying is based more on soft feathers on wings than actual geometrical shapes of birds wings, even correct aerodynamic shape is important to reduce air resistance and turbulance and noise comming out of those.

So I am predicting either that fan blade design is very quiet or then its very loud. Its either end of opposite ends. I don't know why but I just think so.

Post by **NeilBlanchard** » Tue Mar 13, 2007 4:19 pm

Hello,

It is also interesting that the base of the blades where they attach to the hub are also very unusual.

Of course, the proof is in the pudding, so to speak -- but this fan has a tantalizing design.

JazzJackRabbit · Post by **JazzJackRabbit** » Wed Mar 14, 2007 6:21 am

It's interesting to see how in the last few years we saw so many new fan blade designs. For decades the only two shapes we had was traditional Nexus/YL shape (with very minor variations) and oddly shaped Panaflo 12cm 5 blade design. Recently however we saw sharkoon fans with golf ball texture, noctua fans with high angle blades and now this one. Very exciting to finally see some progress in fan blade design. I'd like to see this made into a computer fan 80/92/120mm design.

Chris Chan · Post by **Chris Chan** » Wed Mar 14, 2007 6:41 am

Looks like a very interesting fan blade design, and I'm not even an airflow scientist (word?). Basing it off an owl's wing seems natural, but I don't know the effects of rotational movement versus flapping. And 80cm is the next computer fan! 80, then 120, then 220, now 800 mm fans -- the latest fad.

J. Sparrow · Post by **J. Sparrow** » Wed Mar 14, 2007 9:42 am

Not really surprising, they noticed that we are buying fans at several times their fair price only because of the way they sound.

So I wonder, is it real technical progress or it's just 'marketing strikes back' ? Noctua fans (and their mythological austrian fan istitute) are a perfect example of this dilemma

Felger Carbon · Post by **Felger Carbon** » Wed Mar 14, 2007 10:17 am

JazzJackRabbit wrote:Recently however we saw sharkoon fans with golf ball texture, noctua fans with high angle blades and now this one.

Style, like Caddy tail-fins. Doesn't mean a thing, but it sells. If it sells enough, everybody copies.

Bluefront · Post by **Bluefront** » Wed Mar 14, 2007 11:08 am

This thread is funny in that I recently watched a program on bird wing design......it explained the differences among many bird wing variations. And it did explain the reason the owl can fly silently.....it's the feather design, specifically the trailing edges. Similar to this fan, the trailing edges of the feathers are soft, separated to break up the turbulence at the edge. If this fan design actually works anything like an owl wing, we'll have a silent fan. But I doubt it.....

MC FLMJIG · Post by **MC FLMJIG** » Wed Mar 14, 2007 11:12 am

I have to say if it works it really is a cool looking design. Window cases with a bit of bling would look nice.

Now what is price?

jaganath · Post by **jaganath** » Wed Mar 14, 2007 11:58 am

Felger Carbon wrote:
JazzJackRabbit wrote:Recently however we saw sharkoon fans with golf ball texture, noctua fans with high angle blades and now this one.
Style, like Caddy tail-fins. Doesn't mean a thing, but it sells. If it sells enough, everybody copies.

So I wonder, is it real technical progress or it's just 'marketing strikes back' ? Noctua fans (and their mythological austrian fan istitute) are a perfect example of this dilemma

Noctua fans have been recommended by SPCR, and the Sharkoon Silent Eagles have been very positively reviewed by Madshrimps (in comparison to SPCR top performers like Noctua and Globalwin NCB); in this case it seems it's not just marketing, they really do put out less dB per CFM. I was sceptical too, but I recently got a Silent Eagle 1000 8cm and it really is all but silent at full speed.

So we're right to be sceptical, but there's nothing in the laws of physics that says you can't design a more aerodynamically efficient fan blade. And it seems like Noctua and Sharkoon have done that.

JazzJackRabbit · Post by **JazzJackRabbit** » Wed Mar 14, 2007 12:19 pm

Felger Carbon wrote:
JazzJackRabbit wrote:Recently however we saw sharkoon fans with golf ball texture, noctua fans with high angle blades and now this one.
Style, like Caddy tail-fins. Doesn't mean a thing, but it sells. If it sells enough, everybody copies.

I never said style, I said design. Those two are different.

Nevertheless J. Sparrow raises a valid point, are those fans really quiter than nexus or are they just thermaltake-like PR gimmipicks?

