Dyson's overpriced fan and the Coandă Effect | Hacker News Reader

Dyson's overpriced fan and the Coandă Effect

jgc.org

25 pointsjgrahamc21 comments

Give it a break.

> The Coandă Effect is very well known, and Dyson hasn't invented something revolutionary here

When someone does this to a startup, this place is ripe with "screw the idea, it's all about execution" and "any sufficiently advanced technology is indistinguishable from magic".

I salute Dyson for putting simple physics to work in simple, yet aesthetically pleasing fashion.

In other words, if it's so easy, why aren't YOU selling a £200 Coandă effect deskfan?

I think you are reading too much into that statement. The Coandă Effect was well known and all I claim is that Dyson didn't invent it. My other claim is the £200 is a lot for a fan no matter how cool the technology is.

In other words, if it's so easy, why aren't YOU selling a £200 Coandă effect deskfan?

I never claimed it was easy, you also edited my blog post to remove the bit where I say (although I assume the engineering is very good).

If the market will support it, £200 is not a lot for a fan ;)

Eh? That's like saying, "if the market will support it, $2000 isn't a lot for a pair of jeans." Just because enough people are willing to spend $2000 on jeans to keep the company in profit doesn't mean that they're not expensive.

Why aren't YOU selling a £200 Coandă effect deskfan?

Because there is probably no market.

But the real questions is, "why does a Coandă effect desk fan need to cost 200 quid?" Answer: because there's only one on the market.

There probably was no market .. I think Dyson's brand is big enough to have just created one though. That market is going to be hard to break into for anyone else IMO.

We've made something similar for industrial use. My understanding (given that we only do the machining) is that in an industrial setting they require loud compressors with much larger footprints... so the real engineering feat is probably the motor depending how loud these suckers are (http://www.engadget.com/2009/06/29/dyson-speeds-up-worlds-fa...)

The motor is interesting since it's a "digital" motor called a Switched Reluctance Motor: http://en.wikipedia.org/wiki/Switched_Reluctance_Motor

That's interesting; my best mate works for a company that constructs industrial SR Motors (I think they hold a lot of the patents too). They are crazy cool when you get into bigger sizes/voltages.

I think this might be the real story here. Google about and you will find articles from 2003 talking about this nifty 100,000rpm switched reluctance motor and impeller combination that Dyson's people were working on. I think the air mover is just an answer to "so what do we do with it?"

I still want someone to say what the air mover sounds like. 100,000rpm should put all of the sound energy above 1,500Hz, and higher frequencies are easier to damp, so it is possible the thing is quiet. On the the other hand, the ad copy doesn't say "SILENT!!!".

It's not overpriced, Dyson has to be quick making some money before the Chinese copy it and sell derivatives on every corner of the solar system.

Pricing it anythng lower wouldn't tie in with the Dyson brand. Could you imaging if they were selling these at £20, who then would want one? Everyone who needs a fan already has a fan. But if you have one of these £200 toys sat in your house, you're sure to look cool and feel cool with that fanless air blown in your face.

My personal favorite reference to the Coandă Effect involves urinals:

http://www.straightdope.com/columns/read/2450/urinal-101-aim...

http://ask.metafilter.com/8204/Urinal-Aiming#160007

The in/famous Dyson branding aside, I'd like to measure the fan's volumetric efficiency per watt compared to a conventional inline blade design.

In other words, how much air is moved at what speed given the electrical energy expended to drive the impeller.

I doubt seriously that it's much better than conventional fan designs given that it has 3 distinct regimes of airflow (intake duct, impeller blade, Coanda foil).

Additionally, though inline impellers can be quite efficient, having these 3 distinct vector flow regimes will bleed energy in de/compression inlet/exhaust artifacts (noise and vibration) so it won't be much quieter than a conventional design.

Ok, I found this video linked from their site, and I'm not sure if its a joke. Skip to when he turns the fan on, about 1 minute in.

http://www.youtube.com/watch?v=U1ZcpCY2O6k&feature=playe...

I think it's false advertising to say it has no blades. It uses an internal fan that you can't see to push air.

You're just being overly pedantic. To most people, it has no visible blades, and therefore it has no blades.

Sure, a more accurate wording would have been "no blades that you can stick your fingers in", but you can't expect too much out of marketing people!

Marketing people aren't dumb. They just know that consumers are. "No blades you can stick your fingers in" is accurate, but buyers want catchy and memorable, even at the cost of slight factual inaccuracy.

And that's how a quote like "the greatest piece of sh*t of a movie ever" becomes "the greatest... movie ever" in an ad

Yep! You can blame marketers, but that's their job, and it works. Until society becomes a lot smarter and more cynical, people will be paid to make things popular, and they'll do a lot of really obnoxiously cheap things, and it'll all work.

IIRC they say it is "fanless" - which is technically correct :)

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