Re: Fans vs. Propellers

[Hactar]

In article <XnsA1A565D72160Cho...@94.75.214.39>,
Howard Hale <howar...@notmail.com> wrote:
> Why are ceiling fans typically airplane-propeller shaped, while box fans
> are more boat-propeller shaped?

Box fans are ducted. Does that matter here?

IME both have flat (occasionally bent) blades, not shaped like an airfoil
at all.

What I wonder is, is there an advantage (in terms of air moved per watt)
in having larger, smaller, more, or fewer blades?

> One guess I saw online is that airplane-propeller blades are a lot
> noisier, but then I've never noticed ceiling fans being particularly
> noisy.

The one in my childhood room "grunted" at a particular point in the
revolution, but that's probably not what you mean.

--
-eben QebWe...@vTerYizUonI.nOetP royalty.mine.nu:81
LIBRA: A big promotion is just around the corner for someone
much more talented than you. Laughter is the very best medicine,
remember that when your appendix bursts next week. -- Weird Al

[Tim Wright]

On 4/17/2013 9:20 AM, Hactar wrote:
> In article <XnsA1A565D72160Cho...@94.75.214.39>,
> Howard Hale <howar...@notmail.com> wrote:
>> Why are ceiling fans typically airplane-propeller shaped, while box fans
>> are more boat-propeller shaped?
>
> Box fans are ducted. Does that matter here?
>
> IME both have flat (occasionally bent) blades, not shaped like an airfoil
> at all.
>
> What I wonder is, is there an advantage (in terms of air moved per watt)
> in having larger, smaller, more, or fewer blades?
>
>> One guess I saw online is that airplane-propeller blades are a lot
>> noisier, but then I've never noticed ceiling fans being particularly
>> noisy.
>
> The one in my childhood room "grunted" at a particular point in the
> revolution, but that's probably not what you mean.
>

These guys may just muddy the water a bit more.
http://www.bigassfans.com/

--

Tim W

[Hactar]

In article <fIedncUC5N4qI_PM...@supernews.com>,

Tim Wright <tlwri...@gmail.com> wrote:
> On 4/17/2013 9:20 AM, Hactar wrote:
> > In article <XnsA1A565D72160Cho...@94.75.214.39>,
> > Howard Hale <howar...@notmail.com> wrote:
> >> Why are ceiling fans typically airplane-propeller shaped, while box fans
> >> are more boat-propeller shaped?
> >
> > Box fans are ducted. Does that matter here?
> >
> > IME both have flat (occasionally bent) blades, not shaped like an airfoil
> > at all.
>

> These guys may just muddy the water a bit more.
> http://www.bigassfans.com/

Yeah, those _do_ have an airfoil shape. 24' diameter? Jeez.

[Hactar]

In article <6oftm89e6e57nmu3s...@4ax.com>,
<BillT...@invalid.com> wrote:

> On Wed, 17 Apr 2013 10:20:35 -0400, ebenZ...@verizon.net (Hactar)
> wrote:
>
> >In article <XnsA1A565D72160Cho...@94.75.214.39>,
> >Howard Hale <howar...@notmail.com> wrote:
> >> Why are ceiling fans typically airplane-propeller shaped, while box fans
> >> are more boat-propeller shaped?
> >
> >Box fans are ducted. Does that matter here?
> >
> >IME both have flat (occasionally bent) blades, not shaped like an airfoil
> >at all.
> >
> >What I wonder is, is there an advantage (in terms of air moved per watt)
> >in having larger, smaller, more, or fewer blades?
> >
> >> One guess I saw online is that airplane-propeller blades are a lot
> >> noisier, but then I've never noticed ceiling fans being particularly
> >> noisy.
> >
> >The one in my childhood room "grunted" at a particular point in the
> >revolution, but that's probably not what you mean.
>

> Ermmm... That _wasn't_ the fan...

There was a tennis player in my room and nobody told me? Bastards!

[Tim Wright]

On 4/17/2013 11:39 AM, Hactar wrote:
> In article <fIedncUC5N4qI_PM...@supernews.com>,
> Tim Wright <tlwri...@gmail.com> wrote:
>> On 4/17/2013 9:20 AM, Hactar wrote:
>>> In article <XnsA1A565D72160Cho...@94.75.214.39>,
>>> Howard Hale <howar...@notmail.com> wrote:
>>>> Why are ceiling fans typically airplane-propeller shaped, while box fans
>>>> are more boat-propeller shaped?
>>>
>>> Box fans are ducted. Does that matter here?
>>>
>>> IME both have flat (occasionally bent) blades, not shaped like an airfoil
>>> at all.
>>
>> These guys may just muddy the water a bit more.
>> http://www.bigassfans.com/
>
> Yeah, those _do_ have an airfoil shape. 24' diameter? Jeez.
>

They work very well, and no one can deny they're properly named.