On the other hand, if they are indeed quieter, I don't really see the problem of paying 3x the price. I mean we already pay $15 for nexus, so if this fan will be quieter, paying same price for quieter fan sounds like a win-win scenario. But, I bet it will be a while (if ever) for this fan to come down to computer size and be readily available.

blubberhoofd · Post by **blubberhoofd** » Wed Mar 14, 2007 1:49 pm

hi,

I expected a design more or less like this after I saw a program on helicopter rotor design. The trailing edges seem to be directly copied from avionics not ornithology

jhhoffma · Post by **jhhoffma** » Wed Mar 14, 2007 3:08 pm

blubberhoofd wrote:hi,

I expected a design more or less like this after I saw a program on helicopter rotor design. The trailing edges seem to be directly copied from avionics not ornithology

Maybe you mean aerodynamics? Avionics would be the electronic control system of the aircraft. But I would say that the aerodynamicists copied nature, instead of the other way around...

blubberhoofd · Post by **blubberhoofd** » Wed Mar 14, 2007 10:45 pm

lol,

you're right, got my defenitions mixed up there.

aerodynamics copied nature for a long time. These days the research and development for small companies is not much more than to copy your compettitors product. This is why I like to see a company that looks into more distantly related technology. They probably never saw an owl during the whole R&D proces, all that study was done waaaaaaaaaaaaaaay before by others and it was already translated in aerodynamic design by other engeneers

But as always you should not allow your marketing department to make whacky claims.

roadie · Post by **roadie** » Thu Mar 15, 2007 2:10 am

The serrations at the rear of the fan blades are likely to be vortex generators. You can often see these on F1 cars, where they are known as Gurney Flaps. Their primary purpose is to reduce drag so the design could be good for low noise operation. However, how much time this fan has spent in a wind tunnel is anyone's guess!

jaganath · Post by **jaganath** » Thu Mar 15, 2007 4:45 am

I found a post by our very own frankgehry on the subject:

viewtopic.php?t=27427

Whirl pooling:
This is a broadband noise source generated by air separation from the blade surface and trailing edge. It can be partially controlled by good blade profile design, proper pitch angle and notched or serrated trailing blade edges

The actual JMC page that that quote is from: http://www.jmcproducts.com/cooling_info/noise.shtml

Comair Rotron do loads of fans w/ serrated trailing tip edge:link

so it's not unique.

Aris · Post by **Aris** » Thu Mar 15, 2007 6:06 am

if you think about it, other than motor noise from the hub, there are only 3 other points that i can think of on a standard fan where wind noise can come from.

1. from cross braces to hold the hub in place as wind passes over it.
2. from the leading edge of the fan blade as it cuts through the air.
3. from the trailing edge of the fan blade as the air collides back into itself.

Ive only seen 1 fan try to eliviate the first point. i forget where, but it basically suspended the fan with magnetism from the edges of the casing, and used that magnetism to rotate the blades. Seems like a good idea to eleviate this point of noise, but i havnt seen many companies adopt this technology.

the second point is really hard to completely remove as a source of noise. Most common way i know of to deminish this type of noise is to increase the blade count. I know in helicoptor blade designs, those aircraft with only 2 blades makes significantly more noise from the leading edge of the blade (thud sound) than with aircraft with 4 or more blades.

it seems like this technology is really tackling the third point. When the air comes clashing back together after the blade pass's through it. Its a promising idea to help reduce this type of noise, but i honestly cant remember any other instance of blade design that tried this type of aproch to eleviate this noise source. So i would be skeptical of its usefullness until i actually saw side by side testing of it with a more traditional fan blade design.

jhhoffma · Post by **jhhoffma** » Thu Mar 15, 2007 10:41 am

Aris wrote:the second point is really hard to completely remove as a source of noise. Most common way i know of to deminish this type of noise is to increase the blade count. I know in helicoptor blade designs, those aircraft with only 2 blades makes significantly more noise from the leading edge of the blade (thud sound) than with aircraft with 4 or more blades.

I think I remember hearing about his in respect to the design of the Commanche helicopter. That more blades equals less noise, but there is a point at which the areodynamic resistance to the blades in forward motion make too many blades unworkable, as they become less efficient.

Even the Russians with their huge helicopters maxed out at eight blades...

Kremmit · Post by **Kremmit** » Thu Mar 15, 2007 8:17 pm

Aris wrote:Ive only seen 1 fan try to eliviate the first point. i forget where, but it basically suspended the fan with magnetism from the edges of the casing, and used that magnetism to rotate the blades. Seems like a good idea to eleviate this point of noise, but i havnt seen many companies adopt this technology.

