Why TMD/ hubless fans are a gimmik

Why TMD/ hubless fans are a gimmik *Real Data

I'll say what I've said before about them:

They're underpowered
They don't keep up in airflow
*They really don't decrease the dead zone for all intencive purposes

*Take special note of that.

What you people don't seem to know, or don't place any relevance in is the fact that 80%+ of the airflow comes from the last 30%- of the blades for our fans and their designs.

The simple fact that it has blades going down the middle farther would make you think it puts more air there now wouldn't you? That fact is correct. Where you all get incorrect is that there is very little air moving there...

Enough on the TMD fan's! Overpriced and yall keep getting sucked into them, and it kills me... LoL too funny!

Hey check this out! We're all about to learn the calculation for propeller tip speed!

Formula taken from an article I have for propeller's.

Prop Diameter X Pi / 12 X RPM X 60 / 5280 = Tip Speed in MPH

We'll do my Raptor .46 CU screamer, a TD .051, a Satio 180 and the TDM fan. Why? Because If I'm doing math, I'm doing everything I want to know at one time LoL! Besides... It'll make good conversation at the field...

A) Tip speed
B) Speed 1" down the prop/fan
C) % B is to A

TD .051 with a 6*3" prop @ 32,000 max RPM manf data. Both my tachs top at 30,000
A) 570.90...
B) 95.152 MPH
C) 16.7%

Raptor .46 with an 11*5" @ 17,300 RPM Tached
A) 565.854 MPH
B) 51.441 MPH
C) 9%

Satio 180 with an 18*9.5N @ 11,500 RPM Tached
A) 615.511 MPH
B) 34.195 MPH
C) 5.6%

TMD 70mm blade @ 5,800 RPM Review/manf. data (4.375")
A) 75 MPH
B) 17.246 MPH
C) 22%
* start of actual blade; speed calculating 5mm diameter.
The hub is suppose to be less than 5mm/0.3125 So I'm spotting it some...

5.91 MPH

Read it and weap...

Also keep in mind the TMD fan is of less than average hight. So the blades don't have the same chord wiedth as a normal fan...

This can partially be made up with a higher pitch and a higher lift aerofoil shape of the blades. Alias it can't keep up air movement wise with a 60mm fan at the same or greater rotation speed.

Unfortunaly no computer fan amker has keyed on a more aerofoil shape to their blades yet... They may never... Maybe one day they'll learn about that concept too...

Don't think that'll help much, it wont, but it would be a small gain for nothing more than a new mold design... That's like nearly free gains the way they change molds every now and then...

Wow, I got 6 stars before I moved these from the other thread LoL!

Why Use The Tip-Magnetic Driving Fan (T.M.D. Fan)?
Tip-Magnetic Driving Fan (T.M.D. FAN) relocates motor from traditional location of central hub to the 4 corners.
COOLING POWER
It reduces 75% of traditional motor hub area. This revolutionary breakthrough not only increases 30% of airflow and static pressure, but also brings air stream directly to the centralized heat source. As a result, T.M.D. FAN improves the efficiency of heat dissipation at least 15%.
POWER CONSUMPTION / TORQUE
Locating motor at 4 corners substantially expands the room for winding. Thus, lower power consumption can be easily attained. At the same time, the torque of motor becomes even much more powerful than ever.
ACOUSTIC NOISE / BALANCE
The tips of fan blades are the main source of noise when a fan is rotating. The magnet of T.M.D. FAN surrounds along the tips of fan blades. This "tip-magnetic" design eliminates the major noise source of an impeller and provides the suspended balancing force when impeller is rotating.

What you posted <look up>
What I read:
Blah blah blah, Manufactring BS, Blah blah blah...

I don't meant o be harsh, but that's nothing but marketing bull.

Don't bring up HP/Tourqe ratings, that is nothing but market positioning bull... No fan on the market has a problem with generating power to spin exactly where they want that fan rated...

ACOUSTIC NOISE / BALANCE

That's a load of horse crap too... It prouduces less sound because the blades are so thin...

Has anyone ever thought that their blades are so thin because maybe the motor tech couldn't spin a 70mm fan assembly of a "standerd" depth?