--

Tim W

[bill van]

In article <9qv24a-...@pc.home>, ebenZ...@verizon.net (Hactar)
wrote:

> In article <fIedncUC5N4qI_PM...@supernews.com>,
> Tim Wright <tlwri...@gmail.com> wrote:
> > On 4/17/2013 9:20 AM, Hactar wrote:
> > > In article <XnsA1A565D72160Cho...@94.75.214.39>,
> > > Howard Hale <howar...@notmail.com> wrote:
> > >> Why are ceiling fans typically airplane-propeller shaped, while box fans
> > >> are more boat-propeller shaped?
> > >
> > > Box fans are ducted. Does that matter here?
> > >
> > > IME both have flat (occasionally bent) blades, not shaped like an airfoil
> > > at all.
> >
> > These guys may just muddy the water a bit more.
> > http://www.bigassfans.com/
>
> Yeah, those _do_ have an airfoil shape. 24' diameter? Jeez.

The last few weeks I've been seeing TV commercials for a blade-less fan,
called an air multiplier or air mover. Just a quick web search indicates
it might be a Dyson invention a few years ago. It's not entirely
blade-less, but what moving parts it has are enclosed in the base, so
it's safe for kids and pets. But I think it's expensive compared to
conventional fans.

http://tinyurl.com/cqdhdo6

bill

[Sano]

bill van <bil...@delete.shaw.ca> wrote in
news:billvan-487ADF...@news.shawcable.net:

I have a Dyson rug mower, most excellent piece of kit, but I'd be
hesitant to lend it. It is all plastic or some facsimile of same, I
just don't trust it to be abused.

Which is why I'd be hesitant to try their air mover.

Vornado, specifically the Vornado� 7" Air Circulator, has given me
good service for over ten years. I _have_ taken it apart and cleaned
the bearings occasionally, they can't keep dust out of everything.

On the lowest of it's three settings it's quiet as a church mouse.
Sleeping, no problem. I left the house once and forgot it was on. The
inventor designed sub props for the US Navy if I understand correctly.
I think it can move a stream of air 30 feet or so, on high. Right at
you if need be.

[Tim Wright]

I have a nice little two speed fan that I used to keep on my desk at
work. It had no shroud around the fan blades, because they were made of
cloth. It works quite well. Also a vornado product.

http://www.thegreenhead.com/imgs/vornado-zippi-fan-2.jpg

--

Tim W

[Paul Ciszek]

In article <billvan-487ADF...@news.shawcable.net>,

bill van <bil...@delete.shaw.ca> wrote:
>
>The last few weeks I've been seeing TV commercials for a blade-less fan,
>called an air multiplier or air mover. Just a quick web search indicates
>it might be a Dyson invention a few years ago. It's not entirely
>blade-less, but what moving parts it has are enclosed in the base, so
>it's safe for kids and pets. But I think it's expensive compared to
>conventional fans.
>
>http://tinyurl.com/cqdhdo6

Some Dyson engineeers made a balloon supercollider out of a bunch of them:

http://www.youtube.com/watch?v=4WNcjkZ6d0w


--
"Remember when teachers, public employees, Planned Parenthood, NPR and PBS
crashed the stock market, wiped out half of our 401Ks, took trillions in
TARP money, spilled oil in the Gulf of Mexico, gave themselves billions in
bonuses, and paid no taxes? Yeah, me neither."

[bill van]

In article <kknnf0$1ea$2...@reader1.panix.com>,

nos...@nospam.com (Paul Ciszek) wrote:

> In article <billvan-487ADF...@news.shawcable.net>,
> bill van <bil...@delete.shaw.ca> wrote:
> >
> >The last few weeks I've been seeing TV commercials for a blade-less fan,
> >called an air multiplier or air mover. Just a quick web search indicates
> >it might be a Dyson invention a few years ago. It's not entirely
> >blade-less, but what moving parts it has are enclosed in the base, so
> >it's safe for kids and pets. But I think it's expensive compared to
> >conventional fans.
> >
> >http://tinyurl.com/cqdhdo6
>
> Some Dyson engineeers made a balloon supercollider out of a bunch of them:
>
> http://www.youtube.com/watch?v=4WNcjkZ6d0w

Nice.

[Greg Goss]

bill van <bil...@delete.shaw.ca> wrote:

>it might be a Dyson invention .... But I think it's expensive compared to
>conventional fans.