That was the Y.S. Tech TMD (Tip-Magnetic-Driving) fan. There's a good look at the guts on one here: http://www.dansdata.com/tmdfan.htm

Too bad they were noisy as a roomful of coked-up howler monkeys with drums and kazoos.

psiu · Post by **psiu** » Fri Mar 16, 2007 2:23 am

Kremmit wrote:That was the Y.S. Tech TMD (Tip-Magnetic-Driving) fan. There's a good look at the guts on one here: http://www.dansdata.com/tmdfan.htm

Too bad they were noisy as a roomful of coked-up howler monkeys with drums and kazoos.

LOL!

andyb · Post by **andyb** » Fri Mar 16, 2007 6:03 am

Regarding Helicopters, I have previously heard of 2 designs of blade that reduce noise.

The picture below is of a Westland Merlin, note the tip of the Blade, this was added to increase stability as low levels (so the blades dont go up and down when taking off and landing which is of course dangerous), this had an unexpected side effect, it reduced the noise.

http://en.wikipedia.org/wiki/Image:M-509-merlin.JPG

And this rather interesing one, from the Eurocopter, a much higher number of blades that are NOT set at regular intervals.

http://en.wikipedia.org/wiki/Fenestron

I have no idea if such designs would in any way benefit a slow running computer fan, but they do benefit Helicopter noise.

Andy

PS: I just read to the bottom of the Wiki article and in mentions the Comanche, well done jhhoffma.

thejamppa · Post by **thejamppa** » Sun Mar 18, 2007 8:55 am

I wonder what next? Case fan with two counter-rotating blades? Still, personally as silent air cooler, any silent fan is intrest of mine. I have 120mm sharkoon with that golf ball blades. Even though its 2000 rpm version with whooping 33 to 40 d/BA rating at full speed, its amazingly silent when undervolted. I ordered 1000 rpm version but they got mixed up and I was too lazy to return it so I undervolted fan and it was suprisingly quiet @7 volts and very quiet @ 5 volts.

So yeah, special blade things work. But we all know it takes a lot time to plan something and before its availeble for retailing. But let's hope we get growing numbers of new type silent fans in future.

Even I am sceptical with this owl wing design, I'll keep my eyes open for reviews.

jaganath · Post by **jaganath** » Sun Mar 18, 2007 12:25 pm

I wonder what next? Case fan with two counter-rotating blades?

I think this would be noisier than a single rotor. CR blades are used in helicopters to eliminate the torque problem, not really an issue w/ PC fans.

jhhoffma · Post by **jhhoffma** » Sun Mar 18, 2007 3:51 pm

CR blades would be much louder due to the added turbulence. The Russian Tu-95 Bear (bomber) has counter rotating blades and are said to be the noisiest props ever made. I think Bell also developed a plane near the end of WWII that had CR blades that were excessively loud to the point where the pilots were getting sick.

Another benefit of CR blades, IIRC, was that the helicopter could hover in the same place longer without losing lift due to the pressure loss above the wings, but I can't recall that exactly.

jmke · Post by **jmke** » Thu Apr 19, 2007 9:16 am

jaganath wrote:I was sceptical too, but I recently got a Silent Eagle 1000 8cm and it really is all but silent at full speed.

I tested those back in August 2005; the 80mm are a different breed it seems:
http://www.madshrimps.be/?action=getarticle&articID=354

the 120mm did impress more, and are newer (took Sharkoon more than a year to come out with the 120mm version)

Felger Carbon · Post by **Felger Carbon** » Thu Apr 19, 2007 10:32 am

jmke wrote:
jaganath wrote:(took Sharkoon more than a year to come out with the 120mm version)

Aren't the Sharkoon 120mm fans a version of this Globe fan?

jmke · Post by **jmke** » Thu Apr 19, 2007 11:25 am

possible, look the same except for color

EndoSteel · Post by **EndoSteel** » Thu Apr 19, 2007 12:32 pm

jmke
Look closely at the frame and you'll notice a tiny stylized globe on one of the faces

.

jmke · Post by **jmke** » Fri Apr 20, 2007 12:33 am

found it:) next to the arrows which indicate airflow:)

charonme · Post by **charonme** » Tue Jun 03, 2008 10:14 pm

a year passed. do we have some actual fans?