That's just speculation on my part.

COOLING POWER
It reduces 75% of traditional motor hub area. This revolutionary breakthrough not only increases 30% of airflow and static pressure, but also brings air stream directly to the centralized heat source. As a result, T.M.D. FAN improves the efficiency of heat dissipation at least 15%.

Check the fan rotiation speeds at 1" and 5mm I posted on the TMD fan. Then post that marketing stuff again...

Nope

I just know a quailty design of heatsink and a great fan when I see one.

The rant is on the fan, the sink is good...

You know I could improve the "effeciancy" of any computer fan by on average 300-450% on any fan currently made...

Chop off all but one blade and counterbalance it on the other side.

Maybe next retort come up with some facts of your own to disprove why the differance between the tip speed of the TMD fan is 57.246 MPH faster than the speed 1 inch away from the middle.

Only THEN can you explain how on Earth König Wunder Anhänger is suppose to move air right next to the hub... It spins at 5.91 MPH...

That isn't enough to MOVE air... That dosen't even have enough OOMPH to move air 5mm, let alone more than an inch to the bottom of the viens...

A 69.09 MPH differance... 90% of the air comes from the last 1/3 or less of the diameter of the fan. Just accept the facts

What is wrong with this picture???

Quality huh, if it was quality you wouldnt be worried about all this happening, I quote YOUR reply to my question.

"ME"
So y dont you turn that function off, cant you turn it off disable it? You can have MBM do the same thing at a "higher" temp if you can.

"YOU"
Yeah I could turn the feature off but im not insane! This thing is overclocked like a mother and if my Aerofllow's TMD fan were to stop or the HS fall off I would be out a CPU that is more expensive to replace then a POS mobo. Turning it off is not an option.


"If my Aerofllow's TMD fan were to stop or the HS fall off I would be out a CPU that is more expensive to replace then a POS mobo."


fan stop or HS fall off sounds like you have 2 pieces of junk if you have to worry bout either.

One, I have an 80mm panaflow, I NEVER worry bout it quitting I leave my pc on 24/7, WITHOUT the temp safety option on.

Two, I never worry bout my HS FALLING OFF.


it must be pretty bad if you are always worrying about those things especially number 2.

I'M sure nearly eveyone in heres says they dont worry about there fan stopping unless they have a tmd or a SF2. The fan is junk, and has little to know performance advantage even if it had any which I highly doubt it does, cause I know how a fan works.


Folks get any fan but this one, it has only one person backing it up and I think he is lucky his fan still works . The reasons for this is because they offer little to no advantage, the same amount of noise, and WAY less reliability, if you cant rely on it then it is worthless. chasingapples im not trying to offend you, im just saying the fan is unreliable, which it is and I'd have to say you were being stubborn if you didnt aggree and what they say about there fan on the box or on the site is a bunch of marketing bull, because none of it makes the fan perform better smaller hub dont matter and cutting/flattening (whatever it is called) off the tips will only make it perform worse.

Several posts in this thread are approaching (or have reached) flaming. You know who you are. Please clean this up and have a rational discussion.

-- Paul

I still love you mack! Well lemmie edit and delete some then

sorry

just in response to your calculations, they are wrong. prop diameter is the distance from one tip of a fan blade across the length of the fan to the other tip

the size of the core is irrelivent.

basically the speed in MPH is directly proportional to the RPM and size of the fan

basically a tmd fan and a panaflo both at the same rpm will have the tips of the fan blade moving at the same speed.

what that formula does is calculate the circumference of the circle the fan blade must travel. that gives you a distance. then multiply it by how many times per minute the blade makes a circle and that gives you

distance/minute

divide by 60 and that will give you distance/hour

give that distance whatever unit you measured it in.

i think you screwed up somewhere. not a flame, just a correction

edit: it follows that a 120mm fan at 3500rpm will have fan blades moving faster than an 80mm fan at 3500rpm

BUT: all fans at 80mm running at 3500rpm will have the same prop speed assuming manufacturers keep blade length standard

@Toysrme:
Thanks you!