That's par for Dyson products.
--
I used to own a mind like a steel trap.
Perhaps if I'd specified a brass one, it
wouldn't have rusted like this.

[Sano]

Tim Wright <tlwri...@gmail.com> wrote in
news:iOudndntiK72hvLM...@supernews.com:

That's a pretty thing! I pulled a larger one out of a dumpster some
time back. (Vornado) Ten inch maybe, infinite speed, had a rheostat.
Drywall guys pitched it out, had a multitude of spliced cords and one
broken wire. It was more than I could use and I gave it to a buddy.

[Sano]

Greg Goss <go...@gossg.org> wrote in
news:at9p53...@mid.individual.net:

> bill van <bil...@delete.shaw.ca> wrote:
>
>>it might be a Dyson invention .... But I think it's expensive
>>compared to conventional fans.
>
> That's par for Dyson products.

US$329 apiece, uh, yeah they've got excellent marketing people.

[rroger]

On Apr 17, 10:57 pm, nos...@nospam.com (Paul Ciszek) wrote:
> In article <billvan-487ADF.11402017042...@news.shawcable.net>,

> bill van  <bill...@delete.shaw.ca> wrote:
>
>
>
> >The last few weeks I've been seeing TV commercials for a blade-less fan,
> >called an air multiplier or air mover. Just a quick web search indicates
> >it might be a Dyson invention a few years ago. It's not entirely
> >blade-less, but what moving parts it has are enclosed in the base, so
> >it's safe for kids and pets. But I think it's expensive compared to
> >conventional fans.
>
> >http://tinyurl.com/cqdhdo6
>
> Some Dyson engineeers made a balloon supercollider out of a bunch of them:
>
> http://www.youtube.com/watch?v=4WNcjkZ6d0w
>

Some people, (seem to), have a lot of time on their hands.

[Greg Goss]

Tim Wright <tlwri...@gmail.com> wrote:

>I have a nice little two speed fan that I used to keep on my desk at
>work. It had no shroud around the fan blades, because they were made of
>cloth. It works quite well. Also a vornado product.

My parents had a fifties-era fan with rubber blades. Stopping the fan
with your hand was a pre-teen macho thing between brothers, and the
fan eventually disappeared. I suspect removing the temptation would
have been easier than banning the activity if my parents were worried
about us doing this.

[Hactar]

In article <0c651c2c-5b75-4dc9...@q6g2000yqa.googlegroups.com>,

Well, promoting Dyson products is their job. And if they have fun doing
so, win-win!

[Xho Jingleheimerschmidt]

How many hours does you day have?

Xho

[Hactar]

In article <XnsA1A74DC...@69.16.186.50>,
Sano <gregs.po...@gmail.com> wrote:
> Snidely <snide...@gmail.com> wrote in
> news:mn.958e7dd4c36dc210.127094@snitoo:
>
> > Snidely explained on 4/18/2013 :
> >> Xho Jingleheimerschmidt speculated:

> >>> On 04/17/2013 07:00 AM, Howard Hale wrote:
> >>>> Why are ceiling fans typically airplane-propeller shaped, while
> >>>> box fans are more boat-propeller shaped?
> >>>

> >>> Ceiling fans are not particularly airplane-propeller shaped.
> >
> > They often follow the flying brick technique: go fast enough to
> > make the air WANT to get out of the way.
> >
> >>> Ceiling fans are mostly decorative. And rather slow.
> >>
> >> My experience with ceiling fans (tested a few miles north of you)
> >> is that they move air fairly effectively. Being slow isn't so bad
> >> when you've have a 5 foot diameter. Some ceiling fans are bigger.
>
> The McMaster-Carr warehouse near me has some biguns', might be 20
> foot in diameter.
>
> I don't know if this will correspond to the proper page or not,
>
> http://www.mcmaster.com/#ceiling-mount-fans/=mdyrwz

A way to tell (not for sure, as its behavior might be affected by cookies
or IP or time-of-day) is to open a new tab, and past in the link.
Initially it didn't work for me, but after fat-fingering something it
did. ::shrug::

> They have them in their plant but not in their catalog, though they
> would find them if one wanted them. Great folks if anyone is
> interested. They are premier suppliers.

[Tim Wright]

If they're that big, they're probably from Bigass Fan company.
http://www.bigassfans.com/product/powerfoil-x20-plus/

--

Tim W

[Sano]

Tim Wright <tlwri...@gmail.com> wrote in

news:48ednQRAktyL0uzM...@supernews.com:

I don't remeber the winglets but they were certainly turning slow.
Spec sheet states 95 rpm max. They were under that.