@big_bertha:
I think you've raised some interesting points. One might also keep in mind that the fan blade's linear speed at any given distance along the blade gives an upper bound on the airflow speed emanating from the fan. It doesn't necessarily follow that it will indeed be the airspeed at that point. Case in point: The tips of the fan move the fastest, but the speed of the flow is not at a maximum at those points.

-- Paul

just re-read

it sounded like i meant the math was wrong. its not (or it could be. didnt check). your assumption is though.

i went through the calculation for the benifit of others with no physics knowledge

basically what i am saying is that you cant put a 70mm fan against an 80 or a 92mm fan since the diameter is different

you cant compare apples and oranges


macklin: good point about the effectiveness, but getting an extra 10cfm is not an issue of effeciency.

if it was a max/min prob with noise then yes, but lets say you double speed to get an 85% increase in airflow. that is fine so long as your bearings/assembly can handle the rotational speed.

also, the smaller you get you should be able to go allot faster with a tmd style fan (sub 40mm) since there is such a small moment of inertia and the magnet tips will keep the blade stable at very high rpm. imagine an electric motor. at that size you could almost circle the entire fan in windings. wow. that would make a good 5 1/4 hd cooler fan

I was putting a 70mm fan against some R/C engines I have.

You'll note there is no relevance there, it's not even implied there is any.

BTW The math may be a few tenths/hundredths/thousands off here and there. I was tired then and never really decided where I wanted to round the numbers. hahahahahahaha

That wouldn't make an impact that changes anything said implied or true though...

Prop Diameter X Pi / 12 X RPM X 60 / 5280 = Tip Speed in MPH

I found the same referance online when I did a search.
Duh I should have done that in the first place instead of digging out old mag's!

You can obviosuly plug in any diameter and find the rotation speed. That's what I did. The point is to show how huge of a differance there is between the outside and the inside. Apparantly some people either don't realize there is one, or don't care.

Intresting idea with the sub 40mm's. Maybe they should go do that LoL! Yeah, might as well be spinning a fly wheel with the magnet's on the tips. That's why they sound "jet like". Longer spool up and down times.

Went to bed and just woke up realizing I did the calcs for the TDM fan wrong...

Duh, the prop ratings are different, so I forgot to divide the TMD fan by 2. Not something I had to do on the others. So that puts the tip speed off.

So here's the correct math:
Tip speed = 37.73 MPH
Speed 1 inch from center = 17.26
Speed 5mm from center = 5.39 MPH
The 5mm speed is still only 14.2857142% of the tip speed.
I also rounded to the 10th decimal. Cause that's what this calc showed

The math was wrong, but the point stays the same. Virtually no air is moving at that location.

Toysrme said:

The 5mm speed is still only 14.2857142% of the tip speed.

Click to expand...

...maybe that's where they're getting their 15% increase in performance specs from.

...the design is intriguing(sp), however, it would never match that of an efficient blower.

-Frank

ya looking at the specs for the PCI slot blower at SVC it pushes 40some CFM at 20 some DB in a small compact package only drawing 1.44W. This is impressive, i like the blower idea. And i will do an experiment aobut the center hub space with real world performacne. The TMD haters always asrgue the aeroflow is so good because of the HS designg-the TMD supporters say is so good because of a design for the TMD fan. Im getting an aeroflow because my memory will give up way before i hit a heat problem with any modern cooler (see sig-160 fsb now i want at least 167). When i get this im going to test performance with the TMD fan and then test performance with an imfamous delta black lable at 36 cfm and 47dba rateing. Since the black lable has a proportionally massive hub we will see if not having any air going down the central wind tunnel (as opposed to verry little according to the above calculations) makes a difference. The TMD fan is obviously a decent fan for the croud that doent mind fan noise but doesnt want a screaming black lable around (me and more importantly my mother who is partially funding this experiment-yes i conned her into giving me some money to get a new *quieter* heatsink)

http://www.svc.com/thersk6soca3.html http://www.svc.com/thfatmdfanad.html http://www.nexfan.com/70mmfans.html

Not a bad set-up for 20.00 bones...People still asking about them...So if they ask they will recieve...